1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2011 David Chisnall 5 * Copyright (c) 2023 Klara, Inc. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/types.h> 31 32 #include <stdatomic.h> 33 #include <stdlib.h> 34 35 /** 36 * Linked list of quick exit handlers. These will be invoked in reverse 37 * order of insertion when quick_exit() is called. This is simpler than 38 * the atexit() version, because it is not required to support C++ 39 * destructors or DSO-specific cleanups. 40 */ 41 struct quick_exit_handler { 42 struct quick_exit_handler *next; 43 void (*cleanup)(void); 44 }; 45 46 static _Atomic(struct quick_exit_handler *) handlers; 47 48 int 49 at_quick_exit(void (*func)(void)) 50 { 51 struct quick_exit_handler *h; 52 53 if ((h = calloc(1, sizeof(*h))) == NULL) { 54 return (-1); 55 } 56 h->cleanup = func; 57 while (!atomic_compare_exchange_strong(&handlers, &h->next, h)) { 58 /* nothing */ ; 59 } 60 return (0); 61 } 62 63 void 64 quick_exit(int status) 65 { 66 struct quick_exit_handler *h; 67 68 /* 69 * XXX: The C++ spec requires us to call std::terminate if there is an 70 * exception here. 71 */ 72 for (h = atomic_load_explicit(&handlers, memory_order_acquire); 73 h != NULL; h = h->next) { 74 h->cleanup(); 75 } 76 _Exit(status); 77 } 78