X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FLockFileManager.cpp;h=8fc58017cb0f287f57045c28b79a6fe6dc8d95e0;hb=48e3a273de5a3fee954f650045d6eed6b3591ef7;hp=64404a1a8e77cc23f8f417f44620f4706c96a694;hpb=95fa4005f5aa99878c4053e95b230f0b8b6a4d6d;p=oota-llvm.git diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp index 64404a1a8e7..8fc58017cb0 100644 --- a/lib/Support/LockFileManager.cpp +++ b/lib/Support/LockFileManager.cpp @@ -7,11 +7,15 @@ // //===----------------------------------------------------------------------===// #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 #include +#include #if LLVM_ON_WIN32 #include #endif @@ -27,29 +31,34 @@ 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 Optional >(); - // 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> 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. - bool Existed; - sys::fs::remove(LockFileName, Existed); - return Optional >(); + sys::fs::remove(LockFileName); + return None; } bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) { -#if LLVM_ON_UNIX +#if LLVM_ON_UNIX && !defined(__ANDROID__) char MyHostname[256]; MyHostname[255] = 0; MyHostname[0] = 0; @@ -64,7 +73,12 @@ bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) { LockFileManager::LockFileManager(StringRef FileName) { - LockFileName = FileName; + this->FileName = 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 @@ -76,11 +90,8 @@ LockFileManager::LockFileManager(StringRef FileName) 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; } @@ -105,41 +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 { @@ -157,14 +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; @@ -173,8 +186,9 @@ void LockFileManager::waitForUnlock() { 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 // finish up and remove the lock file. @@ -183,15 +197,49 @@ void LockFileManager::waitForUnlock() { #if LLVM_ON_WIN32 Sleep(Interval); #else - nanosleep(&Interval, NULL); + nanosleep(&Interval, nullptr); #endif - // If the file no longer exists, we're done. - bool Exists = false; - if (!sys::fs::exists(LockFileName.str(), Exists) && !Exists) - return; + bool LockFileJustDisappeared = false; - if (!processStillExecuting((*Owner).first, (*Owner).second)) - return; + // 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 the lock file is no longer there, check if the original file is + // available now. + if (LockFileGone) { + 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 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 @@ -213,4 +261,5 @@ void LockFileManager::waitForUnlock() { ); // Give up. + return Res_Timeout; }