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-rw-r--r--libpthread/linuxthreads/rwlock.c239
-rw-r--r--libpthread/linuxthreads/sysdeps/pthread/pthread.h20
2 files changed, 214 insertions, 45 deletions
diff --git a/libpthread/linuxthreads/rwlock.c b/libpthread/linuxthreads/rwlock.c
index 977fd88af..4a0fb1bba 100644
--- a/libpthread/linuxthreads/rwlock.c
+++ b/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;
diff --git a/libpthread/linuxthreads/sysdeps/pthread/pthread.h b/libpthread/linuxthreads/sysdeps/pthread/pthread.h
index aaab510c3..6613cab88 100644
--- a/libpthread/linuxthreads/sysdeps/pthread/pthread.h
+++ b/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;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 18:32:22 +0000