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-rw-r--r--contrib/llvm/lib/Support/LockFileManager.cpp184
1 files changed, 119 insertions, 65 deletions
diff --git a/contrib/llvm/lib/Support/LockFileManager.cpp b/contrib/llvm/lib/Support/LockFileManager.cpp
index 5b82c36..fb81d60 100644
--- a/contrib/llvm/lib/Support/LockFileManager.cpp
+++ b/contrib/llvm/lib/Support/LockFileManager.cpp
@@ -7,13 +7,12 @@
//
//===----------------------------------------------------------------------===//
#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 "llvm/Support/Signals.h"
#include <sys/stat.h>
#include <sys/types.h>
#if LLVM_ON_WIN32
@@ -22,6 +21,16 @@
#if LLVM_ON_UNIX
#include <unistd.h>
#endif
+
+#if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && (__MAC_OS_X_VERSION_MIN_REQUIRED > 1050)
+#define USE_OSX_GETHOSTUUID 1
+#else
+#define USE_OSX_GETHOSTUUID 0
+#endif
+
+#if USE_OSX_GETHOSTUUID
+#include <uuid/uuid.h>
+#endif
using namespace llvm;
/// \brief Attempt to read the lock file with the given name, if it exists.
@@ -57,20 +66,80 @@ LockFileManager::readLockFile(StringRef LockFileName) {
return None;
}
-bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) {
+static std::error_code getHostID(SmallVectorImpl<char> &HostID) {
+ HostID.clear();
+
+#if USE_OSX_GETHOSTUUID
+ // On OS X, use the more stable hardware UUID instead of hostname.
+ struct timespec wait = {1, 0}; // 1 second.
+ uuid_t uuid;
+ if (gethostuuid(uuid, &wait) != 0)
+ return std::error_code(errno, std::system_category());
+
+ uuid_string_t UUIDStr;
+ uuid_unparse(uuid, UUIDStr);
+ StringRef UUIDRef(UUIDStr);
+ HostID.append(UUIDRef.begin(), UUIDRef.end());
+
+#elif LLVM_ON_UNIX
+ char HostName[256];
+ HostName[255] = 0;
+ HostName[0] = 0;
+ gethostname(HostName, 255);
+ StringRef HostNameRef(HostName);
+ HostID.append(HostNameRef.begin(), HostNameRef.end());
+
+#else
+ StringRef Dummy("localhost");
+ HostID.append(Dummy.begin(), Dummy.end());
+#endif
+
+ return std::error_code();
+}
+
+bool LockFileManager::processStillExecuting(StringRef HostID, int PID) {
#if LLVM_ON_UNIX && !defined(__ANDROID__)
- char MyHostname[256];
- MyHostname[255] = 0;
- MyHostname[0] = 0;
- gethostname(MyHostname, 255);
+ SmallString<256> StoredHostID;
+ if (getHostID(StoredHostID))
+ return true; // Conservatively assume it's executing on error.
+
// Check whether the process is dead. If so, we're done.
- if (MyHostname == Hostname && getsid(PID) == -1 && errno == ESRCH)
+ if (StoredHostID == HostID && getsid(PID) == -1 && errno == ESRCH)
return false;
#endif
return true;
}
+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 {
+ StringRef Filename;
+ bool RemoveImmediately;
+public:
+ RemoveUniqueLockFileOnSignal(StringRef Name)
+ : Filename(Name), RemoveImmediately(true) {
+ sys::RemoveFileOnSignal(Filename, nullptr);
+ }
+ ~RemoveUniqueLockFileOnSignal() {
+ if (!RemoveImmediately) {
+ // Leave the signal handler enabled. It will be removed when the lock is
+ // released.
+ return;
+ }
+ sys::fs::remove(Filename);
+ sys::DontRemoveFileOnSignal(Filename);
+ }
+ void lockAcquired() { RemoveImmediately = false; }
+};
+} // end anonymous namespace
+
LockFileManager::LockFileManager(StringRef FileName)
{
this->FileName = FileName;
@@ -91,24 +160,25 @@ LockFileManager::LockFileManager(StringRef FileName)
UniqueLockFileName += "-%%%%%%%%";
int UniqueLockFileID;
if (std::error_code EC = sys::fs::createUniqueFile(
- UniqueLockFileName.str(), UniqueLockFileID, UniqueLockFileName)) {
+ UniqueLockFileName, UniqueLockFileID, UniqueLockFileName)) {
Error = EC;
return;
}
// Write our process ID to our unique lock file.
{
- raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
+ SmallString<256> HostID;
+ if (auto EC = getHostID(HostID)) {
+ Error = EC;
+ return;
+ }
+ raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
+ Out << HostID << ' ';
#if LLVM_ON_UNIX
- // FIXME: move getpid() call into LLVM
- char hostname[256];
- hostname[255] = 0;
- hostname[0] = 0;
- gethostname(hostname, 255);
- Out << hostname << ' ' << getpid();
+ Out << getpid();
#else
- Out << "localhost 1";
+ Out << "1";
#endif
Out.close();
@@ -116,17 +186,23 @@ 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);
- sys::fs::remove(UniqueLockFileName.c_str());
+ sys::fs::remove(UniqueLockFileName);
return;
}
}
+ // Clean up the unique file on signal, which also releases the lock if it is
+ // held since the .lock symlink will point to a nonexistent file.
+ RemoveUniqueLockFileOnSignal RemoveUniqueFile(UniqueLockFileName);
+
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)
+ sys::fs::create_link(UniqueLockFileName, LockFileName);
+ if (!EC) {
+ RemoveUniqueFile.lockAcquired();
return;
+ }
if (EC != errc::file_exists) {
Error = EC;
@@ -137,11 +213,11 @@ LockFileManager::LockFileManager(StringRef FileName)
// from the lock file.
if ((Owner = readLockFile(LockFileName))) {
// Wipe out our unique lock file (it's useless now)
- sys::fs::remove(UniqueLockFileName.str());
+ sys::fs::remove(UniqueLockFileName);
return;
}
- if (!sys::fs::exists(LockFileName.str())) {
+ if (!sys::fs::exists(LockFileName)) {
// The previous owner released the lock file before we could read it.
// Try to get ownership again.
continue;
@@ -149,7 +225,7 @@ LockFileManager::LockFileManager(StringRef FileName)
// There is a lock file that nobody owns; try to clean it up and get
// ownership.
- if ((EC = sys::fs::remove(LockFileName.str()))) {
+ if ((EC = sys::fs::remove(LockFileName))) {
Error = EC;
return;
}
@@ -171,8 +247,11 @@ LockFileManager::~LockFileManager() {
return;
// Since we own the lock, remove the lock file and our own unique lock file.
- sys::fs::remove(LockFileName.str());
- sys::fs::remove(UniqueLockFileName.str());
+ sys::fs::remove(LockFileName);
+ sys::fs::remove(UniqueLockFileName);
+ // The unique file is now gone, so remove it from the signal handler. This
+ // matches a sys::RemoveFileOnSignal() in LockFileManager().
+ sys::DontRemoveFileOnSignal(UniqueLockFileName);
}
LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
@@ -186,9 +265,9 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
Interval.tv_sec = 0;
Interval.tv_nsec = 1000000;
#endif
- // Don't wait more than five minutes for the file to appear.
- unsigned MaxSeconds = 300;
- bool LockFileGone = false;
+ // Don't wait more than five minutes per iteration. Total timeout for the file
+ // to appear is ~8.5 mins.
+ const unsigned MaxSeconds = 5*60;
do {
// Sleep for the designated interval, to allow the owning process time to
// finish up and remove the lock file.
@@ -199,47 +278,18 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
#else
nanosleep(&Interval, nullptr);
#endif
- bool LockFileJustDisappeared = false;
-
- // If the lock file is still expected to be there, check whether it still
- // is.
- if (!LockFileGone) {
- if (sys::fs::access(LockFileName.c_str(), sys::fs::AccessMode::Exist) ==
- errc::no_such_file_or_directory) {
- 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 (sys::fs::access(LockFileName.c_str(), sys::fs::AccessMode::Exist) ==
+ errc::no_such_file_or_directory) {
+ // If the original file wasn't created, somone thought the lock was dead.
+ if (!sys::fs::exists(FileName))
+ return Res_OwnerDied;
+ return Res_Success;
}
- // 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)) {
+ // If the process owning the lock died without cleaning up, just bail out.
+ if (!processStillExecuting((*Owner).first, (*Owner).second))
return Res_OwnerDied;
- }
// Exponentially increase the time we wait for the lock to be removed.
#if LLVM_ON_WIN32
@@ -263,3 +313,7 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
// Give up.
return Res_Timeout;
}
+
+std::error_code LockFileManager::unsafeRemoveLockFile() {
+ return sys::fs::remove(LockFileName);
+}
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