121 lines
3.6 KiB
C
121 lines
3.6 KiB
C
/* Linuxthreads - a simple clone()-based implementation of Posix */
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/* threads for Linux. */
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/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
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/* */
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/* This program is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU Library General Public License */
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/* as published by the Free Software Foundation; either version 2 */
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/* of the License, or (at your option) any later version. */
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/* */
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/* This program is distributed in the hope that it will be useful, */
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/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
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/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
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/* GNU Library General Public License for more details. */
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/* The "atfork" stuff */
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "pthread.h"
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#include "internals.h"
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#include <bits/libc-lock.h>
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struct handler_list {
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void (*handler)(void);
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struct handler_list * next;
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};
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static pthread_mutex_t pthread_atfork_lock = PTHREAD_MUTEX_INITIALIZER;
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static struct handler_list * pthread_atfork_prepare = NULL;
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static struct handler_list * pthread_atfork_parent = NULL;
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static struct handler_list * pthread_atfork_child = NULL;
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static void pthread_insert_list(struct handler_list ** list,
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void (*handler)(void),
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struct handler_list * newlist,
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int at_end)
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{
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if (handler == NULL) return;
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if (at_end) {
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while(*list != NULL) list = &((*list)->next);
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}
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newlist->handler = handler;
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newlist->next = *list;
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*list = newlist;
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}
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struct handler_list_block {
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struct handler_list prepare, parent, child;
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};
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int __pthread_atfork(void (*prepare)(void),
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void (*parent)(void),
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void (*child)(void))
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{
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struct handler_list_block * block =
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(struct handler_list_block *) malloc(sizeof(struct handler_list_block));
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if (block == NULL) return ENOMEM;
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pthread_mutex_lock(&pthread_atfork_lock);
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/* "prepare" handlers are called in LIFO */
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pthread_insert_list(&pthread_atfork_prepare, prepare, &block->prepare, 0);
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/* "parent" handlers are called in FIFO */
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pthread_insert_list(&pthread_atfork_parent, parent, &block->parent, 1);
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/* "child" handlers are called in FIFO */
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pthread_insert_list(&pthread_atfork_child, child, &block->child, 1);
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pthread_mutex_unlock(&pthread_atfork_lock);
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return 0;
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}
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strong_alias (__pthread_atfork, pthread_atfork)
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static inline void pthread_call_handlers(struct handler_list * list)
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{
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for (/*nothing*/; list != NULL; list = list->next) (list->handler)();
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}
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extern int __libc_fork(void);
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pid_t __fork(void)
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{
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pid_t pid;
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pthread_mutex_lock(&pthread_atfork_lock);
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pthread_call_handlers(pthread_atfork_prepare);
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__pthread_once_fork_prepare();
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__flockfilelist();
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pid = __libc_fork();
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if (pid == 0) {
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__pthread_reset_main_thread();
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__fresetlockfiles();
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__pthread_once_fork_child();
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pthread_call_handlers(pthread_atfork_child);
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pthread_mutex_init(&pthread_atfork_lock, NULL);
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} else {
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__funlockfilelist();
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__pthread_once_fork_parent();
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pthread_call_handlers(pthread_atfork_parent);
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pthread_mutex_unlock(&pthread_atfork_lock);
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}
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return pid;
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}
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weak_alias (__fork, fork);
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#if !defined(_ELIX_LEVEL) || _ELIX_LEVEL >= 4
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pid_t __vfork(void)
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{
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return __fork();
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}
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weak_alias (__vfork, vfork);
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#endif /* !_ELIX_LEVEL || _ELIX_LEVEL >= 4 */
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