view src/child.c @ 72:ad034b57f3b2

fixed Debian bug 536060 (log files are closed after SIGHUP receival) Explanation: When run in daemon mode, first the log files are opened. They get assigned to the file descriptors 3 and 4 usually. Then std{in,out,err} are closed. When SIGHUP comes in, all open files are closes and masqmail reexecutes itself. The new masqmail instance opens the log files at fd 0 and 1 now, but std{in,out,err} are closed afterwards, thus the log files are closed. The fix is to close the log files before std{in,out,err} are closed, in case the log files have higher fds. After std{in,out,err} were closed, the log files get opened again, now. See also: http://bugs.debian.org/536060
author meillo@marmaro.de
date Wed, 16 Jun 2010 10:32:20 +0200
parents 98cda87105a7
children
line wrap: on
line source

/* child.c, Copyright (C) 2000 by Oliver Kurth,
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <syslog.h>
#include <string.h>

#include "masqmail.h"


int
child(const char *command)
{
	int pipe[2];

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, pipe) == 0) {
		pid_t pid;

		pid = fork();
		if (pid == 0) {
			int i, max_fd = sysconf(_SC_OPEN_MAX);
			/* child */
			dup2(pipe[0], 0);
			dup2(pipe[0], 1);
			dup2(pipe[0], 2);

			if (max_fd <= 0)
				max_fd = 64;
			for (i = 3; i < max_fd; i++)
				close(i);

			{
				char *argv[] = { "/bin/sh", "-c", (char *) command, NULL };
				execve(*argv, argv, NULL);
			}
			logwrite(LOG_ALERT, "execve failed: %s\n", strerror(errno));
			_exit(EXIT_FAILURE);
		} else if (pid == -1) {
			return -1;
		} else {
			close(pipe[0]);
			return pipe[1];
		}
	}
	return -2;
}