initial import of latest linuxthreads

1 files changed, 298 insertions, 0 deletions

diff --git a/libpthread/linuxthreads/semaphore.c b/libpthread/linuxthreads/semaphore.c
new file mode 100644
index 000000000..2b13c1450
--- /dev/null
+++ b/libpthread/linuxthreads/semaphore.c
@@ -0,0 +1,298 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix        */
+/* threads for Linux.                                                   */
+/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
+/*                                                                      */
+/* 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.                 */
+
+/* Semaphores a la POSIX 1003.1b */
+
+#include <errno.h>
+#include "pthread.h"
+#include "semaphore.h"
+#include "internals.h"
+#include "spinlock.h"
+#include "restart.h"
+#include "queue.h"
+#include <not-cancel.h>
+
+int sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+  if (value > SEM_VALUE_MAX) {
+    errno = EINVAL;
+    return -1;
+  }
+  if (pshared) {
+    errno = ENOSYS;
+    return -1;
+  }
+  __pthread_init_lock(&sem->__sem_lock);
+  sem->__sem_value = value;
+  sem->__sem_waiting = NULL;
+  return 0;
+}
+
+/* Function called by pthread_cancel to remove the thread from
+   waiting inside sem_wait. */
+
+static int new_sem_extricate_func(void *obj, pthread_descr th)
+{
+  volatile pthread_descr self = thread_self();
+  sem_t *sem = obj;
+  int did_remove = 0;
+
+  __pthread_lock(&sem->__sem_lock, self);
+  did_remove = remove_from_queue(&sem->__sem_waiting, th);
+  __pthread_unlock(&sem->__sem_lock);
+
+  return did_remove;
+}
+
+int sem_wait(sem_t * sem)
+{
+  volatile pthread_descr self = thread_self();
+  pthread_extricate_if extr;
+  int already_canceled = 0;
+  int spurious_wakeup_count;
+
+  /* Set up extrication interface */
+  extr.pu_object = sem;
+  extr.pu_extricate_func = new_sem_extricate_func;
+
+  __pthread_lock(&sem->__sem_lock, self);
+  if (sem->__sem_value > 0) {
+    sem->__sem_value--;
+    __pthread_unlock(&sem->__sem_lock);
+    return 0;
+  }
+  /* Register extrication interface */
+  THREAD_SETMEM(self, p_sem_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
+  /* Enqueue only if not already cancelled. */
+  if (!(THREAD_GETMEM(self, p_canceled)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+    enqueue(&sem->__sem_waiting, self);
+  else
+    already_canceled = 1;
+  __pthread_unlock(&sem->__sem_lock);
+
+  if (already_canceled) {
+    __pthread_set_own_extricate_if(self, 0);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  /* Wait for sem_post or cancellation, or fall through if already canceled */
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      suspend(self);
+      if (THREAD_GETMEM(self, p_sem_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);
+
+  /* Terminate only if the wakeup came from cancellation. */
+  /* Otherwise ignore cancellation because we got the semaphore. */
+
+  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_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+  /* We got the semaphore */
+  return 0;
+}
+
+int sem_trywait(sem_t * sem)
+{
+  int retval;
+
+  __pthread_lock(&sem->__sem_lock, NULL);
+  if (sem->__sem_value == 0) {
+    errno = EAGAIN;
+    retval = -1;
+  } else {
+    sem->__sem_value--;
+    retval = 0;
+  }
+  __pthread_unlock(&sem->__sem_lock);
+  return retval;
+}
+
+int sem_post(sem_t * sem)
+{
+  pthread_descr self = thread_self();
+  pthread_descr th;
+  struct pthread_request request;
+
+  if (THREAD_GETMEM(self, p_in_sighandler) == NULL) {
+    __pthread_lock(&sem->__sem_lock, self);
+    if (sem->__sem_waiting == NULL) {
+      if (sem->__sem_value >= SEM_VALUE_MAX) {
+        /* Overflow */
+        errno = ERANGE;
+        __pthread_unlock(&sem->__sem_lock);
+        return -1;
+      }
+      sem->__sem_value++;
+      __pthread_unlock(&sem->__sem_lock);
+    } else {
+      th = dequeue(&sem->__sem_waiting);
+      __pthread_unlock(&sem->__sem_lock);
+      th->p_sem_avail = 1;
+      WRITE_MEMORY_BARRIER();
+      restart(th);
+    }
+  } else {
+    /* If we're in signal handler, delegate post operation to
+       the thread manager. */
+    if (__pthread_manager_request < 0) {
+      if (__pthread_initialize_manager() < 0) {
+        errno = EAGAIN;
+        return -1;
+      }
+    }
+    request.req_kind = REQ_POST;
+    request.req_args.post = sem;
+    TEMP_FAILURE_RETRY(write_not_cancel(__pthread_manager_request,
+					(char *) &request, sizeof(request)));
+  }
+  return 0;
+}
+
+int sem_getvalue(sem_t * sem, int * sval)
+{
+  *sval = sem->__sem_value;
+  return 0;
+}
+
+int sem_destroy(sem_t * sem)
+{
+  if (sem->__sem_waiting != NULL) {
+    __set_errno (EBUSY);
+    return -1;
+  }
+  return 0;
+}
+
+sem_t *sem_open(const char *name, int oflag, ...)
+{
+  __set_errno (ENOSYS);
+  return SEM_FAILED;
+}
+
+int sem_close(sem_t *sem)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+int sem_unlink(const char *name)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+int sem_timedwait(sem_t *sem, const struct timespec *abstime)
+{
+  pthread_descr self = thread_self();
+  pthread_extricate_if extr;
+  int already_canceled = 0;
+  int spurious_wakeup_count;
+
+  __pthread_lock(&sem->__sem_lock, self);
+  if (sem->__sem_value > 0) {
+    --sem->__sem_value;
+    __pthread_unlock(&sem->__sem_lock);
+    return 0;
+  }
+
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) {
+    /* The standard requires that if the function would block and the
+       time value is illegal, the function returns with an error.  */
+    __pthread_unlock(&sem->__sem_lock);
+    __set_errno (EINVAL);
+    return -1;
+  }
+
+  /* Set up extrication interface */
+  extr.pu_object = sem;
+  extr.pu_extricate_func = new_sem_extricate_func;
+
+  /* Register extrication interface */
+  THREAD_SETMEM(self, p_sem_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
+  /* Enqueue only if not already cancelled. */
+  if (!(THREAD_GETMEM(self, p_canceled)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+    enqueue(&sem->__sem_waiting, self);
+  else
+    already_canceled = 1;
+  __pthread_unlock(&sem->__sem_lock);
+
+  if (already_canceled) {
+    __pthread_set_own_extricate_if(self, 0);
+    __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      if (timedsuspend(self, abstime) == 0) {
+	int was_on_queue;
+
+	/* __pthread_lock will queue back any spurious restarts that
+	   may happen to it. */
+
+	__pthread_lock(&sem->__sem_lock, self);
+	was_on_queue = remove_from_queue(&sem->__sem_waiting, self);
+	__pthread_unlock(&sem->__sem_lock);
+
+	if (was_on_queue) {
+	  __pthread_set_own_extricate_if(self, 0);
+	  __set_errno (ETIMEDOUT);
+	  return -1;
+	}
+
+	/* Eat the outstanding restart() from the signaller */
+	suspend(self);
+      }
+
+      if (THREAD_GETMEM(self, p_sem_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);
+
+  /* Terminate only if the wakeup came from cancellation. */
+  /* Otherwise ignore cancellation because we got the semaphore. */
+
+  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_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
+  }
+  /* We got the semaphore */
+  return 0;
+}