initial import of latest linuxthreads

1 files changed, 304 insertions, 0 deletions

diff --git a/libpthread/linuxthreads/condvar.c b/libpthread/linuxthreads/condvar.c
new file mode 100644
index 000000000..d049d9782
--- /dev/null
+++ b/libpthread/linuxthreads/condvar.c
@@ -0,0 +1,304 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix        */
+/* threads for Linux.                                                   */
+/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
+/* and Pavel Krauz (krauz@fsid.cvut.cz).                                */
+/*                                                                      */
+/* This program 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 License, or (at your option) any later version.               */
+/*                                                                      */
+/* This program 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.                 */
+
+/* Condition variables */
+
+#include <errno.h>
+#include <sched.h>
+#include <stddef.h>
+#include <sys/time.h>
+#include "pthread.h"
+#include "internals.h"
+#include "spinlock.h"
+#include "queue.h"
+#include "restart.h"
+
+int __pthread_cond_init(pthread_cond_t *cond,
+                        const pthread_condattr_t *cond_attr)
+{
+  __pthread_init_lock(&cond->__c_lock);
+  cond->__c_waiting = NULL;
+  return 0;
+}
+strong_alias (__pthread_cond_init, pthread_cond_init)
+
+int __pthread_cond_destroy(pthread_cond_t *cond)
+{
+  if (cond->__c_waiting != NULL) return EBUSY;
+  return 0;
+}
+strong_alias (__pthread_cond_destroy, pthread_cond_destroy)
+
+/* Function called by pthread_cancel to remove the thread from
+   waiting on a condition variable queue. */
+
+static int cond_extricate_func(void *obj, pthread_descr th)
+{
+  volatile pthread_descr self = thread_self();
+  pthread_cond_t *cond = obj;
+  int did_remove = 0;
+
+  __pthread_lock(&cond->__c_lock, self);
+  did_remove = remove_from_queue(&cond->__c_waiting, th);
+  __pthread_unlock(&cond->__c_lock);
+
+  return did_remove;
+}
+
+int __pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
+{
+  volatile pthread_descr self = thread_self();
+  pthread_extricate_if extr;
+  int already_canceled = 0;
+  int spurious_wakeup_count;
+
+  /* Check whether the mutex is locked and owned by this thread.  */
+  if (mutex->__m_kind != PTHREAD_MUTEX_TIMED_NP
+      && mutex->__m_kind != PTHREAD_MUTEX_ADAPTIVE_NP
+      && mutex->__m_owner != self)
+    return EINVAL;
+
+  /* Set up extrication interface */
+  extr.pu_object = cond;
+  extr.pu_extricate_func = cond_extricate_func;
+
+  /* Register extrication interface */
+  THREAD_SETMEM(self, p_condvar_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
+
+  /* Atomically enqueue thread for waiting, but only if it is not
+     canceled. If the thread is canceled, then it will fall through the
+     suspend call below, and then call pthread_exit without
+     having to worry about whether it is still on the condition variable queue.
+     This depends on pthread_cancel setting p_canceled before calling the
+     extricate function. */
+
+  __pthread_lock(&cond->__c_lock, self);
+  if (!(THREAD_GETMEM(self, p_canceled)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+    enqueue(&cond->__c_waiting, self);
+  else
+    already_canceled = 1;
+  __pthread_unlock(&cond->__c_lock);
+
+  if (already_canceled) {
+    __pthread_set_own_extricate_if(self, 0);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  pthread_mutex_unlock(mutex);
+
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      suspend(self);
+      if (THREAD_GETMEM(self, p_condvar_avail) == 0
+	  && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+	      || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+	{
+	  /* Count resumes that don't belong to us. */
+	  spurious_wakeup_count++;
+	  continue;
+	}
+      break;
+    }
+
+  __pthread_set_own_extricate_if(self, 0);
+
+  /* Check for cancellation again, to provide correct cancellation
+     point behavior */
+
+  if (THREAD_GETMEM(self, p_woken_by_cancel)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
+    THREAD_SETMEM(self, p_woken_by_cancel, 0);
+    pthread_mutex_lock(mutex);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  /* Put back any resumes we caught that don't belong to us. */
+  while (spurious_wakeup_count--)
+    restart(self);
+
+  pthread_mutex_lock(mutex);
+  return 0;
+}
+strong_alias (__pthread_cond_wait, pthread_cond_wait)
+
+static int
+pthread_cond_timedwait_relative(pthread_cond_t *cond,
+				pthread_mutex_t *mutex,
+				const struct timespec * abstime)
+{
+  volatile pthread_descr self = thread_self();
+  int already_canceled = 0;
+  pthread_extricate_if extr;
+  int spurious_wakeup_count;
+
+  /* Check whether the mutex is locked and owned by this thread.  */
+  if (mutex->__m_kind != PTHREAD_MUTEX_TIMED_NP
+      && mutex->__m_kind != PTHREAD_MUTEX_ADAPTIVE_NP
+      && mutex->__m_owner != self)
+    return EINVAL;
+
+  /* Set up extrication interface */
+  extr.pu_object = cond;
+  extr.pu_extricate_func = cond_extricate_func;
+
+  /* Register extrication interface */
+  THREAD_SETMEM(self, p_condvar_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
+
+  /* Enqueue to wait on the condition and check for cancellation. */
+  __pthread_lock(&cond->__c_lock, self);
+  if (!(THREAD_GETMEM(self, p_canceled)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+    enqueue(&cond->__c_waiting, self);
+  else
+    already_canceled = 1;
+  __pthread_unlock(&cond->__c_lock);
+
+  if (already_canceled) {
+    __pthread_set_own_extricate_if(self, 0);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  pthread_mutex_unlock(mutex);
+
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      if (!timedsuspend(self, abstime)) {
+	int was_on_queue;
+
+	/* __pthread_lock will queue back any spurious restarts that
+	   may happen to it. */
+
+	__pthread_lock(&cond->__c_lock, self);
+	was_on_queue = remove_from_queue(&cond->__c_waiting, self);
+	__pthread_unlock(&cond->__c_lock);
+
+	if (was_on_queue) {
+	  __pthread_set_own_extricate_if(self, 0);
+	  pthread_mutex_lock(mutex);
+	  return ETIMEDOUT;
+	}
+
+	/* Eat the outstanding restart() from the signaller */
+	suspend(self);
+      }
+
+      if (THREAD_GETMEM(self, p_condvar_avail) == 0
+	  && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+	      || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+	{
+	  /* Count resumes that don't belong to us. */
+	  spurious_wakeup_count++;
+	  continue;
+	}
+      break;
+    }
+
+  __pthread_set_own_extricate_if(self, 0);
+
+  /* The remaining logic is the same as in other cancellable waits,
+     such as pthread_join sem_wait or pthread_cond wait. */
+
+  if (THREAD_GETMEM(self, p_woken_by_cancel)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
+    THREAD_SETMEM(self, p_woken_by_cancel, 0);
+    pthread_mutex_lock(mutex);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  /* Put back any resumes we caught that don't belong to us. */
+  while (spurious_wakeup_count--)
+    restart(self);
+
+  pthread_mutex_lock(mutex);
+  return 0;
+}
+
+int __pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+			     const struct timespec * abstime)
+{
+  /* Indirect call through pointer! */
+  return pthread_cond_timedwait_relative(cond, mutex, abstime);
+}
+strong_alias (__pthread_cond_timedwait, pthread_cond_timedwait)
+
+int __pthread_cond_signal(pthread_cond_t *cond)
+{
+  pthread_descr th;
+
+  __pthread_lock(&cond->__c_lock, NULL);
+  th = dequeue(&cond->__c_waiting);
+  __pthread_unlock(&cond->__c_lock);
+  if (th != NULL) {
+    th->p_condvar_avail = 1;
+    WRITE_MEMORY_BARRIER();
+    restart(th);
+  }
+  return 0;
+}
+strong_alias (__pthread_cond_signal, pthread_cond_signal)
+
+int __pthread_cond_broadcast(pthread_cond_t *cond)
+{
+  pthread_descr tosignal, th;
+
+  __pthread_lock(&cond->__c_lock, NULL);
+  /* Copy the current state of the waiting queue and empty it */
+  tosignal = cond->__c_waiting;
+  cond->__c_waiting = NULL;
+  __pthread_unlock(&cond->__c_lock);
+  /* Now signal each process in the queue */
+  while ((th = dequeue(&tosignal)) != NULL) {
+    th->p_condvar_avail = 1;
+    WRITE_MEMORY_BARRIER();
+    restart(th);
+  }
+  return 0;
+}
+strong_alias (__pthread_cond_broadcast, pthread_cond_broadcast)
+
+int __pthread_condattr_init(pthread_condattr_t *attr)
+{
+  return 0;
+}
+strong_alias (__pthread_condattr_init, pthread_condattr_init)
+
+int __pthread_condattr_destroy(pthread_condattr_t *attr)
+{
+  return 0;
+}
+strong_alias (__pthread_condattr_destroy, pthread_condattr_destroy)
+
+int pthread_condattr_getpshared (const pthread_condattr_t *attr, int *pshared)
+{
+  *pshared = PTHREAD_PROCESS_PRIVATE;
+  return 0;
+}
+
+int pthread_condattr_setpshared (pthread_condattr_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;
+
+  return 0;
+}