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/*
* unshare(1) - command-line interface for unshare(2)
*
* Copyright (C) 2009 Mikhail Gusarov <dottedmag@dottedmag.net>
*
* 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, 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <errno.h>
#include <getopt.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include "nls.h"
#include "c.h"
#include "closestream.h"
#include "strutils.h"
#ifndef CLONE_NEWSNS
# define CLONE_NEWNS 0x00020000
#endif
#ifndef CLONE_NEWUTS
# define CLONE_NEWUTS 0x04000000
#endif
#ifndef CLONE_NEWIPC
# define CLONE_NEWIPC 0x08000000
#endif
#ifndef CLONE_NEWNET
# define CLONE_NEWNET 0x40000000
#endif
#ifndef HAVE_UNSHARE
# include <sys/syscall.h>
static int unshare(int flags)
{
return syscall(SYS_unshare, flags);
}
#endif
static void usage(int status)
{
FILE *out = status == EXIT_SUCCESS ? stdout : stderr;
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] <program> [args...]\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -m, --mount [=<pid>] unshare or migrate mounts namespace\n"
" -u, --uts [=<pid>] unshare or migrate UTS namespace (hostname etc)\n"
" -i, --ipc [=<pid>] unshare or migrate System V IPC namespace\n"
" -n, --net [=<pid>] unshare or migrate network namespace\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("unshare(1)"));
exit(status);
}
int main(int argc, char *argv[])
{
static const struct option longopts[] = {
{ "help", no_argument, 0, 'h' },
{ "version", no_argument, 0, 'V'},
{ "mount", optional_argument, 0, 'm' },
{ "uts", optional_argument, 0, 'u' },
{ "ipc", optional_argument, 0, 'i' },
{ "net", optional_argument, 0, 'n' },
{ NULL, 0, 0, 0 }
};
int namespaces[128]; /* /proc/#/ns/<name> file descriptors */
size_t i, nscount = 0; /* number of used namespaces[] */
int unshare_flags = 0;
int c;
setlocale(LC_MESSAGES, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
memset(namespaces, 0, sizeof(namespaces));
while((c = getopt_long(argc, argv,
"hVm::u::i::n::", longopts, NULL)) != -1) {
const char *ns = NULL;
switch(c) {
case 'h':
usage(EXIT_SUCCESS);
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'm':
ns = "mnt";
if (!optarg)
unshare_flags |= CLONE_NEWNS;
break;
case 'u':
ns = "uts";
if (!optarg)
unshare_flags |= CLONE_NEWUTS;
break;
case 'i':
ns = "ipc";
if (!optarg)
unshare_flags |= CLONE_NEWIPC;
break;
case 'n':
ns = "net";
if (!optarg)
unshare_flags |= CLONE_NEWNET;
break;
default:
usage(EXIT_FAILURE);
}
if (ns && optarg) {
pid_t pid;
char path[512];
if (nscount >= ARRAY_SIZE(namespaces))
err(EXIT_FAILURE, _("too many new namespaces specified"));
if (*optarg == '=')
optarg++;
pid = strtoul_or_err(optarg, _("failed to parse pid argument"));
sprintf(path, "/proc/%lu/ns/%s", (unsigned long) pid, ns);
namespaces[nscount] = open(path, O_RDONLY | O_CLOEXEC);
if (namespaces[nscount] < 0)
err(EXIT_FAILURE, _("cannot open %s"), path);
nscount++;
}
}
if (optind >= argc)
usage(EXIT_FAILURE);
for (i = 0; i < nscount; i++) {
if (setns(namespaces[i], 0) != 0)
err(EXIT_FAILURE, _("setns failed"));
}
if (unshare_flags && unshare(unshare_flags) != 0)
err(EXIT_FAILURE, _("unshare failed"));
/* drop potential root euid/egid if we had been setuid'd */
if (setgid(getgid()) < 0)
err(EXIT_FAILURE, _("cannot set group id"));
if (setuid(getuid()) < 0)
err(EXIT_FAILURE, _("cannot set user id"));
execvp(argv[optind], argv + optind);
err(EXIT_FAILURE, _("exec %s failed"), argv[optind]);
}
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