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.
7 * Dec 2000 Manuel Novoa III
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.
13 * Feb 2001 Manuel Novoa III
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)
22 * Jul 2001 Steve Thayer
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
29 * As a side effect of these changes, abort() no longer calls the exit
30 * functions (it now matches the gnu libc definition).
32 * August 2002 Erik Andersen
33 * Added locking so atexit and friends can be thread safe
35 * August 2005 Stephen Warren
36 * Added __cxa_atexit and __cxa_finalize support
46 libc_hidden_proto(exit)
47 libc_hidden_proto(_exit)
49 #ifdef __UCLIBC_HAS_THREADS__
51 extern pthread_mutex_t mylock;
53 #define LOCK __pthread_mutex_lock(&mylock)
54 #define UNLOCK __pthread_mutex_unlock(&mylock)
57 typedef void (*aefuncp) (void); /* atexit function pointer */
58 typedef void (*oefuncp) (int, void *); /* on_exit function pointer */
59 typedef void (*cxaefuncp) (void *); /* __cxa_atexit function pointer */
65 } ef_type; /* exit function types */
67 /* this is in the L_exit object */
68 extern void (*__exit_cleanup) (int) attribute_hidden;
70 /* these are in the L___do_exit object */
71 extern int __exit_slots attribute_hidden;
72 extern int __exit_count attribute_hidden;
73 extern void __exit_handler(int) attribute_hidden;
74 struct exit_function {
76 * 'type' should be of type of the 'enum ef_type' above but since we
77 * need this element in an atomic operation we have to use 'long int'.
79 long int type; /* enum ef_type */
92 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
93 extern struct exit_function *__exit_function_table attribute_hidden;
95 extern struct exit_function __exit_function_table[__UCLIBC_MAX_ATEXIT] attribute_hidden;
97 extern struct exit_function *__new_exitfn (void) attribute_hidden;
99 /* this is in the L___cxa_atexit object */
100 extern int __cxa_atexit (cxaefuncp, void *arg, void *dso_handle);
103 /* remove old_atexit after 0.9.29 */
104 #if defined(L_atexit) || defined(L_old_atexit)
105 extern void *__dso_handle __attribute__ ((__weak__));
108 * register a function to be called at normal program termination
109 * (the registered function takes no arguments)
112 int attribute_hidden atexit(aefuncp func)
114 int old_atexit(aefuncp func)
118 * glibc casts aefuncp to cxaefuncp.
119 * This seems dodgy, but I guess callling a function with more
120 * parameters than it needs will work everywhere?
122 return __cxa_atexit((cxaefuncp)func, NULL,
123 &__dso_handle == NULL ? NULL : __dso_handle);
126 weak_alias(old_atexit,atexit)
132 * register a function to be called at normal program termination
133 * the registered function takes two arguments:
134 * status - the exit status that was passed to the exit() function
135 * arg - generic argument
137 int on_exit(oefuncp func, void *arg)
139 struct exit_function *efp;
145 efp = __new_exitfn();
150 efp->funcs.on_exit.func = func;
151 efp->funcs.on_exit.arg = arg;
152 /* assign last for thread safety, since we're now unlocked */
153 efp->type = ef_on_exit;
159 #ifdef L___cxa_atexit
160 extern int __cxa_atexit (cxaefuncp func, void *arg, void *dso_handle)
162 struct exit_function *efp;
168 efp = __new_exitfn();
173 efp->funcs.cxa_atexit.func = func;
174 efp->funcs.cxa_atexit.arg = arg;
175 efp->funcs.cxa_atexit.dso_handle = dso_handle;
176 /* assign last for thread safety, since we're now unlocked */
177 efp->type = ef_cxa_atexit;
183 #ifdef L___cxa_finalize
185 * If D is non-NULL, call all functions registered with `__cxa_atexit'
186 * with the same dso handle. Otherwise, if D is NULL, call all of the
187 * registered handlers.
189 void __cxa_finalize (void *dso_handle)
191 struct exit_function *efp;
192 int exit_count_snapshot = __exit_count;
194 /* In reverse order */
195 while (exit_count_snapshot) {
196 efp = &__exit_function_table[--exit_count_snapshot];
199 * We check dso_handle match before we verify the type of the union entry.
200 * However, the atomic_exchange will validate that we were really "allowed"
201 * to read dso_handle...
203 if ((dso_handle == NULL || dso_handle == efp->funcs.cxa_atexit.dso_handle)
204 /* We don't want to run this cleanup more than once. */
205 && !atomic_compare_and_exchange_bool_acq(&efp->type, ef_free, ef_cxa_atexit)
207 /* glibc passes status (0) too, but that's not in the prototype */
208 (*efp->funcs.cxa_atexit.func)(efp->funcs.cxa_atexit.arg);
212 #if 0 /* haven't looked into this yet... */
214 * Remove the registered fork handlers. We do not have to
215 * unregister anything if the program is going to terminate anyway.
217 #ifdef UNREGISTER_ATFORK
219 UNREGISTER_ATFORK (d);
226 #ifdef L___exit_handler
227 int __exit_count = 0; /* Number of registered exit functions */
228 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
229 struct exit_function *__exit_function_table = NULL;
230 int __exit_slots = 0; /* Size of __exit_function_table */
232 struct exit_function __exit_function_table[__UCLIBC_MAX_ATEXIT];
236 * Find and return a new exit_function pointer, for atexit,
237 * onexit and __cxa_atexit to initialize
239 struct exit_function attribute_hidden *__new_exitfn(void)
241 struct exit_function *efp;
245 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
246 /* If we are out of function table slots, make some more */
247 if (__exit_slots < __exit_count+1) {
248 efp=realloc(__exit_function_table,
249 (__exit_slots+20)*sizeof(struct exit_function));
255 __exit_function_table = efp;
259 if (__exit_count >= __UCLIBC_MAX_ATEXIT) {
266 __exit_cleanup = __exit_handler; /* enable cleanup */
267 efp = &__exit_function_table[__exit_count++];
268 efp->type = ef_in_use;
276 * Handle the work of executing the registered exit functions
277 * This is called while we are locked, so no additional locking
280 void __exit_handler(int status)
282 struct exit_function *efp;
284 /* In reverse order */
285 while ( __exit_count ) {
286 efp = &__exit_function_table[--__exit_count];
289 if (efp->funcs.on_exit.func) {
290 (efp->funcs.on_exit.func) (status, efp->funcs.on_exit.arg);
294 if (efp->funcs.cxa_atexit.func) {
295 /* glibc passes status too, but that's not in the prototype */
296 (efp->funcs.cxa_atexit.func) (efp->funcs.cxa_atexit.arg);
301 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
302 /* Free up memory used by the __exit_function_table structure */
303 if (__exit_function_table)
304 free(__exit_function_table);
310 extern void weak_function _stdio_term(void) attribute_hidden;
311 attribute_hidden void (*__exit_cleanup) (int) = 0;
312 #ifdef __UCLIBC_HAS_THREADS__
313 pthread_mutex_t mylock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
316 #ifdef __UCLIBC_CTOR_DTOR__
317 extern void (*__app_fini)(void);
320 extern void (*__rtld_fini)(void);
323 * Normal program termination
327 /* Perform exit-specific cleanup (atexit and on_exit) */
329 if (__exit_cleanup) {
334 #ifdef __UCLIBC_CTOR_DTOR__
335 if (__app_fini != NULL)
338 if (__rtld_fini != NULL)
341 /* If we are using stdio, try to shut it down. At the very least,
342 * this will attempt to commit all buffered writes. It may also
343 * unbuffer all writable files, or close them outright.
344 * Check the stdio routines for details. */
350 libc_hidden_def(exit)