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 #include <bits/uClibc_mutex.h>
47 __UCLIBC_MUTEX_EXTERN(__atexit_lock);
49 libc_hidden_proto(exit)
50 libc_hidden_proto(_exit)
53 typedef void (*aefuncp) (void); /* atexit function pointer */
54 typedef void (*oefuncp) (int, void *); /* on_exit function pointer */
55 typedef void (*cxaefuncp) (void *); /* __cxa_atexit function pointer */
61 } ef_type; /* exit function types */
63 /* this is in the L_exit object */
64 extern void (*__exit_cleanup) (int) attribute_hidden;
66 /* these are in the L___do_exit object */
67 extern int __exit_slots attribute_hidden;
68 extern int __exit_count attribute_hidden;
69 extern void __exit_handler(int) attribute_hidden;
70 struct exit_function {
72 * 'type' should be of type of the 'enum ef_type' above but since we
73 * need this element in an atomic operation we have to use 'long int'.
75 long int type; /* enum ef_type */
88 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
89 extern struct exit_function *__exit_function_table attribute_hidden;
91 extern struct exit_function __exit_function_table[__UCLIBC_MAX_ATEXIT] attribute_hidden;
93 extern struct exit_function *__new_exitfn (void) attribute_hidden;
95 /* this is in the L___cxa_atexit object */
96 extern int __cxa_atexit (cxaefuncp, void *arg, void *dso_handle);
99 /* remove old_atexit after 0.9.29 */
100 #if defined(L_atexit) || defined(L_old_atexit)
101 extern void *__dso_handle __attribute__ ((__weak__));
104 * register a function to be called at normal program termination
105 * (the registered function takes no arguments)
108 int attribute_hidden atexit(aefuncp func)
110 int old_atexit(aefuncp func);
111 int old_atexit(aefuncp func)
115 * glibc casts aefuncp to cxaefuncp.
116 * This seems dodgy, but I guess calling a function with more
117 * parameters than it needs will work everywhere?
119 return __cxa_atexit((cxaefuncp)func, NULL,
120 &__dso_handle == NULL ? NULL : __dso_handle);
123 weak_alias(old_atexit,atexit)
129 * register a function to be called at normal program termination
130 * the registered function takes two arguments:
131 * status - the exit status that was passed to the exit() function
132 * arg - generic argument
134 int on_exit(oefuncp func, void *arg)
136 struct exit_function *efp;
142 efp = __new_exitfn();
147 efp->funcs.on_exit.func = func;
148 efp->funcs.on_exit.arg = arg;
149 /* assign last for thread safety, since we're now unlocked */
150 efp->type = ef_on_exit;
156 #ifdef L___cxa_atexit
157 libc_hidden_proto(__cxa_atexit)
158 int __cxa_atexit (cxaefuncp func, void *arg, void *dso_handle)
160 struct exit_function *efp;
166 efp = __new_exitfn();
171 efp->funcs.cxa_atexit.func = func;
172 efp->funcs.cxa_atexit.arg = arg;
173 efp->funcs.cxa_atexit.dso_handle = dso_handle;
174 /* assign last for thread safety, since we're now unlocked */
175 efp->type = ef_cxa_atexit;
179 libc_hidden_def(__cxa_atexit)
182 #ifdef L___cxa_finalize
184 * If D is non-NULL, call all functions registered with `__cxa_atexit'
185 * with the same dso handle. Otherwise, if D is NULL, call all of the
186 * registered handlers.
188 void __cxa_finalize (void *dso_handle);
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;
243 __UCLIBC_MUTEX_LOCK(__atexit_lock);
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));
254 __exit_function_table = efp;
258 if (__exit_count >= __UCLIBC_MAX_ATEXIT) {
265 __exit_cleanup = __exit_handler; /* enable cleanup */
266 efp = &__exit_function_table[__exit_count++];
267 efp->type = ef_in_use;
270 __UCLIBC_MUTEX_UNLOCK(__atexit_lock);
275 * Handle the work of executing the registered exit functions
276 * This is called while we are locked, so no additional locking
279 void __exit_handler(int status)
281 struct exit_function *efp;
283 /* In reverse order */
284 while ( __exit_count ) {
285 efp = &__exit_function_table[--__exit_count];
288 if (efp->funcs.on_exit.func) {
289 (efp->funcs.on_exit.func) (status, efp->funcs.on_exit.arg);
293 if (efp->funcs.cxa_atexit.func) {
294 /* glibc passes status too, but that's not in the prototype */
295 (efp->funcs.cxa_atexit.func) (efp->funcs.cxa_atexit.arg);
300 #ifdef __UCLIBC_DYNAMIC_ATEXIT__
301 /* Free up memory used by the __exit_function_table structure */
302 free(__exit_function_table);
308 extern void weak_function _stdio_term(void) attribute_hidden;
309 attribute_hidden void (*__exit_cleanup) (int) = 0;
310 __UCLIBC_MUTEX_INIT(__atexit_lock, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);
312 extern void __uClibc_fini(void);
313 libc_hidden_proto(__uClibc_fini)
316 * Normal program termination
320 /* Perform exit-specific cleanup (atexit and on_exit) */
321 __UCLIBC_MUTEX_LOCK(__atexit_lock);
322 if (__exit_cleanup) {
325 __UCLIBC_MUTEX_UNLOCK(__atexit_lock);
329 /* If we are using stdio, try to shut it down. At the very least,
330 * this will attempt to commit all buffered writes. It may also
331 * unbuffer all writable files, or close them outright.
332 * Check the stdio routines for details. */
338 libc_hidden_def(exit)