atexit.c revision 209117
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 209117 2010-06-13 01:13:36Z cperciva $"); 381573Srgrimes 3991697Stegge#include "namespace.h" 401573Srgrimes#include <stddef.h> 411573Srgrimes#include <stdlib.h> 4218516Sphk#include <unistd.h> 4391697Stegge#include <pthread.h> 441573Srgrimes#include "atexit.h" 4591697Stegge#include "un-namespace.h" 461573Srgrimes 4791697Stegge#include "libc_private.h" 4891697Stegge 49123673Skan#define ATEXIT_FN_EMPTY 0 50123673Skan#define ATEXIT_FN_STD 1 51123673Skan#define ATEXIT_FN_CXA 2 52123673Skan 5391697Steggestatic pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 5491697Stegge 5591697Stegge#define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 5691697Stegge#define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 57209117Scperciva#define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) 5891697Stegge 59123673Skanstruct atexit { 60123673Skan struct atexit *next; /* next in list */ 61123673Skan int ind; /* next index in this table */ 62123673Skan struct atexit_fn { 63123673Skan int fn_type; /* ATEXIT_? from above */ 64123673Skan union { 65123673Skan void (*std_func)(void); 66123673Skan void (*cxa_func)(void *); 67123673Skan } fn_ptr; /* function pointer */ 68123673Skan void *fn_arg; /* argument for CXA callback */ 69123673Skan void *fn_dso; /* shared module handle */ 70123673Skan } fns[ATEXIT_SIZE]; /* the table itself */ 71123673Skan}; 7223662Speter 73123673Skanstatic struct atexit *__atexit; /* points to head of LIFO stack */ 74123673Skan 751573Srgrimes/* 76123673Skan * Register the function described by 'fptr' to be called at application 77123673Skan * exit or owning shared object unload time. This is a helper function 78123673Skan * for atexit and __cxa_atexit. 791573Srgrimes */ 80123673Skanstatic int 81123673Skanatexit_register(struct atexit_fn *fptr) 821573Srgrimes{ 831573Srgrimes static struct atexit __atexit0; /* one guaranteed table */ 8492889Sobrien struct atexit *p; 851573Srgrimes 8691697Stegge _MUTEX_LOCK(&atexit_mutex); 871573Srgrimes if ((p = __atexit) == NULL) 881573Srgrimes __atexit = p = &__atexit0; 8991697Stegge else while (p->ind >= ATEXIT_SIZE) { 9091697Stegge struct atexit *old__atexit; 9191697Stegge old__atexit = __atexit; 9291697Stegge _MUTEX_UNLOCK(&atexit_mutex); 9391697Stegge if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 941573Srgrimes return (-1); 9591697Stegge _MUTEX_LOCK(&atexit_mutex); 9691697Stegge if (old__atexit != __atexit) { 9791697Stegge /* Lost race, retry operation */ 9891697Stegge _MUTEX_UNLOCK(&atexit_mutex); 9991697Stegge free(p); 10091697Stegge _MUTEX_LOCK(&atexit_mutex); 10191697Stegge p = __atexit; 10291697Stegge continue; 10391697Stegge } 1041573Srgrimes p->ind = 0; 1051573Srgrimes p->next = __atexit; 1061573Srgrimes __atexit = p; 1071573Srgrimes } 108123673Skan p->fns[p->ind++] = *fptr; 10991697Stegge _MUTEX_UNLOCK(&atexit_mutex); 110123673Skan return 0; 1111573Srgrimes} 112123673Skan 113123673Skan/* 114123673Skan * Register a function to be performed at exit. 115123673Skan */ 116123673Skanint 117123673Skanatexit(void (*func)(void)) 118123673Skan{ 119123673Skan struct atexit_fn fn; 120123673Skan int error; 121123673Skan 122123673Skan fn.fn_type = ATEXIT_FN_STD; 123123673Skan fn.fn_ptr.std_func = func;; 124123673Skan fn.fn_arg = NULL; 125123673Skan fn.fn_dso = NULL; 126123673Skan 127123673Skan error = atexit_register(&fn); 128123673Skan return (error); 129123673Skan} 130123673Skan 131123673Skan/* 132123673Skan * Register a function to be performed at exit or when an shared object 133123673Skan * with given dso handle is unloaded dynamically. 134123673Skan */ 135123673Skanint 136123673Skan__cxa_atexit(void (*func)(void *), void *arg, void *dso) 137123673Skan{ 138123673Skan struct atexit_fn fn; 139123673Skan int error; 140123673Skan 141123673Skan fn.fn_type = ATEXIT_FN_CXA; 142123673Skan fn.fn_ptr.cxa_func = func;; 143123673Skan fn.fn_arg = arg; 144123673Skan fn.fn_dso = dso; 145123673Skan 146123673Skan error = atexit_register(&fn); 147123673Skan return (error); 148123673Skan} 149123673Skan 150123673Skan/* 151123673Skan * Call all handlers registered with __cxa_atexit for the shared 152123673Skan * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 153123673Skan * handlers are called. 154123673Skan */ 155123673Skanvoid 156123673Skan__cxa_finalize(void *dso) 157123673Skan{ 158123673Skan struct atexit *p; 159123673Skan struct atexit_fn fn; 160123673Skan int n; 161123673Skan 162123673Skan _MUTEX_LOCK(&atexit_mutex); 163123673Skan for (p = __atexit; p; p = p->next) { 164123673Skan for (n = p->ind; --n >= 0;) { 165123673Skan if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 166123673Skan continue; /* already been called */ 167123673Skan if (dso != NULL && dso != p->fns[n].fn_dso) 168123673Skan continue; /* wrong DSO */ 169123673Skan fn = p->fns[n]; 170123673Skan /* 171123673Skan Mark entry to indicate that this particular handler 172123673Skan has already been called. 173123673Skan */ 174123673Skan p->fns[n].fn_type = ATEXIT_FN_EMPTY; 175123673Skan _MUTEX_UNLOCK(&atexit_mutex); 176123673Skan 177123673Skan /* Call the function of correct type. */ 178123673Skan if (fn.fn_type == ATEXIT_FN_CXA) 179123673Skan fn.fn_ptr.cxa_func(fn.fn_arg); 180123673Skan else if (fn.fn_type == ATEXIT_FN_STD) 181123673Skan fn.fn_ptr.std_func(); 182123673Skan _MUTEX_LOCK(&atexit_mutex); 183123673Skan } 184123673Skan } 185123673Skan _MUTEX_UNLOCK(&atexit_mutex); 186209117Scperciva if (dso == NULL) 187209117Scperciva _MUTEX_DESTROY(&atexit_mutex); 188123673Skan} 189