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/* setuidgid - run a command with the UID and GID of a specified user
Copyright (C) 2003-2007 Free Software Foundation, Inc.
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 3 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, see <http://www.gnu.org/licenses/>. */
/* Written by Jim Meyering */
#include <config.h>
#include <getopt.h>
#include <stdio.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include "system.h"
#include "error.h"
#include "long-options.h"
#include "mgetgroups.h"
#include "quote.h"
#define PROGRAM_NAME "setuidgid"
/* I wrote this program from scratch, based on the description of
D.J. Bernstein's program: http://cr.yp.to/daemontools/setuidgid.html. */
#define AUTHORS "Jim Meyering"
#define SETUIDGID_FAILURE 111
char *program_name;
void
usage (int status)
{
if (status != EXIT_SUCCESS)
fprintf (stderr, _("Try `%s --help' for more information.\n"),
program_name);
else
{
printf (_("\
Usage: %s USERNAME COMMAND [ARGUMENT]...\n\
or: %s OPTION\n\
"),
program_name, program_name);
fputs (_("\
Drop any supplemental groups, assume the user-ID and group-ID of\n\
the specified USERNAME, and run COMMAND with any specified ARGUMENTs.\n\
Exit with status 111 if unable to assume the required user and group ID.\n\
Otherwise, exit with the exit status of COMMAND.\n\
This program is useful only when run by root (user ID zero).\n\
\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_bug_reporting_address ();
}
exit (status);
}
int
main (int argc, char **argv)
{
char const *user_id;
struct passwd *pwd;
initialize_main (&argc, &argv);
program_name = argv[0];
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
initialize_exit_failure (SETUIDGID_FAILURE);
atexit (close_stdout);
parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, VERSION,
usage, AUTHORS, (char const *) NULL);
if (getopt_long (argc, argv, "+", NULL, NULL) != -1)
usage (SETUIDGID_FAILURE);
if (argc <= optind + 1)
{
if (argc < optind + 1)
error (0, 0, _("missing operand"));
else
error (0, 0, _("missing operand after %s"), quote (argv[optind]));
usage (SETUIDGID_FAILURE);
}
user_id = argv[optind];
pwd = getpwnam (user_id);
if (pwd == NULL)
error (SETUIDGID_FAILURE, errno,
_("unknown user-ID: %s"), quote (user_id));
#if HAVE_SETGROUPS
{
GETGROUPS_T *groups;
int n_groups = mgetgroups (user_id, pwd->pw_gid, &groups);
if (n_groups < 0)
{
n_groups = 1;
groups = xmalloc (sizeof *groups);
*groups = pwd->pw_gid;
}
if (0 < n_groups && setgroups (n_groups, groups))
error (SETUIDGID_FAILURE, errno, _("cannot set supplemental group(s)"));
free (groups);
}
#endif
if (setgid (pwd->pw_gid))
error (SETUIDGID_FAILURE, errno,
_("cannot set group-ID to %lu"), (unsigned long int) pwd->pw_gid);
if (setuid (pwd->pw_uid))
error (SETUIDGID_FAILURE, errno,
_("cannot set user-ID to %lu"), (unsigned long int) pwd->pw_uid);
{
char **cmd = argv + optind + 1;
int exit_status;
execvp (*cmd, cmd);
exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
error (0, errno, _("cannot run command %s"), quote (*cmd));
exit (exit_status);
}
}
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