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/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file Copyright.txt or https://cmake.org/licensing for details. */
#include "cmFileLock.h"
#include "cmSystemTools.h"
#include <cerrno> // errno
#include <cstdio> // SEEK_SET
#include <fcntl.h>
#include <unistd.h>
cmFileLock::cmFileLock() = default;
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();
}
return cmFileLockResult::MakeSystem();
}
cmFileLockResult cmFileLock::OpenFile()
{
this->File = ::open(this->Filename.c_str(), O_RDWR);
if (this->File == -1) {
return cmFileLockResult::MakeSystem();
}
return cmFileLockResult::MakeOk();
}
cmFileLockResult cmFileLock::LockWithoutTimeout()
{
if (this->LockFile(F_SETLKW, F_WRLCK) == -1) {
return cmFileLockResult::MakeSystem();
}
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);
}
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