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<div id="preamble" class="status">
<i>Last Updated: 2017-11-18 Sat 11:21</i>
</div>
<div id="content">
<h1 class="title">CSCI 4061: Exam 2 Review Problems</h1>
<div id="table-of-contents">
<h2>Table of Contents</h2>
<div id="text-table-of-contents">
<ul>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-1">1. Concurrent Printer</a>
<ul>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-1-1">1.1. Printer Manager Process</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-1-2">1.2. Printer Cooperation</a></li>
</ul>
</li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-2">2. Graceful Shutdown</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-3">3. Critical Section</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-4">4. Concurrency and Signals</a>
<ul>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-4-1">4.1. Code Outline</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-4-2">4.2. Implementation Flaws</a></li>
</ul>
</li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-5">5. Read vs Select</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-6">6. Busy Polling versus Interrupt Driven Mutex</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-7">7. Processes vs Threads</a>
<ul>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-7-1">7.1. Similarities and Differences</a></li>
<li><a href="http://www-users.cs.umn.edu/~kauffman/4061/12-exam2-review-problems.html#sec-7-2">7.2. Thread Pitfalls</a></li>
</ul>
</li>
</ul>
</div>
</div>
<div id="outline-container-sec-1" class="outline-2">
<h2 id="sec-1"><span class="section-number-2">1</span> Concurrent Printer</h2>
<div class="outline-text-2" id="text-1">
</div><div id="outline-container-sec-1-1" class="outline-3">
<h3 id="sec-1-1"><span class="section-number-3">1.1</span> Printer Manager Process</h3>
<div class="outline-text-3" id="text-1-1">
<p>
A printer is a shared resource in that there is usually only one
attached to a computing system that many users/processes can access.
</p>
<p>
Consider managing the printer using a "daemon" (background
process). Programs that want to print do not so directly but instead
contact the daemon to request data be printed. The printer daemon
must get data from client processes, feed it to the printer, notify
the client process of the completion of the printing, and then
pick up the next request if any.
</p>
<p>
Describe a simple protocol that could accomplish this by specifying
the following:
</p>
<ul class="org-ul">
<li>What mechanism will you use to allow the printer daemon process to
communicate with a client?
</li>
<li>How will client processes communicate data to the daemon? Keep in
mind that print files have a variety of types and sizes
</li>
<li>How will the daemon process notify client processes of the
completion of the print job or errors that occurred?
</li>
<li>Keep in mind that the printer daemon is a system process started
when the computer boots.
</li>
</ul>
</div>
</div>
<div id="outline-container-sec-1-2" class="outline-3">
<h3 id="sec-1-2"><span class="section-number-3">1.2</span> Printer Cooperation</h3>
<div class="outline-text-3" id="text-1-2">
<p>
As an alternative to the above daemon approach to managing a printer,
consider a protocol that DOES NOT involve a manager. In this setting,
the printer is usable directly by any process. However, processes that
print must obey a protocol you will design to avoid problems. The
printer is associated with a known special file /dev/printer. When
data is written to this file, it is sent directly to the
printer. However, if multiple processes write data simultaneously, the
printing results are likely to become corrupted.
</p>
<p>
Design a protocol that would allow the shared printer resource to be
managed without a manager process.
</p>
<ul class="org-ul">
<li>What mechanism would you use for processes want to print to
coordinate using the /dev/printer file?
</li>
<li>Is it possible in your scheme to guarantee fairness: processes that
are ready to print early actually get to print earlier than later
print attempts?
</li>
</ul>
</div>
</div>
</div>
<div id="outline-container-sec-2" class="outline-2">
<h2 id="sec-2"><span class="section-number-2">2</span> Graceful Shutdown</h2>
<div class="outline-text-2" id="text-2">
<p>
Many system programs run for a long time accumulating data from files
that should be written out before shutting down. Occasionally these
"daemon" processes need to be closed down or restarted but should be
exited "gracefully" as in given an opportunity to write essential data
to files before exiting.
</p>
<p>
Describe a common mechanism in Unix to notify a program that it should
terminate but give it an opportunity to write essential data prior to
exiting. Describe the specific program control structures in the
program and system calls involved in such a graceful shutdown.
</p>
</div>
</div>
<div id="outline-container-sec-3" class="outline-2">
<h2 id="sec-3"><span class="section-number-2">3</span> Critical Section</h2>
<div class="outline-text-2" id="text-3">
<p>
A database manger process is responsible for occasionally writing
database information in main memory to a file so that it is backed up
in the case of a crash. A system administrator can request an
immediate backup by sending the <code>SIGUSR1</code> signal to the manager
process. Backup requests are considered fairly low priority and can
be honored later.
</p>
<p>
The manager process is also responsible for handling certain
operations that are critical to integrity of the database and should
not be interrupted by backup requests.
</p>
<p>
Describe whether it is possible for the manager process to be written
to fulfill both of these requirements. Mention how it might be done
using Unix programming facilities.
</p>
</div>
</div>
<div id="outline-container-sec-4" class="outline-2">
<h2 id="sec-4"><span class="section-number-2">4</span> Concurrency and Signals</h2>
<div class="outline-text-2" id="text-4">
<p>
A simple protocol for communication between Process A and Process B
involves the following steps.
</p>
<p>
Process A
</p>
<ul class="org-ul">
<li>A1: Process A writes its PID to Pipe X
</li>
<li>A2: Process A sleeps waiting for a signal
</li>
<li>A3: Process A wakes up from a signal
</li>
<li>A4: Process A reads an integer from Pipe Y
</li>
<li>B1: Process B reads a PID from Pipe X
</li>
<li>B2: Process B writes an integer to Pipe Y
</li>
<li>B3: Process B signals Process A to wake up and continue
</li>
</ul>
</div>
<div id="outline-container-sec-4-1" class="outline-3">
<h3 id="sec-4-1"><span class="section-number-3">4.1</span> Code Outline</h3>
<div class="outline-text-3" id="text-4-1">
<p>
Give an outline of C code for Process A and Process B which would
(roughly) implement the above protocol. Below
</p>
<div class="org-src-container">
<pre class="src src-c">// PROCESS A
int pipeX[2];
int pipeY[2];
int receive; // put data "received" from Process B in this integer
// assume both pipes opened appropriately
// A1: Process A writes its PID to Pipe X
// A2: Process A sleeps waiting for a signal
// A3: Process A wakes up from a signal
// A4: Process A reads an integer from Pipe Y
</pre>
</div>
<div class="org-src-container">
<pre class="src src-c">// PROCESS B
int pipeX[2];
int pipeY[2];
int send = 42; // integer to "send" to Process A
// assume both pipes opened appropriately
// B1: Process B reads a PID from Pipe X
// B2: Process B writes an integer to Pipe Y
// B3: Process B signals Process A to wake up and continue
</pre>
</div>
</div>
</div>
<div id="outline-container-sec-4-2" class="outline-3">
<h3 id="sec-4-2"><span class="section-number-3">4.2</span> Implementation Flaws</h3>
<div class="outline-text-3" id="text-4-2">
<p>
A naive implementation of the basic protocol outlined is likely to
contain flaws. For example, if Process A merely calls
</p>
<pre class="example">sleep(0);
</pre>
<p>
to await a signal, it may result in Process A never waking
up.
</p>
<p>
Describe a sequence of events using the steps <code>A1, A2,.. B1, B2</code> that
could give rise to the this situation. Also describe how one might fix
this with a slightly more complex sleeping/waiting behavior and
signals handling.
</p>
</div>
</div>
</div>
<div id="outline-container-sec-5" class="outline-2">
<h2 id="sec-5"><span class="section-number-2">5</span> Read vs Select</h2>
<div class="outline-text-2" id="text-5">
<p>
The code below appeared in a lab in files that compared only reading
from two separate files (pipes in this case) versus using the
<code>select()</code> system call. Describe the difference between these blocks.
</p>
<ul class="org-ul">
<li>What pattern of reading do you expect in each? Ex: Do you expect
fixed patterns like <code>ABAB..</code> or <code>ABBABB...</code> or arbitrary
intermingling like <code>ABBABAABBA...</code>?
</li>
<li>Which approach (<code>read()</code>-only or <code>select()/read()</code>) is appropriate
if input is coming at very different rates in pipeA versus pipeB?
Justify your answer.
</li>
</ul>
<div class="org-src-container">
<pre class="src src-c">// file read_AB.c
while(!signaled){
char buf[1024];
int n;
n = read(pipeA[PREAD], buf, 1024);
buf[n] = '\0';
fprintf(stdout,"A had: |%s|\n",buf);
n = read(pipeB[PREAD], buf, 1024);
buf[n] = '\0';
fprintf(stdout,"B had: |%s|\n",buf);
}
</pre>
</div>
<div class="org-src-container">
<pre class="src src-c">// file select_AB.c
while(!signaled){
fd_set read_set;
FD_ZERO(&amp;read_set);
FD_SET(pipeA[PREAD], &amp;read_set);
FD_SET(pipeB[PREAD], &amp;read_set);
int maxfd = pipeA[PREAD];
maxfd = (maxfd &lt; pipeB[PREAD]) ? pipeB[PREAD] : maxfd;
select(maxfd+1, &amp;read_set, NULL, NULL, NULL);
char buf[1024];
int n;
if(FD_ISSET(pipeA[PREAD], &amp;read_set)){
n = read(pipeA[PREAD], buf, 1024);
buf[n] = '\0';
fprintf(stdout,"A had: |%s|\n",buf);
}
if(FD_ISSET(pipeB[PREAD], &amp;read_set)){
n = read(pipeB[PREAD], buf, 1024);
buf[n] = '\0';
fprintf(stdout,"B had: |%s|\n",buf);
}
}
</pre>
</div>
</div>
</div>
<div id="outline-container-sec-6" class="outline-2">
<h2 id="sec-6"><span class="section-number-2">6</span> Busy Polling versus Interrupt Driven Mutex</h2>
<div class="outline-text-2" id="text-6">
<p>
Cee Lohacker is working on a drone with a small embedded processor and
Unix which provides POSIX threads and mutexes. Unfortunately, the
drone is manufactured in Easternopia and Cee cannot understand the
Easternopian dialect of the documentation. She needs know whether
mutexes on this system use
</p>
<ul class="org-ul">
<li>Busy polling to acquire a lock
</li>
<li>Interrupt driven waiting acquire a lock
</li>
</ul>
<p>
Writes the following short C program to test the mutexes and runs it
with the <code>time</code> command.
</p>
<div class="org-src-container">
<pre class="src src-sh"><span class="linenr"> 1: </span>&gt; cat mut_test.c
<span class="linenr"> 2: </span>#include &lt;pthread.h&gt;
<span class="linenr"> 3: </span>#include &lt;stdio.h&gt;
<span class="linenr"> 4: </span>#include &lt;unistd.h&gt;
<span class="linenr"> 5: </span>
<span class="linenr"> 6: </span>int glob = 1;
<span class="linenr"> 7: </span>pthread_mutex_t glob_lock;
<span class="linenr"> 8: </span>
<span class="linenr"> 9: </span>void *doit(void *param){
<span class="linenr">10: </span> pthread_mutex_lock(&amp;glob_lock);
<span class="linenr">11: </span> glob = glob*2;
<span class="linenr">12: </span> sleep(2);
<span class="linenr">13: </span> pthread_mutex_unlock(&amp;glob_lock);
<span class="linenr">14: </span> return NULL;
<span class="linenr">15: </span>}
<span class="linenr">16: </span>
<span class="linenr">17: </span>int main(){
<span class="linenr">18: </span> pthread_mutex_init(&amp;glob_lock, NULL);
<span class="linenr">19: </span> printf("BEFORE glob: %d\n",glob);
<span class="linenr">20: </span> pthread_t threads[3];
<span class="linenr">21: </span> for(int i=0; i&lt;3; i++){
<span class="linenr">22: </span> pthread_create(&amp;threads[i], NULL, doit, NULL);
<span class="linenr">23: </span> }
<span class="linenr">24: </span> for(int i=0; i&lt;3; i++){
<span class="linenr">25: </span> pthread_join(threads[i], (void **) NULL);
<span class="linenr">26: </span> }
<span class="linenr">27: </span> printf("AFTER glob: %d\n",glob);
<span class="linenr">28: </span> pthread_mutex_destroy(&amp;glob_lock);
<span class="linenr">29: </span> return 0;
<span class="linenr">30: </span>}
<span class="linenr">31: </span>
<span class="linenr">32: </span>&gt; gcc mut_test.c -lpthread
<span class="linenr">33: </span>
<span class="linenr">34: </span>&gt; time a.out
<span class="linenr">35: </span>BEFORE glob: 1
<span class="linenr">36: </span>AFTER glob: ??? # glob final value
<span class="linenr">37: </span>
<span class="linenr">38: </span>real ??? # Wall time
<span class="linenr">39: </span>user ??? # User CPU time
<span class="linenr">40: </span>sys ???
</pre>
</div>
<p>
Answer the following questions
</p>
<ol class="org-ol">
<li>What is the expected value for <code>glob</code> after the code is run (marked
<code># glob final value</code>)?
</li>
<li>Assuming the mutexes use BUSY polling, what times are expected for
<ul class="org-ul">
<li>Real/Wall time?
</li>
<li>User CPU time?
</li>
</ul>
<p>
Explain your reasoning.
</p>
</li>
<li>Assuming the mutexes use INTERRUPT-DRIVEN waiting, what times are
expected for
<ul class="org-ul">
<li>Real/Wall time?
</li>
<li>User CPU time?
</li>
</ul>
<p>
Explain your reasoning.
</p>
</li>
</ol>
</div>
</div>
<div id="outline-container-sec-7" class="outline-2">
<h2 id="sec-7"><span class="section-number-2">7</span> Processes vs Threads</h2>
<div class="outline-text-2" id="text-7">
</div><div id="outline-container-sec-7-1" class="outline-3">
<h3 id="sec-7-1"><span class="section-number-3">7.1</span> Similarities and Differences</h3>
<div class="outline-text-3" id="text-7-1">
<p>
Outline the similarities and differences between Processes and
Threads. Describe some details of the assumptions that each makes
about what memory is shared versus private. Describe the tradeoffs
associated with using one versus the others on issues such as system
tools, security, and efficiency.
</p>
</div>
</div>
<div id="outline-container-sec-7-2" class="outline-3">
<h3 id="sec-7-2"><span class="section-number-3">7.2</span> Thread Pitfalls</h3>
<div class="outline-text-3" id="text-7-2">
<p>
Recall the Pi calculation program discussed in class. One version of
this program spawned multiple threads to run the following worker
function.
</p>
<div class="org-src-container">
<pre class="src src-c">int total_hits = 0;
int points_per_thread = -1;
void *compute_pi(void *arg){
long thread_id = (long) arg;
unsigned int rstate = 123456789 * thread_id;
for (int i = 0; i &lt; points_per_thread; i++) {
double x = ((double) rand_r(&amp;rstate)) / ((double) RAND_MAX);
double y = ((double) rand_r(&amp;rstate)) / ((double) RAND_MAX);
if (x*x + y*y &lt;= 1.0){
total_hits++;
}
}
return NULL;
}
</pre>
</div>
<ol class="org-ol">
<li>Why was it necessary to use the <code>rand_r()</code> function rather than the
standard <code>rand()</code> function to generate random numbers?
</li>
<li>Do all the worker threads generate identical random sequences of
numbers or are they different? Explain your reasoning.
</li>
<li>It was determined in discussion that this version <b>always</b>
underestimates the value of Pi. Explain why and how one might fix
this while also maintaining the efficiency of using multiple
threads to get speedup.
</li>
</ol>
</div>
</div>
</div>
</div>
<div id="postamble" class="status">
<hr> <i> Author: Chris Kauffman (<a href="mailto:kauffman@phaedrus">kauffman@phaedrus</a>) <br> Date: 2017-11-18 Sat 11:21 <br> </i>
</div>
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I have familiarized myself with the contents of the CSCI 4061 syllabus
and agree to abide by the policies contained within it. I will obey
the PRIME DIRECTIVE. I understand that the Kauffman section of 4061
(001) is not coordinated with the Tripathi section (010) and will not
seek or render unauthorized help from students or staff in that
section. As a University of Minnesota student, I agree to follow the
Student Code of Conduct and will treat my classmates and the course
staff with honest respect.
Signed,
Michael Zhang

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#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
typedef struct {
char elem[2];
double x, y, z;
int charge;
double mass;
} atom_t;
void write_atoms(char *fname, atom_t *atoms, int len) {
int fd = open(fname, O_CREAT | O_WRONLY);
for (int i = 0; i < len; ++i) {
write(fd, &atoms[i], sizeof(atom_t));
}
close(fd);
}
double *read_masses(char *fname, int *setlen) {
int fd = open(fname, O_RDONLY);
int size = lseek(fd, 0, SEEK_END);
double *result = (double *)malloc(size);
lseek(fd, 0, SEEK_SET);
int count = 0;
atom_t atom;
while (1) {
int bytes = read(fd, &atom, sizeof(atom_t));
if (!bytes) break;
result[count++] = atom.mass;
}
close(fd);
*setlen = count;
return result;
}
int main() {
atom_t atoms[5] = {{"C", 0.0, 1.0, 2.5, 0, 12.011},
{"O", 1.0, 3.5, 6.0, 0, 15.999}};
write_atoms("atoms.dat", atoms, 5);
int len = -1;
double *masses = read_masses("atoms.dat", &len);
printf("read %d masses:\n", len);
for (int i = 0; i < len; ++i) {
printf("mass[%d] = %lf\n", i, masses[i]);
}
free(masses);
return 0;
}

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__________________
LAB 01 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1
=========
Show output of the collatz sequence program starting at 17.
Enter the starting integer: 17
The next value in the Collatz sequence is 52
Show output of steps (0:NO, any other int: yes): 1
Step 0: 17
Step 1: 52
Step 2: 26
Step 3: 13
Step 4: 40
Step 5: 20
Step 6: 10
Step 7: 5
Step 8: 16
Step 9: 8
Step 10: 4
Step 11: 2
Step 12: 1
The starting value 17 converged to 1 in 12 steps
PROBLEM 2
=========
Paste the Makefile you created for the lcd-clock project below.
CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
clock_sim: lcd_clock.o lcd_clock_main.o lcd_clock.h lcd_update.o
$(CC) -o clock_sim $^
@echo "clock_sim ready for duty"
lcd_clock.o: lcd_clock.c lcd_clock.h
$(CC) -c $<
lcd_clock_main.o: lcd_clock_main.c lcd_clock.h
$(CC) -c $<
lcd_update.o: lcd_update.c lcd_clock.h
$(CC) -c $<
test: clock_tests
@echo "Running clock_tests"
./clock_tests
@echo "Tests Complete"
clock_tests: lcd_tests.c lcd_clock.o lcd_update.o lcd_clock.h
$(CC) -o $@ $^
clean:
rm -f *.o

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# See Makefile-commented for explanation
CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
collcalc : collatz.o collatz_main.o
$(CC) -o collcalc collatz.o collatz_main.o
@echo collcalc is ready
collatz_main.o : collatz_main.c collatz.h
$(CC) -c collatz_main.c
collatz.o : collatz.c collatz.h
$(CC) -c $<
test : collatz_test
./collatz_test
collatz_test : collatz_test.o collatz.o collatz.h
$(CC) -o $@ $^
collatz_test.o : collatz_test.c collatz.h
$(CC) -c $<
clean:
@echo Cleaning up object files
rm -f *.o
realclean:
@echo Removing objects and programs
rm -f *.o collcalc collatz_test

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# Makefile to create the collatz programs. To use, type
# > make
# Which will create the collcalc program. Alternatively
# > make collcalc
# will also create the collcalc program.
#
# To create the test program and run it do
# > make test
#
# Makefiles are divided into "rules" comprised of target,
# dependencies, and commands to execute to finish the target.
#
# target : dependency1 dependency2
# command1
# command2
# @command3 which is not printed
# command4
#
# Some targets are files to create like the "collcalc" program or
# "collatz_main.o" file. Other targets are "virtual" which simply
# specify other targets to do or commands to run.
CFLAGS = -Wall -g # variable holding options to the c compile
CC = gcc $(CFLAGS) # variable holding the compilation command
collcalc : collatz.o collatz_main.o collatz.h # collcalc is a program, depends on two files, is default target
$(CC) -o collcalc collatz.o collatz_main.o # when the other files are ready, compile collcalc
@echo collcalc is ready # issue a report that the program is ready
collatz_main.o : collatz_main.c collatz.h # collatz_main.o depends on two source files
$(CC) -c collatz_main.c # compile only, don't link yet
collatz.o : collatz.c collatz.h # collatz.o depends on collatz.c and collatz.h
$(CC) -c $< # compile, use shortcut $< which becomes "collatz.c"
test : collatz_test # test is another target, depends on collatz_test program
./collatz_test # when collatz_test exists, run it
collatz_test : collatz_test.o collatz.o collatz.h # program depends on several object files and header
$(CC) -o $@ $^ # compile using shortcuts: $@ becomes collatz_test, $^ is all dependecies
collatz_test.o : collatz_test.c collatz.h # object file depends on C source and header
$(CC) -c $< # compile to object code using shortcut, $< becomes "collatz_test.c"
clean: # No dependencies: clean is the de facto cleanup target
@echo Cleaning up object files # Report what's happening
rm -f *.o # Remove all the .o files which are likely no longer needed
realclean:
@echo Removing objects and programs # "realclean" often used to get rid of everything
rm -f *.o collcalc collatz_test # remove .o and programs that have been built

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#include <stdio.h>
#include "collatz.h"
/* Compute the next step in the collatz sequence */
int collatz_next(int n){
if(n < 1){
return -1;
}
else if(n==1){
return 1;
}
else if(n % 2 == 0){
return n / 2;
}
else{
return n*3 + 1;
}
}
// Count how many steps are in the collatz sequence
int collatz_steps(int n, int print_output){
int steps = 0;
if(print_output){
printf("Step %d: %d\n",steps,n);
}
while(n > 1){
n = collatz_next(n);
steps++;
if(print_output){
printf("Step %d: %d\n",steps,n);
}
}
return steps;
}

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// Header file for collatz problems
#ifndef COLLATZ_H
#define COLLZTZ_H 1
// Returns next number in the collatz sequence. If parameter n is less
// than 1, return -1. If n is equal to 1, return 1 as the sequence has
// converged. If n is bigger than 1, determine if it is even or
// odd. If n is even, return half its value. If n is odd, return three
// times its value plus one.
int collatz_next(int n);
// Returns the number of steps to converge to 1 for starting point
// n. Use the function collatz_next() in a loop to determine the next
// value at each step. Return the number of steps to converge, 15 in
// the example below where n=22. If paramter n is less than or equal
// to 1, return 0.
//
// If the argument print_output is zero, this function should not
// print anything. If the argument is non-zero, print each step in
// the sequence starting with the initial value of at Step 0. For
// example, if n=22 and print_output=1, produce output like the
// following:
//
// Step 0: 22
// Step 1: 11
// Step 2: 34
// Step 3: 17
// Step 4: 52
// Step 5: 26
// Step 6: 13
// Step 7: 40
// Step 8: 20
// Step 9: 10
// Step 10: 5
// Step 11: 16
// Step 12: 8
// Step 13: 4
// Step 14: 2
// Step 15: 1
int collatz_steps(int n, int print_output);
#endif

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lab01-code/collatz/collatz_main.c Normal file
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#include <stdio.h>
#include "collatz.h"
int main(int argc, char **argv){
int nstart;
printf("Enter the starting integer: ");
scanf("%d", &nstart);
int nnext = collatz_next(nstart);
printf("The next value in the Collatz sequence is %d\n",nnext);
int verbose;
printf("Show output of steps (0:NO, any other int: yes): ");
scanf("%d", &verbose);
int steps = collatz_steps(nstart,verbose);
printf("The starting value %d converged to 1 in %d steps\n",
nstart,steps);
return 0;
}

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lab01-code/collatz/collatz_test.c Normal file
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#include <stdio.h>
#include "collatz.h"
#define TESTID "P2"
int failures = 0;
void test_next(int test, int n, int expected){
int actual = collatz_next(n);
if(expected != actual){
printf("Failed %s Test %d\nCall: collatz_next(%d)\nExpect: %d\nActual: %d\n",
TESTID,test, n,expected,actual);
failures++;
}
}
#define MAX_SIZE 5096
void test_steps(int test, int n, int expected){
int actual = collatz_steps(n,0);
if(expected != actual){
printf("Failed %s Test %d\nCall: collatz_steps(%d)\nExpect: %d\nActual: %d\n",
TESTID,test, n,expected,actual);
failures++;
return;
}
}
int main(int argc, char **argv){
int test = 1;
test_next(test++, 1 , 1 );
test_next(test++, 0 , -1 );
test_next(test++, -5 , -1 );
test_next(test++, 5 , 16 );
test_next(test++, 16 , 8 );
test_next(test++, 20 , 10 );
test_next(test++, 15 , 46 );
test_steps(test++, -7, 0 );
test_steps(test++, 1, 0 );
test_steps(test++, 5, 5 );
test_steps(test++, 14, 17);
test_steps(test++, 30, 18);
test_steps(test++, 22, 15);
test_steps(test++, 6, 8 );
if(failures == 0){
printf("OK\n");
}
else{
printf("FAILURES\n");
}
printf("Passed %d / %d tests\n",test-failures,test);
return 0;
}

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lab01-code/lcd-clock/Makefile Normal file
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CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
clock_sim: lcd_clock.o lcd_clock_main.o lcd_clock.h lcd_update.o
$(CC) -o clock_sim $^
@echo "clock_sim ready for duty"
lcd_clock.o: lcd_clock.c lcd_clock.h
$(CC) -c $<
lcd_clock_main.o: lcd_clock_main.c lcd_clock.h
$(CC) -c $<
lcd_update.o: lcd_update.c lcd_clock.h
$(CC) -c $<
test: clock_tests
@echo "Running clock_tests"
./clock_tests
@echo "Tests Complete"
clock_tests: lcd_tests.c lcd_clock.o lcd_update.o lcd_clock.h
$(CC) -o $@ $^
clean:
rm -f *.o

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lab01-code/lcd-clock/lcd_clock.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lcd_clock.h"
#define LCD_MAX_BITS 30
/* Global variable used to control the LCD display. Making changes to
this variable will change the clock time */
int LCD_DISPLAY_PORT;
/* Time of day in seconds; set by the hardware, read only */
int TIME_OF_DAY_SEC;
/* Reset an lcd_display to be empty */
void reset_lcd_display(lcd_display *lcd){
int i,j;
for(i=0; i<5; i++){
for(j=0; j<32; j++){
lcd->chars[i][j] = ' ';
}
lcd->chars[i][31] = '\0';
}
lcd->chars[1][12] = 'o';
lcd->chars[3][12] = 'o';
}
/* Print an lcd_display */
void print_lcd_display(lcd_display *lcd){
int i=0;
for(i=0; i<5; i++){
printf("%s\n",lcd->chars[i]);
}
}
/* Data and functions to set the state of the lcd clock display */
/* Position and char in display */
typedef struct {
int r,c; char ch;
} charpos;
/* Collection of characters corresponding to one bit in the state being set */
typedef struct {
int len;
charpos pos[2];
} charpos_coll;
/* Correspondence of bit positions to which characters should be set */
charpos_coll bits2chars[LCD_MAX_BITS] = {
{ .len=2, .pos={{ 0,19,'~'}, { 0,20,'~'},} }, // 0
{ .len=1, .pos={{ 1,21,'|'}, } }, // 1
{ .len=1, .pos={{ 3,21,'|'}, } }, // 2
{ .len=2, .pos={{ 4,19,'~'}, { 4,20,'~'},} }, // 3
{ .len=1, .pos={{ 3,18,'|'}, } }, // 4
{ .len=1, .pos={{ 1,18,'|'}, } }, // 5
{ .len=2, .pos={{ 2,19,'~'}, { 2,20,'~'},} }, // 6
{ .len=2, .pos={{ 0,14,'~'}, { 0,15,'~'},} }, // 7
{ .len=1, .pos={{ 1,16,'|'}, } }, // 8
{ .len=1, .pos={{ 3,16,'|'}, } }, // 9
{ .len=2, .pos={{ 4,14,'~'}, { 4,15,'~'},} }, // 10
{ .len=1, .pos={{ 3,13,'|'}, } }, // 11
{ .len=1, .pos={{ 1,13,'|'}, } }, // 12
{ .len=2, .pos={{ 2,14,'~'}, { 2,15,'~'},} }, // 13
{ .len=2, .pos={{ 0, 9,'~'}, { 0,10,'~'},} }, // 14
{ .len=1, .pos={{ 1,11,'|'}, } }, // 15
{ .len=1, .pos={{ 3,11,'|'}, } }, // 16
{ .len=2, .pos={{ 4, 9,'~'}, { 4,10,'~'},} }, // 17
{ .len=1, .pos={{ 3, 8,'|'}, } }, // 18
{ .len=1, .pos={{ 1, 8,'|'}, } }, // 19
{ .len=2, .pos={{ 2, 9,'~'}, { 2,10,'~'},} }, // 20
{ .len=2, .pos={{ 0, 4,'~'}, { 0, 5,'~'},} }, // 21
{ .len=1, .pos={{ 1, 6,'|'}, } }, // 22
{ .len=1, .pos={{ 3, 6,'|'}, } }, // 23
{ .len=2, .pos={{ 4, 4,'~'}, { 4, 5,'~'},} }, // 24
{ .len=1, .pos={{ 3, 3,'|'}, } }, // 25
{ .len=1, .pos={{ 1, 3,'|'}, } }, // 26
{ .len=2, .pos={{ 2, 4,'~'}, { 2, 5,'~'},} }, // 27
{ .len=2, .pos={{ 3, 0,'A'}, { 3, 1,'M'},} }, // 28
{ .len=2, .pos={{ 4, 0,'P'}, { 4, 1,'M'},} }, // 29
};
/* Assumes ints are at least 32 bits */
void set_lcd_display_state(lcd_display *lcd, int state){
int i,j;
int mask = 0x1;
reset_lcd_display(lcd);
for(i=0; i<LCD_MAX_BITS; i++){
if( state & (mask << i) ){ // ith bit set, fill in characters
charpos_coll coll = bits2chars[i];
for(j=0; j<coll.len; j+=2){
charpos pos = coll.pos[j];
lcd->chars[pos.r][pos.c] = pos.ch;
}
}
}
}
/* Use the global LCD_DISPLAY_PORT to print the time */
void print_lcd_clock(){
lcd_display lcd;
set_lcd_display_state(&lcd, LCD_DISPLAY_PORT);
print_lcd_display(&lcd);
return;
}
/* Print the most signficant (right-most) to least signficant bit in
the integer passed in */
#define INT_BITS 32
void showbits(int x){
int i;
int mask = 0x1;
for(i=INT_BITS-1; i>=0; i--){
int shifted_mask = mask << i;
if(shifted_mask & x){
putchar('1');
} else {
putchar('0');
}
}
/* Equivalent short version */
// (x&(1<<i)) ? putchar('1'): putchar('0');
}

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#ifndef LCD_CLOCK_H
#define LCD_CLOCK_H 1
/* Global variable used to control the LCD display. Making changes to
this variable will change the clock time */
extern int LCD_DISPLAY_PORT;
/* Time of day in seconds; set by the hardward, read only */
extern int TIME_OF_DAY_SEC;
/* Convenience struct for representing the LCD clock as characters */
typedef struct {
char chars[5][32];
} lcd_display;
/* Use the global LCD_DISPLAY_PORT to print the time */
void print_lcd_clock();
/* Print the most signficant (right-most) to least signficant bit in
the integer passed in */
void showbits(int x);
// Breaks time down into 12-hour format
typedef struct{
int hours;
int minutes;
int seconds;
int ispm;
} tod_t;
// Breaks down the give time of day in seconds into a tod_t struct
tod_t time_breakdown(int time_of_day);
// Produce an integer which are the bits representing how the LCD
// should display based on the given time of day
int display_bits_from_tod(tod_t tod);
// Update the global variable LCD_DISPLAY_PORT to match the current
// time of day
void lcd_update();
#endif

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#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "lcd_clock.h"
int main(int argc, char **argv){
if(argc < 2){ /* Set TIME_OF_DAY_SEC to the actual time */
time_t rawtime; /* Get raw time */
time( &rawtime );
struct tm *info; /* Store broken down time */
info = localtime( &rawtime ); /* Get a broken down time */
/* Calculate the seconds since the beginning of the day */
TIME_OF_DAY_SEC = info->tm_sec + 60*info->tm_min + 60*60*info->tm_hour;
}
else{ /* Set time based on argument given */
TIME_OF_DAY_SEC = atoi(argv[1]);
}
printf("TIME_OF_DAY_SEC set to: %d\n", TIME_OF_DAY_SEC);
int time_max = 24 * 60 * 60;
if(TIME_OF_DAY_SEC >= time_max){
printf("Time %d exceeds max %d\n",TIME_OF_DAY_SEC,time_max);
return -1;
}
tod_t tod = time_breakdown(TIME_OF_DAY_SEC);
printf("tod = time_breakdown( %5d );\n",TIME_OF_DAY_SEC);
printf("tod is { \n");
printf(" .hours = %d\n",tod.hours);
printf(" .minutes = %d\n",tod.minutes);
printf(" .seconds = %d\n",tod.seconds);
printf(" .ispm = %d\n",tod.ispm);
printf("} \n");
printf("Simulated time is: %02d : %02d : %02d %s\n",
tod.hours,tod.minutes,tod.seconds,(tod.ispm ? "pm" : "am"));
printf("\nChecking results for display bits\n");
int state = display_bits_from_tod(tod);
printf("state = display_bits_from_tod(tod);\n");
printf("\nstate is:\n");
printf(" 3 2 1 0\n");
printf("index: 10987654321098765432109876543210\n");
printf("bits: "); showbits(state); printf("\n");
printf("guide: | | | | |\n");
printf("\nRunning lcd_update()\n");
lcd_update();
printf("\nLCD_DISPLAY_PORT is:\n");
printf(" 3 2 1 0\n");
printf("index: 10987654321098765432109876543210\n");
printf("bits: "); showbits(LCD_DISPLAY_PORT); printf("\n");
printf("guide: | | | | |\n");
printf("\nLCD Clock Display:\n");
print_lcd_clock();
return 0;
}

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#include <string.h>
#include <math.h>
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include "lcd_clock.h"
#define TESTID "lcd_update.c"
int failures = 0;
int testn = 0;
#define TOLERANCE 1e-4
#define GENTEST 0
int compare_tod_t(tod_t x, tod_t y){
return
x.hours == y.hours &&
x.minutes == y.minutes &&
x.seconds == y.seconds &&
x.ispm == y.ispm;
}
void print_tod_t(tod_t tod){
printf("{\n");
printf(" .hours = %d,\n",tod.hours);
printf(" .minutes = %d,\n",tod.minutes);
printf(" .seconds = %d,\n",tod.seconds);
printf(" .ispm = %d,\n",tod.ispm);
printf("}\n");
}
void test_time_breakdown(int time_sec, tod_t expect){
testn++;
printf("Running %s Test %d for time_breakdown()\n", TESTID,testn);
TIME_OF_DAY_SEC = -1;
LCD_DISPLAY_PORT = -1;
tod_t actual = time_breakdown(time_sec);
if(TIME_OF_DAY_SEC != -1 || LCD_DISPLAY_PORT != -1){
printf("\nFailed %s Test %d for time_breakdown()\n", TESTID,testn);
printf("Do not modify TIME_OF_DAY_SEC or LCD_DISPLAY_PORT in this function\n");
failures++;
}
else if( !compare_tod_t(actual,expect) ){
printf("\nFailed %s Test %d for time_breakdown()\n", TESTID,testn);
printf("Actual and Expected tod_t differ\n");
printf("time_sec: %d\n",time_sec);
printf("EXPECT: "); print_tod_t(expect);
printf("ACTUAL: "); print_tod_t(actual);
failures++;
}
return;
}
void test_display_bits_from_tod(tod_t tod, int expect){
testn++;
printf("Running %s Test %d for display_bits_from_tod()\n", TESTID,testn);
TIME_OF_DAY_SEC = -1;
LCD_DISPLAY_PORT = -1;
int actual = display_bits_from_tod(tod);
if(TIME_OF_DAY_SEC != -1 || LCD_DISPLAY_PORT != -1){
printf("\nFailed %s Test %d for display_bits_from_tod()\n", TESTID,testn);
printf("Do not modify TIME_OF_DAY_SEC or LCD_DISPLAY_PORT in this function\n");
failures++;
}
else if(actual != expect){
printf("\nFailed %s Test %d for display_bits_from_tod()\n", TESTID,testn);
printf("Actual and Expected bits differ\n");
printf("tod = \n"); print_tod_t(tod);
printf(" 3 2 1 0\n");
printf("index: 10987654321098765432109876543210\n");
printf("EXPECT: "); showbits(expect); printf("\n");
printf("ACTUAL: "); showbits(actual); printf("\n");
printf("guide: | | | | |\n");
printf("\n");
failures++;
}
return;
}
void test_lcd_update(int time_sec, int expect){
testn++;
printf("Running %s Test %d for lcd_update()\n", TESTID,testn);
TIME_OF_DAY_SEC = time_sec;
lcd_update();
if(LCD_DISPLAY_PORT != expect || TIME_OF_DAY_SEC != time_sec){
printf("\nFailed %s Test %d for lcd_update()\n", TESTID,testn);
printf("Expect TIME_OF_DAY_SEC: %d\n",time_sec);
printf("Actual TIME_OF_DAY_SEC: %d\n",TIME_OF_DAY_SEC);
printf("Bits of LCD_DISPLAY_PORT\n");
printf("index: 10987654321098765432109876543210\n");
printf("EXPECT: "); showbits(expect); printf("\n");
printf("ACTUAL: "); showbits(LCD_DISPLAY_PORT); printf("\n");
printf("guide: | | | | |\n");
printf("\n");
failures++;
}
return;
}
typedef struct {
int time_sec;
tod_t tod;
int bits;
} lcd_test_case;
/* Global array of test data; terminated by a struct with time_sec=-1 */
lcd_test_case tests[] = {
{ .time_sec = 0,
.tod = {
.hours = 12,
.minutes = 0,
.seconds = 0,
.ispm = 0,
},
.bits=0b00010000110101101101111110111111,
},
{ .time_sec = 101,
.tod = {
.hours = 12,
.minutes = 1,
.seconds = 41,
.ispm = 0,
},
.bits=0b00010000110101101101111110000110,
},
{ .time_sec = 4170,
.tod = {
.hours = 1,
.minutes = 9,
.seconds = 30,
.ispm = 0,
},
.bits=0b00010000000000011001111111101111,
},
{ .time_sec = 43199,
.tod = {
.hours = 11,
.minutes = 59,
.seconds = 59,
.ispm = 0,
},
.bits=0b00010000110000011011011011101111,
},
{ .time_sec = 43200,
.tod = {
.hours = 12,
.minutes = 0,
.seconds = 0,
.ispm = 1,
},
.bits=0b00100000110101101101111110111111,
},
{ .time_sec = 47089,
.tod = {
.hours = 1,
.minutes = 4,
.seconds = 49,
.ispm = 1,
},
.bits=0b00100000000000011001111111100110,
},
{ .time_sec = 67089,
.tod = {
.hours = 6,
.minutes = 38,
.seconds = 9,
.ispm = 1,
},
.bits=0b00100000000111110110011111111111,
},
{ .time_sec = 86399,
.tod = {
.hours = 11,
.minutes = 59,
.seconds = 59,
.ispm = 1,
},
.bits=0b00100000110000011011011011101111,
},
{ .time_sec = 46348,
.tod = {
.hours = 12,
.minutes = 52,
.seconds = 28,
.ispm = 1,
},
.bits=0b00100000110101101111011011011011,
},
{ .time_sec = -1, },
};
int main(int argc, char **argv){
int i;
/* Run time_breakdown() tests */
for(i=0; tests[i].time_sec != -1; i++){
test_time_breakdown(tests[i].time_sec,tests[i].tod);
}
/* Run display_bits_from_tod() tests */
for(i=0; tests[i].time_sec != -1; i++){
test_display_bits_from_tod(tests[i].tod,tests[i].bits);
}
/* Run lcd_update() tests */
for(i=0; tests[i].time_sec != -1; i++){
test_lcd_update(tests[i].time_sec,tests[i].bits);
}
printf("%s Tests Passed/Run: %d / %d\n",TESTID,(testn-failures),testn);
return failures;
}

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#include "lcd_clock.h"
// Breaks down the give time of day in seconds into a tod_t struct
tod_t time_breakdown(int time_of_day_sec){
int tod_hours = time_of_day_sec / 3600;
int ispm = tod_hours >= 12 ? 1 : 0;
tod_hours = tod_hours % 12;
tod_hours = tod_hours == 0 ? 12 : tod_hours;
int tod_minutes = (time_of_day_sec / 60) % 60;
int tod_seconds = time_of_day_sec % 60;
tod_t tod = {.hours = tod_hours,
.minutes = tod_minutes,
.seconds = tod_seconds,
.ispm = ispm};
return tod;
}
// Binary masks for each digit for ease of setting
int digit_masks[10] = {
0b0111111, // zero
0b0000110, // one
0b1011011, // two
0b1001111, // three
0b1100110, // four
0b1101101, // five
0b1111101, // six
0b0000111, // seven
0b1111111, // eight
0b1101111, // nine
};
#define BLANK 0b0000000 // blank
#define AM_MASK (0x1 << 28)
#define PM_MASK (0x1 << 29)
int display_bits_from_tod(tod_t tod){
int hr_tens = tod.hours >= 10 ? digit_masks[1] : BLANK;
int hr_ones = digit_masks[tod.hours % 10];
int mn_tens = digit_masks[tod.minutes / 10];
int mn_ones = digit_masks[tod.minutes % 10];
int ampm = tod.ispm ? PM_MASK : AM_MASK;
int state = 0;
state |= (mn_ones << 0);
state |= (mn_tens << 7);
state |= (hr_ones << 14);
state |= (hr_tens << 21);
state |= ampm;
return state;
}
/* Examine the TIME_OF_DAY_SEC to determine hour, minute, and am/pm.
Set the LCD_DISPLAY_PORT bits to show the proper time. */
void lcd_update(){
tod_t tod = time_breakdown(TIME_OF_DAY_SEC);
int state = display_bits_from_tod(tod);
LCD_DISPLAY_PORT = state;
}

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#!/bin/bash
# Loop to produce various example times. clock_sim program must be
# built preceding use.
for t in 999 7777 121212; do
echo '> clock_sim' $t
./clock_sim $t
echo
echo
done

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#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "hw6.h"
#include "lcd_clock.h"
int main(int argc, char **argv){
if(argc < 2){ /* Set TIME_OF_DAY_SEC to the actual time */
time_t rawtime; /* Get raw time */
time( &rawtime );
struct tm *info; /* Store broken down time */
info = localtime( &rawtime ); /* Get a broken down time */
/* Calculate the seconds since the beginning of the day */
TIME_OF_DAY_SEC = info->tm_sec + 60*info->tm_min + 60*60*info->tm_hour;
}
else{ /* Set time based on argument given */
TIME_OF_DAY_SEC = atoi(argv[1]);
}
int time_max = 24 * 60 * 60;
if(TIME_OF_DAY_SEC >= time_max){
printf("Time %d exceeds max %d\n",TIME_OF_DAY_SEC,time_max);
return -1;
}
tod_t tod = time_breakdown(TIME_OF_DAY_SEC);
printf("tod = time_breakdown( %5d ); //",TIME_OF_DAY_SEC);
printf(" %02d : %02d : %02d %s\n",
tod.hours,tod.minutes,tod.seconds,(tod.ispm ? "pm" : "am"));
printf("tod is { \n");
printf(" .hours = %d\n",tod.hours);
printf(" .minutes = %d\n",tod.minutes);
printf(" .seconds = %d\n",tod.seconds);
printf(" .ispm = %d\n",tod.ispm);
printf("} \n");
return 0;
}

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__________________
LAB 02 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `fork1.c'
===================
A
~
Compile and run the program in `fork1.c'. Show it's output below.
I am number 1, my pid is 9162
I am number 0, my pid is 9161
I am number 3, my pid is 9164
I am number 8, my pid is 9160
I am number 4, my pid is 9165
I am number 2, my pid is 9163
I am number 7, my pid is 9168
I am number 5, my pid is 9166
I am number 6, my pid is 9167
B
~
Is the output ordered or disordered with respect to the "I am
number..." statements? Why?
It's disordered in that the output has been printed to the screen out of order,
because spawning each process and then executing the print statement could take
an indeterminate amount of time for each process, so it ends up out of order.
However, PIDs are in the same order as the child's number, since PIDs are usually
created in an incremental manner so processes created later will have a larger
PID.
C
~
Add calls to the wait() or waitpid() function to ensure that the
output is ordered.
#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void) {
int i;
for (i = 0; i < 8; i++) {
pid_t child = fork();
if (child == 0) {
break;
} else { // make sure this is only executed on the parent process
waitpid(child, 0, 0); // wait for the child process to exit with status 0
}
}
printf("I am number %d, my pid is %d\n", i, getpid());
return 0;
}
D
~
How many parents and children are there in this program? What is their
arrangement?
There's 1 parent and 8 children, with the parent process printing "I am
number 8" (since it only prints after it's spawned all the children, leaving
i = 8 when it reaches the printf statement).
PROBLEM 2 `fork-exec1.c'
========================
A
~
Compile and run the program in `fork-exec1.c'. Show it's output below.
Running command 'ls'
------------------
total 84K
drwxr-xr-x 2 michael michael 4.0K Sep 18 02:26 .
drwxrwxr-x 4 michael michael 4.0K Sep 18 02:18 ..
-rwxrwxr-x 1 michael michael 8.6K Sep 18 02:24 fork1
-rw-r--r-- 1 michael michael 408 Sep 18 02:25 fork1.c
-rwxrwxr-x 1 michael michael 8.6K Sep 18 02:26 fork-exec1
-rw-r--r-- 1 michael michael 360 Sep 13 13:56 fork-exec1.c
-rw-r--r-- 1 michael michael 2.4K Sep 18 02:26 QUESTIONS.txt
B
~
Adjust the contents of the `child_argv[]' array. Try remove the "-l"
element, try adding on ".." prior to the final NULL, or make other
modifications INCLUDING for the 0th "ls" string. Recompile and
describe whether the output has changed.
Changed the line to:
char *child_argv[] = {"ls","-lc","-ah","/home",NULL};
Ouptut:
Running command 'ls'
------------------
total 24K
drwxr-xr-x 4 root root 4.0K Sep 5 10:27 .
drwxr-xr-x 24 root root 4.0K Sep 12 17:24 ..
drwxr-xr-x 3 root root 4.0K Sep 5 10:27 .ecryptfs
drwx------ 44 michael michael 12K Sep 18 02:29 michael
C
~
Change the child_cmd string from "ls" to be something else like "gcc"
or "cat". Recompile ad explain what happens now.
Changed the line to:
char *child_argv[] = {"--", "derpalerp",NULL};
char *child_cmd = "cowsay";
Output:
Running command 'cowsay'
------------------
___________
< derpalerp >
-----------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
D
~
Currently `fork-exec1.c' does not reach the bottom statements.
,----
| printf("------------------\n");
| printf("Finished\n");
`----
Correct this by doing the following:
- Fork a child process
- Have ONLY the child process call execvp()
- Have the parent process wait() for the child
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void){
char *child_argv[] = {"--", "derpalerp",NULL};
char *child_cmd = "cowsay";
printf("Running command '%s'\n",child_cmd);
printf("------------------\n");
pid_t child = fork();
if (child == 0) { // child
execvp(child_cmd,child_argv);
} else {
waitpid(child, 0, 0);
printf("------------------\n");
printf("Finished\n");
}
return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void){
char *child_argv[] = {"--", "derpalerp",NULL};
char *child_cmd = "cowsay";
printf("Running command '%s'\n",child_cmd);
printf("------------------\n");
pid_t child = fork();
if (child == 0) { // child
execvp(child_cmd,child_argv);
} else {
waitpid(child, 0, 0);
printf("------------------\n");
printf("Finished\n");
}
return 0;
}

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#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void) {
int i;
for (i = 0; i < 8; i++) {
pid_t child = fork();
if (child == 0) {
break;
} else { // make sure this is only executed on the parent process
waitpid(child, 0, 0); // wait for the child process to exit with status 0
}
}
printf("I am number %d, my pid is %d\n", i, getpid());
return 0;
}

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__________________
LAB 03 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `wait-fork.c'
=======================
A
~
Compile and run the program in `wait-loop.c'. Does the loop in the
program ever end? How must one "exit" the program?
The program doesn't end, since there's a while loop that continuously asks the
user for input, without any option that makes it exit. The only way to "exit"
the program is to terminate it either through sending the signal using ^C, or
else opening another terminal window and killing the process by id.
B
~
Alter the code so that when the child has completed execution, the
program breaks out of the loop and the program ends normally. Paste in
the code you used for this.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void) {
// Make sure to compile sleep_print first:
// gcc -o sleep_print sleep_print.c
char *child_argv[] = {"./sleep_print", "5", "CHILD: Awake and Done", NULL};
pid_t child_pid = fork();
if (child_pid == 0) {
execvp(child_argv[0], child_argv);
perror("errno indicates");
printf("Couldn't run '%s': is it compiled??\n", child_argv[0]);
exit(1);
}
while (1) {
printf("Type text then press enter to check on child:\n");
char buffer[1024];
char *input = fgets(buffer, 1024, stdin);
input[strlen(input) - 1] = '\0'; // Eliminate newline in buffer
printf("Entered text: '%s'\n", input);
printf("Waiting\n");
int status;
pid_t pid = waitpid(child_pid, &status, 0);
if (pid == child_pid) {
printf("CHILD FINISHED: ");
printf("\n");
break;
} else {
printf("Child not finished: wait returned %d\n", pid);
}
printf("\n");
}
printf("Exiting wait-loop\n");
return 0;
}
C
~
Adjust the code so that the exit status of the child process is
printed when it finishes. Make sure to use the macros
`WIFEXITED(status)' and `WEXITSTATUS(status)' to deal with the
`status' set by `waitpid()'. Paste the code you added for your
answer.
if (WIFEXITED(status)) {
printf("CHILD FINISHED: %d", WEXITSTATUS(status));
printf("\n");
break;
}
D
~
Make changes so that if the user types in the string `quit', the
program exits immediately without waiting further for the
child. Example:
,----
| > a.out
| Type text then press enter to check on child:
| quit
| Entered text: 'quit'
| Quitting
| Exiting wait-loop
| > CHILD: Awake and Done
`----
Note that the child eventually prints output to the screen which is
fine.
You will need to check the user input using the `strncmp()'
function. Do some research on this function as it will prove generally
useful.
Paste the code you used below.
E
~
The current call to `waitpid()' blocks, pausing execution of the
parent process until the child finishes. Look up the option to pass to
`waitpid()' that will allow it to do a non-blocking wait which returns
immediately if the child is not finished. A sample behavior is below.
,----
| > a.out
| Type text then press enter to check on child:
| stuff
| Entered text: 'stuff'
| Waiting
| Child not finished: wait returned 0
|
| Type text then press enter to check on child:
| more stuff
| Entered text: 'more stuff'
| Waiting
| Child not finished: wait returned 0
|
| Type text then press enter to check on child:
| CHILD: Awake and Done
| Looks like you're finally up
| Entered text: 'Looks like you're finally up'
| Waiting
| CHILD FINISHED: Exit status 5
| Exiting wait-loop
| >
`----
Paste your entire code for `wait-loop.c' below.

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#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
// usage: sleep_die secs
//
// Sleep for given number of seconds then raise SIGINT which will
// cause the program to die.
int main(int argc, char *argv[]){
int secs = atoi(argv[1]);
struct timespec tm = {
.tv_nsec = 0,
.tv_sec = secs,
};
nanosleep(&tm,NULL);
printf("O happy dagger! This is thy sheath;\n");
printf("there rust, and let me die.\n");
raise(SIGINT);
return secs;
}

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#include <time.h>
#include <stdio.h>
#include <stdlib.h>
// usage: sleep_print secs message
//
// Sleep for the given number of seconds then print the given message
int main(int argc, char *argv[]){
int secs = atoi(argv[1]);
struct timespec tm = {
.tv_nsec = 0,
.tv_sec = secs,
};
nanosleep(&tm,NULL);
for(int i=2; i<argc; i++){
printf("%s ",argv[i]);
}
printf("\n");
return secs;
}

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void) {
// Make sure to compile sleep_print first:
// gcc -o sleep_print sleep_print.c
char *child_argv[] = {"./sleep_print", "5", "CHILD: Awake and Done", NULL};
pid_t child_pid = fork();
if (child_pid == 0) {
execvp(child_argv[0], child_argv);
perror("errno indicates");
printf("Couldn't run '%s': is it compiled??\n", child_argv[0]);
exit(1);
}
while (1) {
printf("Type text then press enter to check on child:\n");
char buffer[1024];
char *input = fgets(buffer, 1024, stdin);
input[strlen(input) - 1] = '\0'; // Eliminate newline in buffer
printf("Entered text: '%s'\n", input);
printf("Waiting\n");
int status;
pid_t pid = waitpid(child_pid, &status, 0);
if (pid == child_pid) {
if (WIFEXITED(status)) {
printf("CHILD FINISHED: %d", WEXITSTATUS(status));
printf("\n");
break;
}
} else {
printf("Child not finished: wait returned %d\n", pid);
}
printf("\n");
}
printf("Exiting wait-loop\n");
return 0;
}

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__________________
LAB 04 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `parent_listen.c'
===========================
A
~
Compile and run the program in `parent_listen.c'. Show it's output
below.
Child wrote 17 bytes
Parent read 17 bytes
Child said: 'Send $$$ please!'
B
~
Consider the call to pipe(). Do some research to figure out what a
pipe does and explain in a few sentences.
According to the manpage, a pipe is "a unidirectional data channel that can be
used for interprocess communication." Simply put, it's a way for processes to
communicate with each other through a file-like object, with a read end and a
write end that can be used by separate processes.
C
~
Observe the calls to read() and write(). Their meaning should be
self-evident (read and write data) but the parameters to these
functions are interesting. Do some reading and explain the 3
parameters to each of them. Also explain their return value.
The arguments for read and write are: int fd, void *buf, and size_t count. count
is obvious, and *buf is the buffer that the function is writing to, but the
argument of interest is fd. fd is a numerical file descriptor that can be used
to ask the kernel to make read/write transfers. File descriptors can be linked
to tty IO (stdin, stdout) or files or even sockets or pipes.
Also, the return value is simply the number of bytes that have been transferred.
D
~
If you run the program a number of times, you may see output in
different orders: the child may report writing data before the parent
has read it. Adjust the position of the wait() call to guarantee that
the order is always
- Child wrote
- Parent read
- Child said
Paste your code below.
The wait() call will guarantee that the rest of the code will not run until the
child has terminated, or, more specifically, until after the print statement has
been executed. The code does not need to be changed.
PROBLEM 2 `capture_stdout.c'
============================
A
~
Compile and run the program in `capture_stdout.c'. Show its output.
Process 28530 Piping
28530 Read from the my_pipe
28530 Read: '28530 In the pipe, five by five'
B
~
The calls `dup()' and `dup2()' are used in this program to manipulate
file descriptors. Explain the effects of the lines below.
,----
| int stdout_bak = dup(STDOUT_FILENO);
| dup2(my_pipe[PWRITE], STDOUT_FILENO);
| ...
| dup2(stdout_bak, STDOUT_FILENO);
`----
The first line makes a copy of STDOUT_FILENO and stores it into stdout_bak. The
second line changes my_pipe[PWRITE] to be the fd of STDOUT_FILENO, and finally
the last line changes STDOUT_FILENO back to the stored value that was created in
the first of the three lines.
C
~
The use of `printf()' normally puts output directly on the
screen. Explain why the statement
,----
| printf("%d In the pipe, five by five",
| getpid());
`----
does not print to screen as usual.
This statement does not print because by this time, the output tty STDOUT_FILENO
has had its fd changed such that it will be writing to a pipe rather than the
standard tty output.
D
~
Modify the code so that the `In the pipe...' expression is printed by
a child process.
- Add a `fork()' AFTER `dup2()' redirects standard output but before
the print
- Add an `if()' to distinguish between parent and child
- The child should print then exit
- The parent should restore stdout then read from the pipe
- Add a `wait()' to guarantee the parent waits for the child to
complete prior to reading from the pipe
Paste your completed code below

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// Redirect standard output temporarily to a pipe, then restore
// standard output and retrieve the captured output
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#define PREAD 0 // index of read end of pipe
#define PWRITE 1 // index of write end of pipe
int main() {
setvbuf(stdout, NULL, _IONBF, 0); // Turn off I/O buffering
printf("Process %d Piping\n", getpid());
int my_pipe[2];
pipe(my_pipe);
int stdout_bak =
dup(STDOUT_FILENO); // Duplicate stdout so it can be restored later
dup2(my_pipe[PWRITE], STDOUT_FILENO); // Redirect stdout to pipe
pid_t pid = fork();
if (pid == 0) {
printf(
"%d In the pipe, five by five", // Should not show up on the screen
getpid());
close(my_pipe[PWRITE]); // Close the write end of the pipe
exit(0);
}
wait(NULL);
dup2(stdout_bak,
STDOUT_FILENO); // Restore stdout: redirect to backed up fd
printf("%d Read from the my_pipe\n", getpid());
char buf[2048];
int bytes_read = read(my_pipe[PREAD], buf, 2048);
buf[bytes_read] = '\0'; // Not null-terminated by default, append '\0'
close(my_pipe[PREAD]); // Close read end
printf("%d Read: '%s'\n", getpid(), buf); // Show earlier output
return 0;
}

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#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <errno.h>
#include <string.h>
#define PREAD 0 // index of read end of pipe
#define PWRITE 1 // index of write end of pipe
#define BUFSIZE 1024
int main(int argc, char *argv[]) {
int par_child_pipe[2];
int pipe_result = pipe(par_child_pipe);
if(pipe_result != 0) {
perror("Failed to create pipe");
exit(1);
}
pid_t child_pid = fork();
if(child_pid <0){
perror("Failed to fork");
exit(1);
}
// CHILD CODE
if(child_pid == 0){
char *msg = "Send $$$ please!";
int msg_len = strlen(msg)+1;
int bytes_written = write(par_child_pipe[PWRITE], msg, msg_len);
printf("Child wrote %d bytes\n",bytes_written);
fflush(stdout);
close(par_child_pipe[PWRITE]);
close(par_child_pipe[PREAD]);
exit(0);
}
// PARENT CODE
wait(NULL);
char buffer[BUFSIZE];
// printf("Child %d started\n",child_pid);
int bytes_read = read(par_child_pipe[PREAD], buffer, BUFSIZE);
close(par_child_pipe[PWRITE]);
close(par_child_pipe[PREAD]);
printf("Parent read %d bytes\n",bytes_read);
printf("Child said: '%s'\n",buffer);
// wait(NULL);
return 0;
}

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101
102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126
127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151
152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201
202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226
227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276
277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301
302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326
327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376
377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401
402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426
427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451
452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476
477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501
502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526
527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551
552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576
577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601
602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626
627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651
652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676
677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701
702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726
727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751
752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801
802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826
827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876
877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901
902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926
927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951
952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000
1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060
1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180
1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320
1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340
1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360
1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380
1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400
1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420
1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480
1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500
1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520
1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540
1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580
1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600
1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620
1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680
1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700
1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720
1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740
1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760
1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780
1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800
1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840
1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860
1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880
1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900
1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960
1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040
2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060
2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080
2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100
2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120
2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140
2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160
2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180
2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200
2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220
2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240
2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260
2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280
2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300
2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320
2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340
2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360
2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380
2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400
2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420
2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440
2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460
2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480
2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500
2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520
2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540
2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560
2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580
2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600
2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620
2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640
2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660
2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680
2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700
2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720
2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740
2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760
2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780
2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800
2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820
2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840
2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860
2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880
2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900
2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920
2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940
2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960
2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980
2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185
186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205
206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265
266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305
306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345
346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365
366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385
386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405
406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465
466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485
486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505
506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525
526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545
546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565
566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585
586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625
626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705
706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725
726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765
766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785
786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865
866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945
946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115
1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307
1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323
1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355
1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387
1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451
1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563
1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611
1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691
1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723
1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739
1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771
1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803
1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819
1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867
1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883
1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915
1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931
1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947
1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963
1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027
2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075
2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091
2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107
2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139
2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155
2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171
2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187
2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203
2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251
2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267
2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283
2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299
2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315
2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331
2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363
2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379
2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395
2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411
2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475
2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491
2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523
2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539
2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555
2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571
2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587
2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619
2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635
2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651
2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667
2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683
2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699
2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715
2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747
2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763
2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779
2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811
2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827
2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843
2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859
2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875
2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891
2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907
2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923
2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939
2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955
2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971
2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987
2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003
3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019
3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035
3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051
3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067
3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083
3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099
3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115
3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131
3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147
3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163
3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179
3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195
3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211
3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227
3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243
3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259
3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275
3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291
3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307
3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323
3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339
3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355
3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371
3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387
3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403
3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419
3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435
3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451
3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467
3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483
3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499
3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515
3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531
3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547
3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563
3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579
3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595
3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611
3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627
3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643
3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659
3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675
3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691
3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707
3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723
3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739
3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755
3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771
3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787
3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803
3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819
3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835
3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851
3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867
3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883
3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899
3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915
3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931
3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947
3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963
3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979
3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995
3996 3997 3998 3999 4000

487
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185
186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205
206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265
266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305
306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345
346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365
366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385
386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405
406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465
466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485
486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505
506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525
526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545
546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565
566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585
586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625
626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705
706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725
726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765
766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785
786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865
866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945
946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115
1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307
1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323
1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355
1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387
1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451
1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563
1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611
1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691
1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723
1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739
1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771
1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803
1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819
1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867
1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883
1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915
1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931
1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947
1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963
1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027
2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075
2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091
2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107
2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139
2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155
2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171
2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187
2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203
2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251
2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267
2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283
2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299
2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315
2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331
2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363
2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379
2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395
2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411
2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475
2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491
2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523
2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539
2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555
2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571
2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587
2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619
2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635
2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651
2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667
2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683
2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699
2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715
2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747
2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763
2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779
2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811
2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827
2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843
2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859
2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875
2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891
2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907
2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923
2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939
2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955
2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971
2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987
2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003
3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019
3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035
3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051
3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067
3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083
3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099
3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115
3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131
3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147
3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163
3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179
3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195
3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211
3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227
3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243
3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259
3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275
3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291
3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307
3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323
3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339
3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355
3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371
3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387
3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403
3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419
3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435
3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451
3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467
3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483
3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499
3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515
3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531
3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547
3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563
3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579
3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595
3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611
3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627
3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643
3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659
3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675
3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691
3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707
3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723
3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739
3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755
3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771
3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787
3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803
3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819
3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835
3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851
3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867
3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883
3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899
3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915
3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931
3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947
3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963
3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979
3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995
3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011
4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027
4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043
4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059
4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075
4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091
4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107
4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123
4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139
4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155
4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171
4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187
4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203
4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219
4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235
4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251
4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267
4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283
4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299
4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315
4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331
4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347
4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363
4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379
4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395
4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411
4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427
4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443
4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459
4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475
4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491
4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507
4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523
4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539
4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555
4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571
4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587
4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603
4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619
4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635
4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651
4652 4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667
4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683
4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699
4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715
4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731
4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747
4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763
4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779
4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795
4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811
4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827
4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840 4841 4842 4843
4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859
4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873 4874 4875
4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891
4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907
4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923
4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939
4940 4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955
4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971
4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987
4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003
5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019
5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034 5035
5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051
5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067
5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083
5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099
5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115
5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131
5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147
5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163
5164 5165 5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179
5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195
5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211
5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227
5228 5229 5230 5231 5232 5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243
5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259
5260 5261 5262 5263 5264 5265 5266 5267 5268 5269 5270 5271 5272 5273 5274 5275
5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291
5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307
5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323
5324 5325 5326 5327 5328 5329 5330 5331 5332 5333 5334 5335 5336 5337 5338 5339
5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355
5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369 5370 5371
5372 5373 5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384 5385 5386 5387
5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403
5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419
5420 5421 5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435
5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451
5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467
5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483
5484 5485 5486 5487 5488 5489 5490 5491 5492 5493 5494 5495 5496 5497 5498 5499
5500 5501 5502 5503 5504 5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515
5516 5517 5518 5519 5520 5521 5522 5523 5524 5525 5526 5527 5528 5529 5530 5531
5532 5533 5534 5535 5536 5537 5538 5539 5540 5541 5542 5543 5544 5545 5546 5547
5548 5549 5550 5551 5552 5553 5554 5555 5556 5557 5558 5559 5560 5561 5562 5563
5564 5565 5566 5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577 5578 5579
5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590 5591 5592 5593 5594 5595
5596 5597 5598 5599 5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611
5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627
5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643
5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659
5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672 5673 5674 5675
5676 5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689 5690 5691
5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707
5708 5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721 5722 5723
5724 5725 5726 5727 5728 5729 5730 5731 5732 5733 5734 5735 5736 5737 5738 5739
5740 5741 5742 5743 5744 5745 5746 5747 5748 5749 5750 5751 5752 5753 5754 5755
5756 5757 5758 5759 5760 5761 5762 5763 5764 5765 5766 5767 5768 5769 5770 5771
5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787
5788 5789 5790 5791 5792 5793 5794 5795 5796 5797 5798 5799 5800 5801 5802 5803
5804 5805 5806 5807 5808 5809 5810 5811 5812 5813 5814 5815 5816 5817 5818 5819
5820 5821 5822 5823 5824 5825 5826 5827 5828 5829 5830 5831 5832 5833 5834 5835
5836 5837 5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851
5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862 5863 5864 5865 5866 5867
5868 5869 5870 5871 5872 5873 5874 5875 5876 5877 5878 5879 5880 5881 5882 5883
5884 5885 5886 5887 5888 5889 5890 5891 5892 5893 5894 5895 5896 5897 5898 5899
5900 5901 5902 5903 5904 5905 5906 5907 5908 5909 5910 5911 5912 5913 5914 5915
5916 5917 5918 5919 5920 5921 5922 5923 5924 5925 5926 5927 5928 5929 5930 5931
5932 5933 5934 5935 5936 5937 5938 5939 5940 5941 5942 5943 5944 5945 5946 5947
5948 5949 5950 5951 5952 5953 5954 5955 5956 5957 5958 5959 5960 5961 5962 5963
5964 5965 5966 5967 5968 5969 5970 5971 5972 5973 5974 5975 5976 5977 5978 5979
5980 5981 5982 5983 5984 5985 5986 5987 5988 5989 5990 5991 5992 5993 5994 5995
5996 5997 5998 5999 6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010 6011
6012 6013 6014 6015 6016 6017 6018 6019 6020 6021 6022 6023 6024 6025 6026 6027
6028 6029 6030 6031 6032 6033 6034 6035 6036 6037 6038 6039 6040 6041 6042 6043
6044 6045 6046 6047 6048 6049 6050 6051 6052 6053 6054 6055 6056 6057 6058 6059
6060 6061 6062 6063 6064 6065 6066 6067 6068 6069 6070 6071 6072 6073 6074 6075
6076 6077 6078 6079 6080 6081 6082 6083 6084 6085 6086 6087 6088 6089 6090 6091
6092 6093 6094 6095 6096 6097 6098 6099 6100 6101 6102 6103 6104 6105 6106 6107
6108 6109 6110 6111 6112 6113 6114 6115 6116 6117 6118 6119 6120 6121 6122 6123
6124 6125 6126 6127 6128 6129 6130 6131 6132 6133 6134 6135 6136 6137 6138 6139
6140 6141 6142 6143 6144 6145 6146 6147 6148 6149 6150 6151 6152 6153 6154 6155
6156 6157 6158 6159 6160 6161 6162 6163 6164 6165 6166 6167 6168 6169 6170 6171
6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183 6184 6185 6186 6187
6188 6189 6190 6191 6192 6193 6194 6195 6196 6197 6198 6199 6200 6201 6202 6203
6204 6205 6206 6207 6208 6209 6210 6211 6212 6213 6214 6215 6216 6217 6218 6219
6220 6221 6222 6223 6224 6225 6226 6227 6228 6229 6230 6231 6232 6233 6234 6235
6236 6237 6238 6239 6240 6241 6242 6243 6244 6245 6246 6247 6248 6249 6250 6251
6252 6253 6254 6255 6256 6257 6258 6259 6260 6261 6262 6263 6264 6265 6266 6267
6268 6269 6270 6271 6272 6273 6274 6275 6276 6277 6278 6279 6280 6281 6282 6283
6284 6285 6286 6287 6288 6289 6290 6291 6292 6293 6294 6295 6296 6297 6298 6299
6300 6301 6302 6303 6304 6305 6306 6307 6308 6309 6310 6311 6312 6313 6314 6315
6316 6317 6318 6319 6320 6321 6322 6323 6324 6325 6326 6327 6328 6329 6330 6331
6332 6333 6334 6335 6336 6337 6338 6339 6340 6341 6342 6343 6344 6345 6346 6347
6348 6349 6350 6351 6352 6353 6354 6355 6356 6357 6358 6359 6360 6361 6362 6363
6364 6365 6366 6367 6368 6369 6370 6371 6372 6373 6374 6375 6376 6377 6378 6379
6380 6381 6382 6383 6384 6385 6386 6387 6388 6389 6390 6391 6392 6393 6394 6395
6396 6397 6398 6399 6400 6401 6402 6403 6404 6405 6406 6407 6408 6409 6410 6411
6412 6413 6414 6415 6416 6417 6418 6419 6420 6421 6422 6423 6424 6425 6426 6427
6428 6429 6430 6431 6432 6433 6434 6435 6436 6437 6438 6439 6440 6441 6442 6443
6444 6445 6446 6447 6448 6449 6450 6451 6452 6453 6454 6455 6456 6457 6458 6459
6460 6461 6462 6463 6464 6465 6466 6467 6468 6469 6470 6471 6472 6473 6474 6475
6476 6477 6478 6479 6480 6481 6482 6483 6484 6485 6486 6487 6488 6489 6490 6491
6492 6493 6494 6495 6496 6497 6498 6499 6500 6501 6502 6503 6504 6505 6506 6507
6508 6509 6510 6511 6512 6513 6514 6515 6516 6517 6518 6519 6520 6521 6522 6523
6524 6525 6526 6527 6528 6529 6530 6531 6532 6533 6534 6535 6536 6537 6538 6539
6540 6541 6542 6543 6544 6545 6546 6547 6548 6549 6550 6551 6552 6553 6554 6555
6556 6557 6558 6559 6560 6561 6562 6563 6564 6565 6566 6567 6568 6569 6570 6571
6572 6573 6574 6575 6576 6577 6578 6579 6580 6581 6582 6583 6584 6585 6586 6587
6588 6589 6590 6591 6592 6593 6594 6595 6596 6597 6598 6599 6600 6601 6602 6603
6604 6605 6606 6607 6608 6609 6610 6611 6612 6613 6614 6615 6616 6617 6618 6619
6620 6621 6622 6623 6624 6625 6626 6627 6628 6629 6630 6631 6632 6633 6634 6635
6636 6637 6638 6639 6640 6641 6642 6643 6644 6645 6646 6647 6648 6649 6650 6651
6652 6653 6654 6655 6656 6657 6658 6659 6660 6661 6662 6663 6664 6665 6666 6667
6668 6669 6670 6671 6672 6673 6674 6675 6676 6677 6678 6679 6680 6681 6682 6683
6684 6685 6686 6687 6688 6689 6690 6691 6692 6693 6694 6695 6696 6697 6698 6699
6700 6701 6702 6703 6704 6705 6706 6707 6708 6709 6710 6711 6712 6713 6714 6715
6716 6717 6718 6719 6720 6721 6722 6723 6724 6725 6726 6727 6728 6729 6730 6731
6732 6733 6734 6735 6736 6737 6738 6739 6740 6741 6742 6743 6744 6745 6746 6747
6748 6749 6750 6751 6752 6753 6754 6755 6756 6757 6758 6759 6760 6761 6762 6763
6764 6765 6766 6767 6768 6769 6770 6771 6772 6773 6774 6775 6776 6777 6778 6779
6780 6781 6782 6783 6784 6785 6786 6787 6788 6789 6790 6791 6792 6793 6794 6795
6796 6797 6798 6799 6800 6801 6802 6803 6804 6805 6806 6807 6808 6809 6810 6811
6812 6813 6814 6815 6816 6817 6818 6819 6820 6821 6822 6823 6824 6825 6826 6827
6828 6829 6830 6831 6832 6833 6834 6835 6836 6837 6838 6839 6840 6841 6842 6843
6844 6845 6846 6847 6848 6849 6850 6851 6852 6853 6854 6855 6856 6857 6858 6859
6860 6861 6862 6863 6864 6865 6866 6867 6868 6869 6870 6871 6872 6873 6874 6875
6876 6877 6878 6879 6880 6881 6882 6883 6884 6885 6886 6887 6888 6889 6890 6891
6892 6893 6894 6895 6896 6897 6898 6899 6900 6901 6902 6903 6904 6905 6906 6907
6908 6909 6910 6911 6912 6913 6914 6915 6916 6917 6918 6919 6920 6921 6922 6923
6924 6925 6926 6927 6928 6929 6930 6931 6932 6933 6934 6935 6936 6937 6938 6939
6940 6941 6942 6943 6944 6945 6946 6947 6948 6949 6950 6951 6952 6953 6954 6955
6956 6957 6958 6959 6960 6961 6962 6963 6964 6965 6966 6967 6968 6969 6970 6971
6972 6973 6974 6975 6976 6977 6978 6979 6980 6981 6982 6983 6984 6985 6986 6987
6988 6989 6990 6991 6992 6993 6994 6995 6996 6997 6998 6999 7000 7001 7002 7003
7004 7005 7006 7007 7008 7009 7010 7011 7012 7013 7014 7015 7016 7017 7018 7019
7020 7021 7022 7023 7024 7025 7026 7027 7028 7029 7030 7031 7032 7033 7034 7035
7036 7037 7038 7039 7040 7041 7042 7043 7044 7045 7046 7047 7048 7049 7050 7051
7052 7053 7054 7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065 7066 7067
7068 7069 7070 7071 7072 7073 7074 7075 7076 7077 7078 7079 7080 7081 7082 7083
7084 7085 7086 7087 7088 7089 7090 7091 7092 7093 7094 7095 7096 7097 7098 7099
7100 7101 7102 7103 7104 7105 7106 7107 7108 7109 7110 7111 7112 7113 7114 7115
7116 7117 7118 7119 7120 7121 7122 7123 7124 7125 7126 7127 7128 7129 7130 7131
7132 7133 7134 7135 7136 7137 7138 7139 7140 7141 7142 7143 7144 7145 7146 7147
7148 7149 7150 7151 7152 7153 7154 7155 7156 7157 7158 7159 7160 7161 7162 7163
7164 7165 7166 7167 7168 7169 7170 7171 7172 7173 7174 7175 7176 7177 7178 7179
7180 7181 7182 7183 7184 7185 7186 7187 7188 7189 7190 7191 7192 7193 7194 7195
7196 7197 7198 7199 7200 7201 7202 7203 7204 7205 7206 7207 7208 7209 7210 7211
7212 7213 7214 7215 7216 7217 7218 7219 7220 7221 7222 7223 7224 7225 7226 7227
7228 7229 7230 7231 7232 7233 7234 7235 7236 7237 7238 7239 7240 7241 7242 7243
7244 7245 7246 7247 7248 7249 7250 7251 7252 7253 7254 7255 7256 7257 7258 7259
7260 7261 7262 7263 7264 7265 7266 7267 7268 7269 7270 7271 7272 7273 7274 7275
7276 7277 7278 7279 7280 7281 7282 7283 7284 7285 7286 7287 7288 7289 7290 7291
7292 7293 7294 7295 7296 7297 7298 7299 7300 7301 7302 7303 7304 7305 7306 7307
7308 7309 7310 7311 7312 7313 7314 7315 7316 7317 7318 7319 7320 7321 7322 7323
7324 7325 7326 7327 7328 7329 7330 7331 7332 7333 7334 7335 7336 7337 7338 7339
7340 7341 7342 7343 7344 7345 7346 7347 7348 7349 7350 7351 7352 7353 7354 7355
7356 7357 7358 7359 7360 7361 7362 7363 7364 7365 7366 7367 7368 7369 7370 7371
7372 7373 7374 7375 7376 7377 7378 7379 7380 7381 7382 7383 7384 7385 7386 7387
7388 7389 7390 7391 7392 7393 7394 7395 7396 7397 7398 7399 7400 7401 7402 7403
7404 7405 7406 7407 7408 7409 7410 7411 7412 7413 7414 7415 7416 7417 7418 7419
7420 7421 7422 7423 7424 7425 7426 7427 7428 7429 7430 7431 7432 7433 7434 7435
7436 7437 7438 7439 7440 7441 7442 7443 7444 7445 7446 7447 7448 7449 7450 7451
7452 7453 7454 7455 7456 7457 7458 7459 7460 7461 7462 7463 7464 7465 7466 7467
7468 7469 7470 7471 7472 7473 7474 7475 7476 7477 7478 7479 7480 7481 7482 7483
7484 7485 7486 7487 7488 7489 7490 7491 7492 7493 7494 7495 7496 7497 7498 7499
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7516 7517 7518 7519 7520 7521 7522 7523 7524 7525 7526 7527 7528 7529 7530 7531
7532 7533 7534 7535 7536 7537 7538 7539 7540 7541 7542 7543 7544 7545 7546 7547
7548 7549 7550 7551 7552 7553 7554 7555 7556 7557 7558 7559 7560 7561 7562 7563
7564 7565 7566 7567 7568 7569 7570 7571 7572 7573 7574 7575 7576 7577 7578 7579
7580 7581 7582 7583 7584 7585 7586 7587 7588 7589 7590 7591 7592 7593 7594 7595
7596 7597 7598 7599 7600 7601 7602 7603 7604 7605 7606 7607 7608 7609 7610 7611
7612 7613 7614 7615 7616 7617 7618 7619 7620 7621 7622 7623 7624 7625 7626 7627
7628 7629 7630 7631 7632 7633 7634 7635 7636 7637 7638 7639 7640 7641 7642 7643
7644 7645 7646 7647 7648 7649 7650 7651 7652 7653 7654 7655 7656 7657 7658 7659
7660 7661 7662 7663 7664 7665 7666 7667 7668 7669 7670 7671 7672 7673 7674 7675
7676 7677 7678 7679 7680 7681 7682 7683 7684 7685 7686 7687 7688 7689 7690 7691
7692 7693 7694 7695 7696 7697 7698 7699 7700 7701 7702 7703 7704 7705 7706 7707
7708 7709 7710 7711 7712 7713 7714 7715 7716 7717 7718 7719 7720 7721 7722 7723
7724 7725 7726 7727 7728 7729 7730 7731 7732 7733 7734 7735 7736 7737 7738 7739
7740 7741 7742 7743 7744 7745 7746 7747 7748 7749 7750 7751 7752 7753 7754 7755
7756 7757 7758 7759 7760 7761 7762 7763 7764 7765 7766 7767 7768 7769 7770 7771
7772 7773 7774 7775 7776 7777 7778 7779 7780 7781 7782 7783 7784 7785 7786 7787
7788 7789 7790 7791 7792 7793 7794 7795 7796 7797 7798 7799 7800 7801 7802 7803
7804 7805 7806 7807 7808 7809 7810 7811 7812 7813 7814 7815 7816 7817 7818 7819
7820 7821 7822 7823 7824 7825 7826 7827 7828 7829 7830 7831 7832 7833 7834 7835
7836 7837 7838 7839 7840 7841 7842 7843 7844 7845 7846 7847 7848 7849 7850 7851
7852 7853 7854 7855 7856 7857 7858 7859 7860 7861 7862 7863 7864 7865 7866 7867
7868 7869 7870 7871 7872 7873 7874 7875 7876 7877 7878 7879 7880 7881 7882 7883
7884 7885 7886 7887 7888 7889 7890 7891 7892 7893 7894 7895 7896 7897 7898 7899
7900 7901 7902 7903 7904 7905 7906 7907 7908 7909 7910 7911 7912 7913 7914 7915
7916 7917 7918 7919 7920 7921 7922 7923 7924 7925 7926 7927 7928 7929 7930 7931
7932 7933 7934 7935 7936 7937 7938 7939 7940 7941 7942 7943 7944 7945 7946 7947
7948 7949 7950 7951 7952 7953 7954 7955 7956 7957 7958 7959 7960 7961 7962 7963
7964 7965 7966 7967 7968 7969 7970 7971 7972 7973 7974 7975 7976 7977 7978 7979
7980 7981 7982 7983 7984 7985 7986 7987 7988 7989 7990 7991 7992 7993 7994 7995
7996 7997 7998 7999 8000

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__________________
LAB 05 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `dirops.c'
====================
A
~
Examine the source code of `dirops.c' closely. It makes use of a
variety of system calls to produce a semi-interesting effect. Compile
and run it several times. Describe the overall intent of the program
based on its output and the code you understand.
It lists the files in the current directory, their files sizes, determines the
largest file in the directory, and then copies that to a new file
"<filename>.copy". An observation I made was that the directories . and .. are
fixed at 4096 bytes.
B ~
What set of system calls is used by the program to determine all the
files in the current directory? Describe briefly how these calls work
together.
readdir returns the next entry in the directory listing.
C
~
Identify the system call that `dirops.c' uses to find the sizes of
files. Describe briefly how this call works.
This line: stat(file->d_name, &sb); retrieves information from the operating
system about how the file is stored on the disk, including inode numbers,
ownership, file size, and so on.
D
~
The following line sets up the read/write permissions that the copied
file will have.
,----
| mode_t perms = S_IRUSR | S_IWUSR;
`----
Modify this line so that the copied file is readable by the group as
well as the user.
/Optional challenge:/ Set the permissions to be identical to the
original file. `stat()' is one way to find out the permissions for the
original file.
I found the list of user permissions in the 'stat' manpage: S_IRGRP. The
modified line looks like:
mode_t perms = S_IRUSR | S_IWUSR | S_IRGRP;
In order to find out what the original permissions were, another stat call must
be performed on the file with the largest size. Ideally, this should be done by
file descriptor, but since we are traversing the directory, it's impractical to
keep all the file descriptors open until we identify the largest file. Here's
how I would do it:
struct stat s;
stat(max_name, &s);
mode_t perms = s.st_mode;
E
~
`dirops.c' contains a subtle bug in the following bit of code towards
the end of the file.
,----
| while( (nbytes = read(infd, buf, BUFSIZE)) > 0){
| write(outfd, buf, BUFSIZE);
| }
`----
You should observe that every time program is run, it will identify a
copied file as the largest and make another copy due to this bug. It
may help to examine the ends of the copied files with the `tail
file.txt.copy' command which will show the last 10 lines.
Explain what is wrong with the loop and paste a fixed version below.
The problem is that the buffer is full before the final loop, which may be less
than BUFSIZE bytes, but the write command is still writing BUFSIZE bytes. Sicne
there's no mechanism to automatically clear out the remaining bytes, they get
written to the file as well. The solution is to only write the number of bytes
that have been read, since it was stored anyways but not used.
44 while ((nbytes = read(infd, buf, BUFSIZE)) > 0) {
45 write(outfd, buf, nbytes);
46 }

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#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/sysmacros.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#define NAMELEN 2048
#define BUFSIZE 1024
int main(int argc, char *argv[]) {
long long max_size = 0;
char max_name[NAMELEN] = {};
DIR *dir = opendir(".");
struct dirent *file = NULL;
while( (file = readdir(dir)) != NULL){
struct stat sb;
stat(file->d_name, &sb);
printf("%-30s : %lld bytes\n",
file->d_name, (long long) sb.st_size);
if(sb.st_size > max_size){
max_size = sb.st_size;
strncpy(max_name, file->d_name, NAMELEN);
}
}
closedir(dir);
printf("Largest file: %s with %lld bytes\n",
max_name, max_size);
char copy_name[NAMELEN];
snprintf(copy_name, NAMELEN, "%s.copy", max_name);
printf("Copying %s to %s\n",max_name,copy_name);
char buf[BUFSIZE];
int infd = open(max_name, O_RDONLY);
int flags = O_WRONLY | O_CREAT | O_TRUNC;
mode_t perms = S_IRUSR | S_IWUSR;
int outfd = open(copy_name, flags, perms);
int nbytes;
while( (nbytes = read(infd, buf, BUFSIZE)) > 0){
write(outfd, buf, BUFSIZE);
}
printf("Copy complete\n");
close(infd);
close(outfd);
return 0;
}

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#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#define NAMELEN 2048
#define BUFSIZE 1024
int main(int argc, char *argv[]) {
long long max_size = 0;
char max_name[NAMELEN] = {};
DIR *dir = opendir(".");
struct dirent *file = NULL;
while ((file = readdir(dir)) != NULL) {
struct stat sb;
stat(file->d_name, &sb);
printf("%-30s : %lld bytes\n", file->d_name, (long long)sb.st_size);
if (sb.st_size > max_size) {
max_size = sb.st_size;
strncpy(max_name, file->d_name, NAMELEN);
}
}
closedir(dir);
printf("Largest file: %s with %lld bytes\n", max_name, max_size);
char copy_name[NAMELEN];
snprintf(copy_name, NAMELEN, "%s.copy", max_name);
printf("Copying %s to %s\n", max_name, copy_name);
char buf[BUFSIZE];
int infd = open(max_name, O_RDONLY);
int flags = O_WRONLY | O_CREAT | O_TRUNC;
mode_t perms = S_IRUSR | S_IWUSR;
int outfd = open(copy_name, flags, perms);
int nbytes;
while ((nbytes = read(infd, buf, BUFSIZE)) > 0) {
write(outfd, buf, nbytes);
}
printf("Copy complete\n");
close(infd);
close(outfd);
return 0;
}

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_________________
LAB 06 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `birth_death.c'
=========================
A
~
Compile `circle_of_life.c' to the program `circle_of_life' and run
it. Examine the results and feel free to terminate execution
early. Examine the source code if desired though it is merely a
print/sleep loop.
Compile `birth_death.c' to the program `birth_death'. This program is
invoked with two arguments, another program name and a "lifetime"
which is an integer number of seconds. Run it like
,----
| $> ./birth_death ./circle_of_life 4
`----
and show the output below.
Nants ingonyama bagithi baba
Sithi uhm ingonyama
Nants ingonyama bagithi baba
Sithi uhm ingonyama
kill result: 0
child process 13697 terminated with signal 2
B
~
Examine the source code for `birth_death.c' and determine the system
call the parent program (`birth_death') uses to send signals to the
child program. Paste this line below and explain which signal is being
sent.
int result = kill(pid,SIGINT)
This line invokes the kill system call and tells the child to kill itself.
C
~
`birth_death.c' waits for a child to finish then outputs what signal
caused it to be terminated if that was the cause of death. Paste the
lines of code which determine if a child was terminated due to a
signal below and mention the macros used for this purpose.
32 if(WIFSIGNALED(status)){ // check if a signal ended the child
33 printf("child process %d terminated with signal %d\n",
34 pid,WTERMSIG(status));
35 }
Macros used were WIFSIGNALED to check if the child was terminated by a signal,
and WTERMSIG which retruns the actual signal.
D
~
Compile the program `no_interruptions.c' and run it with
`birth_death'. Show your results below.
Note that you may need to send signals to `no_interruptions' to
forcibly end it. The `pkill' command is useful for this as in
,----
| pkill no_inter # send TERM signal to proc name matching "no_inter"
| pkill -KILL no_inter # send KILL signal to proc name matching "no_inter"
`----
Ma-na na-na!
Ma-na na-na!
Ma-na na-na!
Ma-na na-na!
kill result: 0
No SIGINT-erruptions allowed.
Ma-na na-na!
Ma-na na-na!
Ma-na na-na!
Ma-na na-na!
Try to SIGTERM me? Piss off!
Ma-na na-na!
Ma-na na-na!
Ma-na na-na!
E
~
Examine the `no_interruptions.c' code and describe how it is able to
avoid being killed when receiving the interrupt and TERM signals. Show
the lines of code used to accomplish this signal handling.
It uses signal handlers to catch the signals and handle them by not terminating
itself, contrary to what the signal is telling it to do. The only signal it
can't avoid is SIGKILL (and SIGSTOP but not used here) which forcefully
terminates it.
28 // Set handling functions for programs
29 signal(SIGINT, handle_SIGINT);
30 signal(SIGTERM, handle_SIGTERM);
PROBLEM 2 `start_stop.c'
========================
A
~
Compile `start_stop.c' to the program `start_stop'. This program is
invoked identically to `birth_death' with two arguments, another
program name and an "interval" which is an integer number of
seconds. Run it like
,----
| $> ./start_stop ./circle_of_life 3
`----
and show the output below. You may terminate the program early once
you see the pattern.
Nants ingonyama bagithi baba
Sithi uhm ingonyama
Nants ingonyama bagithi baba
SIGSTOP result: 0
SIGCONT result: 0
Sithi uhm ingonyama
Ingonyama
Siyo Nqoba
SIGSTOP result: 0
SIGCONT result: 0
Ingonyama Ingonyama nengw' enamabala
From the day we arrive on the planet
And blinking, step into the Sun
B
~
Describe at a high level the effect that `start_stop' has on a child
process it runs
start_stop pauses and resumes the execution of the child process periodically
(more precisely, based on the interval passed through the next argument), so in
this case, it would let the child run for 3 seconds, then pause for 3 seconds,
and then resume the loop until the child finished executing.
C
~
Examine the source code of `start_stop.c' and determine the types of
signals it uses to alter behavior of its child process and paste the
corresponding lines of code below.
It uses the SIGSTOP signall with kill(), which stops the program that's
executing but its behavior is more like pause. It resumes execution with SIGCONT
afterwards. The relevant lines of code are:
25 result = kill(pid,SIGSTOP);
28 result = kill(pid,SIGCONT);
D
~
The program `no_interruptions.c' establishes signal handlers for some
signals allowing it to ignore signals that would normally terminate a
process. Investigate whether it is possible to similarly ignore the
signal used by `start_stop' to pause its child process. Hint: Consider
the provided program `cant_catch_sigstop.c' and run it with
`start_stop'.
According to the manpage for SIGNAL(2), SIGSTOP cannot be caught by the program:
The signals SIGKILL and SIGSTOP cannot be caught or ignored.
As expected, the output of cant_catch_sigstop is:
I'm awake, I'm awake!
I'm awake, I'm awake!
SIGSTOP result: 0
SIGCONT result: 0
I'm awake, I'm awake!
I'm awake, I'm awake!
and the signal has not been caught.

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#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
int main(int argc, char *argv[]){
if(argc < 3){
printf("usage: %s <program> <int>\n",argv[0]);
exit(0);
}
char *child_prog = argv[1]; // program to run as a child
int lifetime = atoi(argv[2]); // time to wait to end child
int pid = fork(); // fork execution
if(pid == 0){ // CHILD
execlp(child_prog, child_prog, NULL); // execute specified program
}
int status, ret; // PARENT
while(1){ // Loop until child done
sleep(lifetime); // sleep for given "lifetime" of child
ret = waitpid(pid, &status, WNOHANG); // check on child
if(ret == pid){ // if child is finished
break; // break from loop
}
int result = kill(pid,SIGINT); // send a interrupt signal to child
printf("kill result: %d\n",result); // check on delivery
}
if(WIFSIGNALED(status)){ // check if a signal ended the child
printf("child process %d terminated with signal %d\n",
pid,WTERMSIG(status));
}
exit(0);
}

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// A C program that does not terminate from an interrupt signal.
// Usually pressing Ctrl-C sends this to the foreground program.
//
// To stop this program from running, open another terminal and try
// > pkill -9 a.out
// assuming you named the output program a.out
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
// Function run when a SIGINT is sent to the program
void handle_SIGSTOP(int sig_num) {
// Reset handler to catch SIGINT next time.
signal(SIGSTOP, handle_SIGSTOP);
printf("\nThere's no SIGSTOPping me!\n");
fflush(stdout);
}
int main() {
// Set handling functions for programs
signal(SIGSTOP, handle_SIGSTOP);
/* Infinite loop */
while (1) {
sleep(1);
printf("I'm awake, I'm awake!\n");
fflush(stdout);
}
return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
// https://genius.com/Walt-disney-records-circle-of-life-lyrics
char *lyrics[] = {
"Nants ingonyama bagithi baba",
"Sithi uhm ingonyama",
"Nants ingonyama bagithi baba",
"Sithi uhm ingonyama",
"Ingonyama",
"Siyo Nqoba",
"Ingonyama Ingonyama nengw' enamabala ",
"From the day we arrive on the planet",
"And blinking, step into the Sun",
"There's more to be seen than can ever be seen",
"More to do than can ever be done",
"Some say eat or be eaten",
"Some say live and let live",
"But all are agreed as they join the stampede",
"You should never take more than you give",
"In the circle of life",
"It's the wheel of fortune",
"It's the leap of faith",
"It's the band of hope",
"Till we find our place",
"On the path unwinding",
"In the circle, the circle of life",
"Some of us fall by the wayside",
"And some of us soar to the stars",
"And some of us sail through our troubles",
"And some have to live with the scars",
"There's far too much to take in here",
"More to find than can ever be found",
"But the Sun rolling high through the sapphire sky",
"Keeps great and small on the endless round",
NULL
};
int main(){
int index = 0;
while(lyrics[index] != NULL){
printf("%s\n",lyrics[index]);
fflush(stdout);
index++;
sleep(1);
}
exit(0);
}

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// A C program that does not terminate from an interrupt signal.
// Usually pressing Ctrl-C sends this to the foreground program.
//
// To stop this program from running, open another terminal and try
// > pkill -9 a.out
// assuming you named the output program a.out
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
// Function run when a SIGINT is sent to the program
void handle_SIGINT(int sig_num) {
// Reset handler to catch SIGINT next time.
signal(SIGINT, handle_SIGINT);
printf("\nNo SIGINT-erruptions allowed.\n");
fflush(stdout);
}
// Function run when a SIGTERM is sent to the program
void handle_SIGTERM(int sig_num) {
// Reset handler to catch SIGTERM next time.
signal(SIGTERM, handle_SIGTERM);
printf("\nTry to SIGTERM me? Piss off!\n");
fflush(stdout);
}
int main () {
// Set handling functions for programs
signal(SIGINT, handle_SIGINT);
signal(SIGTERM, handle_SIGTERM);
/* Infinite loop */
while(1) {
sleep(1);
printf("Ma-na na-na!\n");
fflush(stdout);
}
return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
int main(int argc, char *argv[]){
if(argc < 3){
printf("usage: %s <program> <int>\n",argv[0]);
exit(0);
}
char *child_prog = argv[1]; // program to run as a child
int interval = atoi(argv[2]); // time to allow child to run
int pid = fork(); // fork execution
if(pid == 0){ // CHILD
execlp(child_prog, child_prog, NULL); // execute specified program
}
int status, ret; // PARENT
while(1){ // Loop until child done
int result;
sleep(interval); // interval to allow child to run
result = kill(pid,SIGSTOP); // send a stop signal to child
printf("SIGSTOP result: %d\n",result); // check on delivery
sleep(interval); // interval to allow child to run
result = kill(pid,SIGCONT); // send a continue signal to child
printf("SIGCONT result: %d\n",result); // check on delivery
ret = waitpid(pid, &status, WNOHANG); // check on child
if(ret == pid){ // if child is finished
break; // break from loop
}
}
if(WIFSIGNALED(status)){ // check if a signal ended the child
printf("child process %d terminated with signal %d\n",
pid,WTERMSIG(status));
}
exit(0);
}

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all : sleep_print select_AB read_AB
sleep_print : sleep_print.c
gcc -o $@ $^
select_AB : select_AB.c
gcc -o $@ $^
read_AB : read_AB.c
gcc -o $@ $^
select_AB_children_alive : select_AB_children_alive.c
gcc -o $@ $^
clean :
rm -f sleep_print select_AB read_AB

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__________________
LAB 07 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `sleep_print.c'
=========================
A
~
Compile `sleep_print.c' using the provided `Makefile' which compiles
it to `sleep_print'. Run the program as
,----
| ./sleep_print 1 "hello"
`----
After a few seconds, press Ctrl-C to send an interrupt signal. Paste
the results of your run below.
1 : hello 2 : hello 3 : hello 4 : hello 5 : hello 6 : hello 7 : hello ^Csleep_print: signaled, setting flag
8 : hello sleep_print: finishing
B
~
Examine the code for `sleep_print.c' and note the use of the
`sigaction()' function to set up signal handlers. Inspect the signal
handler function and describe how the signal handler causes the
`sleep_print' to shut down in the space below.
The signal handler changes a global variable that the while loop is using to
determine whether or not to continue. When the signal handler is called, the
value is changed so the loop stops.
PROBLEM 2 `read_AB.c'
=====================
Note that `read_AB.c' uses the same techniques as `sleep_print.c' to
set up signal handlers and shut down on receiving a signal.
A
~
Compile `read_AB.c' and run it. Paste the results of running it for a
few seconds below. Use Ctl-C to send an interrupt to end the program.
read_AB: listening for children
A had: | 1 : AAAA |
B had: | 1 : BBBB |
A had: | 2 : AAAA |
B had: | 2 : BBBB |
A had: | 3 : AAAA 4 : AAAA 5 : AAAA |
B had: | 3 : BBBB |
A had: | 6 : AAAA 7 : AAAA 8 : AAAA |
^Csleep_print: signaled, setting flag
sleep_print: signaled, setting flag
read_AB: signaled, setting flag
B had: | 4 : BBBB |
read_AB: finishing
sleep_print: signaled, setting flag
sleep_print: signaled, setting flag
sleep_print: finishing
sleep_print: finishing
B
~
Examine the code for `read_AB.c' and note where `pipe(), fork(),
dup2()' are used to set up a communication channel for two children
referred to as A and B. Note that these two children both run
`sleep_print' but A has a 1 second delay while B has a 3 second delay.
Note the main `while()' of `read_AB' which repeatedly reads from the
pipes of its children.
In the space below explain why the output for the program has the
ordering that it does despite A producing A at a faster rate (every 1
second) than B (every 3 seconds).
In the 3 second delay that it took B to print out its second output, A had
already printed out 3 more lines, and they were all loaded up in the pipe ready
to be read. That's why the next line for A had 3 outputs.
C
~
In the output for `read_AB' there should be some lines for Child A
that look like
,----
| A had: | 1 : AAAA |
`----
but also some lines that look like
,----
| A had: | 4 : AAAA 5 : AAAA |
`----
and
,----
| A had: |15 : AAAA 16 : AAAA 17 : AAAA |
`----
while Child B lines always look like
,----
| B had: | 4 : BBBB |
`----
Explain why there is variance in Child A lines while Child B lines
look the same.
For child A, it really depends on exactly when it started relative to when B
started. For example,
A: | | | |
B: | |
may only show 2 counters worth of AAAAs while
A: | | | |
B: | |
will show 3counters worth of AAAAs. In the first case, it really just comes down
to the scheduler and the order in which these processes are executed.
PROBLEM 3 `select_AB.c'
=======================
Note that `select_AB.c' uses the same techniques as `sleep_print.c' to
set up signal handlers and shut down on receiving a signal.
A
~
Compile `select_AB.c' and run it. Paste the results of running it for
a few seconds below. Use Ctl-C to send an interrupt to end the
program.
select_AB: listening for children
A had: | 1 : AAAA |
A had: | 2 : AAAA |
B had: | 1 : BBBB |
A had: | 3 : AAAA |
A had: | 4 : AAAA |
A had: | 5 : AAAA |
B had: | 2 : BBBB |
A had: | 6 : AAAA |
A had: | 7 : AAAA |
A had: | 8 : AAAA |
B had: | 3 : BBBB |
A had: | 9 : AAAA |
A had: |10 : AAAA |
^Csleep_print: signaled, setting flag
sleep_print: signaled, setting flag
select_AB: signaled, setting flag
sleep_print: finishing
sleep_print: finishing
B had: | 4 : BBBB |
select_AB: finishing
B
~
Examine the code for `select_AB.c'. Like `read_AB', it uses `pipe(),
fork(), dup2()' to set up a communication channel for two children, A
and B, which run `sleep_print' at differing rates. However, the main
`while()' of `select_AB' uses the `select()' system call to sleep
until output is available from a child.
In the space below explain why the output for the `select_AB' has the
ordering that it does and why it differs from `read_AB'.
The select() system call "allow a program to monitor multiple file descriptors,
waiting until one or more of the file descriptors become 'ready' for some class
of I/O operation," according to the man page. This means that the parent process
is actually able to monitor both pipes and select whichever one has output
first. Then it prints that directly to the screen. That's why A's output never
get loaded up multiple times in the buffer and B's still prints once every 3 of
A's prints, unlike read_AB, which reads A and B in a fixed order, so if A is
ready to print again before B has even gotten a chance to print, it will just
sit in the queue on top of the previous one.
C
~
The output for `read_AB' contained mixed lengths for child A output as
in
,----
| A had: | 1 : AAAA |
| A had: | 4 : AAAA 5 : AAAA |
| A had: |15 : AAAA 16 : AAAA 17 : AAAA |
`----
Explain why the output for `select_AB' does not have such differences.
Since select_AB monitors the pipes, it will print immediately after the pipe
that A used has something to write. If I recall correctly, this is what's used
in many IRC servers to handle inputs coming in from multiple clients.

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// Start two child processes which run sleep_print with differing
// delays and messages. Their output is redirected through pipes
// readable by the parent. The main loop alternates reading from each
// child in turn. Handle interrupt and terminate signals gracefully
// by setting a flag to shut down.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#define PREAD 0 // read and write ends of pipes
#define PWRITE 1
int signaled = 0; // global variable controls exit from main loop
void handle_signals(int signo){ // handler for some signals
char *msg = "read_AB: signaled, setting flag\n"; // print a message about the signal
write(STDERR_FILENO,msg,strlen(msg)); // avoid fprintf() as it is not reentrant
signaled = 1; // set global variable to indicate signal received
return;
}
int make_child(int pip[], char *delay, char *msg){ // Create a child which runs sleep_print
pipe(pip);
int pid = fork();
if(pid != 0){ // PARENT
return pid; // just return child pid
}
dup2(pip[PWRITE], STDOUT_FILENO); // CHILD: redirect standard out to pipe
execlp("./sleep_print","./sleep_print",delay,msg,NULL); // should not return
perror("exec failed");
exit(1);
}
int main() {
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigemptyset(&my_sa.sa_mask); // don't block any other signals during handling
my_sa.sa_flags = SA_RESTART; // always restart system calls on signals possible
sigaction(SIGTERM, &my_sa, NULL); // register SIGTERM with given action
sigaction(SIGINT, &my_sa, NULL); // register SIGINT with given action
int pipeA[2], pipeB[2]; // pipes for children to speak to parent
int pidA = make_child(pipeA, "1", "AAAA"); // create two children with different
int pidB = make_child(pipeB, "3", "BBBB"); // messages and delays between prints
close(pipeA[PWRITE]); // Parent doesn't use the write ends
close(pipeB[PWRITE]);
printf("read_AB: listening for children\n");
while(!signaled){ // enter a loop to listen until signaled or children die
char buf[1024];
int n;
n = read(pipeA[PREAD], buf, 1024); // read from pipeA
buf[n] = '\0';
fprintf(stdout,"A had: |%s|\n",buf);
n = read(pipeB[PREAD], buf, 1024); // read from pipeB
buf[n] = '\0';
fprintf(stdout,"B had: |%s|\n",buf);
}
kill(pidA, SIGTERM); // keyboard interrupt will signal children but a
kill(pidB, SIGTERM); // 'kill read_AB' will not, so always signal them here
fprintf(stderr,"read_AB: finishing\n");
exit(0);
}

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// Start two child processes which run sleep_print with differing
// delays and messages. Their output is redirected through pipes
// readable by the parent. Use select() to grab input from either
// pipe as it becomes available. Handle interrupt and terminate
// signals gracefully by setting a flag to shut down.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#define PREAD 0 // read and write ends of pipes
#define PWRITE 1
int signaled = 0; // global variable controls exit from main loop
void handle_signals(int signo){ // handler for some signals
char *msg = "select_AB: signaled, setting flag\n"; // print a message about the signal
write(STDERR_FILENO,msg,strlen(msg)); // avoid fprintf() as it is not reentrant
signaled = 1; // set global variable to indicate signal received
return;
}
int make_child(int pip[], char *delay, char *msg){ // Create a child which runs sleep_print
pipe(pip);
int pid = fork();
if(pid != 0){ // PARENT
return pid; // just return child pid
}
dup2(pip[PWRITE], STDOUT_FILENO); // CHILD: redirect standard out to pipe
execlp("./sleep_print","./sleep_print",delay,msg,NULL); // should not return
perror("exec failed");
exit(1);
}
int main() {
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigemptyset(&my_sa.sa_mask); // don't block any other signals during handling
my_sa.sa_flags = SA_RESTART; // always restart system calls on signals possible
sigaction(SIGTERM, &my_sa, NULL); // register SIGTERM with given action
sigaction(SIGINT, &my_sa, NULL); // register SIGINT with given action
int pipeA[2], pipeB[2]; // pipes for children to speak to parent
int pidA = make_child(pipeA, "1", "AAAA"); // create two children with different
int pidB = make_child(pipeB, "3", "BBBB"); // messages and delays between prints
close(pipeA[PWRITE]); // Parent doesn't use the write ends
close(pipeB[PWRITE]);
printf("select_AB: listening for children\n");
while(!signaled){ // enter a loop to listen until signaled or children die
fd_set read_set; // set of file descriptors for select()
FD_ZERO(&read_set); // init the set
FD_SET(pipeA[PREAD], &read_set); // set fds to contain read ends of pipe
FD_SET(pipeB[PREAD], &read_set);
int maxfd = pipeA[PREAD]; // need maximum fd for select()
maxfd = (maxfd < pipeB[PREAD]) ? pipeB[PREAD] : maxfd;
select(maxfd+1, &read_set, NULL, NULL, NULL); // sleep, wake up if any pipe ready for reading
char buf[1024];
int n;
if(FD_ISSET(pipeA[PREAD], &read_set)){ // check if pipeA has anything
n = read(pipeA[PREAD], buf, 1024); // read from pipe
buf[n] = '\0';
fprintf(stdout,"A had: |%s|\n",buf);
}
if(FD_ISSET(pipeB[PREAD], &read_set)){ // check if pipeB has anything
n = read(pipeB[PREAD], buf, 1024); // read from pipe
buf[n] = '\0';
fprintf(stdout,"B had: |%s|\n",buf);
}
}
kill(pidA, SIGTERM); // keyboard interrupt will signal children but a
kill(pidB, SIGTERM); // 'kill select_AB' will not, so always signal them here
fprintf(stderr,"select_AB: finishing\n");
exit(0);
}

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// In an infinite loop, sleep for an interval and then print a
// message. Catch interrupt and terminate signals and cause the loop
// program to end by adjusting a global flag.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
int signaled = 0; // global variable controls exit from main loop
void handle_signals(int signo){ // handler for some signals
char *msg = "sleep_print: signaled, setting flag\n"; // print a message about the signal
write(STDERR_FILENO,msg,strlen(msg)); // avoid fprintf() as it is not reentrant
signaled = 1; // set global variable to indicate signal received
return;
}
int main(int argc, char *argv[]){
if(argc < 3){
printf("usage: %s <delay> <message>\n", argv[0]);
exit(1);
}
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigemptyset(&my_sa.sa_mask); // don't block any other signals during handling
my_sa.sa_flags = SA_RESTART; // always restart system calls on signals possible
sigaction(SIGTERM, &my_sa, NULL); // register SIGTERM with given action
sigaction(SIGINT, &my_sa, NULL); // register SIGINT with given action
int delay = atoi(argv[1]); // sleep delay
char *message = argv[2]; // message to print
int count=1;
while(!signaled){
sleep(delay);
printf("%2d : %s ",count,message);
fflush(stdout);
count++;
}
fprintf(stderr,"sleep_print: finishing\n"); // print to stderr in case stdout is going to a pipe
return 0;
}

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CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
all : em_server em_client
em_server : em_server.c
$(CC) -o $@ $^
em_client : em_client.c
$(CC) -o $@ $^
clean :
rm -f em_server em_client *.fifo

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__________________
LAB 08 QUESTIONS
__________________
- Name: (FILL THIS in)
- NetID: (THE kauf0095 IN kauf0095@umn.edu)
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `server_em.c'
=======================
A
~
Examine the source code for `em_server.c'. Note of the 3 FIFOs that
are used: Requests, Completions, and Data. Describe what appears to
be the purpose of each from the server perspective.
B
~
What mechanism is used to notify clients that their request has been
filled and that data is ready on the Data FIFO?
C
~
How many clients have information on each of the FIFOs:
- On the Request FIFO?
- On the Completion FIFO?
- On the Data FIFO?
PROBLEM 2 `client_em.c'
=======================
Note that `read_AB.c' uses the same techniques as `sleep_print.c' to
set up signal handlers and shut down on receiving a signal.
A
~
Examine the `while()' loop in the client. When waiting for the server
to respond, does the client make use of busy waiting (polling),
interrupt-driven waiting, or something in between?
B
~
Experiment with changing the while() loop associated with server
responses. Time running 100 transactions using the provided
`run_simulations.sh' script as in
,----
| $> time run_simulation.sh 100 > xxx
`----
Note the timing. You may need to discuss with your TA how to interpret
the results of the shell `time' command which measures CPU utilization
for programs.
Comment out the `while()' loop associated with waiting and un-comment
the other `while()' loop. Re-run the above script invocation and
report the differences in timing.
PROBLEM 3 Protocol
==================
A
~
Describe the overall protocol used by the client and server to
communicate. Use the labels in the messages like `C SERVER' and `B
CLIENT' to help you organize the order what happens when and things
can happen in an unpredictable order.
B
~
In an initial version of the programs, the client used the following
line to wait for a server response.
,----
| raise(SIGSTOP);
`----
The `raise()' command sends a signal to the running process so that
the effect of this line is to stop the current process until a signal
to continue is received. This approach was found to fail in many
cases causing the entire system to stall.
Based on your understanding of the protocol above, WHY could simply
stopping the client process result a breakdown?
You may wish to uncomment and try this version in the code.

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// Client code to look up an email based on name
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
// structure to store a lookup_t. client fills in with name, server
// fills in email if found in
typedef struct {
int pid;
char name[256];
char email[256];
} lookup_t;
int signalled = 0;
void handle_signals(int sig_num){
signalled = 1;
}
int main(int argc, char *argv[]){
setvbuf(stdout, NULL, _IONBF, 0);
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigaction(SIGCONT, &my_sa, NULL); // register SIGCONT with given action
if(argc < 2){
printf("usage: %s <name>\n",argv[0]);
exit(1);
}
lookup_t request = {};
request.pid = getpid();
strcpy(request.name, argv[1]);
int requests_fd = open("requests.fifo", O_RDWR); // open read/write in case server hasn't started
int completions_fd = open("completions.fifo", O_RDWR); // open read or write only may cause hangs if the
int data_fd = open("data.fifo", O_RDWR); // other end of the pipe has not be openened
printf("%d A CLIENT: sending request: {pid=%d name=\"%s\" }\n",
request.pid, request.pid, request.name);
write(requests_fd, &request, sizeof(lookup_t));
printf("%d B CLIENT: pid %d stopping\n",request.pid,request.pid);
while(!signalled){
sleep(1); // sleep for 1 second, wake up on on signal
}
// while(!signalled); // poll for busy waiting
// raise(SIGSTOP); // buggy waiting
// if(!signalled){ // also buggy but much harder to hit a stall
// raise(SIGSTOP); // try 'run_simulation.sh 3000' if you have some time
// }
printf("%d B CLIENT: pid %d signalled to continue\n",request.pid,request.pid);
lookup_t response;
read(data_fd, &response, sizeof(lookup_t));
printf("%d C CLIENT: received response: {pid=%d name=\"%s\" email=\"%s\"}\n",
response.pid, response.pid, response.name, response.email);
if(request.pid != response.pid){
printf("CLIENT PROBLEM: PID %d vs %d\n", request.pid, response.pid);
exit(1);
}
int pid = getpid();
write(completions_fd, &pid, sizeof(int));
printf("%d D CLIENT: pid %d indicating completion\n",request.pid,request.pid);
// printf("CLIENT: result: %s\n",response.email);
exit(0);
}

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// Server code which contains a name/email pairs and will fulfill
// requests from a client through FIFOs.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
// data the server has and clients want: pairings of name and email
char *data[][2] = {
{"Chris Kauffman" ,"kauffman@umn.edu"},
{"Christopher Jonathan" ,"jonat003@umn.edu"},
{"Amy Larson" ,"larson@cs.umn.edu"},
{"Chris Dovolis" ,"dovolis@cs.umn.edu"},
{"Dan Knights" ,"knights@cs.umn.edu"},
{"George Karypis" ,"karypis@cs.umn.edu"},
{"Steven Jensen" ,"sjensen@cs.umn.edu"},
{"Daniel Keefe" ,"dfk@umn.edu"},
{"Michael W. Whalen" ,"whalen@cs.umn.edu"},
{"Catherine Qi Zhao" ,"qzhao@umn.edu"},
{"Dan Challou" ,"challou@cs.umn.edu"},
{"Steven Wu" ,"zsw@umn.edu"},
{"Michael Steinbach" ,"steinbac@cs.umn.edu"},
{"Jon Weissman" ,"jon@cs.umn.edu"},
{"Victoria Interrante" ,"interran@cs.umn.edu"},
{"Shana Watters" ,"watt0087@umn.edu"},
{"James Parker" ,"jparker@cs.umn.edu"},
{"James Moen" ,"moen0017@cs.umn.edu"},
{"Daniel Giesel" ,"giese138@umn.edu"},
{"Jon Read" ,"readx028@umn.edu"},
{"Sara Stokowski" ,"stoko004@umn.edu"},
{NULL , NULL},
};
// structure to store a lookup_t. client fills in with name, server
// fills in email if found in
typedef struct {
int pid;
char name[256];
char email[256];
} lookup_t;
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
printf("starting server\n");
remove("requests.fifo");
remove("completions.fifo");
remove("data.fifo");
printf("SERVER: removed old fifos\n");
mkfifo("requests.fifo", S_IRUSR | S_IWUSR);
mkfifo("completions.fifo", S_IRUSR | S_IWUSR);
mkfifo("data.fifo", S_IRUSR | S_IWUSR);
printf("SERVER: created new fifos\n");
int requests_fd = open("requests.fifo", O_RDWR); // open read/write in case server hasn't started
int completions_fd = open("completions.fifo", O_RDWR); // open read or write only may cause hangs if the
int data_fd = open("data.fifo", O_RDWR); // other end of the pipe has not be openened
printf("SERVER: opened FIFOs, listening\n");
while(1){
lookup_t request;
read(requests_fd, &request, sizeof(lookup_t));
printf("%d B SERVER: received request {pid=%d name=\"%s\" }\n",
request.pid, request.pid, request.name);
char *name = request.name;
int found = 0;
for(int i=0; data[i][0] != NULL; i++){
if(strcmp(name, data[i][0]) == 0){
strcpy(request.email, data[i][1]);
found = 1;
}
}
if(!found){
strcpy(request.email, "NOT FOUND");
}
printf("%d B SERVER: filling request {pid=%d name=\"%s\" email=\"%s\" }\n",
request.pid,request.pid, request.name, request.email);
write(data_fd, &request, sizeof(request));
printf("%d B SERVER: signaling pid %d\n",
request.pid, request.pid);
kill(request.pid, SIGCONT);
int done_pid = -1;
read(completions_fd, &done_pid, sizeof(int));
printf("%d E SERVER: %d completion\n",done_pid,done_pid);
if(request.pid != done_pid){
printf("Server Problems: PID %d vs %d",
request.pid, done_pid);
}
}
exit(0);
}

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#!/bin/bash
#
# usage: run_smulations.sh 20
#
# Start an em_server then run multiple simultaneous em_clients
# connecting to find various emails. Accepts a command line argument
# which is the number of clients to run.
nclients=10
if (( $# >= 1 )); then
nclients=$1
fi
names=(
"Chris Kauffman"
"Christopher Jonathan"
"Amy Larson"
"Chris Dovolis"
"Dan Knights"
"George Karypis"
"Steven Jensen"
"Daniel Keefe"
"Michael W. Whalen"
"Catherine Qi Zhao"
"Dan Challou"
"Steven Wu"
"Michael Steinbach"
"Jon Weissman"
"Victoria Interrante"
"Shana Watters"
"James Parker"
"James Moen"
"Daniel Giesel"
"Jon Read"
"Sara Stokowski"
)
len=${#names[*]}
# kill em_server
./em_server &
em_server_pid=$!
# start em_clients
pids=()
for i in `seq 0 $nclients`; do
idx=$((i % len))
# echo "${names[idx]}"
./em_client "${names[idx]}" &
pids[i]=$!
done
# echo "${pids[*]}"
# wait for jobs to finish
for pid in ${pids[*]}; do
wait $pid
done
kill $em_server_pid

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CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
all : em_server_mq em_client_mq \
em_server_fifo em_client_fifo
em_server_mq : em_server_mq.c
$(CC) -o $@ $^
em_client_mq : em_client_mq.c
$(CC) -o $@ $^
em_server_fifo : em_server_fifo.c
$(CC) -o $@ $^
em_client_fifo : em_client_fifo.c
$(CC) -o $@ $^
clean :
rm -f em_server_mq em_client_mq \
em_server_fifo em_client_fifo \
*.fifo

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__________________
LAB 09 QUESTIONS
__________________
- Name: Michael Zhang
- NetID: zhan4854
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete Lab01.
PROBLEM 1 `em_server_mq.c' and `em_server_mq.c'
===============================================
A
~
Examine the source code for `em_server_mq.c' and
`em_client_mq.c'. Describe the lines of code which are used to
establish the message queues used for communication. How many message
queues are there?
There's one message queue for the server, and one for the client. These are
created by msgget(key, 0644 | IPC_CREAT) where key was obtained by ftok using
the identity of the party that called it.
B
~
Describe the sending and receiving functions used in the server to put
messages onto the queue. Focus your attention on the server side
first. Describe each argument of the send/receive functions and its
purpose. You may wish to consult the textbook or manual page for the
functions to get more information.
To put a message onto the message queue you would use msgsnd, and send the
object containing the request information that you need.
C
~
Describe the protocol that appears to be used for communication. What
steps are taken by a client to make a request for an email address
lookup? How does the server respond? You may find it useful to use the
letters associated with print statements like "A" and "D". Note any
operations that might happen in an arbitrary order.
The protocol looks like this:
- The client first sends { name = argv[1], mtype = pid }.
- The server msgrcvs this, reads the name and name and mtype from the request
object and looks up the email associated with the name.
- The server then sends back { name = request.name, mtype = request.mtype,
email = the email that was looked up. }
- The email client makes sure that the pid that the mtype returned is the same
as the pid that it requested with.
D
~
Recall that the previous email lookup server/client that used FIFOs
would answer requests on a Data FIFO. The Server would only allow one
Client to access the Data FIFO at a time. This was to prevent the
client from retrieving data from the queue that was not intended for
them.
In the Message Queue server/client, potentially many clients are
accessing the To-Client queue simultaneously. Describe why there is
not a problem in this setting. Look carefully at the arguments used in
the `msgrcv()' call in the client.
This isn't a problem because msgrcv takes in a flag msgtype which in this case
is the pid of the client. This way, msgrcv will only return the messages
intended for the correct client. Of course, this isn't a valid security measure
but it produces the correct result.
E
~
In the FIFO server/client, sleeping and signaling was used to avoid
busily waiting for availability of the data. This complicated the
protocol somewhat in order to get more efficient resource utilization.
There is NO explicit sleeping in the Message Queue server/client which
might indicate it is less efficient as processes busily wait for
messages. Do some research on `msgsnd() / msgrcv()' calls to determine
if they are busy waiting (polling) or interrupt driven operations.
Confirm these answers by running `run_simulations_mq.sh' on a large
number of client and timing the results. A sample run might be
,----
| > time ./run_simulation_mq.sh 1000 > ~/tmp/xxx
`----
According to MSGOP(2), "If insufficient space is available in the queue, then
the default behavior of msgsnd() is to block until space becomes available. If
IPC_NOWAIT is specified in msgflg, then the call instead fails with the error
EAGAIN." This means they will wait for the message queue to become available
(after the other clients have read from it) before it sends.

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// Client code to look up an email based on name
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
// structure to store a lookup_t. client fills in with name, server
// fills in email if found in
typedef struct {
int pid;
char name[256];
char email[256];
} lookup_t;
int signalled = 0;
void handle_signals(int sig_num){
signalled = 1;
}
int main(int argc, char *argv[]){
setvbuf(stdout, NULL, _IONBF, 0);
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigaction(SIGCONT, &my_sa, NULL); // register SIGCONT with given action
if(argc < 2){
printf("usage: %s <name>\n",argv[0]);
exit(1);
}
lookup_t request = {};
request.pid = getpid();
strcpy(request.name, argv[1]);
int requests_fd = open("requests.fifo", O_RDWR); // open read/write in case server hasn't started
int completions_fd = open("completions.fifo", O_RDWR); // open read or write only may cause hangs if the
int data_fd = open("data.fifo", O_RDWR); // other end of the pipe has not be openened
printf("%d A CLIENT: sending request: {pid=%d name=\"%s\" }\n",
request.pid, request.pid, request.name);
write(requests_fd, &request, sizeof(lookup_t));
printf("%d B CLIENT: pid %d stopping\n",request.pid,request.pid);
while(!signalled){
struct timespec tm = {.tv_nsec = 1000};
nanosleep(&tm,NULL); // sleep a short duration
// sleep(1); // sleep for 1 second, wake up on on signal
}
// while(!signalled); // poll for busy waiting
// raise(SIGSTOP); // buggy waiting
// if(!signalled){ // also buggy but much harder to hit a stall
// raise(SIGSTOP); // try 'run_simulation.sh 3000' if you have some time
// }
printf("%d B CLIENT: pid %d signalled to continue\n",request.pid,request.pid);
lookup_t response;
read(data_fd, &response, sizeof(lookup_t));
printf("%d C CLIENT: received response: {pid=%d name=\"%s\" email=\"%s\"}\n",
response.pid, response.pid, response.name, response.email);
if(request.pid != response.pid){
printf("CLIENT PROBLEM: PID %d vs %d\n", request.pid, response.pid);
exit(1);
}
int pid = getpid();
write(completions_fd, &pid, sizeof(int));
printf("%d D CLIENT: pid %d indicating completion\n",request.pid,request.pid);
// printf("CLIENT: result: %s\n",response.email);
exit(0);
}

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// Client code to look up an email based on name; contacts servers via
// System V IPC message queues.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/msg.h>
// structure to store a lookup. client fills in with name, server
// fills in email if found in
typedef struct {
long mtype; // contains PID of sending process
char name[256]; // name desired
char email[256]; // email associated with name
} lookup_t;
int main(int argc, char *argv[]){
setvbuf(stdout, NULL, _IONBF, 0);
if(argc < 2){
printf("usage: %s <name>\n",argv[0]);
exit(1);
}
key_t key;
key = ftok("em_server_mq.c", 0);
int to_server_qid = msgget(key, 0644 | IPC_CREAT);
key = ftok("em_client_mq.c", 0);
int to_clients_qid = msgget(key, 0644 | IPC_CREAT);
int my_pid = getpid();
lookup_t request = {};
request.mtype = my_pid;
strcpy(request.name, argv[1]);
printf("%ld A CLIENT: sending request: {pid=%ld name=\"%s\" }\n",
request.mtype, request.mtype, request.name);
msgsnd(to_server_qid, &request, sizeof(lookup_t), 0);
lookup_t response = {};
msgrcv(to_clients_qid, &response, sizeof(lookup_t), my_pid, 0);
printf("%ld D CLIENT: received response: {pid=%ld name=\"%s\" email=\"%s\"}\n",
response.mtype, response.mtype, response.name, response.email);
if(my_pid != response.mtype){
printf("CLIENT PROBLEM: PID %d vs %ld\n", my_pid, response.mtype);
exit(1);
}
exit(0);
}

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// Server code which contains a name/email pairs and will fulfill
// requests from a client through FIFOs.
#include <errno.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
// data the server has and clients want: pairings of name and email
char *data[][2] = {
{"Chris Kauffman", "kauffman@umn.edu"},
{"Christopher Jonathan", "jonat003@umn.edu"},
{"Amy Larson", "larson@cs.umn.edu"},
{"Chris Dovolis", "dovolis@cs.umn.edu"},
{"Dan Knights", "knights@cs.umn.edu"},
{"George Karypis", "karypis@cs.umn.edu"},
{"Steven Jensen", "sjensen@cs.umn.edu"},
{"Daniel Keefe", "dfk@umn.edu"},
{"Michael W. Whalen", "whalen@cs.umn.edu"},
{"Catherine Qi Zhao", "qzhao@umn.edu"},
{"Dan Challou", "challou@cs.umn.edu"},
{"Steven Wu", "zsw@umn.edu"},
{"Michael Steinbach", "steinbac@cs.umn.edu"},
{"Jon Weissman", "jon@cs.umn.edu"},
{"Victoria Interrante", "interran@cs.umn.edu"},
{"Shana Watters", "watt0087@umn.edu"},
{"James Parker", "jparker@cs.umn.edu"},
{"James Moen", "moen0017@cs.umn.edu"},
{"Daniel Giesel", "giese138@umn.edu"},
{"Jon Read", "readx028@umn.edu"},
{"Sara Stokowski", "stoko004@umn.edu"},
{NULL, NULL},
};
// structure to store a lookup_t. client fills in with name, server
// fills in email if found in
typedef struct {
int pid;
char name[256];
char email[256];
} lookup_t;
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
printf("starting server\n");
remove("requests.fifo");
remove("completions.fifo");
remove("data.fifo");
printf("SERVER: removed old fifos\n");
mkfifo("requests.fifo", S_IRUSR | S_IWUSR);
mkfifo("completions.fifo", S_IRUSR | S_IWUSR);
mkfifo("data.fifo", S_IRUSR | S_IWUSR);
printf("SERVER: created new fifos\n");
int requests_fd = open(
"requests.fifo", O_RDWR); // open read/write in case server hasn't started
int completions_fd =
open("completions.fifo",
O_RDWR); // open read or write only may cause hangs if the
int data_fd =
open("data.fifo", O_RDWR); // other end of the pipe has not be openened
printf("SERVER: opened FIFOs, listening\n");
while (1) {
lookup_t request;
read(requests_fd, &request, sizeof(lookup_t));
printf("%d B SERVER: received request {pid=%d name=\"%s\" }\n",
request.pid, request.pid, request.name);
char *name = request.name;
int found = 0;
for (int i = 0; data[i][0] != NULL; i++) {
if (strcmp(name, data[i][0]) == 0) {
strcpy(request.email, data[i][1]);
found = 1;
}
}
if (!found) {
strcpy(request.email, "NOT FOUND");
}
printf(
"%d B SERVER: filling request {pid=%d name=\"%s\" email=\"%s\" }\n",
request.pid, request.pid, request.name, request.email);
write(data_fd, &request, sizeof(request));
printf("%d B SERVER: signaling pid %d\n", request.pid, request.pid);
kill(request.pid, SIGCONT);
int done_pid = -1;
read(completions_fd, &done_pid, sizeof(int));
printf("%d E SERVER: %d completion\n", done_pid, done_pid);
if (request.pid != done_pid) {
printf("Server Problems: PID %d vs %d", request.pid, done_pid);
}
}
exit(0);
}

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// Server code which contains a name/email pairs and will fulfill
// requests from a client through System V IPC message queues.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <sys/ipc.h>
#include <sys/msg.h>
// data the server has and clients want: pairings of name and email
char *data[][2] = {
{"Chris Kauffman" ,"kauffman@umn.edu"},
{"Christopher Jonathan" ,"jonat003@umn.edu"},
{"Amy Larson" ,"larson@cs.umn.edu"},
{"Chris Dovolis" ,"dovolis@cs.umn.edu"},
{"Dan Knights" ,"knights@cs.umn.edu"},
{"George Karypis" ,"karypis@cs.umn.edu"},
{"Steven Jensen" ,"sjensen@cs.umn.edu"},
{"Daniel Keefe" ,"dfk@umn.edu"},
{"Michael W. Whalen" ,"whalen@cs.umn.edu"},
{"Catherine Qi Zhao" ,"qzhao@umn.edu"},
{"Dan Challou" ,"challou@cs.umn.edu"},
{"Steven Wu" ,"zsw@umn.edu"},
{"Michael Steinbach" ,"steinbac@cs.umn.edu"},
{"Jon Weissman" ,"jon@cs.umn.edu"},
{"Victoria Interrante" ,"interran@cs.umn.edu"},
{"Shana Watters" ,"watt0087@umn.edu"},
{"James Parker" ,"jparker@cs.umn.edu"},
{"James Moen" ,"moen0017@cs.umn.edu"},
{"Daniel Giesel" ,"giese138@umn.edu"},
{"Jon Read" ,"readx028@umn.edu"},
{"Sara Stokowski" ,"stoko004@umn.edu"},
{NULL , NULL},
};
// structure to store a lookup. client fills in with name, server
// fills in email if found in
typedef struct {
long mtype; // contains PID of sending process
char name[256]; // name desired
char email[256]; // email associated with name
} lookup_t;
int signalled = 0;
void handle_signals(int sig_num){
signalled = 1;
}
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
struct sigaction my_sa = {}; // portable signal handling setup with sigaction()
my_sa.sa_handler = handle_signals; // run function handle_signals
sigaction(SIGTERM, &my_sa, NULL); // register SIGCONT with given action
sigaction(SIGINT, &my_sa, NULL); // register SIGCONT with given action
printf("starting server\n");
key_t key;
key = ftok("em_server_mq.c", 0);
int to_server_qid = msgget(key, 0644 | IPC_CREAT);
key = ftok("em_client_mq.c", 0);
int to_clients_qid = msgget(key, 0644 | IPC_CREAT);
printf("SERVER: created/attached to message queues\n");
while(!signalled){
lookup_t request;
msgrcv(to_server_qid, &request, sizeof(lookup_t), 0, 0);
printf("%ld B SERVER: received request {pid=%ld name=\"%s\" }\n",
request.mtype, request.mtype, request.name);
char *name = request.name;
int found = 0;
for(int i=0; data[i][0] != NULL; i++){
if(strcmp(name, data[i][0]) == 0){
strcpy(request.email, data[i][1]);
found = 1;
}
}
if(!found){
strcpy(request.email, "NOT FOUND");
}
printf("%ld C SERVER: filling request {pid=%ld name=\"%s\" email=\"%s\" }\n",
request.mtype,request.mtype, request.name, request.email);
msgsnd(to_clients_qid, &request, sizeof(request), 0);
}
msgctl(to_server_qid, IPC_RMID, NULL); // clean up the message queues
msgctl(to_clients_qid, IPC_RMID, NULL);
exit(0);
}

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#!/bin/bash
#
# usage: run_smulations.sh 20
#
# Start an em_server then run multiple simultaneous em_clients
# connecting to find various emails. Accepts a command line argument
# which is the number of clients to run.
nclients=10
if (( $# >= 1 )); then
nclients=$1
fi
names=(
"Chris Kauffman"
"Christopher Jonathan"
"Amy Larson"
"Chris Dovolis"
"Dan Knights"
"George Karypis"
"Steven Jensen"
"Daniel Keefe"
"Michael W. Whalen"
"Catherine Qi Zhao"
"Dan Challou"
"Steven Wu"
"Michael Steinbach"
"Jon Weissman"
"Victoria Interrante"
"Shana Watters"
"James Parker"
"James Moen"
"Daniel Giesel"
"Jon Read"
"Sara Stokowski"
)
len=${#names[*]} # length of the array of names
./em_server_fifo & # start the server
em_server_pid=$!
# sleep 0.25 # short pause to ensure server starts up
nclients=$((nclients-1)) # decrement as we are starting at 0
pids=() # track em_clients pids
for i in `seq 0 $nclients`; do
idx=$((i % len)) # index of email addressfish out one emal address
email="${names[idx]}" # fish out an email address
# echo "${names[idx]}"
./em_client_fifo "$email" & # start client with email address
pids[i]=$! # keep track of pid of last process: client
done
# echo "${pids[*]}"
# wait for jobs to finish
for pid in ${pids[*]}; do # wait for all clients to finish
wait $pid
done
kill $em_server_pid # kill the server

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#!/bin/bash
#
# usage: run_smulations.sh 20
#
# Start an em_server then run multiple simultaneous em_clients
# connecting to find various emails. Accepts a command line argument
# which is the number of clients to run.
nclients=10
if (( $# >= 1 )); then
nclients=$1
fi
names=(
"Chris Kauffman"
"Christopher Jonathan"
"Amy Larson"
"Chris Dovolis"
"Dan Knights"
"George Karypis"
"Steven Jensen"
"Daniel Keefe"
"Michael W. Whalen"
"Catherine Qi Zhao"
"Dan Challou"
"Steven Wu"
"Michael Steinbach"
"Jon Weissman"
"Victoria Interrante"
"Shana Watters"
"James Parker"
"James Moen"
"Daniel Giesel"
"Jon Read"
"Sara Stokowski"
)
len=${#names[*]} # length of the array of names
./em_server_mq & # start the server
em_server_pid=$!
# sleep 0.25 # short pause to ensure server starts up
nclients=$((nclients-1)) # decrement as we are starting at 0
pids=() # track em_clients pids
for i in `seq 0 $nclients`; do
idx=$((i % len)) # index of email addressfish out one emal address
email="${names[idx]}" # fish out an email address
# echo "${names[idx]}"
./em_client_mq "$email" & # start client with email address
pids[i]=$! # keep track of pid of last process: client
done
# echo "${pids[*]}"
# wait for jobs to finish
for pid in ${pids[*]}; do # wait for all clients to finish
wait $pid
done
kill $em_server_pid # kill the server

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run
bt
q

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{
"files.associations": {
"*.pyx": "python",
"string.h": "c"
}
}

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CFLAGS = -Wall -g
CC = gcc $(CFLAGS)
all : philosophers_ipc philosophers_pthread
philosophers_ipc : philosophers_ipc.c
$(CC) -o $@ $^
philosophers_pthread: philosophers_pthread.c
$(CC) -pthread -o $@ $^
clean :
rm -f *.o philosophers_ipc # philosophers_pthread

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// Dining philosophers (swansons) using System V Semaphores
// Original: http://www.lisha.ufsc.br/~guto/teaching/os/exercise/phil.html
// Modified by Chris Kauffman
//
// This version uses a C array of semaphores. Each System V semaphore
// itself can be an array but of the 5 distinct semphores in the C array are
// initialized to contain only a single counter at sem_num=0.
//
// Short random delays are added between each philosophers
// thinking/eating cycle to generate some variance in execution order
//
// To see the multiple processes, run the following commands
// > gcc -o philosophers philosophers.c
// > philosophers > xxx & watch -d -n 0.1 'ps ux | grep philosophers'
// Ctrl-c to stop the "watch" command (may screw up the terminal display)
#include <stdio.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#define N_PHILOSOPHERS 5 // Number of philosophers
const int MEALS_TO_FINISH =
10; // Number of iterations before philosophers finish
const int MAX_DELAY = 50000; // Maximum delay in nanos between meal iterations
// Semaphore ids
int utensils[N_PHILOSOPHERS]; // IDs for arrays of IPC semaphores
int philosopher(int n); // Defined after main()
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
int i, status;
pid_t phil[N_PHILOSOPHERS];
printf("The Dining Swansons (Philosophers) Problem\n");
// Parent process only:
//
// Allocate utensils: semaphores which are initially set to value
// one. Each semaphore is only a single counter with sem_num=0.
for (i = 0; i < N_PHILOSOPHERS; i++) {
utensils[i] = semget(IPC_PRIVATE, 1, IPC_CREAT | 0600);
semctl(utensils[i], 0, SETVAL, 1);
}
// Parent generates child processes
for (i = 0; i < N_PHILOSOPHERS; i++) {
int pid = fork();
if (pid == 0) { // child has pid 0
int ret = philosopher(i); // child acts as philosopher
exit(ret); // then exits
} else { // parent gets pid > 0
phil[i] = pid; // parent tracks children
}
}
// Parent waits on all children to finish
for (i = 0; i < N_PHILOSOPHERS; i++) {
waitpid(phil[i], &status, 0);
}
printf("JJ: All Swansons finished, cleaning up the diner\n");
// Eliminate the utensils and table semaphores
for (i = 0; i < N_PHILOSOPHERS; i++) {
semctl(utensils[i], 0, IPC_RMID, 0);
}
return 0;
}
// Code for dining philosopher child processes
int philosopher(int n) {
int i, first, second;
struct sembuf op; // Used to perform semaphore operations
op.sem_flg = 0;
op.sem_num =
0; // C array of semaphores each with 1, op always on the 0th sem
srand(time(NULL)); // Seed random number generator
// Avoid deadlock via slightly different order of utensil requests
// for last philospher
// first utensil to get, most go for n first, last philospher goes for 0
// first
first = (n != N_PHILOSOPHERS - 1) ? n : 0;
// second utensil to get, last philopher goes for n second
second = (n != N_PHILOSOPHERS - 1) ? n + 1 : n;
printf("Swanson %d wants utensils %d and %d\n", n, first, second);
printf("Swanson %d at the table\n", n);
// Main loop of thinking/eating cycles
for (i = 0; i < MEALS_TO_FINISH; i++) {
int sleep_time = rand() % MAX_DELAY;
usleep(sleep_time); // sleep for for a short time
printf("%2d: Swanson %d is contemplating his awesomeness ...\n", i, n);
// get first utensil
op.sem_op = -1;
semop(utensils[first], &op, 1);
printf("%2d: Swanson %d got utensil %d\n", i, n, first);
// get second utensil
op.sem_op = -1;
semop(utensils[second], &op, 1);
printf("%2d: Swanson %d got utensil %d\n", i, n, second);
printf("%2d: Swanson %d is eating an egg ...\n", i, n);
usleep(sleep_time); // sleep for for a short time
// release first utensil
op.sem_op = +1;
semop(utensils[first], &op, 1);
// release second utensil
op.sem_op = +1;
semop(utensils[second], &op, 1);
}
printf("Swanson %d leaving the diner\n", n);
exit(n);
}

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lab10-code/philosophers_pthread.c Normal file
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// MODIFY THIS FILE to use pthreads rather than IPC. Lines marked with
// **CHANGE** indicate lines that are higly likely to need alterations.
#include <error.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sem.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#define N_PHILOSOPHERS 5 // Number of philosophers
const int MEALS_TO_FINISH = 2; // Number of iterations before finish
const int MAX_DELAY = 50000; // Maximum delay in nanos between meal iterations
pthread_mutex_t utensils[N_PHILOSOPHERS];
void *philosopher(void *n);
// **CHANGE** to have prototype compatible with thread entry points
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
int i, status;
pthread_t phil[N_PHILOSOPHERS];
printf("The Dining Swansons (Philosophers) Problem\n");
// Parent thread only:
//
// Allocate utensils: mutexes
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_mutex_init(&utensils[i], NULL);
}
// Parent generates child processes
int numbers[N_PHILOSOPHERS];
for (i = 0; i < N_PHILOSOPHERS; i++) {
numbers[i] = i; // workaround for wrong numbers
status = pthread_create(&phil[i], NULL, &philosopher, &numbers[i]);
if (status) {
fprintf(stderr, "Could not create thread: %s\n", strerror(status));
exit(1);
}
}
// Parent waits on all children to finish
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_join(phil[i], NULL);
}
printf("JJ: All Swansons finished, cleaning up the diner\n");
// Eliminate the utensils and table semaphores
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_mutex_destroy(&utensils[i]);
}
return 0;
}
// Code for dining philosopher child processes
void *philosopher(void *arg) {
int n = *(int *)arg;
int i, first, second;
srand(time(NULL)); // Seed random number generator
// Avoid deadlock via slightly different order of utensil requests
// for last philospher
// first utensil to get, most go for n first, last philospher goes for 0
// first
first = (n != N_PHILOSOPHERS - 1) ? n : 0;
// second utensil to get, last philopher goes for n second
second = (n != N_PHILOSOPHERS - 1) ? n + 1 : n;
printf("Swanson %d wants utensils %d and %d\n", n, first, second);
printf("Swanson %d at the table\n", n);
// Main loop of thinking/eating cycles
for (i = 0; i < MEALS_TO_FINISH; i++) {
int sleep_time = rand() % MAX_DELAY;
usleep(sleep_time); // sleep for for a short time
printf("%2d: Swanson %d is contemplating his awesomeness ...\n", i, n);
// get first utensil
pthread_mutex_lock(&utensils[first]);
printf("%2d: Swanson %d got utensil %d\n", i, n, first);
// get second utensil
pthread_mutex_lock(&utensils[second]);
printf("%2d: Swanson %d got utensil %d\n", i, n, second);
printf("%2d: Swanson %d is eating an egg ...\n", i, n);
usleep(sleep_time); // sleep for for a short time
// release first utensil
pthread_mutex_unlock(&utensils[first]);
// release second utensil
pthread_mutex_unlock(&utensils[second]);
}
printf("Swanson %d leaving the diner\n", n);
return NULL;
}

108
lab10-code/philosophers_pthread.txt Normal file
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// MODIFY THIS FILE to use pthreads rather than IPC. Lines marked with
// **CHANGE** indicate lines that are higly likely to need alterations.
#include <error.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sem.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#define N_PHILOSOPHERS 5 // Number of philosophers
const int MEALS_TO_FINISH = 2; // Number of iterations before finish
const int MAX_DELAY = 50000; // Maximum delay in nanos between meal iterations
pthread_mutex_t utensils[N_PHILOSOPHERS];
void *philosopher(void *n);
// **CHANGE** to have prototype compatible with thread entry points
int main() {
setvbuf(stdout, NULL, _IONBF, 0);
int i, status;
pthread_t phil[N_PHILOSOPHERS];
printf("The Dining Swansons (Philosophers) Problem\n");
// Parent thread only:
//
// Allocate utensils: mutexes
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_mutex_init(&utensils[i], NULL);
}
// Parent generates child processes
int numbers[N_PHILOSOPHERS];
for (i = 0; i < N_PHILOSOPHERS; i++) {
numbers[i] = i; // workaround for wrong numbers
status = pthread_create(&phil[i], NULL, &philosopher, &numbers[i]);
if (status) {
fprintf(stderr, "Could not create thread: %s\n", strerror(status));
exit(1);
}
}
// Parent waits on all children to finish
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_join(phil[i], NULL);
}
printf("JJ: All Swansons finished, cleaning up the diner\n");
// Eliminate the utensils and table semaphores
for (i = 0; i < N_PHILOSOPHERS; i++) {
pthread_mutex_destroy(&utensils[i]);
}
return 0;
}
// Code for dining philosopher child processes
void *philosopher(void *arg) {
int n = *(int *)arg;
int i, first, second;
srand(time(NULL)); // Seed random number generator
// Avoid deadlock via slightly different order of utensil requests
// for last philospher
// first utensil to get, most go for n first, last philospher goes for 0
// first
first = (n != N_PHILOSOPHERS - 1) ? n : 0;
// second utensil to get, last philopher goes for n second
second = (n != N_PHILOSOPHERS - 1) ? n + 1 : n;
printf("Swanson %d wants utensils %d and %d\n", n, first, second);
printf("Swanson %d at the table\n", n);
// Main loop of thinking/eating cycles
for (i = 0; i < MEALS_TO_FINISH; i++) {
int sleep_time = rand() % MAX_DELAY;
usleep(sleep_time); // sleep for for a short time
printf("%2d: Swanson %d is contemplating his awesomeness ...\n", i, n);
// get first utensil
pthread_mutex_lock(&utensils[first]);
printf("%2d: Swanson %d got utensil %d\n", i, n, first);
// get second utensil
pthread_mutex_lock(&utensils[second]);
printf("%2d: Swanson %d got utensil %d\n", i, n, second);
printf("%2d: Swanson %d is eating an egg ...\n", i, n);
usleep(sleep_time); // sleep for for a short time
// release first utensil
pthread_mutex_unlock(&utensils[first]);
// release second utensil
pthread_mutex_unlock(&utensils[second]);
}
printf("Swanson %d leaving the diner\n", n);
return NULL;
}

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lab10-code/pthreads_picalc_mutex.c Normal file
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// Working version of threaded picalc. Uses a mutex to lock the global
// variable total_hits so that one thread accesses it at a time. This
// version is inefficient due to the busy waiting and contention
// associated with mutex locking.
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
// Global variables shared by all threads
int total_hits=0;
int points_per_thread = -1;
pthread_mutex_t lock;
void *compute_pi(void *arg){
long thread_id = (long) arg;
unsigned int rstate = 123456789 * thread_id; // give each thread its own starting point
for (int i = 0; i < points_per_thread; i++) {
double x = ((double) rand_r(&rstate)) / ((double) RAND_MAX);
double y = ((double) rand_r(&rstate)) / ((double) RAND_MAX);
if (x*x + y*y <= 1.0){
pthread_mutex_lock(&lock); // lock global variable
total_hits++; // update
pthread_mutex_unlock(&lock); // unlock global variable
}
}
return NULL;
}
int main(int argc, char **argv) {
if(argc < 2){
printf("usage: %s <num_samples> [num_threads]\n",argv[0]);
printf(" num_samples: int, how many sample points to try, higher gets closer to pi\n");
printf(" num_threads: int, number of threads to use for the computation, default 4\n");
return -1;
}
int npoints = atoi(argv[1]); // number of samples
int num_threads = argc>2 ? atoi(argv[2]) : 4; // number of threads
points_per_thread = npoints / num_threads; // init global variables
pthread_mutex_init(&lock, NULL); // create a lock
pthread_t threads[num_threads]; // track each thread
for(long p=0; p<num_threads; p++){ // launch each thread
pthread_create(&threads[p],NULL,compute_pi, (void *) (p+1));
}
for(int p=0; p<num_threads; p++){ // wait for each thread to finish
pthread_join(threads[p], (void **) NULL);
}
pthread_mutex_destroy(&lock); // get rid of the lock
double pi_est = ((double)total_hits) / npoints * 4.0;
printf("npoints: %8d\n",npoints);
printf("hits: %8d\n",total_hits);
printf("pi_est: %f\n",pi_est);
}

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