CMake/Source/cmFileLockUnix.cxx
Betsy McPhail 1f289095f9 file(LOCK): Close file descriptor/handle when releasing a lock
The file lock functionality added in commit v3.2.0-rc1~297^2~1 (file:
Add LOCK subcommand to do file and directory locking, 2014-11-26) forgot
to close the lock file descriptors.  Eventually it was possible to run
out of file descriptors and locks could not longer be acquired.  Fix
this by closing the file descriptor or handle when we are done with it.
Also set the member back to the initial value from the constructor
to leave everything in a consistent state (useful for debugging).

Co-Author: Ruslan Baratov <ruslan_baratov@yahoo.com>
2015-03-25 09:00:51 -04:00

107 lines
2.3 KiB
C++

/*============================================================================
CMake - Cross Platform Makefile Generator
Copyright 2014 Ruslan Baratov
Distributed under the OSI-approved BSD License (the "License");
see accompanying file Copyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the License for more information.
============================================================================*/
#include "cmFileLock.h"
#include <errno.h> // errno
#include <stdio.h> // SEEK_SET
#include <fcntl.h>
#include <unistd.h>
#include "cmSystemTools.h"
cmFileLock::cmFileLock(): File(-1)
{
}
cmFileLockResult cmFileLock::Release()
{
if (this->Filename.empty())
{
return cmFileLockResult::MakeOk();
}
const int lockResult = this->LockFile(F_SETLK, F_UNLCK);
this->Filename = "";
::close(this->File);
this->File = -1;
if (lockResult == 0)
{
return cmFileLockResult::MakeOk();
}
else
{
return cmFileLockResult::MakeSystem();
}
}
cmFileLockResult cmFileLock::OpenFile()
{
this->File = ::open(this->Filename.c_str(), O_RDWR);
if (this->File == -1)
{
return cmFileLockResult::MakeSystem();
}
else
{
return cmFileLockResult::MakeOk();
}
}
cmFileLockResult cmFileLock::LockWithoutTimeout()
{
if (this->LockFile(F_SETLKW, F_WRLCK) == -1)
{
return cmFileLockResult::MakeSystem();
}
else
{
return cmFileLockResult::MakeOk();
}
}
cmFileLockResult cmFileLock::LockWithTimeout(unsigned long seconds)
{
while (true)
{
if (this->LockFile(F_SETLK, F_WRLCK) == -1)
{
if (errno != EACCES && errno != EAGAIN)
{
return cmFileLockResult::MakeSystem();
}
}
else
{
return cmFileLockResult::MakeOk();
}
if (seconds == 0)
{
return cmFileLockResult::MakeTimeout();
}
--seconds;
cmSystemTools::Delay(1000);
}
}
int cmFileLock::LockFile(int cmd, int type)
{
struct ::flock lock;
lock.l_start = 0;
lock.l_len = 0; // lock all bytes
lock.l_pid = 0; // unused (for F_GETLK only)
lock.l_type = static_cast<short>(type); // exclusive lock
lock.l_whence = SEEK_SET;
return ::fcntl(this->File, cmd, &lock);
}