From ed218e5820742f08d42f213ad6881eaf15f35f71 Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Mon, 17 Aug 2009 17:07:22 +0000
Subject: [PATCH] Add locking around signal handler registration.

llvm-svn: 79254
---
 lib/System/Unix/Signals.inc | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/System/Unix/Signals.inc b/lib/System/Unix/Signals.inc
index e385e0c5566..d39e1e99a0c 100644
--- a/lib/System/Unix/Signals.inc
+++ b/lib/System/Unix/Signals.inc
@@ -14,6 +14,7 @@
 
 #include "Unix.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/System/Mutex.h"
 #include <vector>
 #include <algorithm>
 #if HAVE_EXECINFO_H
@@ -33,6 +34,8 @@ using namespace llvm;
 
 static RETSIGTYPE SignalHandler(int Sig);  // defined below.
 
+static SmartMutex<true> SignalsMutex;
+
 /// InterruptFunction - The function to call if ctrl-c is pressed.
 static void (*InterruptFunction)() = 0;
 
@@ -113,6 +116,7 @@ static RETSIGTYPE SignalHandler(int Sig) {
   sigfillset(&SigMask);
   sigprocmask(SIG_UNBLOCK, &SigMask, 0);
 
+  SignalsMutex.acquire();
   if (FilesToRemove != 0)
     while (!FilesToRemove->empty()) {
       FilesToRemove->back().eraseFromDisk(true);
@@ -122,14 +126,19 @@ static RETSIGTYPE SignalHandler(int Sig) {
   if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) {
     if (InterruptFunction) {
       void (*IF)() = InterruptFunction;
+      SignalsMutex.release();
       InterruptFunction = 0;
       IF();        // run the interrupt function.
       return;
     }
+    
+    SignalsMutex.release();
     raise(Sig);   // Execute the default handler.
     return;
   }
 
+  SignalsMutex.release();
+
   // Otherwise if it is a fault (like SEGV) run any handler.
   if (CallBacksToRun)
     for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
@@ -139,18 +148,23 @@ static RETSIGTYPE SignalHandler(int Sig) {
 
 
 void llvm::sys::SetInterruptFunction(void (*IF)()) {
+  SignalsMutex.acquire();
   InterruptFunction = IF;
+  SignalsMutex.release();
   RegisterHandlers();
 }
 
 // RemoveFileOnSignal - The public API
 bool llvm::sys::RemoveFileOnSignal(const sys::Path &Filename,
                                    std::string* ErrMsg) {
+  SignalsMutex.acquire();
   if (FilesToRemove == 0)
     FilesToRemove = new std::vector<sys::Path>();
 
   FilesToRemove->push_back(Filename);
 
+  SignalsMutex.release();
+
   RegisterHandlers();
   return false;
 }