htl/forward.c

   1 /* Libc stubs for pthread functions.  Hurd pthread version.
   2    Copyright (C) 2002-2019 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <dlfcn.h>
  21 #include <stdlib.h>
  22 #include <shlib-compat.h>
  23 #include <pthread-functions.h>
  24 #include <libc-lock.h>
  25 #include <fork.h>
  26
  27 /* Pointers to the libc functions.  */
  28 struct pthread_functions __libc_pthread_functions attribute_hidden;
  29 int __libc_pthread_functions_init attribute_hidden;
  30
  31
  32 #define FORWARD2(name, rettype, decl, params, defaction) \
  33 rettype                                                                       \
  34 name decl                                                                     \
  35 {                                                                             \
  36   if (!__libc_pthread_functions_init)                                         \
  37     defaction;                                                                \
  38                                                                               \
  39   return PTHFCT_CALL (ptr_##name, params);                                    \
  40 }
  41
  42 /* Same as FORWARD2, only without return.  */
  43 #define FORWARD_NORETURN(name, rettype, decl, params, defaction) \
  44 rettype                                                                       \
  45 name decl                                                                     \
  46 {                                                                             \
  47   if (!__libc_pthread_functions_init)                                         \
  48     defaction;                                                                \
  49                                                                               \
  50   PTHFCT_CALL (ptr_##name, params);                                           \
  51 }
  52
  53 #define FORWARD(name, decl, params, defretval) \
  54   FORWARD2 (name, int, decl, params, return defretval)
  55
  56 FORWARD (pthread_attr_destroy, (pthread_attr_t *attr), (attr), 0)
  57
  58 FORWARD (pthread_attr_init, (pthread_attr_t *attr), (attr), 0)
  59
  60 FORWARD (pthread_attr_getdetachstate,
  61          (const pthread_attr_t *attr, int *detachstate), (attr, detachstate),
  62          0)
  63 FORWARD (pthread_attr_setdetachstate, (pthread_attr_t *attr, int detachstate),
  64          (attr, detachstate), 0)
  65
  66 FORWARD (pthread_attr_getinheritsched,
  67          (const pthread_attr_t *attr, int *inherit), (attr, inherit), 0)
  68 FORWARD (pthread_attr_setinheritsched, (pthread_attr_t *attr, int inherit),
  69          (attr, inherit), 0)
  70
  71 FORWARD (pthread_attr_getschedparam,
  72          (const pthread_attr_t *attr, struct sched_param *param),
  73          (attr, param), 0)
  74 FORWARD (pthread_attr_setschedparam,
  75          (pthread_attr_t *attr, const struct sched_param *param),
  76          (attr, param), 0)
  77
  78 FORWARD (pthread_attr_getschedpolicy,
  79          (const pthread_attr_t *attr, int *policy), (attr, policy), 0)
  80 FORWARD (pthread_attr_setschedpolicy, (pthread_attr_t *attr, int policy),
  81          (attr, policy), 0)
  82
  83 FORWARD (pthread_attr_getscope,
  84          (const pthread_attr_t *attr, int *scope), (attr, scope), 0)
  85 FORWARD (pthread_attr_setscope, (pthread_attr_t *attr, int scope),
  86          (attr, scope), 0)
  87
  88
  89 FORWARD (pthread_condattr_destroy, (pthread_condattr_t *attr), (attr), 0)
  90 FORWARD (pthread_condattr_init, (pthread_condattr_t *attr), (attr), 0)
  91
  92
  93 FORWARD (pthread_cond_broadcast, (pthread_cond_t *cond), (cond), 0)
  94 FORWARD (pthread_cond_destroy, (pthread_cond_t *cond), (cond), 0)
  95 FORWARD (pthread_cond_init,
  96          (pthread_cond_t *cond, const pthread_condattr_t *cond_attr),
  97          (cond, cond_attr), 0)
  98 FORWARD (pthread_cond_signal, (pthread_cond_t *cond), (cond), 0)
  99 FORWARD (pthread_cond_wait, (pthread_cond_t *cond, pthread_mutex_t *mutex),
 100          (cond, mutex), 0)
 101 FORWARD (pthread_cond_timedwait,
 102          (pthread_cond_t *cond, pthread_mutex_t *mutex,
 103           const struct timespec *abstime), (cond, mutex, abstime), 0)
 104
 105 FORWARD (pthread_equal, (pthread_t thread1, pthread_t thread2),
 106          (thread1, thread2), 1)
 107
 108
 109 /* Use an alias to avoid warning, as pthread_exit is declared noreturn.  */
 110 FORWARD_NORETURN (__pthread_exit, void, (void *retval), (retval),
 111                   exit (EXIT_SUCCESS))
 112 strong_alias (__pthread_exit, pthread_exit);
 113
 114
 115 FORWARD (pthread_getschedparam,
 116          (pthread_t target_thread, int *policy, struct sched_param *param),
 117          (target_thread, policy, param), 0)
 118 FORWARD (pthread_setschedparam,
 119          (pthread_t target_thread, int policy,
 120           const struct sched_param *param), (target_thread, policy, param), 0)
 121
 122
 123 FORWARD (pthread_mutex_destroy, (pthread_mutex_t *mutex), (mutex), 0)
 124
 125 FORWARD (pthread_mutex_init,
 126          (pthread_mutex_t *mutex, const pthread_mutexattr_t *mutexattr),
 127          (mutex, mutexattr), 0)
 128
 129 FORWARD (pthread_mutex_lock, (pthread_mutex_t *mutex), (mutex), 0)
 130
 131 FORWARD (pthread_mutex_unlock, (pthread_mutex_t *mutex), (mutex), 0)
 132
 133
 134 FORWARD2 (pthread_self, pthread_t, (void), (), return 0)
 135
 136
 137 FORWARD (__pthread_setcancelstate, (int state, int *oldstate),
 138          (state, oldstate), 0)
 139 strong_alias (__pthread_setcancelstate, pthread_setcancelstate);
 140
 141 FORWARD (pthread_setcanceltype, (int type, int *oldtype), (type, oldtype), 0)
 142
 143 struct __pthread_cancelation_handler *dummy_list;
 144 FORWARD2 (__pthread_get_cleanup_stack, struct __pthread_cancelation_handler **,
 145           (void), (), return &dummy_list);
 146
 147 \f
 148 /* Fork interaction */
 149
 150 struct atfork
 151 {
 152   void (*prepare) (void);
 153   void (*parent) (void);
 154   void (*child) (void);
 155   void *dso_handle;
 156   struct atfork *prev;
 157   struct atfork *next;
 158 };
 159
 160 /* TODO: better locking */
 161 __libc_lock_define_initialized (static, atfork_lock);
 162 static struct atfork *fork_handlers, *fork_last_handler;
 163
 164 static void
 165 atfork_pthread_prepare (void)
 166 {
 167   struct atfork *handlers, *last_handler;
 168
 169   __libc_lock_lock (atfork_lock);
 170   handlers = fork_handlers;
 171   last_handler = fork_last_handler;
 172   __libc_lock_unlock (atfork_lock);
 173
 174   if (last_handler == NULL)
 175     return;
 176
 177   while (1)
 178     {
 179       if (last_handler->prepare != NULL)
 180         last_handler->prepare ();
 181       if (last_handler == handlers)
 182         break;
 183       last_handler = last_handler->prev;
 184     }
 185 }
 186 text_set_element (_hurd_atfork_prepare_hook, atfork_pthread_prepare);
 187
 188 static void
 189 atfork_pthread_parent (void)
 190 {
 191   struct atfork *handlers;
 192
 193   __libc_lock_lock (atfork_lock);
 194   handlers = fork_handlers;
 195   __libc_lock_unlock (atfork_lock);
 196
 197   while (handlers != NULL)
 198     {
 199       if (handlers->parent != NULL)
 200         handlers->parent ();
 201       handlers = handlers->next;
 202     }
 203 }
 204 text_set_element (_hurd_atfork_parent_hook, atfork_pthread_parent);
 205
 206 static void
 207 atfork_pthread_child (void)
 208 {
 209   struct atfork *handlers;
 210
 211   __libc_lock_lock (atfork_lock);
 212   handlers = fork_handlers;
 213   __libc_lock_unlock (atfork_lock);
 214
 215   while (handlers != NULL)
 216     {
 217       if (handlers->child != NULL)
 218         handlers->child ();
 219       handlers = handlers->next;
 220     }
 221 }
 222 text_set_element (_hurd_atfork_child_hook, atfork_pthread_child);
 223
 224 int
 225 __register_atfork (void (*prepare) (void),
 226                    void (*parent) (void),
 227                    void (*child) (void),
 228                    void *dso_handle)
 229 {
 230   struct atfork *new = malloc (sizeof (*new));
 231   if (new == NULL)
 232     return errno;
 233
 234   new->prepare = prepare;
 235   new->parent = parent;
 236   new->child = child;
 237   new->dso_handle = dso_handle;
 238   new->prev = NULL;
 239
 240   __libc_lock_lock (atfork_lock);
 241   new->next = fork_handlers;
 242   if (fork_handlers != NULL)
 243     fork_handlers->prev = new;
 244   fork_handlers = new;
 245   if (fork_last_handler == NULL)
 246     fork_last_handler = new;
 247   __libc_lock_unlock (atfork_lock);
 248
 249   return 0;
 250 }
 251 libc_hidden_def (__register_atfork)
 252
 253 void
 254 __unregister_atfork (void *dso_handle)
 255 {
 256   struct atfork **handlers, *prev = NULL, *next;
 257   __libc_lock_lock (atfork_lock);
 258   handlers = &fork_handlers;
 259   while (*handlers != NULL)
 260     {
 261       if ((*handlers)->dso_handle == dso_handle)
 262         {
 263           /* Drop this handler from the list.  */
 264           if (*handlers == fork_last_handler)
 265             {
 266               /* Was last, new last is prev, if any.  */
 267               fork_last_handler = prev;
 268             }
 269
 270           next = (*handlers)->next;
 271           if (next != NULL)
 272             next->prev = prev;
 273           *handlers = next;
 274         }
 275       else
 276         {
 277           /* Just proceed to next handler.  */
 278           prev = *handlers;
 279           handlers = &prev->next;
 280         }
 281     }
 282   __libc_lock_unlock (atfork_lock);
 283 }