IABSD.fr/src/lib/librthread/rthread_fork.c

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• Author : mpi
  Date : 2017-10-29 08:45:53
  Hash : 9f79a698
  Message : Prefer <elf.h> to the non portable <sys/exec_elf.h>. ok jca@, deraadt@

• lib/librthread/rthread_fork.c

• /*	$OpenBSD: rthread_fork.c,v 1.23 2017/10/29 08:45:53 mpi Exp $ */
  
  /*
   * Copyright (c) 2008 Kurt Miller <kurt@openbsd.org>
   * Copyright (c) 2008 Philip Guenther <guenther@openbsd.org>
   * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
   * All rights reserved.
   *
   * 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. Neither the name of the author nor the names of any co-contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
   *
   * $FreeBSD: /repoman/r/ncvs/src/lib/libc_r/uthread/uthread_atfork.c,v 1.1 2004/12/10 03:36:45 grog Exp $
   */
  
  #ifndef NO_PIC
  #include <sys/types.h>
  #include <elf.h>
  #pragma weak _DYNAMIC
  #endif
  
  #include <errno.h>
  #include <pthread.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <tib.h>
  #include <unistd.h>
  
  #include "rthread.h"
  #include "rthread_cb.h"
  
  /* make {fork,vfork,getthrid} call _thread_sys_{fork,vfork,getthrid} */
  REDIRECT_SYSCALL(fork);
  REDIRECT_SYSCALL(vfork);
  REDIRECT_SYSCALL(getthrid);
  
  static pid_t
  _dofork(pid_t (*sys_fork)(void))
  {
  	pthread_t me;
  	pid_t newid;
  	extern int _post_threaded;
  
  	if (!_threads_ready)
  		return sys_fork();
  
  	me = pthread_self();
  
  	/*
  	 * Protect important libc/ld.so critical areas across the fork call.
  	 * dlclose() will grab the atexit lock via __cxa_finalize() so lock
  	 * the dl_lock first. malloc()/free() can use arc4random(), so lock
  	 * malloc_lock before arc4_lock
  	 */
  
  #ifndef NO_PIC
  	if (_DYNAMIC)
  		_rthread_dl_lock(0);
  #endif
  
  	newid = _thread_dofork(sys_fork);
  
  	if (newid == 0) {
  		struct tib *tib = me->tib;
  #ifndef NO_PIC
  		/* reinitialize the lock in the child */
  		if (_DYNAMIC)
  			_rthread_dl_lock(2);
  #endif
  		/* update this thread's structure */
  		tib->tib_tid = getthrid();
  		me->donesem.lock = _SPINLOCK_UNLOCKED;
  		me->flags_lock = _SPINLOCK_UNLOCKED;
  
  		/* reinit the thread list */
  		LIST_INIT(&_thread_list);
  		LIST_INSERT_HEAD(&_thread_list, me, threads);
  		_thread_lock = _SPINLOCK_UNLOCKED;
  
  		/* single threaded now */
  		__isthreaded = 0;
  		_post_threaded = 0; /* notyet... */
  	}
  #ifndef NO_PIC
  	else if (_DYNAMIC)
  		_rthread_dl_lock(1);
  #endif
  	return newid;
  }
  
  pid_t
  _thread_fork(void)
  {
  	return _dofork(&fork);
  }
  
  pid_t
  _thread_vfork(void)
  {
  	return _dofork(&vfork);
  }