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/*
** Copyright (C) 2006 Olivier DEMBOUR
** $Id: main.c,v 1.28.4.2 2009/12/07 08:46:29 dembour Exp $
**
**
** 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <pwd.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdlib.h>
#include <fcntl.h>
#include <time.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <grp.h>
#include "config.h"
#include "server.h"
#include "dns.h"
#include "list.h"
#include "socket.h"
#include "options.h"
#include "debug.h"
#include "myerror.h"
#include "log.h"
int debug;
int detach_process(t_conf *conf)
{
int fd;
pid_t pid;
FILE *pidfile;
if (!(pid = fork()))
{ /* child */
if (setsid() < 0)
{
perror("");
return (-1);
}
if ((fd = open("/dev/null", O_RDWR)) == -1)
return (-1);
fclose(stdin); fclose(stdout); fclose(stderr);
dup2(fd, 0); dup2(fd, 1); dup2(fd, 2);
close(fd);
return (0);
}
if (!conf->pidfile)
exit (0);
else if (! (pidfile = fopen(conf->pidfile, "w")))
{
LOG("Could not open pidfile %s\n", conf->pidfile);
exit (0);
}
fprintf(pidfile, "%ld\n", (long) pid);
fclose(pidfile);
exit (0);
}
/*
Just do a real DNS request to load libresolv
before the chroot
*/
void load_resolv(t_conf *conf)
{
struct addrinfo *res;
struct addrinfo hints;
char *domain;
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME;
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
/*
jump the subdomain, do not try to resolv ourself
because we are not a real DNS server
*/
if (!(domain = strchr(conf->my_domain, '.'))
|| (!*++domain))
domain = conf->my_domain;
if (!getaddrinfo(domain, NULL, &hints, &res))
freeaddrinfo(res);
}
int jail(t_conf *conf)
{
struct passwd *pwd = 0;
FILE *pid_file;
if (!conf->foreground)
detach_process(conf);
if ((conf->user) && (!(pwd = getpwnam(conf->user))))
{
LOG("User unknown %s", conf->user);
return (-1);
}
if (conf->pid_file)
{
pid_file = fopen(conf->pid_file, "w");
if (pid_file)
{
fprintf(pid_file, "%d\n", getpid());
fclose(pid_file);
}
else
{
LOG("Failed to write pidfile");
return (-1);
}
}
if (conf->chroot)
{
DPRINTF(1, "Chroot to %s\n", conf->chroot);
load_resolv(conf);
if ((chroot(conf->chroot) == -1) || chdir("/"))
{
LOG("Failed to chroot in %s\n", conf->chroot);
return (-1);
}
}
if (pwd)
{
DPRINTF(1, "Change to user %s\n", conf->user);
if (setgroups(0, NULL) || setgid(pwd->pw_gid) || setuid(pwd->pw_uid))
{
LOG("Failed to change to user %s\n", conf->user);
return (-1);
}
}
#ifdef RLIMIT_NPROC
struct rlimit rlim;
/* fork() is not need anymore, disable it */
rlim.rlim_max = rlim.rlim_cur = 0;
if (setrlimit(RLIMIT_NPROC, &rlim))
return (-1);
#endif
return (0);
}
int main(int argc, char **argv)
{
t_conf my_conf;
t_conf *conf;
conf = &my_conf;
if (get_option(argc, argv, conf))
return (-1);
openlog("dns2tcp", LOG_PID , LOG_SYSLOG);
signal(SIGPIPE, SIG_IGN);
if (!bind_socket(conf))
{
LOG("Starting Server v%s...", VERSION);
if (jail(conf))
return (-1);
srand(getpid()^time(0));
do_server(conf);
}
closelog();
return (0);
}
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