sysdeps/nptl/stdio-lock.h

   1 /* Thread package specific definitions of stream lock type.  NPTL version.
   2    Copyright (C) 2000-2019 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 #ifndef _STDIO_LOCK_H
  20 #define _STDIO_LOCK_H 1
  21
  22 #include <libc-lock.h>
  23 #include <lowlevellock.h>
  24
  25
  26 /* The locking here is very inexpensive, even for inlining.  */
  27 #define _IO_lock_inexpensive    1
  28
  29 typedef struct { int lock; int cnt; void *owner; } _IO_lock_t;
  30 #define _IO_lock_t_defined 1
  31
  32 #define _IO_lock_initializer { LLL_LOCK_INITIALIZER, 0, NULL }
  33
  34 #define _IO_lock_init(_name) \
  35   ((void) ((_name) = (_IO_lock_t) _IO_lock_initializer))
  36
  37 #define _IO_lock_fini(_name) \
  38   ((void) 0)
  39
  40 #define _IO_lock_lock(_name) \
  41   do {                                                                        \
  42     void *__self = THREAD_SELF;                                               \
  43     if ((_name).owner != __self)                                              \
  44       {                                                                       \
  45         lll_lock ((_name).lock, LLL_PRIVATE);                                 \
  46         (_name).owner = __self;                                               \
  47       }                                                                       \
  48     ++(_name).cnt;                                                            \
  49   } while (0)
  50
  51 #define _IO_lock_trylock(_name) \
  52   ({                                                                          \
  53     int __result = 0;                                                         \
  54     void *__self = THREAD_SELF;                                               \
  55     if ((_name).owner != __self)                                              \
  56       {                                                                       \
  57         if (lll_trylock ((_name).lock) == 0)                                  \
  58           {                                                                   \
  59             (_name).owner = __self;                                           \
  60             (_name).cnt = 1;                                                  \
  61           }                                                                   \
  62         else                                                                  \
  63           __result = EBUSY;                                                   \
  64       }                                                                       \
  65     else                                                                      \
  66       ++(_name).cnt;                                                          \
  67     __result;                                                                 \
  68   })
  69
  70 #define _IO_lock_unlock(_name) \
  71   do {                                                                        \
  72     if (--(_name).cnt == 0)                                                   \
  73       {                                                                       \
  74         (_name).owner = NULL;                                                 \
  75         lll_unlock ((_name).lock, LLL_PRIVATE);                               \
  76       }                                                                       \
  77   } while (0)
  78
  79
  80
  81 #define _IO_cleanup_region_start(_fct, _fp) \
  82   __libc_cleanup_region_start (((_fp)->_flags & _IO_USER_LOCK) == 0, _fct, _fp)
  83 #define _IO_cleanup_region_start_noarg(_fct) \
  84   __libc_cleanup_region_start (1, _fct, NULL)
  85 #define _IO_cleanup_region_end(_doit) \
  86   __libc_cleanup_region_end (_doit)
  87
  88 #if defined _LIBC && IS_IN (libc)
  89
  90 # ifdef __EXCEPTIONS
  91 #  define _IO_acquire_lock(_fp) \
  92   do {                                                                        \
  93     FILE *_IO_acquire_lock_file                                               \
  94         __attribute__((cleanup (_IO_acquire_lock_fct)))                       \
  95         = (_fp);                                                              \
  96     _IO_flockfile (_IO_acquire_lock_file);
  97 # else
  98 #  define _IO_acquire_lock(_fp) _IO_acquire_lock_needs_exceptions_enabled
  99 # endif
 100 # define _IO_release_lock(_fp) ; } while (0)
 101
 102 #endif
 103
 104 #endif /* stdio-lock.h */