1/*
2   Unix SMB/Netbios implementation.
3   Version 1.9.
4   external program running routine
5   Copyright (C) Andrew Tridgell 1992-1998
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software
19   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20*/
21
22#include "includes.h"
23
24
25/*******************************************************************
26close the low 3 fd's and open dev/null in their place
27********************************************************************/
28static void close_fds(void)
29{
30  int fd;
31  int i;
32  close(0); close(1); close(2);
33  /* try and use up these file descriptors, so silly
34     library routines writing to stdout etc won't cause havoc */
35  for (i=0;i<3;i++) {
36    fd = open("/dev/null",O_RDWR,0);
37    if (fd < 0) fd = open("/dev/null",O_WRONLY,0);
38    if (fd != i) return;
39  }
40}
41
42
43/*
44This is a wrapper around the system() call to allow commands to run correctly
45as non root from a program which is switching between root and non-root
46
47It takes 3 arguments as uid,gid,command and runs command after
48becoming a non-root user */
49 int main(int argc,char *argv[])
50{
51  uid_t uid;
52  gid_t gid;
53
54  close_fds();
55
56  if (argc != 4) exit(2);
57
58  uid = (uid_t)atoi(argv[1]);
59  gid = (gid_t)atoi(argv[2]);
60
61  become_user_permanently( uid, gid);
62
63  /* paranoia :-) */
64  if (getuid() != uid)
65    return(3);
66
67  if (geteuid() != getuid())
68    return(4);
69
70  /* this is to make sure that the system() call doesn't run forever */
71  alarm(30);
72
73  return(system(argv[3]));
74}
75