erl_child_setup.c

来自「OTP是开放电信平台的简称」· C语言 代码 · 共 102 行

 /* ``The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved via the world wide web at http://www.erlang.org/.
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Initial Developer of the Original Code is Ericsson Utvecklings AB.
 * Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
 * AB. All Rights Reserved.''
 * 
 *     $Id$
 */

/*
 * After a vfork() (or fork()) the child exec()s to this program which
 * sets up the child and exec()s to the user program (see spawn_start()
 * in sys.c and ticket OTP-4389).
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#define NEED_CHILD_SETUP_DEFINES
#include "sys.h"

#ifdef SIG_SIGSET		/* Old SysV */
void sys_sigrelease(int sig)
{
    sigrelse(sig);
}
#else /* !SIG_SIGSET */
#ifdef SIG_SIGNAL		/* Old BSD */
sys_sigrelease(int sig)
{
    sigsetmask(sigblock(0) & ~sigmask(sig));
}
#else /* !SIG_SIGNAL */	/* The True Way - POSIX!:-) */
void sys_sigrelease(int sig)
{
    sigset_t mask;

    sigemptyset(&mask);
    sigaddset(&mask, sig);
    sigprocmask(SIG_UNBLOCK, &mask, (sigset_t *)NULL);
}
#endif /* !SIG_SIGNAL */
#endif /* !SIG_SIGSET */

int
main(int argc, char *argv[])
{
    int i, from, to;

    /* OBSERVE!
     * Keep child setup after fork() (implemented in sys.c) up to date
     * if changes are made here.
     */

    if (argc != CS_ARGV_NO_OF_ARGS)
	return 1;

    for (i = 0; i < CS_ARGV_NO_OF_DUP2_OPS; i++) {
	if (argv[CS_ARGV_DUP2_OP_IX(i)][0] == '-'
	    && argv[CS_ARGV_DUP2_OP_IX(i)][1] == '\0')
	    break;
	if (sscanf(argv[CS_ARGV_DUP2_OP_IX(i)], "%d:%d", &from, &to) != 2)
	    return 1;
	if (dup2(from, to) < 0)
	    return 1;
    }

    if (sscanf(argv[CS_ARGV_FD_CR_IX], "%d:%d", &from, &to) != 2)
	return 1;
    for (i = from; i <= to; i++)
	(void) close(i);

    if (!(argv[CS_ARGV_WD_IX][0] == '.' && argv[CS_ARGV_WD_IX][1] == '\0')
	&& chdir(argv[CS_ARGV_WD_IX]) < 0)
	return 1;

#if defined(USE_SETPGRP_NOARGS)		/* SysV */
    (void) setpgrp();
#elif defined(USE_SETPGRP)		/* BSD */
    (void) setpgrp(0, getpid());
#else					/* POSIX */
    (void) setsid();
#endif

    sys_sigrelease(SIGCHLD);
    sys_sigrelease(SIGINT);
    sys_sigrelease(SIGUSR1);

    execl("/bin/sh", "sh", "-c", argv[CS_ARGV_CMD_IX], (char *) NULL);
    return 1;
}