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-rw-r--r--lib/Support/LockFileManager.cpp95
1 files changed, 56 insertions, 39 deletions
diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp
index ec951f33a36a..77baf7ac4bdd 100644
--- a/lib/Support/LockFileManager.cpp
+++ b/lib/Support/LockFileManager.cpp
@@ -24,7 +24,7 @@
#include <sys/types.h>
#include <system_error>
#include <tuple>
-#if LLVM_ON_WIN32
+#if _WIN32
#include <windows.h>
#endif
#if LLVM_ON_UNIX
@@ -43,7 +43,7 @@
using namespace llvm;
-/// \brief Attempt to read the lock file with the given name, if it exists.
+/// Attempt to read the lock file with the given name, if it exists.
///
/// \param LockFileName The name of the lock file to read.
///
@@ -123,21 +123,33 @@ bool LockFileManager::processStillExecuting(StringRef HostID, int PID) {
namespace {
-/// An RAII helper object for cleanups.
-class RAIICleanup {
- std::function<void()> Fn;
- bool Canceled = false;
-
+/// 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:
- RAIICleanup(std::function<void()> Fn) : Fn(Fn) {}
+ RemoveUniqueLockFileOnSignal(StringRef Name)
+ : Filename(Name), RemoveImmediately(true) {
+ sys::RemoveFileOnSignal(Filename, nullptr);
+ }
- ~RAIICleanup() {
- if (Canceled)
+ ~RemoveUniqueLockFileOnSignal() {
+ if (!RemoveImmediately) {
+ // Leave the signal handler enabled. It will be removed when the lock is
+ // released.
return;
- Fn();
+ }
+ sys::fs::remove(Filename);
+ sys::DontRemoveFileOnSignal(Filename);
}
- void cancel() { Canceled = true; }
+ void lockAcquired() { RemoveImmediately = false; }
};
} // end anonymous namespace
@@ -160,22 +172,16 @@ LockFileManager::LockFileManager(StringRef FileName)
return;
// Create a lock file that is unique to this instance.
- Expected<sys::fs::TempFile> Temp =
- sys::fs::TempFile::create(LockFileName + "-%%%%%%%%");
- if (!Temp) {
- std::error_code EC = errorToErrorCode(Temp.takeError());
- std::string S("failed to create unique file with prefix ");
- S.append(LockFileName.str());
+ UniqueLockFileName = LockFileName;
+ UniqueLockFileName += "-%%%%%%%%";
+ int UniqueLockFileID;
+ if (std::error_code EC = sys::fs::createUniqueFile(
+ UniqueLockFileName, UniqueLockFileID, UniqueLockFileName)) {
+ std::string S("failed to create unique file ");
+ S.append(UniqueLockFileName.str());
setError(EC, S);
return;
}
- UniqueLockFile = std::move(*Temp);
-
- // Make sure we discard the temporary file on exit.
- RAIICleanup RemoveTempFile([&]() {
- if (Error E = UniqueLockFile->discard())
- setError(errorToErrorCode(std::move(E)));
- });
// Write our process ID to our unique lock file.
{
@@ -185,46 +191,54 @@ LockFileManager::LockFileManager(StringRef FileName)
return;
}
- raw_fd_ostream Out(UniqueLockFile->FD, /*shouldClose=*/false);
+ raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
Out << HostID << ' ';
#if LLVM_ON_UNIX
Out << getpid();
#else
Out << "1";
#endif
- Out.flush();
+ Out.close();
if (Out.has_error()) {
// We failed to write out PID, so report the error, remove the
// unique lock file, and fail.
std::string S("failed to write to ");
- S.append(UniqueLockFile->TmpName);
+ S.append(UniqueLockFileName.str());
setError(Out.error(), S);
+ 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 (true) {
// Create a link from the lock file name. If this succeeds, we're done.
std::error_code EC =
- sys::fs::create_link(UniqueLockFile->TmpName, LockFileName);
+ sys::fs::create_link(UniqueLockFileName, LockFileName);
if (!EC) {
- RemoveTempFile.cancel();
+ RemoveUniqueFile.lockAcquired();
return;
}
if (EC != errc::file_exists) {
std::string S("failed to create link ");
raw_string_ostream OSS(S);
- OSS << LockFileName.str() << " to " << UniqueLockFile->TmpName;
+ OSS << LockFileName.str() << " to " << UniqueLockFileName.str();
setError(EC, OSS.str());
return;
}
// Someone else managed to create the lock file first. Read the process ID
// from the lock file.
- if ((Owner = readLockFile(LockFileName)))
- return; // RemoveTempFile will delete out our unique lock file.
+ if ((Owner = readLockFile(LockFileName))) {
+ // Wipe out our unique lock file (it's useless now)
+ sys::fs::remove(UniqueLockFileName);
+ return;
+ }
if (!sys::fs::exists(LockFileName)) {
// The previous owner released the lock file before we could read it.
@@ -236,7 +250,7 @@ LockFileManager::LockFileManager(StringRef FileName)
// ownership.
if ((EC = sys::fs::remove(LockFileName))) {
std::string S("failed to remove lockfile ");
- S.append(LockFileName.str());
+ S.append(UniqueLockFileName.str());
setError(EC, S);
return;
}
@@ -271,14 +285,17 @@ LockFileManager::~LockFileManager() {
// Since we own the lock, remove the lock file and our own unique lock file.
sys::fs::remove(LockFileName);
- consumeError(UniqueLockFile->discard());
+ 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() {
if (getState() != LFS_Shared)
return Res_Success;
-#if LLVM_ON_WIN32
+#if _WIN32
unsigned long Interval = 1;
#else
struct timespec Interval;
@@ -293,7 +310,7 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
// finish up and remove the lock file.
// FIXME: Should we hook in to system APIs to get a notification when the
// lock file is deleted?
-#if LLVM_ON_WIN32
+#if _WIN32
Sleep(Interval);
#else
nanosleep(&Interval, nullptr);
@@ -312,7 +329,7 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
return Res_OwnerDied;
// Exponentially increase the time we wait for the lock to be removed.
-#if LLVM_ON_WIN32
+#if _WIN32
Interval *= 2;
#else
Interval.tv_sec *= 2;
@@ -323,7 +340,7 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
}
#endif
} while (
-#if LLVM_ON_WIN32
+#if _WIN32
Interval < MaxSeconds * 1000
#else
Interval.tv_sec < (time_t)MaxSeconds
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-06 02:27:59 +0000