tools-src/uClibc/libc/stdlib/atexit.c

   1 /* Copyright (C) 1995,1996 Robert de Bath <rdebath@cix.compulink.co.uk>
   2  * This file is part of the Linux-8086 C library and is distributed
   3  * under the GNU Library General Public License.
   4  */
   5
   6 /*
   7  * Dec 2000          Manuel Novoa III
   8  *
   9  *   Made atexit handling conform to standards... i.e. no args.
  10  *   Removed on_exit since it did not match gnu libc definition.
  11  *   Combined atexit and __do_exit into one object file.
  12  *
  13  * Feb 2001          Manuel Novoa III
  14  *
  15  *   Reworked file after addition of __uClibc_main.
  16  *   Changed name of __do_exit to atexit_handler.
  17  *   Changed name of __cleanup to __uClibc_cleanup.
  18  *   Moved declaration of __uClibc_cleanup to __uClibc_main
  19  *      where it is initialized with (possibly weak alias)
  20  *      _stdio_term.
  21  *
  22  * Jul 2001          Steve Thayer
  23  *
  24  *   Added an on_exit implementation (that now matches gnu libc definition.)
  25  *   Pulled atexit_handler out of the atexit object since it is now required by
  26  *   on_exit as well.  Renamed it to __exit_handler.
  27  *   Fixed a problem where exit functions stop getting called if one of
  28  *   them calls exit().
  29  *   As a side effect of these changes, abort() no longer calls the exit
  30  *   functions (it now matches the gnu libc definition).
  31  *
  32  * August 2002    Erik Andersen
  33  *   Added locking so atexit and friends can be thread safe
  34  *
  35  */
  36
  37 #define _GNU_SOURCE
  38 #include <features.h>
  39 #include <unistd.h>
  40 #include <stdlib.h>
  41 #include <errno.h>
  42
  43
  44 #ifdef __UCLIBC_HAS_THREADS__
  45 #include <pthread.h>
  46 extern pthread_mutex_t mylock;
  47 # define LOCK   pthread_mutex_lock(&mylock)
  48 # define UNLOCK pthread_mutex_unlock(&mylock);
  49 #else
  50 # define LOCK
  51 # define UNLOCK
  52 #endif
  53
  54
  55 typedef void (*aefuncp) (void);         /* atexit function pointer */
  56 typedef void (*oefuncp) (int, void *);  /* on_exit function pointer */
  57 typedef enum {
  58         ef_atexit,
  59         ef_on_exit
  60 } ef_type; /* exit function types */
  61
  62 /* this is in the L_exit object */
  63 extern void (*__exit_cleanup) (int);
  64
  65 /* these are in the L___do_exit object */
  66 extern int __exit_slots;
  67 extern int __exit_count;
  68 extern void __exit_handler(int);
  69 struct exit_function {
  70         ef_type type;   /* ef_atexit or ef_on_exit */
  71         union {
  72                 aefuncp atexit;
  73                 struct {
  74                         oefuncp func;
  75                         void *arg;
  76                 } on_exit;
  77         } funcs;
  78 };
  79 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
  80 extern struct exit_function *__exit_function_table;
  81 #else
  82 extern struct exit_function __exit_function_table[__UCLIBC_MAX_ATEXIT];
  83 #endif
  84
  85 #ifdef L_atexit
  86         /*
  87  * register a function to be called at normal program termination
  88  * (the registered function takes no arguments)
  89          */
  90 int atexit(aefuncp func)
  91 {
  92     struct exit_function *efp;
  93
  94     LOCK;
  95     if (func) {
  96 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
  97         /* If we are out of function table slots, make some more */
  98         if (__exit_slots < __exit_count+1) {
  99             __exit_function_table=realloc(__exit_function_table,
 100                     (__exit_slots+20)*sizeof(struct exit_function));
 101             if (__exit_function_table==NULL) {
 102                 UNLOCK;
 103                 __set_errno(ENOMEM);
 104                 return -1;
 105             }
 106             __exit_slots+=20;
 107         }
 108 #else
 109         if (__exit_count >= __UCLIBC_MAX_ATEXIT) {
 110             UNLOCK;
 111             __set_errno(ENOMEM);
 112             return -1;
 113         }
 114 #endif
 115         __exit_cleanup = __exit_handler; /* enable cleanup */
 116         efp = &__exit_function_table[__exit_count++];
 117         efp->type = ef_atexit;
 118         efp->funcs.atexit = func;
 119     }
 120     UNLOCK;
 121     return 0;
 122 }
 123 #endif
 124
 125 #ifdef L_on_exit
 126 /*
 127  * register a function to be called at normal program termination
 128  * the registered function takes two arguments:
 129  *     status - the exit status that was passed to the exit() function
 130  *     arg - generic argument
 131  */
 132 int on_exit(oefuncp func, void *arg)
 133 {
 134     struct exit_function *efp;
 135
 136     LOCK;
 137     if (func) {
 138 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
 139         /* If we are out of function table slots, make some more */
 140         if (__exit_slots < __exit_count+1) {
 141             __exit_function_table=realloc(__exit_function_table,
 142                     (__exit_slots+20)*sizeof(struct exit_function));
 143             if (__exit_function_table==NULL) {
 144                 UNLOCK;
 145                 __set_errno(ENOMEM);
 146                 return -1;
 147             }
 148             __exit_slots+=20;
 149         }
 150 #else
 151         if (__exit_count >= __UCLIBC_MAX_ATEXIT) {
 152             UNLOCK;
 153             __set_errno(ENOMEM);
 154             return -1;
 155         }
 156 #endif
 157
 158         __exit_cleanup = __exit_handler; /* enable cleanup */
 159         efp = &__exit_function_table[__exit_count++];
 160         efp->type = ef_on_exit;
 161         efp->funcs.on_exit.func = func;
 162         efp->funcs.on_exit.arg = arg;
 163     }
 164     UNLOCK;
 165     return 0;
 166 }
 167 #endif
 168
 169 #ifdef L___exit_handler
 170 int __exit_count = 0; /* Number of registered exit functions */
 171 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
 172 struct exit_function *__exit_function_table = NULL;
 173 int __exit_slots = 0; /* Size of __exit_function_table */
 174 #else
 175 struct exit_function __exit_function_table[__UCLIBC_MAX_ATEXIT];
 176 #endif
 177
 178
 179 /*
 180  * Handle the work of executing the registered exit functions
 181  * This is called while we are locked, so no additional locking
 182  * is needed...
 183  */
 184 void __exit_handler(int status)
 185 {
 186         struct exit_function *efp;
 187
 188         /* In reverse order */
 189         while ( __exit_count ) {
 190                 efp = &__exit_function_table[--__exit_count];
 191                 switch (efp->type) {
 192                 case ef_on_exit:
 193                         if (efp->funcs.on_exit.func) {
 194                                 (efp->funcs.on_exit.func) (status, efp->funcs.on_exit.arg);
 195                         }
 196                         break;
 197                 case ef_atexit:
 198                         if (efp->funcs.atexit) {
 199                                 (efp->funcs.atexit) ();
 200                         }
 201                         break;
 202                 }
 203         }
 204 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
 205         /* Free up memory used by the __exit_function_table structure */
 206         if (__exit_function_table)
 207             free(__exit_function_table);
 208 #endif
 209 }
 210 #endif
 211
 212 #ifdef L_exit
 213 extern void weak_function _stdio_term(void);
 214 void (*__exit_cleanup) (int) = 0;
 215 #ifdef __UCLIBC_HAS_THREADS__
 216 pthread_mutex_t mylock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
 217 #endif
 218
 219 /*
 220  * Normal program termination
 221  */
 222 void exit(int rv)
 223 {
 224         /* Perform exit-specific cleanup (atexit and on_exit) */
 225         LOCK;
 226         if (__exit_cleanup) {
 227                 __exit_cleanup(rv);
 228         }
 229         UNLOCK;
 230
 231     /* If we are using stdio, try to shut it down.  At the very least,
 232          * this will attempt to commit all buffered writes.  It may also
 233          * unbuffer all writable files, or close them outright.
 234          * Check the stdio routines for details. */
 235         if (_stdio_term)
 236             _stdio_term();
 237
 238         _exit(rv);
 239 }
 240 #endif