llvm/llvm/lib/Support/LockFileManager.cpp

//===--- LockFileManager.cpp - File-level Locking Utility------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/LockFileManager.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/ExponentialBackoff.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/raw_ostream.h"
#include <cerrno>
#include <chrono>
#include <ctime>
#include <memory>
#include <sys/stat.h>
#include <sys/types.h>
#include <system_error>
#include <thread>
#include <tuple>

#ifdef _WIN32
#include <windows.h>
#endif
#if LLVM_ON_UNIX
#include <unistd.h>
#endif

#if defined(__APPLE__) && defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ > 1050)
#define USE_OSX_GETHOSTUUID …
#else
#define USE_OSX_GETHOSTUUID …
#endif

#if USE_OSX_GETHOSTUUID
#include <uuid/uuid.h>
#endif

usingnamespacellvm;

/// Attempt to read the lock file with the given name, if it exists.
///
/// \param LockFileName The name of the lock file to read.
///
/// \returns The process ID of the process that owns this lock file
std::optional<std::pair<std::string, int>>
LockFileManager::readLockFile(StringRef LockFileName) { … }

static std::error_code getHostID(SmallVectorImpl<char> &HostID) { … }

bool LockFileManager::processStillExecuting(StringRef HostID, int PID) { … }

namespace {

/// An RAII helper object ensure that the unique lock file is removed.
///
/// Ensures that if there is an error or a signal before we finish acquiring the
/// lock, the unique file will be removed. And if we successfully take the lock,
/// the signal handler is left in place so that signals while the lock is held
/// will remove the unique lock file. The caller should ensure there is a
/// matching call to sys::DontRemoveFileOnSignal when the lock is released.
class RemoveUniqueLockFileOnSignal { … };

} // end anonymous namespace

LockFileManager::LockFileManager(StringRef FileName)
{ … }

LockFileManager::LockFileState LockFileManager::getState() const { … }

std::string LockFileManager::getErrorMessage() const { … }

LockFileManager::~LockFileManager() { … }

LockFileManager::WaitForUnlockResult
LockFileManager::waitForUnlock(const unsigned MaxSeconds) { … }

std::error_code LockFileManager::unsafeRemoveLockFile() { … }