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obscure thread-safety fix

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git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@31108 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
Richard Frith-MacDonald 2010-08-10 18:51:53 +00:00
parent 50662ad093
commit a11aedbca8
2 changed files with 38 additions and 27 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
2010-08-10 Richard Frith-Macdonald <rfm@gnu.org>
* Source/NSTask.m: thread-safety fix.
2010-08-10 Richard Frith-Macdonald <rfm@gnu.org>
* Source/NSRunLoop.m:

61
Source/NSTask.m
View file

@ -228,7 +228,6 @@ pty_slave(const char* name)
@interface NSTask (Private)
- (NSString *) _fullLaunchPath;
- (void) _sendNotification;
- (void) _collectChild;
- (void) _terminatedChild: (int)status;
@end
@ -259,8 +258,22 @@ pty_slave(const char* name)
if (tasksLock == nil)
{
tasksLock = [NSRecursiveLock new];
/* The activeTasks map contains all task objects corresponding
* to running subtasks, and retains them until the subtask
* actually terminates.
* The previous implementation stored non-retained objects and
* the -finalize method removed them from the table, but this
* caused a thread safety issue event though table access was
* lock protected:
* If thread1 releases the task at the same time that the subtask
* dies and is 'reaped' by thread2, then there is a window such
* that thread1 can enter -dealloc while thread2 is retaining the
* object in an NSNotification. Then thread1 completes deallocation
* while thread2 performs the notification. Then thread2 tries to
* release the object ... but it's already deallocated.
*/
activeTasks = NSCreateMapTable(NSIntMapKeyCallBacks,
NSNonOwnedPointerMapValueCallBacks, 0);
NSObjectMapValueCallBacks, 0);
}
[gnustep_global_lock unlock];
@ -288,9 +301,7 @@ pty_slave(const char* name)
- (void) finalize
{
[tasksLock lock];
NSMapRemove(activeTasks, (void*)(intptr_t)_taskId);
[tasksLock unlock];
return;
}
- (void) dealloc
@ -880,8 +891,20 @@ pty_slave(const char* name)
return val;
}
- (void) _sendNotification
- (void) _collectChild
{
[self subclassResponsibility: _cmd];
}
- (void) _terminatedChild: (int)status
{
[tasksLock lock];
IF_NO_GC([[self retain] autorelease];)
NSMapRemove(activeTasks, (void*)(intptr_t)_taskId);
[tasksLock unlock];
_terminationStatus = status;
_hasCollected = YES;
_hasTerminated = YES;
if (_hasNotified == NO)
{
NSNotification *n;
@ -898,25 +921,6 @@ pty_slave(const char* name)
}
}
- (void) _collectChild
{
[self subclassResponsibility: _cmd];
}
- (void) _terminatedChild: (int)status
{
[tasksLock lock];
NSMapRemove(activeTasks, (void*)(intptr_t)_taskId);
[tasksLock unlock];
_terminationStatus = status;
_hasCollected = YES;
_hasTerminated = YES;
if (_hasNotified == NO)
{
[self _sendNotification];
}
}
@end
#ifdef __MINGW__
@ -1005,7 +1009,9 @@ static DWORD WINAPI _threadFunction(LPVOID t)
NSConcreteWindowsTask *task;
[tasksLock lock];
task = (NSConcreteWindowsTask*)NSMapGet(activeTasks, (void*)(intptr_t) taskId);
task = (NSConcreteWindowsTask*)NSMapGet(activeTasks,
(void*)(intptr_t) taskId);
IF_NO_GC([[task retain] autorelease];)
[tasksLock unlock];
if (task == nil)
{
@ -1344,6 +1350,7 @@ GSPrivateCheckTasks()
#if defined(WAITDEBUG)
[tasksLock lock];
t = (NSTask*)NSMapGet(activeTasks, (void*)(intptr_t)result);
IF_NO_GC([[t retain] autorelease];)
[tasksLock unlock];
if (t != nil)
{
@ -1356,7 +1363,7 @@ GSPrivateCheckTasks()
{
[tasksLock lock];
t = (NSTask*)NSMapGet(activeTasks, (void*)(intptr_t)result);
IF_NO_GC(AUTORELEASE(RETAIN(t));)
IF_NO_GC([[t retain] autorelease];)
[tasksLock unlock];
if (t != nil)
{