2.5-18.1

1 files changed, 316 insertions, 11 deletions

diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c
index 7008af3d97..66aca8e4b2 100644
--- a/nptl/pthread_mutex_trylock.c
+++ b/nptl/pthread_mutex_trylock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2006, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -17,7 +17,9 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <assert.h>
 #include <errno.h>
+#include <stdlib.h>
 #include "pthreadP.h"
 #include <lowlevellock.h>
 
@@ -26,13 +28,13 @@ int
 __pthread_mutex_trylock (mutex)
      pthread_mutex_t *mutex;
 {
-  pid_t id;
+  int oldval;
+  pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
 
   switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
     {
       /* Recursive mutex.  */
     case PTHREAD_MUTEX_RECURSIVE_NP:
-      id = THREAD_GETMEM (THREAD_SELF, tid);
       /* Check whether we already hold the mutex.  */
       if (mutex->__data.__owner == id)
 	{
@@ -56,20 +58,323 @@ __pthread_mutex_trylock (mutex)
       break;
 
     case PTHREAD_MUTEX_ERRORCHECK_NP:
-      /* Error checking mutex.  We do not check for deadlocks.  */
-    default:
-      /* Correct code cannot set any other type.  */
+      /* Check whether we already hold the mutex.  */
+      if (__builtin_expect (mutex->__data.__owner == id, 0))
+	return EDEADLK;
+
+      /* FALLTHROUGH */
+
     case PTHREAD_MUTEX_TIMED_NP:
     case PTHREAD_MUTEX_ADAPTIVE_NP:
       /* Normal mutex.  */
-      if (lll_mutex_trylock (mutex->__data.__lock) == 0)
+      if (lll_mutex_trylock (mutex->__data.__lock) != 0)
+	break;
+
+      /* Record the ownership.  */
+      mutex->__data.__owner = id;
+      ++mutex->__data.__nusers;
+
+      return 0;
+
+
+    case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP:
+    case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP:
+    case PTHREAD_MUTEX_ROBUST_NORMAL_NP:
+    case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP:
+      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
+		     &mutex->__data.__list.__next);
+
+      oldval = mutex->__data.__lock;
+      do
 	{
-	  /* Record the ownership.  */
-	  mutex->__data.__owner = THREAD_GETMEM (THREAD_SELF, tid);
-	  ++mutex->__data.__nusers;
+	again:
+	  if ((oldval & FUTEX_OWNER_DIED) != 0)
+	    {
+	      /* The previous owner died.  Try locking the mutex.  */
+	      int newval = id | (oldval & FUTEX_WAITERS);
 
-	  return 0;
+	      newval
+		= atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						       newval, oldval);
+
+	      if (newval != oldval)
+		{
+		  oldval = newval;
+		  goto again;
+		}
+
+	      /* We got the mutex.  */
+	      mutex->__data.__count = 1;
+	      /* But it is inconsistent unless marked otherwise.  */
+	      mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT;
+
+	      ENQUEUE_MUTEX (mutex);
+	      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+	      /* Note that we deliberately exist here.  If we fall
+		 through to the end of the function __nusers would be
+		 incremented which is not correct because the old
+		 owner has to be discounted.  */
+	      return EOWNERDEAD;
+	    }
+
+	  /* Check whether we already hold the mutex.  */
+	  if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0))
+	    {
+	      if (mutex->__data.__kind
+		  == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP)
+		{
+		  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
+				 NULL);
+		  return EDEADLK;
+		}
+
+	      if (mutex->__data.__kind
+		  == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP)
+		{
+		  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
+				 NULL);
+
+		  /* Just bump the counter.  */
+		  if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
+		    /* Overflow of the counter.  */
+		    return EAGAIN;
+
+		  ++mutex->__data.__count;
+
+		  return 0;
+		}
+	    }
+
+	  oldval = lll_robust_mutex_trylock (mutex->__data.__lock, id);
+	  if (oldval != 0 && (oldval & FUTEX_OWNER_DIED) == 0)
+	    {
+	      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+	      return EBUSY;
+	    }
+
+	  if (__builtin_expect (mutex->__data.__owner
+				== PTHREAD_MUTEX_NOTRECOVERABLE, 0))
+	    {
+	      /* This mutex is now not recoverable.  */
+	      mutex->__data.__count = 0;
+	      if (oldval == id)
+		lll_mutex_unlock (mutex->__data.__lock);
+	      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+	      return ENOTRECOVERABLE;
+	    }
 	}
+      while ((oldval & FUTEX_OWNER_DIED) != 0);
+
+      ENQUEUE_MUTEX (mutex);
+      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+      mutex->__data.__owner = id;
+      ++mutex->__data.__nusers;
+      mutex->__data.__count = 1;
+
+      return 0;
+
+    case PTHREAD_MUTEX_PI_RECURSIVE_NP:
+    case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
+    case PTHREAD_MUTEX_PI_NORMAL_NP:
+    case PTHREAD_MUTEX_PI_ADAPTIVE_NP:
+    case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP:
+    case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP:
+    case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP:
+    case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP:
+      {
+	int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP;
+	int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP;
+
+	if (robust)
+	  /* Note: robust PI futexes are signaled by setting bit 0.  */
+	  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
+			 (void *) (((uintptr_t) &mutex->__data.__list.__next)
+				   | 1));
+
+	oldval = mutex->__data.__lock;
+
+	/* Check whether we already hold the mutex.  */
+	if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0))
+	  {
+	    if (kind == PTHREAD_MUTEX_ERRORCHECK_NP)
+	      {
+		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+		return EDEADLK;
+	      }
+
+	    if (kind == PTHREAD_MUTEX_RECURSIVE_NP)
+	      {
+		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+		/* Just bump the counter.  */
+		if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
+		  /* Overflow of the counter.  */
+		  return EAGAIN;
+
+		++mutex->__data.__count;
+
+		return 0;
+	      }
+	  }
+
+	oldval
+	  = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						 id, 0);
+
+	if (oldval != 0)
+	  {
+	    if ((oldval & FUTEX_OWNER_DIED) == 0)
+	      {
+		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+		return EBUSY;
+	      }
+
+	    assert (robust);
+
+	    /* The mutex owner died.  The kernel will now take care of
+	       everything.  */
+	    INTERNAL_SYSCALL_DECL (__err);
+	    int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock,
+				      FUTEX_TRYLOCK_PI, 0, 0);
+
+	    if (INTERNAL_SYSCALL_ERROR_P (e, __err)
+		&& INTERNAL_SYSCALL_ERRNO (e, __err) == EWOULDBLOCK)
+	      {
+		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+		return EBUSY;
+	      }
+
+	    oldval = mutex->__data.__lock;
+	  }
+
+	if (__builtin_expect (oldval & FUTEX_OWNER_DIED, 0))
+	  {
+	    atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED);
+
+	    /* We got the mutex.  */
+	    mutex->__data.__count = 1;
+	    /* But it is inconsistent unless marked otherwise.  */
+	    mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT;
+
+	    ENQUEUE_MUTEX (mutex);
+	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+
+	    /* Note that we deliberately exit here.  If we fall
+	       through to the end of the function __nusers would be
+	       incremented which is not correct because the old owner
+	       has to be discounted.  */
+	    return EOWNERDEAD;
+	  }
+
+	if (robust
+	    && __builtin_expect (mutex->__data.__owner
+				 == PTHREAD_MUTEX_NOTRECOVERABLE, 0))
+	  {
+	    /* This mutex is now not recoverable.  */
+	    mutex->__data.__count = 0;
+
+	    INTERNAL_SYSCALL_DECL (__err);
+	    INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock,
+			      FUTEX_UNLOCK_PI, 0, 0);
+
+	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+	    return ENOTRECOVERABLE;
+	  }
+
+	if (robust)
+	  {
+	    ENQUEUE_MUTEX_PI (mutex);
+	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
+	  }
+
+	mutex->__data.__owner = id;
+	++mutex->__data.__nusers;
+	mutex->__data.__count = 1;
+
+	return 0;
+      }
+
+    case PTHREAD_MUTEX_PP_RECURSIVE_NP:
+    case PTHREAD_MUTEX_PP_ERRORCHECK_NP:
+    case PTHREAD_MUTEX_PP_NORMAL_NP:
+    case PTHREAD_MUTEX_PP_ADAPTIVE_NP:
+      {
+	int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP;
+
+	oldval = mutex->__data.__lock;
+
+	/* Check whether we already hold the mutex.  */
+	if (mutex->__data.__owner == id)
+	  {
+	    if (kind == PTHREAD_MUTEX_ERRORCHECK_NP)
+	      return EDEADLK;
+
+	    if (kind == PTHREAD_MUTEX_RECURSIVE_NP)
+	      {
+		/* Just bump the counter.  */
+		if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
+		  /* Overflow of the counter.  */
+		  return EAGAIN;
+
+		++mutex->__data.__count;
+
+		return 0;
+	      }
+	  }
+
+	int oldprio = -1, ceilval;
+	do
+	  {
+	    int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK)
+			  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
+
+	    if (__pthread_current_priority () > ceiling)
+	      {
+		if (oldprio != -1)
+		  __pthread_tpp_change_priority (oldprio, -1);
+		return EINVAL;
+	      }
+
+	    int retval = __pthread_tpp_change_priority (oldprio, ceiling);
+	    if (retval)
+	      return retval;
+
+	    ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
+	    oldprio = ceiling;
+
+	    oldval
+	      = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						     ceilval | 1, ceilval);
+
+	    if (oldval == ceilval)
+	      break;
+	  }
+	while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval);
+
+	if (oldval != ceilval)
+	  {
+	    __pthread_tpp_change_priority (oldprio, -1);
+	    break;
+	  }
+
+	assert (mutex->__data.__owner == 0);
+	/* Record the ownership.  */
+	mutex->__data.__owner = id;
+	++mutex->__data.__nusers;
+	mutex->__data.__count = 1;
+
+	return 0;
+      }
+      break;
+
+    default:
+      /* Correct code cannot set any other type.  */
+      return EINVAL;
     }
 
   return EBUSY;