sysdeps/mach/hurd/htl/pt-mutex.h

   1 /* Internal definitions for pthreads library.
   2    Copyright (C) 2016-2020 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 #ifndef _PT_MUTEX_H
  20 #define _PT_MUTEX_H     1
  21
  22 /* Special ID used to signal an unrecoverable robust mutex. */
  23 #define NOTRECOVERABLE_ID   (1U << 31)
  24
  25 /* Common path for robust mutexes. Assumes the variable 'ret'
  26  * is bound in the function this is called from. */
  27 #define ROBUST_LOCK(self, mtxp, cb, ...)   \
  28   if (mtxp->__owner_id == NOTRECOVERABLE_ID)   \
  29     return ENOTRECOVERABLE;   \
  30   else if (mtxp->__owner_id == self->thread   \
  31            && __getpid () == (int)(mtxp->__lock & LLL_OWNER_MASK))   \
  32     {   \
  33       if (mtxp->__type == PT_MTX_RECURSIVE)   \
  34         {   \
  35           if (__glibc_unlikely (mtxp->__cnt + 1 == 0))   \
  36             return EAGAIN;   \
  37           \
  38           ++mtxp->__cnt;   \
  39           return 0;   \
  40         }   \
  41       else if (mtxp->__type == PT_MTX_ERRORCHECK)   \
  42         return EDEADLK;   \
  43     }   \
  44   \
  45   ret = cb (mtxp->__lock, ##__VA_ARGS__);   \
  46   if (ret == 0 || ret == EOWNERDEAD)   \
  47     {   \
  48       if (mtxp->__owner_id == ENOTRECOVERABLE)   \
  49         ret = ENOTRECOVERABLE;   \
  50       else   \
  51         {   \
  52           mtxp->__owner_id = self->thread;   \
  53           mtxp->__cnt = 1;   \
  54           if (ret == EOWNERDEAD)   \
  55             {   \
  56               mtxp->__lock = mtxp->__lock | LLL_DEAD_OWNER;   \
  57               atomic_write_barrier ();   \
  58             }   \
  59         }   \
  60     }   \
  61   (void)0
  62
  63 /* Check that a thread owns the mutex. For non-robust, task-shared
  64  * objects, we have to check the thread *and* process-id. */
  65 #define mtx_owned_p(mtx, pt, flags)   \
  66   ((mtx)->__owner_id == (pt)->thread   \
  67    && (((flags) & GSYNC_SHARED) == 0   \
  68        || (mtx)->__shpid == __getpid ()))
  69
  70 /* Record a thread as the owner of the mutex. */
  71 #define mtx_set_owner(mtx, pt, flags)   \
  72   (void)   \
  73     ({   \
  74        (mtx)->__owner_id = (pt)->thread;   \
  75        if ((flags) & GSYNC_SHARED)   \
  76          (mtx)->__shpid = __getpid ();   \
  77      })
  78
  79 /* Redefined mutex types. The +1 is for binary compatibility. */
  80 #define PT_MTX_NORMAL       __PTHREAD_MUTEX_TIMED
  81 #define PT_MTX_RECURSIVE    (__PTHREAD_MUTEX_RECURSIVE + 1)
  82 #define PT_MTX_ERRORCHECK   (__PTHREAD_MUTEX_ERRORCHECK + 1)
  83
  84 /* Mutex type, including robustness. */
  85 #define MTX_TYPE(mtxp)   \
  86   ((mtxp)->__type | ((mtxp)->__flags & PTHREAD_MUTEX_ROBUST))
  87
  88 extern int __getpid (void) __attribute__ ((const));
  89
  90 #endif /* pt-mutex.h */