2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
43 #include "namespace.h"
49 #include "un-namespace.h"
51 #include "libc_private.h"
53 #define ATEXIT_FN_EMPTY 0
54 #define ATEXIT_FN_STD 1
55 #define ATEXIT_FN_CXA 2
57 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
59 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x)
60 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x)
63 struct atexit *next; /* next in list */
64 int ind; /* next index in this table */
66 int fn_type; /* ATEXIT_? from above */
68 void (*std_func)(void);
69 void (*cxa_func)(void *);
70 } fn_ptr; /* function pointer */
71 void *fn_arg; /* argument for CXA callback */
72 void *fn_dso; /* shared module handle */
73 } fns[ATEXIT_SIZE]; /* the table itself */
76 static struct atexit *__atexit; /* points to head of LIFO stack */
79 * Register the function described by 'fptr' to be called at application
80 * exit or owning shared object unload time. This is a helper function
81 * for atexit and __cxa_atexit.
84 atexit_register(struct atexit_fn *fptr)
86 static struct atexit __atexit0; /* one guaranteed table */
89 _MUTEX_LOCK(&atexit_mutex);
90 if ((p = __atexit) == NULL)
91 __atexit = p = &__atexit0;
92 else while (p->ind >= ATEXIT_SIZE) {
93 struct atexit *old__atexit;
94 old__atexit = __atexit;
95 _MUTEX_UNLOCK(&atexit_mutex);
96 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL)
98 _MUTEX_LOCK(&atexit_mutex);
99 if (old__atexit != __atexit) {
100 /* Lost race, retry operation */
101 _MUTEX_UNLOCK(&atexit_mutex);
103 _MUTEX_LOCK(&atexit_mutex);
111 p->fns[p->ind++] = *fptr;
112 _MUTEX_UNLOCK(&atexit_mutex);
117 * Register a function to be performed at exit.
120 atexit(void (*func)(void))
125 fn.fn_type = ATEXIT_FN_STD;
126 fn.fn_ptr.std_func = func;;
130 error = atexit_register(&fn);
135 * Register a function to be performed at exit or when an shared object
136 * with given dso handle is unloaded dynamically.
139 __cxa_atexit(void (*func)(void *), void *arg, void *dso)
144 fn.fn_type = ATEXIT_FN_CXA;
145 fn.fn_ptr.cxa_func = func;;
149 error = atexit_register(&fn);
154 * Call all handlers registered with __cxa_atexit for the shared
155 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining
156 * handlers are called.
159 __cxa_finalize(void *dso)
165 _MUTEX_LOCK(&atexit_mutex);
166 for (p = __atexit; p; p = p->next) {
167 for (n = p->ind; --n >= 0;) {
168 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY)
169 continue; /* already been called */
170 if (dso != NULL && dso != p->fns[n].fn_dso)
171 continue; /* wrong DSO */
174 Mark entry to indicate that this particular handler
175 has already been called.
177 p->fns[n].fn_type = ATEXIT_FN_EMPTY;
178 _MUTEX_UNLOCK(&atexit_mutex);
180 /* Call the function of correct type. */
181 if (fn.fn_type == ATEXIT_FN_CXA)
182 fn.fn_ptr.cxa_func(fn.fn_arg);
183 else if (fn.fn_type == ATEXIT_FN_STD)
184 fn.fn_ptr.std_func();
185 _MUTEX_LOCK(&atexit_mutex);
188 _MUTEX_UNLOCK(&atexit_mutex);