diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp index acb310efeec..957f2fdd7a5 100644 --- a/lib/Support/LockFileManager.cpp +++ b/lib/Support/LockFileManager.cpp @@ -115,25 +115,42 @@ LockFileManager::LockFileManager(StringRef FileName) } } - // 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) - 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) + 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. - sys::fs::remove(UniqueLockFileName.str()); - if ((Owner = readLockFile(LockFileName))) - return; + if (EC != errc::file_exists) { + Error = EC; + return; + } - // There is a lock file that nobody owns; try to clean it up and report - // an error. - sys::fs::remove(LockFileName.str()); - Error = EC; + // 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; + } + + 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 get + // ownership. + if ((EC = sys::fs::remove(LockFileName.str()))) { + Error = EC; + return; + } + } } LockFileManager::LockFileState LockFileManager::getState() const {