Update.
[kopensolaris-gnu/glibc.git] / linuxthreads / rwlock.c
index e1401c3..f565f18 100644 (file)
@@ -5,20 +5,21 @@
    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.  */
 
+#include <bits/libc-lock.h>
 #include <errno.h>
 #include <pthread.h>
 #include <stdlib.h>
 #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 +66,8 @@ 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 +87,10 @@ 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;
+    THREAD_SETMEM (self, p_readlock_free, info->pr_next);
   else
     info = malloc(sizeof *info);
 
@@ -70,8 +99,8 @@ 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;
 }
@@ -161,11 +190,12 @@ 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
        {
@@ -177,14 +207,13 @@ rwlock_have_already(pthread_descr *pself, pthread_rwlock_t *rwlock,
 
   *pout_of_mem = out_of_mem;
   *pexisting = existing;
-  *pself = self;
 
   return have_lock_already;
 }
 
 int
-pthread_rwlock_init (pthread_rwlock_t *rwlock,
-                    const pthread_rwlockattr_t *attr)
+__pthread_rwlock_init (pthread_rwlock_t *rwlock,
+                      const pthread_rwlockattr_t *attr)
 {
   __pthread_init_lock(&rwlock->__rw_lock);
   rwlock->__rw_readers = 0;
@@ -205,10 +234,11 @@ pthread_rwlock_init (pthread_rwlock_t *rwlock,
 
   return 0;
 }
+strong_alias (__pthread_rwlock_init, pthread_rwlock_init)
 
 
 int
-pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
+__pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
 {
   int readers;
   _pthread_descr writer;
@@ -223,22 +253,23 @@ pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
 
   return 0;
 }
+strong_alias (__pthread_rwlock_destroy, pthread_rwlock_destroy)
 
 int
-pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
 {
   pthread_descr self = NULL;
   pthread_readlock_info *existing;
   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))
@@ -255,16 +286,88 @@ 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;
+    }
+
+  return 0;
+}
+strong_alias (__pthread_rwlock_rdlock, pthread_rwlock_rdlock)
+
+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++;
+       ++self->p_untracked_readlock_count;
     }
 
   return 0;
 }
+strong_alias (__pthread_rwlock_timedrdlock, pthread_rwlock_timedrdlock)
 
 int
-pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
 {
   pthread_descr self = thread_self();
   pthread_readlock_info *existing;
@@ -295,18 +398,19 @@ 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;
 }
+strong_alias (__pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock)
 
 
 int
-pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
 {
   pthread_descr self = thread_self ();
 
@@ -326,10 +430,68 @@ pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
       suspend (self); /* This is not a cancellation point */
     }
 }
+strong_alias (__pthread_rwlock_wrlock, pthread_rwlock_wrlock)
 
 
 int
-pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
+__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);
+       }
+    }
+}
+strong_alias (__pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock)
+
+
+int
+__pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
 {
   int result = EBUSY;
 
@@ -343,10 +505,11 @@ pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
 
   return result;
 }
+strong_alias (__pthread_rwlock_trywrlock, pthread_rwlock_trywrlock)
 
 
 int
-pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 {
   pthread_descr torestart;
   pthread_descr th;
@@ -411,20 +574,22 @@ 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);
            }
        }
     }
 
   return 0;
 }
+strong_alias (__pthread_rwlock_unlock, pthread_rwlock_unlock)
 
 
 
@@ -432,17 +597,18 @@ int
 pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
 {
   attr->__lockkind = 0;
-  attr->__pshared = 0;
+  attr->__pshared = PTHREAD_PROCESS_PRIVATE;
 
   return 0;
 }
 
 
 int
-pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
+__pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
 {
   return 0;
 }
+strong_alias (__pthread_rwlockattr_destroy, pthread_rwlockattr_destroy)
 
 
 int
@@ -459,6 +625,10 @@ 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;