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/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <dlezcano at fr.ibm.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define _GNU_SOURCE
#include <stdio.h>
#undef _GNU_SOURCE
#include <stdlib.h>
#include <unistd.h>
#include <libgen.h>
#include <getopt.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <pwd.h>
#include "caps.h"
#include "log.h"
#include "namespace.h"
#include "cgroup.h"
#include "error.h"
lxc_log_define(lxc_unshare_ui, lxc);
void usage(char *cmd)
{
fprintf(stderr, "%s <options> [command]\n", basename(cmd));
fprintf(stderr, "Options are:\n");
fprintf(stderr, "\t -s flags: Ored list of flags to unshare:\n" \
"\t MOUNT, PID, UTSNAME, IPC, USER, NETWORK\n");
fprintf(stderr, "\t -u <id> : new id to be set if -s USER is specified\n");
fprintf(stderr, "\t if -f or -s PID is specified, <command> is mandatory)\n");
_exit(1);
}
static uid_t lookup_user(const char *optarg)
{
int bufflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char buff[bufflen];
char name[sysconf(_SC_LOGIN_NAME_MAX)];
uid_t uid = -1;
struct passwd pwent;
struct passwd *pent;
if (!optarg || (optarg[0] == '\0'))
return uid;
if (sscanf(optarg, "%u", &uid) < 1) {
/* not a uid -- perhaps a username */
if (sscanf(optarg, "%s", name) < 1)
return uid;
if (getpwnam_r(name, &pwent, buff, bufflen, &pent) || !pent) {
ERROR("invalid username %s", name);
return uid;
}
uid = pent->pw_uid;
} else {
if (getpwuid_r(uid, &pwent, buff, bufflen, &pent) || !pent) {
ERROR("invalid uid %d", uid);
uid = -1;
return uid;
}
}
return uid;
}
static char *namespaces_list[] = {
"MOUNT", "PID", "UTSNAME", "IPC",
"USER", "NETWORK"
};
static int cloneflags_list[] = {
CLONE_NEWNS, CLONE_NEWPID, CLONE_NEWUTS, CLONE_NEWIPC,
CLONE_NEWUSER, CLONE_NEWNET
};
static int lxc_namespace_2_cloneflag(char *namespace)
{
int i, len;
len = sizeof(namespaces_list)/sizeof(namespaces_list[0]);
for (i = 0; i < len; i++)
if (!strcmp(namespaces_list[i], namespace))
return cloneflags_list[i];
ERROR("invalid namespace name %s", namespace);
return -1;
}
static int lxc_fill_namespace_flags(char *flaglist, int *flags)
{
char *token, *saveptr = NULL;
int aflag;
if (!flaglist) {
ERROR("need at least one namespace to unshare");
return -1;
}
token = strtok_r(flaglist, "|", &saveptr);
while (token) {
aflag = lxc_namespace_2_cloneflag(token);
if (aflag < 0)
return -1;
*flags |= aflag;
token = strtok_r(NULL, "|", &saveptr);
}
return 0;
}
struct start_arg {
char ***args;
int *flags;
uid_t *uid;
};
static int do_start(void *arg)
{
struct start_arg *start_arg = arg;
char **args = *start_arg->args;
int flags = *start_arg->flags;
uid_t uid = *start_arg->uid;
if (flags & CLONE_NEWUSER && setuid(uid)) {
ERROR("failed to set uid %d: %s", uid, strerror(errno));
exit(1);
}
execvp(args[0], args);
ERROR("failed to exec: '%s': %s", args[0], strerror(errno));
return 1;
}
int main(int argc, char *argv[])
{
int opt, status;
int ret;
char *pid_name;
char *namespaces = NULL;
char **args;
int flags = 0;
uid_t uid = -1; /* valid only if (flags & CLONE_NEWUSER) */
pid_t pid;
struct start_arg start_arg = {
.args = &args,
.uid = &uid,
.flags = &flags,
};
while ((opt = getopt(argc, argv, "s:u:")) != -1) {
switch (opt) {
case 's':
namespaces = optarg;
break;
case 'u':
uid = lookup_user(optarg);
if (uid == -1)
return 1;
}
}
args = &argv[optind];
ret = lxc_caps_init();
if (ret)
return ret;
ret = lxc_fill_namespace_flags(namespaces, &flags);
if (ret)
usage(argv[0]);
if (!(flags & CLONE_NEWUSER) && uid != -1) {
ERROR("-u <uid> needs -s USER option");
return 1;
}
pid = lxc_clone(do_start, &start_arg, flags);
if (pid < 0) {
ERROR("failed to clone");
return -1;
}
if (waitpid(pid, &status, 0) < 0) {
ERROR("failed to wait for '%d'", pid);
return -1;
}
if (asprintf(&pid_name, "%d", pid) == -1) {
ERROR("pid_name: failed to allocate memory");
return -1;
}
lxc_cgroup_destroy(pid_name);
free(pid_name);
return lxc_error_set_and_log(pid, status);
}
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