X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FLockFileManager.cpp;h=8fc58017cb0f287f57045c28b79a6fe6dc8d95e0;hb=9f52e1da3c6a6e798733704b0acf6920d00eb3d2;hp=b1ff22c2e68fa25f1b2a5878cbd282a088a653e7;hpb=47cfec02842f885b46ea0d3c812793e660691640;p=oota-llvm.git diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp index b1ff22c2e68..8fc58017cb0 100644 --- a/lib/Support/LockFileManager.cpp +++ b/lib/Support/LockFileManager.cpp @@ -9,8 +9,10 @@ #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 #include @@ -29,22 +31,25 @@ using namespace llvm; /// \returns The process ID of the process that owns this lock file Optional > 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 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. - OwningPtr MB; - if (MemoryBuffer::getFile(LockFileName, MB)) { - StringRef Hostname; - StringRef PIDStr; - tie(Hostname, PIDStr) = getToken(MB->getBuffer(), " "); - int PID; - if (PIDStr.getAsInteger(10, PID)) - return std::make_pair(std::string(Hostname), PID); + ErrorOr> 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(), " "); + 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. @@ -69,7 +74,11 @@ 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 @@ -81,10 +90,8 @@ LockFileManager::LockFileManager(StringRef FileName) 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; } @@ -109,41 +116,44 @@ LockFileManager::LockFileManager(StringRef FileName) // 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 { @@ -161,14 +171,13 @@ LockFileManager::~LockFileManager() { 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; @@ -188,26 +197,25 @@ void LockFileManager::waitForUnlock() { #if LLVM_ON_WIN32 Sleep(Interval); #else - nanosleep(&Interval, NULL); + nanosleep(&Interval, nullptr); #endif - 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; LockFileJustDisappeared = true; - Exists = false; } } // 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 @@ -230,7 +238,7 @@ void LockFileManager::waitForUnlock() { // owning the lock died without cleaning up, just bail out. if (!LockFileGone && !processStillExecuting((*Owner).first, (*Owner).second)) { - return; + return Res_OwnerDied; } // Exponentially increase the time we wait for the lock to be removed. @@ -253,4 +261,5 @@ void LockFileManager::waitForUnlock() { ); // Give up. + return Res_Timeout; }