atexit.c 5.8 KB

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