1  /* pthread_mutex_trylock.  Hurd version.
       2     Copyright (C) 2016-2023 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  hidden_def (__pthread_mutex_trylock)
      84  strong_alias (__pthread_mutex_trylock, _pthread_mutex_trylock)
      85  weak_alias (__pthread_mutex_trylock, pthread_mutex_trylock)