#include "llvm/Support/LockFileManager.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Errc.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include <sys/stat.h>
#include <sys/types.h>
/// \returns The process ID of the process that owns this lock file
Optional<std::pair<std::string, int> >
LockFileManager::readLockFile(StringRef LockFileName) {
- // Check whether the lock file exists. If not, clearly there's nothing
- // to read, so we just return.
- if (!sys::fs::exists(LockFileName))
- return None;
-
// Read the owning host and PID out of the lock file. If it appears that the
// owning process is dead, the lock file is invalid.
- std::unique_ptr<MemoryBuffer> MB;
- if (MemoryBuffer::getFile(LockFileName, MB))
+ ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
+ MemoryBuffer::getFile(LockFileName);
+ if (!MBOrErr) {
+ sys::fs::remove(LockFileName);
return None;
+ }
+ MemoryBuffer &MB = *MBOrErr.get();
StringRef Hostname;
StringRef PIDStr;
- std::tie(Hostname, PIDStr) = getToken(MB->getBuffer(), " ");
+ std::tie(Hostname, PIDStr) = getToken(MB.getBuffer(), " ");
PIDStr = PIDStr.substr(PIDStr.find_first_not_of(" "));
int PID;
- if (!PIDStr.getAsInteger(10, PID))
- return std::make_pair(std::string(Hostname), PID);
+ if (!PIDStr.getAsInteger(10, PID)) {
+ auto Owner = std::make_pair(std::string(Hostname), PID);
+ if (processStillExecuting(Owner.first, Owner.second))
+ return Owner;
+ }
// Delete the lock file. It's invalid anyway.
sys::fs::remove(LockFileName);
LockFileManager::LockFileManager(StringRef FileName)
{
this->FileName = FileName;
- LockFileName = FileName;
+ if (std::error_code EC = sys::fs::make_absolute(this->FileName)) {
+ Error = EC;
+ return;
+ }
+ LockFileName = this->FileName;
LockFileName += ".lock";
// If the lock file already exists, don't bother to try to create our own
UniqueLockFileName = LockFileName;
UniqueLockFileName += "-%%%%%%%%";
int UniqueLockFileID;
- if (error_code EC
- = sys::fs::createUniqueFile(UniqueLockFileName.str(),
- UniqueLockFileID,
- UniqueLockFileName)) {
+ if (std::error_code EC = sys::fs::createUniqueFile(
+ UniqueLockFileName.str(), UniqueLockFileID, UniqueLockFileName)) {
Error = EC;
return;
}
}
while (1) {
- // Create a symbolic link from the lock file name. If this succeeds, we're
- // done. Note that we are using symbolic link because hard links are not
- // supported by all filesystems.
- error_code EC
- = sys::fs::create_symbolic_link(UniqueLockFileName.str(),
- LockFileName.str());
- if (EC == errc::success)
+ // Create a link from the lock file name. If this succeeds, we're done.
+ std::error_code EC =
+ sys::fs::create_link(UniqueLockFileName.str(), LockFileName.str());
+ if (!EC)
return;
if (EC != errc::file_exists) {
sys::fs::remove(UniqueLockFileName.str());
}
-void LockFileManager::waitForUnlock() {
+LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
if (getState() != LFS_Shared)
- return;
+ return Res_Success;
#if LLVM_ON_WIN32
unsigned long Interval = 1;
Interval.tv_sec = 0;
Interval.tv_nsec = 1000000;
#endif
- // Don't wait more than five minutes for the file to appear.
- unsigned MaxSeconds = 300;
- bool LockFileGone = false;
+ // Don't wait more than five minutes per iteration. Total timeout for the file
+ // to appear is ~8.5 mins.
+ const unsigned MaxSeconds = 5*60;
do {
// Sleep for the designated interval, to allow the owning process time to
// finish up and remove the lock file.
#if LLVM_ON_WIN32
Sleep(Interval);
#else
- nanosleep(&Interval, NULL);
+ nanosleep(&Interval, nullptr);
#endif
- bool LockFileJustDisappeared = false;
- // If the lock file is still expected to be there, check whether it still
- // is.
- if (!LockFileGone) {
- bool Exists;
- if (!sys::fs::exists(LockFileName.str(), Exists) && !Exists) {
- LockFileGone = true;
- LockFileJustDisappeared = true;
- }
+ if (sys::fs::access(LockFileName.c_str(), sys::fs::AccessMode::Exist) ==
+ errc::no_such_file_or_directory) {
+ // If the original file wasn't created, somone thought the lock was dead.
+ if (!sys::fs::exists(FileName.str()))
+ return Res_OwnerDied;
+ return Res_Success;
}
- // If the lock file is no longer there, check if the original file is
- // available now.
- if (LockFileGone) {
- if (sys::fs::exists(FileName.str())) {
- return;
- }
-
- // The lock file is gone, so now we're waiting for the original file to
- // show up. If this just happened, reset our waiting intervals and keep
- // waiting.
- if (LockFileJustDisappeared) {
- MaxSeconds = 5;
-
-#if LLVM_ON_WIN32
- Interval = 1;
-#else
- Interval.tv_sec = 0;
- Interval.tv_nsec = 1000000;
-#endif
- continue;
- }
- }
-
- // If we're looking for the lock file to disappear, but the process
- // owning the lock died without cleaning up, just bail out.
- if (!LockFileGone &&
- !processStillExecuting((*Owner).first, (*Owner).second)) {
- return;
- }
+ // If the process owning the lock died without cleaning up, just bail out.
+ if (!processStillExecuting((*Owner).first, (*Owner).second))
+ return Res_OwnerDied;
// Exponentially increase the time we wait for the lock to be removed.
#if LLVM_ON_WIN32
);
// Give up.
+ return Res_Timeout;
+}
+
+std::error_code LockFileManager::unsafeRemoveLockFile() {
+ return sys::fs::remove(LockFileName.str());
}
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