//
//===----------------------------------------------------------------------===//
#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 <fstream>
#include <sys/stat.h>
#include <sys/types.h>
#if LLVM_ON_WIN32
/// \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.
- bool Exists = false;
- if (sys::fs::exists(LockFileName, Exists) || !Exists)
- return Optional<std::pair<std::string, int> >();
-
// 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.
- int PID = 0;
- std::string Hostname;
- std::ifstream Input(LockFileName.str().c_str());
- if (Input >> Hostname >> PID && PID > 0 &&
- processStillExecuting(Hostname, PID))
- return std::make_pair(Hostname, PID);
+ ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
+ MemoryBuffer::getFile(LockFileName);
+ if (!MBOrErr) {
+ sys::fs::remove(LockFileName);
+ return None;
+ }
+ std::unique_ptr<MemoryBuffer> MB = std::move(MBOrErr.get());
+
+ StringRef Hostname;
+ StringRef PIDStr;
+ std::tie(Hostname, PIDStr) = getToken(MB->getBuffer(), " ");
+ PIDStr = PIDStr.substr(PIDStr.find_first_not_of(" "));
+ int 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.
- bool Existed;
- sys::fs::remove(LockFileName, Existed);
- return Optional<std::pair<std::string, int> >();
+ sys::fs::remove(LockFileName);
+ return None;
}
bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) {
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::unique_file(UniqueLockFileName.str(),
- UniqueLockFileID,
- UniqueLockFileName,
- /*makeAbsolute=*/false)) {
+ if (std::error_code EC = sys::fs::createUniqueFile(
+ UniqueLockFileName.str(), UniqueLockFileID, UniqueLockFileName)) {
Error = EC;
return;
}
// We failed to write out PID, so make up an excuse, remove the
// unique lock file, and fail.
Error = make_error_code(errc::no_space_on_device);
- bool Existed;
- sys::fs::remove(UniqueLockFileName.c_str(), Existed);
+ sys::fs::remove(UniqueLockFileName.c_str());
return;
}
}
- // Create a hard link from the lock file name. If this succeeds, we're done.
- error_code EC
- = sys::fs::create_hard_link(UniqueLockFileName.str(),
- LockFileName.str());
- if (EC == errc::success)
- return;
+ while (1) {
+ // 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;
- // Creating the hard link failed.
+ if (EC != errc::file_exists) {
+ Error = EC;
+ return;
+ }
-#ifdef LLVM_ON_UNIX
- // The creation of the hard link may appear to fail, but if stat'ing the
- // unique file returns a link count of 2, then we can still declare success.
- struct stat StatBuf;
- if (stat(UniqueLockFileName.c_str(), &StatBuf) == 0 &&
- StatBuf.st_nlink == 2)
- return;
-#endif
+ // Someone else managed to create the lock file first. Read the process ID
+ // from the lock file.
+ if ((Owner = readLockFile(LockFileName))) {
+ // Wipe out our unique lock file (it's useless now)
+ sys::fs::remove(UniqueLockFileName.str());
+ return;
+ }
- // Someone else managed to create the lock file first. Wipe out our unique
- // lock file (it's useless now) and read the process ID from the lock file.
- bool Existed;
- sys::fs::remove(UniqueLockFileName.str(), Existed);
- if ((Owner = readLockFile(LockFileName)))
- return;
+ if (!sys::fs::exists(LockFileName.str())) {
+ // The previous owner released the lock file before we could read it.
+ // Try to get ownership again.
+ continue;
+ }
- // There is a lock file that nobody owns; try to clean it up and report
- // an error.
- sys::fs::remove(LockFileName.str(), Existed);
- Error = EC;
+ // There is a lock file that nobody owns; try to clean it up and get
+ // ownership.
+ if ((EC = sys::fs::remove(LockFileName.str()))) {
+ Error = EC;
+ return;
+ }
+ }
}
LockFileManager::LockFileState LockFileManager::getState() const {
return;
// Since we own the lock, remove the lock file and our own unique lock file.
- bool Existed;
- sys::fs::remove(LockFileName.str(), Existed);
- sys::fs::remove(UniqueLockFileName.str(), Existed);
+ sys::fs::remove(LockFileName.str());
+ 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 an hour for the file to appear.
- const unsigned MaxSeconds = 3600;
+ // Don't wait more than five minutes for the file to appear.
+ unsigned MaxSeconds = 300;
bool LockFileGone = false;
do {
// Sleep for the designated interval, to allow the owning process time to
#if LLVM_ON_WIN32
Sleep(Interval);
#else
- nanosleep(&Interval, NULL);
+ nanosleep(&Interval, nullptr);
#endif
- // If the lock file no longer exists, wait for the actual file.
- bool Exists = false;
+ 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;
- Exists = false;
+ LockFileJustDisappeared = true;
}
}
+
+ // If the lock file is no longer there, check if the original file is
+ // available now.
if (LockFileGone) {
- if (!sys::fs::exists(FileName.str(), Exists) && Exists)
- return;
+ if (sys::fs::exists(FileName.str())) {
+ return Res_Success;
+ }
+
+ // 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 (!processStillExecuting((*Owner).first, (*Owner).second))
- return;
+ // 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 Res_OwnerDied;
+ }
// Exponentially increase the time we wait for the lock to be removed.
#if LLVM_ON_WIN32
);
// Give up.
+ return Res_Timeout;
}
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