sync with glibc and import pthread_rwlock_timed{rd,wr}lock in the process

libpthread/linuxthreads/rwlock.c

@@ -1,20 +1,20 @@
 /* Read-write lock implementation.
-   Copyright (C) 1998 Free Software Foundation, Inc.
+   Copyright (C) 1998, 2000 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Xavier Leroy <Xavier.Leroy@inria.fr>
    and Ulrich Drepper <drepper@cygnus.com>, 1998.
 
    The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Library General Public License as
-   published by the Free Software Foundation; either version 2 of the
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
    License, or (at your option) any later version.
 
    The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Library General Public License for more details.
+   Lesser General Public License for more details.
 
-   You should have received a copy of the GNU Library General Public
+   You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; see the file COPYING.LIB.  If not,
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
@@ -27,6 +27,33 @@
 #include "spinlock.h"
 #include "restart.h"
 
+/* Function called by pthread_cancel to remove the thread from
+   waiting inside pthread_rwlock_timedrdlock or pthread_rwlock_timedwrlock. */
+
+static int rwlock_rd_extricate_func(void *obj, pthread_descr th)
+{
+  pthread_rwlock_t *rwlock = obj;
+  int did_remove = 0;
+
+  __pthread_lock(&rwlock->__rw_lock, NULL);
+  did_remove = remove_from_queue(&rwlock->__rw_read_waiting, th);
+  __pthread_unlock(&rwlock->__rw_lock);
+
+  return did_remove;
+}
+
+static int rwlock_wr_extricate_func(void *obj, pthread_descr th)
+{
+  pthread_rwlock_t *rwlock = obj;
+  int did_remove = 0;
+
+  __pthread_lock(&rwlock->__rw_lock, NULL);
+  did_remove = remove_from_queue(&rwlock->__rw_write_waiting, th);
+  __pthread_unlock(&rwlock->__rw_lock);
+
+  return did_remove;
+}
+
 /*
  * Check whether the calling thread already owns one or more read locks on the
  * specified lock. If so, return a pointer to the read lock info structure
@@ -38,7 +65,8 @@ rwlock_is_in_list(pthread_descr self, pthread_rwlock_t *rwlock)
 {
   pthread_readlock_info *info;
 
-  for (info = self->p_readlock_list; info != NULL; info = info->pr_next)
+  for (info = THREAD_GETMEM (self, p_readlock_list); info != NULL;
+       info = info->pr_next)
     {
       if (info->pr_lock == rwlock)
 	return info;
@@ -58,10 +86,10 @@ rwlock_is_in_list(pthread_descr self, pthread_rwlock_t *rwlock)
 static pthread_readlock_info *
 rwlock_add_to_list(pthread_descr self, pthread_rwlock_t *rwlock)
 {
-  pthread_readlock_info *info = self->p_readlock_free;
+  pthread_readlock_info *info = THREAD_GETMEM (self, p_readlock_free);
 
-  if (info != NULL) 
-    self->p_readlock_free = info->pr_next;
+  if (info != NULL)
+    THREAD_SETMEM (self, p_readlock_free, info->pr_next);
   else
     info = malloc(sizeof *info);
 
@@ -70,8 +98,8 @@ rwlock_add_to_list(pthread_descr self, pthread_rwlock_t *rwlock)
 
   info->pr_lock_count = 1;
   info->pr_lock = rwlock;
-  info->pr_next = self->p_readlock_list;
-  self->p_readlock_list = info;
+  info->pr_next = THREAD_GETMEM (self, p_readlock_list);
+  THREAD_SETMEM (self, p_readlock_list, info);
 
   return info;
 }
@@ -100,7 +128,7 @@ rwlock_remove_from_list(pthread_descr self, pthread_rwlock_t *rwlock)
 	  return info;
 	}
     }
-  
+
   return NULL;
 }
 
@@ -137,7 +165,7 @@ rwlock_can_rdlock(pthread_rwlock_t *rwlock, int have_lock_already)
  * This function helps support brain-damaged recursive read locking
  * semantics required by Unix 98, while maintaining write priority.
  * This basically determines whether this thread already holds a read lock
- * already. It returns 1 if so, otherwise it returns 0.  
+ * already. It returns 1 if so, otherwise it returns 0.
  *
  * If the thread has any ``untracked read locks'' then it just assumes
  * that this lock is among them, just to be safe, and returns 1.
@@ -161,11 +189,12 @@ rwlock_have_already(pthread_descr *pself, pthread_rwlock_t *rwlock,
   if (rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_WRITER_NP)
     {
       if (!self)
-	self = thread_self();
+	*pself = self = thread_self();
 
       existing = rwlock_is_in_list(self, rwlock);
 
-      if (existing != NULL || self->p_untracked_readlock_count > 0)
+      if (existing != NULL
+	  || THREAD_GETMEM (self, p_untracked_readlock_count) > 0)
 	have_lock_already = 1;
       else
 	{
@@ -177,7 +206,6 @@ rwlock_have_already(pthread_descr *pself, pthread_rwlock_t *rwlock,
 
   *pout_of_mem = out_of_mem;
   *pexisting = existing;
-  *pself = self;
 
   return have_lock_already;
 }
@@ -207,6 +235,7 @@ pthread_rwlock_init (pthread_rwlock_t *rwlock,
 }
 
 
+
 int
 pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
 {
@@ -224,6 +253,7 @@ pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
   return 0;
 }
 
+
 int
 pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
 {
@@ -232,13 +262,13 @@ pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
   int out_of_mem, have_lock_already;
 
   have_lock_already = rwlock_have_already(&self, rwlock,
-      &existing, &out_of_mem);
+					  &existing, &out_of_mem);
+
+  if (self == NULL)
+    self = thread_self ();
 
   for (;;)
     {
-      if (self == NULL)
-	self = thread_self ();
-
       __pthread_lock (&rwlock->__rw_lock, self);
 
       if (rwlock_can_rdlock(rwlock, have_lock_already))
@@ -255,14 +285,86 @@ pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
   if (have_lock_already || out_of_mem)
     {
       if (existing != NULL)
-	existing->pr_lock_count++;
+	++existing->pr_lock_count;
       else
-	self->p_untracked_readlock_count++;
+	++self->p_untracked_readlock_count;
     }
-  
+
   return 0;
 }
 
+
+int
+pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
+			      const struct timespec *abstime)
+{
+  pthread_descr self = NULL;
+  pthread_readlock_info *existing;
+  int out_of_mem, have_lock_already;
+  pthread_extricate_if extr;
+
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  have_lock_already = rwlock_have_already(&self, rwlock,
+					  &existing, &out_of_mem);
+
+  if (self == NULL)
+    self = thread_self ();
+
+  /* Set up extrication interface */
+  extr.pu_object = rwlock;
+  extr.pu_extricate_func = rwlock_rd_extricate_func;
+
+  /* Register extrication interface */
+  __pthread_set_own_extricate_if (self, &extr);
+
+  for (;;)
+    {
+      __pthread_lock (&rwlock->__rw_lock, self);
+
+      if (rwlock_can_rdlock(rwlock, have_lock_already))
+	break;
+
+      enqueue (&rwlock->__rw_read_waiting, self);
+      __pthread_unlock (&rwlock->__rw_lock);
+      /* This is not a cancellation point */
+      if (timedsuspend (self, abstime) == 0)
+	{
+	  int was_on_queue;
+
+	  __pthread_lock (&rwlock->__rw_lock, self);
+	  was_on_queue = remove_from_queue (&rwlock->__rw_read_waiting, self);
+	  __pthread_unlock (&rwlock->__rw_lock);
+
+	  if (was_on_queue)
+	    {
+	      __pthread_set_own_extricate_if (self, 0);
+	      return ETIMEDOUT;
+	    }
+
+	  /* Eat the outstanding restart() from the signaller */
+	  suspend (self);
+	}
+    }
+
+  __pthread_set_own_extricate_if (self, 0);
+
+  ++rwlock->__rw_readers;
+  __pthread_unlock (&rwlock->__rw_lock);
+
+  if (have_lock_already || out_of_mem)
+    {
+      if (existing != NULL)
+	++existing->pr_lock_count;
+      else
+	++self->p_untracked_readlock_count;
+    }
+
+  return 0;
+}
+
+
 int
 pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
 {
@@ -277,7 +379,7 @@ pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
   __pthread_lock (&rwlock->__rw_lock, self);
 
   /* 0 is passed to here instead of have_lock_already.
-     This is to meet Single Unix Spec requirements: 
+     This is to meet Single Unix Spec requirements:
      if writers are waiting, pthread_rwlock_tryrdlock
      does not acquire a read lock, even if the caller has
      one or more read locks already. */
@@ -295,16 +397,17 @@ pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
       if (have_lock_already || out_of_mem)
 	{
 	  if (existing != NULL)
-	    existing->pr_lock_count++;
+	    ++existing->pr_lock_count;
 	  else
-	    self->p_untracked_readlock_count++;
+	    ++self->p_untracked_readlock_count;
 	}
     }
-  
+
   return retval;
 }
 
 
+
 int
 pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
 {
@@ -328,6 +431,64 @@ pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
 }
 
 
+
+int
+pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
+			      const struct timespec *abstime)
+{
+  pthread_descr self;
+  pthread_extricate_if extr;
+
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  self = thread_self ();
+
+  /* Set up extrication interface */
+  extr.pu_object = rwlock;
+  extr.pu_extricate_func =  rwlock_wr_extricate_func;
+
+  /* Register extrication interface */
+  __pthread_set_own_extricate_if (self, &extr);
+
+  while(1)
+    {
+      __pthread_lock (&rwlock->__rw_lock, self);
+
+      if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL)
+	{
+	  rwlock->__rw_writer = self;
+	  __pthread_set_own_extricate_if (self, 0);
+	  __pthread_unlock (&rwlock->__rw_lock);
+	  return 0;
+	}
+
+      /* Suspend ourselves, then try again */
+      enqueue (&rwlock->__rw_write_waiting, self);
+      __pthread_unlock (&rwlock->__rw_lock);
+      /* This is not a cancellation point */
+      if (timedsuspend (self, abstime) == 0)
+	{
+	  int was_on_queue;
+
+	  __pthread_lock (&rwlock->__rw_lock, self);
+	  was_on_queue = remove_from_queue (&rwlock->__rw_write_waiting, self);
+	  __pthread_unlock (&rwlock->__rw_lock);
+
+	  if (was_on_queue)
+	    {
+	      __pthread_set_own_extricate_if (self, 0);
+	      return ETIMEDOUT;
+	    }
+
+	  /* Eat the outstanding restart() from the signaller */
+	  suspend (self);
+	}
+    }
+}
+
+
+
 int
 pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
 {
@@ -345,6 +506,7 @@ pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
 }
 
 
+
 int
 pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 {
@@ -362,8 +524,9 @@ pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 	}
       rwlock->__rw_writer = NULL;
 
-      if (rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
-	  || (th = dequeue (&rwlock->__rw_write_waiting)) == NULL)
+      if ((rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+	   && !queue_is_empty(&rwlock->__rw_read_waiting))
+	  || (th = dequeue(&rwlock->__rw_write_waiting)) == NULL)
 	{
 	  /* Restart all waiting readers.  */
 	  torestart = rwlock->__rw_read_waiting;
@@ -410,14 +573,15 @@ pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 	    {
 	      if (victim->pr_lock_count == 0)
 		{
-		  victim->pr_next = self->p_readlock_free;
-		  self->p_readlock_free = victim;
+		  victim->pr_next = THREAD_GETMEM (self, p_readlock_free);
+		  THREAD_SETMEM (self, p_readlock_free, victim);
 		}
 	    }
 	  else
 	    {
-	      if (self->p_untracked_readlock_count > 0)
-		self->p_untracked_readlock_count--;
+	      int val = THREAD_GETMEM (self, p_untracked_readlock_count);
+	      if (val > 0)
+		THREAD_SETMEM (self, p_untracked_readlock_count, val - 1);
 	    }
 	}
     }
@@ -427,11 +591,12 @@ pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 
 
 
+
 int
 pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
 {
   attr->__lockkind = 0;
-  attr->__pshared = 0;
+  attr->__pshared = PTHREAD_PROCESS_PRIVATE;
 
   return 0;
 }
@@ -444,6 +609,7 @@ pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
 }
 
 
+
 int
 pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *attr, int *pshared)
 {
@@ -458,6 +624,10 @@ pthread_rwlockattr_setpshared (pthread_rwlockattr_t *attr, int pshared)
   if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
     return EINVAL;
 
+  /* For now it is not possible to shared a conditional variable.  */
+  if (pshared != PTHREAD_PROCESS_PRIVATE)
+    return ENOSYS;
+
   attr->__pshared = pshared;
 
   return 0;
@@ -477,6 +647,7 @@ pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *attr, int pref)
 {
   if (pref != PTHREAD_RWLOCK_PREFER_READER_NP
       && pref != PTHREAD_RWLOCK_PREFER_WRITER_NP
+      && pref != PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP
       && pref != PTHREAD_RWLOCK_DEFAULT_NP)
     return EINVAL;
 

libpthread/linuxthreads/sysdeps/pthread/pthread.h

@@ -462,27 +462,25 @@ extern int pthread_rwlock_rdlock (pthread_rwlock_t *__rwlock) __THROW;
 /* Try to acquire read lock for RWLOCK.  */
 extern int pthread_rwlock_tryrdlock (pthread_rwlock_t *__rwlock) __THROW;
 
+# ifdef __USE_XOPEN2K
+/* Try to acquire read lock for RWLOCK or return after specfied time.  */
+extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
+				       __const struct timespec *__restrict
+				       __abstime) __THROW;
+# endif
+
 /* Acquire write lock for RWLOCK.  */
 extern int pthread_rwlock_wrlock (pthread_rwlock_t *__rwlock) __THROW;
 
 /* Try to acquire write lock for RWLOCK.  */
 extern int pthread_rwlock_trywrlock (pthread_rwlock_t *__rwlock) __THROW;
 
-#if 0
-/* Not yet implemented in uClibc! */
-
-#ifdef __USE_XOPEN2K
-/* Try to acquire read lock for RWLOCK or return after specfied time.  */
-extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
-				       __const struct timespec *__restrict
-				       __abstime) __THROW;
+# ifdef __USE_XOPEN2K
 /* Try to acquire write lock for RWLOCK or return after specfied time.  */
 extern int pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
 				       __const struct timespec *__restrict
 				       __abstime) __THROW;
-#endif
-#endif
-
+# endif
 
 /* Unlock RWLOCK.  */
 extern int pthread_rwlock_unlock (pthread_rwlock_t *__rwlock) __THROW;