sysdeps/mach/hurd/htl/pt-mutex-trylock.c

   1 /* pthread_mutex_trylock.  Hurd version.
   2    Copyright (C) 2016-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library;  if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <pthread.h>
  20 #include <stdlib.h>
  21 #include <assert.h>
  22 #include <pt-internal.h>
  23 #include "pt-mutex.h"
  24 #include <hurdlock.h>
  25
  26 int
  27 __pthread_mutex_trylock (pthread_mutex_t *mtxp)
  28 {
  29   struct __pthread *self;
  30   int ret;
  31
  32   switch (MTX_TYPE (mtxp))
  33     {
  34     case PT_MTX_NORMAL:
  35       ret = lll_trylock (&mtxp->__lock);
  36       if (ret)
  37         ret = EBUSY;
  38       break;
  39
  40     case PT_MTX_RECURSIVE:
  41       self = _pthread_self ();
  42       if (mtx_owned_p (mtxp, self, mtxp->__flags))
  43         {
  44           if (__glibc_unlikely (mtxp->__cnt + 1 == 0))
  45             return EAGAIN;
  46
  47           ++mtxp->__cnt;
  48           ret = 0;
  49         }
  50       else if ((ret = lll_trylock (&mtxp->__lock)) == 0)
  51         {
  52           mtx_set_owner (mtxp, self, mtxp->__flags);
  53           mtxp->__cnt = 1;
  54         }
  55       else
  56         ret = EBUSY;
  57
  58       break;
  59
  60     case PT_MTX_ERRORCHECK:
  61       self = _pthread_self ();
  62       if ((ret = lll_trylock (&mtxp->__lock)) == 0)
  63         mtx_set_owner (mtxp, self, mtxp->__flags);
  64       else
  65         ret = EBUSY;
  66       break;
  67
  68     case PT_MTX_NORMAL | PTHREAD_MUTEX_ROBUST:
  69     case PT_MTX_RECURSIVE | PTHREAD_MUTEX_ROBUST:
  70     case PT_MTX_ERRORCHECK | PTHREAD_MUTEX_ROBUST:
  71       self = _pthread_self ();
  72       ROBUST_LOCK (self, mtxp, __lll_robust_trylock);
  73       break;
  74
  75     default:
  76       ret = EINVAL;
  77       break;
  78     }
  79
  80   return ret;
  81 }
  82
  83 strong_alias (__pthread_mutex_trylock, _pthread_mutex_trylock)
  84 strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock)