[llvm-commits] [llvm] r172033 - in /llvm/trunk: include/llvm/Support/LockFileManager.h lib/Support/LockFileManager.cpp

[Douglas Gregor]

Author: dgregor
Date: Wed Jan  9 20:01:35 2013
New Revision: 172033

URL: http://llvm.org/viewvc/llvm-project?rev=172033&view=rev
Log:
Fix a race condition in the lock-file manager: once the lock file is
gone, check for the actual file we care about.

Modified:
    llvm/trunk/include/llvm/Support/LockFileManager.h
    llvm/trunk/lib/Support/LockFileManager.cpp

Modified: llvm/trunk/include/llvm/Support/LockFileManager.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/LockFileManager.h?rev=172033&r1=172032&r2=172033&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/LockFileManager.h (original)
+++ llvm/trunk/include/llvm/Support/LockFileManager.h Wed Jan  9 20:01:35 2013
@@ -41,6 +41,7 @@
   };
 
 private:
+  SmallString<128> FileName;
   SmallString<128> LockFileName;
   SmallString<128> UniqueLockFileName;
 

Modified: llvm/trunk/lib/Support/LockFileManager.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/LockFileManager.cpp?rev=172033&r1=172032&r2=172033&view=diff
==============================================================================
--- llvm/trunk/lib/Support/LockFileManager.cpp (original)
+++ llvm/trunk/lib/Support/LockFileManager.cpp Wed Jan  9 20:01:35 2013
@@ -64,6 +64,7 @@
 
 LockFileManager::LockFileManager(StringRef FileName)
 {
+  this->FileName = FileName;
   LockFileName = FileName;
   LockFileName += ".lock";
 
@@ -175,6 +176,7 @@
 #endif
   // Don't wait more than an hour for the file to appear.
   const unsigned MaxSeconds = 3600;
+  bool LockFileGone = false;
   do {
     // Sleep for the designated interval, to allow the owning process time to
     // finish up and remove the lock file.
@@ -185,10 +187,18 @@
 #else
     nanosleep(&Interval, NULL);
 #endif
-    // If the file no longer exists, we're done.
+    // If the lock file no longer exists, wait for the actual file.
     bool Exists = false;
-    if (!sys::fs::exists(LockFileName.str(), Exists) && !Exists)
-      return;
+    if (!LockFileGone) {
+      if (!sys::fs::exists(LockFileName.str(), Exists) && !Exists) {
+        LockFileGone = true;
+        Exists = false;
+      }
+    }
+    if (LockFileGone) {
+      if (!sys::fs::exists(FileName.str(), Exists) && Exists)
+        return;
+    }
 
     if (!processStillExecuting((*Owner).first, (*Owner).second))
       return;