atexit.c revision 211894
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 4. Neither the name of the University nor the names of its contributors 171573Srgrimes * may be used to endorse or promote products derived from this software 181573Srgrimes * without specific prior written permission. 191573Srgrimes * 201573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 211573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 221573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 231573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 241573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 251573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 261573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 271573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 281573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 291573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 301573Srgrimes * SUCH DAMAGE. 311573Srgrimes */ 321573Srgrimes 331573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 3423662Speterstatic char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; 351573Srgrimes#endif /* LIBC_SCCS and not lint */ 3692986Sobrien#include <sys/cdefs.h> 3792986Sobrien__FBSDID("$FreeBSD: head/lib/libc/stdlib/atexit.c 211894 2010-08-27 19:57:17Z kib $"); 381573Srgrimes 3991697Stegge#include "namespace.h" 40211706Skib#include <link.h> 411573Srgrimes#include <stddef.h> 421573Srgrimes#include <stdlib.h> 4318516Sphk#include <unistd.h> 4491697Stegge#include <pthread.h> 451573Srgrimes#include "atexit.h" 4691697Stegge#include "un-namespace.h" 471573Srgrimes 4891697Stegge#include "libc_private.h" 4991697Stegge 50123673Skan#define ATEXIT_FN_EMPTY 0 51123673Skan#define ATEXIT_FN_STD 1 52123673Skan#define ATEXIT_FN_CXA 2 53123673Skan 5491697Steggestatic pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 5591697Stegge 5691697Stegge#define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 5791697Stegge#define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 58209117Scperciva#define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) 5991697Stegge 60123673Skanstruct atexit { 61123673Skan struct atexit *next; /* next in list */ 62123673Skan int ind; /* next index in this table */ 63123673Skan struct atexit_fn { 64123673Skan int fn_type; /* ATEXIT_? from above */ 65123673Skan union { 66123673Skan void (*std_func)(void); 67123673Skan void (*cxa_func)(void *); 68123673Skan } fn_ptr; /* function pointer */ 69123673Skan void *fn_arg; /* argument for CXA callback */ 70123673Skan void *fn_dso; /* shared module handle */ 71123673Skan } fns[ATEXIT_SIZE]; /* the table itself */ 72123673Skan}; 7323662Speter 74123673Skanstatic struct atexit *__atexit; /* points to head of LIFO stack */ 75123673Skan 761573Srgrimes/* 77123673Skan * Register the function described by 'fptr' to be called at application 78123673Skan * exit or owning shared object unload time. This is a helper function 79123673Skan * for atexit and __cxa_atexit. 801573Srgrimes */ 81123673Skanstatic int 82123673Skanatexit_register(struct atexit_fn *fptr) 831573Srgrimes{ 841573Srgrimes static struct atexit __atexit0; /* one guaranteed table */ 8592889Sobrien struct atexit *p; 861573Srgrimes 8791697Stegge _MUTEX_LOCK(&atexit_mutex); 881573Srgrimes if ((p = __atexit) == NULL) 891573Srgrimes __atexit = p = &__atexit0; 9091697Stegge else while (p->ind >= ATEXIT_SIZE) { 9191697Stegge struct atexit *old__atexit; 9291697Stegge old__atexit = __atexit; 9391697Stegge _MUTEX_UNLOCK(&atexit_mutex); 9491697Stegge if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 951573Srgrimes return (-1); 9691697Stegge _MUTEX_LOCK(&atexit_mutex); 9791697Stegge if (old__atexit != __atexit) { 9891697Stegge /* Lost race, retry operation */ 9991697Stegge _MUTEX_UNLOCK(&atexit_mutex); 10091697Stegge free(p); 10191697Stegge _MUTEX_LOCK(&atexit_mutex); 10291697Stegge p = __atexit; 10391697Stegge continue; 10491697Stegge } 1051573Srgrimes p->ind = 0; 1061573Srgrimes p->next = __atexit; 1071573Srgrimes __atexit = p; 1081573Srgrimes } 109123673Skan p->fns[p->ind++] = *fptr; 11091697Stegge _MUTEX_UNLOCK(&atexit_mutex); 111123673Skan return 0; 1121573Srgrimes} 113123673Skan 114123673Skan/* 115123673Skan * Register a function to be performed at exit. 116123673Skan */ 117123673Skanint 118123673Skanatexit(void (*func)(void)) 119123673Skan{ 120123673Skan struct atexit_fn fn; 121123673Skan int error; 122123673Skan 123123673Skan fn.fn_type = ATEXIT_FN_STD; 124211704Skib fn.fn_ptr.std_func = func; 125123673Skan fn.fn_arg = NULL; 126123673Skan fn.fn_dso = NULL; 127123673Skan 128123673Skan error = atexit_register(&fn); 129123673Skan return (error); 130123673Skan} 131123673Skan 132123673Skan/* 133123673Skan * Register a function to be performed at exit or when an shared object 134123673Skan * with given dso handle is unloaded dynamically. 135123673Skan */ 136123673Skanint 137123673Skan__cxa_atexit(void (*func)(void *), void *arg, void *dso) 138123673Skan{ 139123673Skan struct atexit_fn fn; 140123673Skan int error; 141123673Skan 142123673Skan fn.fn_type = ATEXIT_FN_CXA; 143211704Skib fn.fn_ptr.cxa_func = func; 144123673Skan fn.fn_arg = arg; 145123673Skan fn.fn_dso = dso; 146123673Skan 147123673Skan error = atexit_register(&fn); 148123673Skan return (error); 149123673Skan} 150123673Skan 151211706Skib#pragma weak __pthread_cxa_finalize 152211706Skibvoid __pthread_cxa_finalize(const struct dl_phdr_info *); 153211706Skib 154123673Skan/* 155123673Skan * Call all handlers registered with __cxa_atexit for the shared 156123673Skan * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 157123673Skan * handlers are called. 158123673Skan */ 159123673Skanvoid 160123673Skan__cxa_finalize(void *dso) 161123673Skan{ 162211706Skib struct dl_phdr_info phdr_info; 163123673Skan struct atexit *p; 164123673Skan struct atexit_fn fn; 165211706Skib int n, has_phdr; 166123673Skan 167211706Skib if (dso != NULL) 168211706Skib has_phdr = _rtld_addr_phdr(dso, &phdr_info); 169211706Skib else 170211706Skib has_phdr = 0; 171211706Skib 172123673Skan _MUTEX_LOCK(&atexit_mutex); 173123673Skan for (p = __atexit; p; p = p->next) { 174123673Skan for (n = p->ind; --n >= 0;) { 175123673Skan if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 176123673Skan continue; /* already been called */ 177123673Skan fn = p->fns[n]; 178211706Skib if (dso != NULL && dso != fn.fn_dso) { 179211706Skib /* wrong DSO ? */ 180211706Skib if (!has_phdr || !__elf_phdr_match_addr( 181211706Skib &phdr_info, fn.fn_ptr.cxa_func)) 182211706Skib continue; 183211706Skib } 184123673Skan /* 185123673Skan Mark entry to indicate that this particular handler 186123673Skan has already been called. 187123673Skan */ 188123673Skan p->fns[n].fn_type = ATEXIT_FN_EMPTY; 189123673Skan _MUTEX_UNLOCK(&atexit_mutex); 190123673Skan 191123673Skan /* Call the function of correct type. */ 192123673Skan if (fn.fn_type == ATEXIT_FN_CXA) 193123673Skan fn.fn_ptr.cxa_func(fn.fn_arg); 194123673Skan else if (fn.fn_type == ATEXIT_FN_STD) 195123673Skan fn.fn_ptr.std_func(); 196123673Skan _MUTEX_LOCK(&atexit_mutex); 197123673Skan } 198123673Skan } 199123673Skan _MUTEX_UNLOCK(&atexit_mutex); 200209117Scperciva if (dso == NULL) 201209117Scperciva _MUTEX_DESTROY(&atexit_mutex); 202211706Skib 203211894Skib if (has_phdr && &__pthread_cxa_finalize != NULL) 204211706Skib __pthread_cxa_finalize(&phdr_info); 205123673Skan} 206