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/* chroot -- run command or shell with special root directory
Copyright (C) 95, 96, 1997, 1999-2004, 2007-2009
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 Roland McGrath. */
#include <config.h>
#include <getopt.h>
#include <stdio.h>
#include <sys/types.h>
#include <grp.h>
#include "system.h"
#include "error.h"
#include "long-options.h"
#include "quote.h"
#include "userspec.h"
#include "xstrtol.h"
/* The official name of this program (e.g., no `g' prefix). */
#define PROGRAM_NAME "chroot"
#define AUTHORS proper_name ("Roland McGrath")
#ifndef MAXGID
# define MAXGID GID_T_MAX
#endif
enum
{
GROUPS = UCHAR_MAX + 1,
USERSPEC
};
static struct option const long_opts[] =
{
{"groups", required_argument, NULL, GROUPS},
{"userspec", required_argument, NULL, USERSPEC},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
/* Groups is a comma separated list of additional groups. */
static int
set_additional_groups (char const *groups)
{
GETGROUPS_T *gids = NULL;
size_t n_gids_allocated = 0;
size_t n_gids = 0;
char *buffer = xstrdup (groups);
char const *tmp;
int ret;
for (tmp = strtok (buffer, ","); tmp; tmp = strtok (NULL, ","))
{
struct group *g;
unsigned long int value;
if (xstrtoul (tmp, NULL, 10, &value, "") == LONGINT_OK && value <= MAXGID)
{
g = getgrgid (value);
}
else
{
g = getgrnam (tmp);
if (g != NULL)
value = g->gr_gid;
}
if (g == NULL)
{
error (0, errno, _("cannot find group %s"), tmp);
free (buffer);
return 1;
}
if (n_gids == n_gids_allocated)
gids = x2nrealloc (gids, &n_gids_allocated, sizeof *gids);
gids[n_gids++] = value;
}
free (buffer);
ret = setgroups (n_gids, gids);
free (gids);
return ret;
}
void
usage (int status)
{
if (status != EXIT_SUCCESS)
fprintf (stderr, _("Try `%s --help' for more information.\n"),
program_name);
else
{
printf (_("\
Usage: %s [OPTION] NEWROOT [COMMAND [ARG]...]\n\
or: %s OPTION\n\
"), program_name, program_name);
fputs (_("\
Run COMMAND with root directory set to NEWROOT.\n\
\n\
"), stdout);
fputs (_("\
--userspec=USER:GROUP specify user and group (ID or name) to use\n\
--groups=G_LIST specify supplementary groups as g1,g2,..,gN\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
fputs (_("\
\n\
If no command is given, run ``${SHELL} -i'' (default: /bin/sh).\n\
"), stdout);
emit_bug_reporting_address ();
}
exit (status);
}
int
main (int argc, char **argv)
{
int c;
char const *userspec = NULL;
char const *groups = NULL;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
initialize_exit_failure (EXIT_FAILURE);
atexit (close_stdout);
parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
usage, AUTHORS, (char const *) NULL);
while ((c = getopt_long (argc, argv, "+", long_opts, NULL)) != -1)
{
switch (c)
{
case USERSPEC:
userspec = optarg;
break;
case GROUPS:
groups = optarg;
break;
default:
usage (EXIT_FAILURE);
}
}
if (argc <= optind)
{
error (0, 0, _("missing operand"));
usage (EXIT_FAILURE);
}
if (chroot (argv[optind]) != 0)
error (EXIT_FAILURE, errno, _("cannot change root directory to %s"),
argv[optind]);
if (chdir ("/"))
error (EXIT_FAILURE, errno, _("cannot chdir to root directory"));
if (argc == optind + 1)
{
/* No command. Run an interactive shell. */
char *shell = getenv ("SHELL");
if (shell == NULL)
shell = bad_cast ("/bin/sh");
argv[0] = shell;
argv[1] = bad_cast ("-i");
argv[2] = NULL;
}
else
{
/* The following arguments give the command. */
argv += optind + 1;
}
if (userspec)
{
uid_t uid = -1;
gid_t gid = -1;
char *user;
char *group;
char const *err = parse_user_spec (userspec, &uid, &gid, &user, &group);
bool fail = false;
if (err)
error (EXIT_FAILURE, errno, "%s", err);
free (user);
free (group);
/* Attempt to set all three: supplementary groups, group ID, user ID.
Diagnose any failures. If any have failed, exit before execvp. */
if (groups && set_additional_groups (groups))
{
error (0, errno, _("failed to set additional groups"));
fail = true;
}
if (gid != (gid_t) -1 && setgid (gid))
{
error (0, errno, _("failed to set group-ID"));
fail = true;
}
if (uid != (uid_t) -1 && setuid (uid))
{
error (0, errno, _("failed to set user-ID"));
fail = true;
}
if (fail)
exit (EXIT_FAILURE);
}
/* Execute the given command. */
execvp (argv[0], argv);
{
int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
error (0, errno, _("cannot run command %s"), quote (argv[0]));
exit (exit_status);
}
}
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