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fix(util/file_lock): handle permission denied at lock creation

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see #925

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2015-12-15 09:41:11 -08:00
parent 42eda36225
commit c07345d47f
1 changed files with 15 additions and 7 deletions
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22
src/util/file_lock.cpp
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@ -5,10 +5,11 @@ Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <string>
#include <sys/file.h>
#include <errno.h>
#include "util/exception.h"
#include "util/sstream.h"
#include "util/file_lock.h"
#include <sys/file.h>
#ifdef LEAN_WINDOWS
#include <windows.h>
@ -75,12 +76,19 @@ file_lock::file_lock(char const * fname, bool exclusive):
m_fname(fname), m_fd(-1) {
m_fname += ".lock";
m_fd = open(m_fname.c_str(), O_CREAT, 0xFFFF);
if (m_fd == -1)
throw exception(sstream() << "failed to lock file '" << fname << "'");
int status = flock(m_fd, exclusive ? LOCK_EX : LOCK_SH);
// TODO(Leo): should we use a loop and keep checking, and fail after k seconds?
if (status == -1)
throw exception(sstream() << "failed to lock file '" << fname << "'");
if (m_fd == -1) {
if (errno == EACCES) {
// We don't have permission to create the file, the folder containing fname is probably readonly.
// fname is probably part of the Lean installation in a system directory.
// So, we ignore the file_lock in this case.
} else {
throw exception(sstream() << "failed to lock file '" << fname << "'");
}
} else {
int status = flock(m_fd, exclusive ? LOCK_EX : LOCK_SH);
if (status == -1)
throw exception(sstream() << "failed to lock file '" << fname << "'");
}
}
file_lock::~file_lock() {
if (m_fd != -1) {