lib/libc_r/uthread/uthread_find_thread.c

   1 /*
   2  * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by John Birrell.
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * $FreeBSD: src/lib/libc_r/uthread/uthread_find_thread.c,v 1.5.2.2 2002/10/22 14:44:03 fjoe Exp $
  33  * $DragonFly: src/lib/libc_r/uthread/uthread_find_thread.c,v 1.2 2003/06/17 06:26:48 dillon Exp $
  34  */
  35 #include <errno.h>
  36 #include <pthread.h>
  37 #include "pthread_private.h"
  38
  39 /* Find a thread in the linked list of active threads: */
  40 int
  41 _find_thread(pthread_t pthread)
  42 {
  43         pthread_t pthread1;
  44
  45         /* Check if the caller has specified an invalid thread: */
  46         if (pthread == NULL || pthread->magic != PTHREAD_MAGIC)
  47                 /* Invalid thread: */
  48                 return(EINVAL);
  49
  50         /*
  51          * Defer signals to protect the thread list from access
  52          * by the signal handler:
  53          */
  54         _thread_kern_sig_defer();
  55
  56         /* Search for the specified thread: */
  57         TAILQ_FOREACH(pthread1, &_thread_list, tle) {
  58                 if (pthread == pthread1)
  59                         break;
  60         }
  61
  62         /* Undefer and handle pending signals, yielding if necessary: */
  63         _thread_kern_sig_undefer();
  64
  65         /* Return zero if the thread exists: */
  66         return ((pthread1 != NULL) ? 0:ESRCH);
  67 }