diff options
Diffstat (limited to 'lib/libc/stdlib/atexit.c')
| -rw-r--r-- | lib/libc/stdlib/atexit.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/libc/stdlib/atexit.c b/lib/libc/stdlib/atexit.c new file mode 100644 index 0000000..511172a --- /dev/null +++ b/lib/libc/stdlib/atexit.c @@ -0,0 +1,205 @@ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <link.h> +#include <stddef.h> +#include <stdlib.h> +#include <unistd.h> +#include <pthread.h> +#include "atexit.h" +#include "un-namespace.h" + +#include "libc_private.h" + +#define ATEXIT_FN_EMPTY 0 +#define ATEXIT_FN_STD 1 +#define ATEXIT_FN_CXA 2 + +static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; + +#define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) +#define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) +#define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) + +struct atexit { + struct atexit *next; /* next in list */ + int ind; /* next index in this table */ + struct atexit_fn { + int fn_type; /* ATEXIT_? from above */ + union { + void (*std_func)(void); + void (*cxa_func)(void *); + } fn_ptr; /* function pointer */ + void *fn_arg; /* argument for CXA callback */ + void *fn_dso; /* shared module handle */ + } fns[ATEXIT_SIZE]; /* the table itself */ +}; + +static struct atexit *__atexit; /* points to head of LIFO stack */ + +/* + * Register the function described by 'fptr' to be called at application + * exit or owning shared object unload time. This is a helper function + * for atexit and __cxa_atexit. + */ +static int +atexit_register(struct atexit_fn *fptr) +{ + static struct atexit __atexit0; /* one guaranteed table */ + struct atexit *p; + + _MUTEX_LOCK(&atexit_mutex); + if ((p = __atexit) == NULL) + __atexit = p = &__atexit0; + else while (p->ind >= ATEXIT_SIZE) { + struct atexit *old__atexit; + old__atexit = __atexit; + _MUTEX_UNLOCK(&atexit_mutex); + if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) + return (-1); + _MUTEX_LOCK(&atexit_mutex); + if (old__atexit != __atexit) { + /* Lost race, retry operation */ + _MUTEX_UNLOCK(&atexit_mutex); + free(p); + _MUTEX_LOCK(&atexit_mutex); + p = __atexit; + continue; + } + p->ind = 0; + p->next = __atexit; + __atexit = p; + } + p->fns[p->ind++] = *fptr; + _MUTEX_UNLOCK(&atexit_mutex); + return 0; +} + +/* + * Register a function to be performed at exit. + */ +int +atexit(void (*func)(void)) +{ + struct atexit_fn fn; + int error; + + fn.fn_type = ATEXIT_FN_STD; + fn.fn_ptr.std_func = func; + fn.fn_arg = NULL; + fn.fn_dso = NULL; + + error = atexit_register(&fn); + return (error); +} + +/* + * Register a function to be performed at exit or when an shared object + * with given dso handle is unloaded dynamically. + */ +int +__cxa_atexit(void (*func)(void *), void *arg, void *dso) +{ + struct atexit_fn fn; + int error; + + fn.fn_type = ATEXIT_FN_CXA; + fn.fn_ptr.cxa_func = func; + fn.fn_arg = arg; + fn.fn_dso = dso; + + error = atexit_register(&fn); + return (error); +} + +#pragma weak __pthread_cxa_finalize +void __pthread_cxa_finalize(const struct dl_phdr_info *); + +/* + * Call all handlers registered with __cxa_atexit for the shared + * object owning 'dso'. Note: if 'dso' is NULL, then all remaining + * handlers are called. + */ +void +__cxa_finalize(void *dso) +{ + struct dl_phdr_info phdr_info; + struct atexit *p; + struct atexit_fn fn; + int n, has_phdr; + + if (dso != NULL) + has_phdr = _rtld_addr_phdr(dso, &phdr_info); + else + has_phdr = 0; + + _MUTEX_LOCK(&atexit_mutex); + for (p = __atexit; p; p = p->next) { + for (n = p->ind; --n >= 0;) { + if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) + continue; /* already been called */ + fn = p->fns[n]; + if (dso != NULL && dso != fn.fn_dso) { + /* wrong DSO ? */ + if (!has_phdr || !__elf_phdr_match_addr( + &phdr_info, fn.fn_ptr.cxa_func)) + continue; + } + /* + Mark entry to indicate that this particular handler + has already been called. + */ + p->fns[n].fn_type = ATEXIT_FN_EMPTY; + _MUTEX_UNLOCK(&atexit_mutex); + + /* Call the function of correct type. */ + if (fn.fn_type == ATEXIT_FN_CXA) + fn.fn_ptr.cxa_func(fn.fn_arg); + else if (fn.fn_type == ATEXIT_FN_STD) + fn.fn_ptr.std_func(); + _MUTEX_LOCK(&atexit_mutex); + } + } + _MUTEX_UNLOCK(&atexit_mutex); + if (dso == NULL) + _MUTEX_DESTROY(&atexit_mutex); + + if (has_phdr && &__pthread_cxa_finalize != NULL) + __pthread_cxa_finalize(&phdr_info); +} |
