/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd 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.
systemd 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 systemd; If not, see .
***/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "sd-daemon.h"
#include "sd-bus.h"
#include "sd-id128.h"
#include "log.h"
#include "util.h"
#include "mkdir.h"
#include "macro.h"
#include "audit.h"
#include "missing.h"
#include "cgroup-util.h"
#include "strv.h"
#include "path-util.h"
#include "loopback-setup.h"
#include "dev-setup.h"
#include "fdset.h"
#include "build.h"
#include "fileio.h"
#include "bus-util.h"
#include "bus-error.h"
#include "ptyfwd.h"
#include "bus-kernel.h"
#include "env-util.h"
#include "def.h"
typedef enum LinkJournal {
LINK_NO,
LINK_AUTO,
LINK_HOST,
LINK_GUEST
} LinkJournal;
static char *arg_directory = NULL;
static char *arg_user = NULL;
static sd_id128_t arg_uuid = {};
static char *arg_machine = NULL;
static const char *arg_slice = NULL;
static bool arg_private_network = false;
static bool arg_read_only = false;
static bool arg_boot = false;
static LinkJournal arg_link_journal = LINK_AUTO;
static uint64_t arg_retain =
(1ULL << CAP_CHOWN) |
(1ULL << CAP_DAC_OVERRIDE) |
(1ULL << CAP_DAC_READ_SEARCH) |
(1ULL << CAP_FOWNER) |
(1ULL << CAP_FSETID) |
(1ULL << CAP_IPC_OWNER) |
(1ULL << CAP_KILL) |
(1ULL << CAP_LEASE) |
(1ULL << CAP_LINUX_IMMUTABLE) |
(1ULL << CAP_NET_BIND_SERVICE) |
(1ULL << CAP_NET_BROADCAST) |
(1ULL << CAP_NET_RAW) |
(1ULL << CAP_SETGID) |
(1ULL << CAP_SETFCAP) |
(1ULL << CAP_SETPCAP) |
(1ULL << CAP_SETUID) |
(1ULL << CAP_SYS_ADMIN) |
(1ULL << CAP_SYS_CHROOT) |
(1ULL << CAP_SYS_NICE) |
(1ULL << CAP_SYS_PTRACE) |
(1ULL << CAP_SYS_TTY_CONFIG) |
(1ULL << CAP_SYS_RESOURCE) |
(1ULL << CAP_SYS_BOOT) |
(1ULL << CAP_AUDIT_WRITE) |
(1ULL << CAP_AUDIT_CONTROL) |
(1ULL << CAP_MKNOD);
static char **arg_bind = NULL;
static char **arg_bind_ro = NULL;
static char **arg_setenv = NULL;
static int help(void) {
printf("%s [OPTIONS...] [PATH] [ARGUMENTS...]\n\n"
"Spawn a minimal namespace container for debugging, testing and building.\n\n"
" -h --help Show this help\n"
" --version Print version string\n"
" -D --directory=NAME Root directory for the container\n"
" -b --boot Boot up full system (i.e. invoke init)\n"
" -u --user=USER Run the command under specified user or uid\n"
" --uuid=UUID Set a specific machine UUID for the container\n"
" -M --machine=NAME Set the machine name for the container\n"
" -S --slice=SLICE Place the container in the specified slice\n"
" --private-network Disable network in container\n"
" --read-only Mount the root directory read-only\n"
" --capability=CAP In addition to the default, retain specified\n"
" capability\n"
" --drop-capability=CAP Drop the specified capability from the default set\n"
" --link-journal=MODE Link up guest journal, one of no, auto, guest, host\n"
" -j Equivalent to --link-journal=host\n"
" --bind=PATH[:PATH] Bind mount a file or directory from the host into\n"
" the container\n"
" --bind-ro=PATH[:PATH] Similar, but creates a read-only bind mount\n"
" --setenv=NAME=VALUE Pass an environment variable to PID 1\n",
program_invocation_short_name);
return 0;
}
static int parse_argv(int argc, char *argv[]) {
enum {
ARG_VERSION = 0x100,
ARG_PRIVATE_NETWORK,
ARG_UUID,
ARG_READ_ONLY,
ARG_CAPABILITY,
ARG_DROP_CAPABILITY,
ARG_LINK_JOURNAL,
ARG_BIND,
ARG_BIND_RO,
ARG_SETENV,
};
static const struct option options[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, ARG_VERSION },
{ "directory", required_argument, NULL, 'D' },
{ "user", required_argument, NULL, 'u' },
{ "private-network", no_argument, NULL, ARG_PRIVATE_NETWORK },
{ "boot", no_argument, NULL, 'b' },
{ "uuid", required_argument, NULL, ARG_UUID },
{ "read-only", no_argument, NULL, ARG_READ_ONLY },
{ "capability", required_argument, NULL, ARG_CAPABILITY },
{ "drop-capability", required_argument, NULL, ARG_DROP_CAPABILITY },
{ "link-journal", required_argument, NULL, ARG_LINK_JOURNAL },
{ "bind", required_argument, NULL, ARG_BIND },
{ "bind-ro", required_argument, NULL, ARG_BIND_RO },
{ "machine", required_argument, NULL, 'M' },
{ "slice", required_argument, NULL, 'S' },
{ "setenv", required_argument, NULL, ARG_SETENV },
{}
};
int c, r;
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "+hD:u:bM:jS:", options, NULL)) >= 0) {
switch (c) {
case 'h':
return help();
case ARG_VERSION:
puts(PACKAGE_STRING);
puts(SYSTEMD_FEATURES);
return 0;
case 'D':
free(arg_directory);
arg_directory = canonicalize_file_name(optarg);
if (!arg_directory) {
log_error("Invalid root directory: %m");
return -ENOMEM;
}
break;
case 'u':
free(arg_user);
arg_user = strdup(optarg);
if (!arg_user)
return log_oom();
break;
case ARG_PRIVATE_NETWORK:
arg_private_network = true;
break;
case 'b':
arg_boot = true;
break;
case ARG_UUID:
r = sd_id128_from_string(optarg, &arg_uuid);
if (r < 0) {
log_error("Invalid UUID: %s", optarg);
return r;
}
break;
case 'S':
arg_slice = strdup(optarg);
if (!arg_slice)
return log_oom();
break;
case 'M':
if (!hostname_is_valid(optarg)) {
log_error("Invalid machine name: %s", optarg);
return -EINVAL;
}
free(arg_machine);
arg_machine = strdup(optarg);
if (!arg_machine)
return log_oom();
break;
case ARG_READ_ONLY:
arg_read_only = true;
break;
case ARG_CAPABILITY:
case ARG_DROP_CAPABILITY: {
char *state, *word;
size_t length;
FOREACH_WORD_SEPARATOR(word, length, optarg, ",", state) {
cap_value_t cap;
char *t;
t = strndup(word, length);
if (!t)
return log_oom();
if (cap_from_name(t, &cap) < 0) {
log_error("Failed to parse capability %s.", t);
free(t);
return -EINVAL;
}
free(t);
if (c == ARG_CAPABILITY)
arg_retain |= 1ULL << (uint64_t) cap;
else
arg_retain &= ~(1ULL << (uint64_t) cap);
}
break;
}
case 'j':
arg_link_journal = LINK_GUEST;
break;
case ARG_LINK_JOURNAL:
if (streq(optarg, "auto"))
arg_link_journal = LINK_AUTO;
else if (streq(optarg, "no"))
arg_link_journal = LINK_NO;
else if (streq(optarg, "guest"))
arg_link_journal = LINK_GUEST;
else if (streq(optarg, "host"))
arg_link_journal = LINK_HOST;
else {
log_error("Failed to parse link journal mode %s", optarg);
return -EINVAL;
}
break;
case ARG_BIND:
case ARG_BIND_RO: {
_cleanup_free_ char *a = NULL, *b = NULL;
char *e;
char ***x;
x = c == ARG_BIND ? &arg_bind : &arg_bind_ro;
e = strchr(optarg, ':');
if (e) {
a = strndup(optarg, e - optarg);
b = strdup(e + 1);
} else {
a = strdup(optarg);
b = strdup(optarg);
}
if (!a || !b)
return log_oom();
if (!path_is_absolute(a) || !path_is_absolute(b)) {
log_error("Invalid bind mount specification: %s", optarg);
return -EINVAL;
}
r = strv_extend(x, a);
if (r < 0)
return log_oom();
r = strv_extend(x, b);
if (r < 0)
return log_oom();
break;
}
case ARG_SETENV: {
char **n;
if (!env_assignment_is_valid(optarg)) {
log_error("Environment variable assignment '%s' is not valid.", optarg);
return -EINVAL;
}
n = strv_env_set(arg_setenv, optarg);
if (!n)
return log_oom();
strv_free(arg_setenv);
arg_setenv = n;
break;
}
case '?':
return -EINVAL;
default:
assert_not_reached("Unhandled option");
}
}
return 1;
}
static int mount_all(const char *dest) {
typedef struct MountPoint {
const char *what;
const char *where;
const char *type;
const char *options;
unsigned long flags;
bool fatal;
} MountPoint;
static const MountPoint mount_table[] = {
{ "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true }, /* Bind mount first */
{ NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */
{ "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true },
{ "devpts", "/dev/pts", "devpts","newinstance,ptmxmode=0666,mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, true },
{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
{ "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
#ifdef HAVE_SELINUX
{ "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false }, /* Bind mount first */
{ NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, false }, /* Then, make it r/o */
#endif
};
unsigned k;
int r = 0;
for (k = 0; k < ELEMENTSOF(mount_table); k++) {
_cleanup_free_ char *where = NULL;
int t;
where = strjoin(dest, "/", mount_table[k].where, NULL);
if (!where)
return log_oom();
t = path_is_mount_point(where, true);
if (t < 0) {
log_error("Failed to detect whether %s is a mount point: %s", where, strerror(-t));
if (r == 0)
r = t;
continue;
}
/* Skip this entry if it is not a remount. */
if (mount_table[k].what && t > 0)
continue;
mkdir_p(where, 0755);
if (mount(mount_table[k].what,
where,
mount_table[k].type,
mount_table[k].flags,
mount_table[k].options) < 0 &&
mount_table[k].fatal) {
log_error("mount(%s) failed: %m", where);
if (r == 0)
r = -errno;
}
}
return r;
}
static int mount_binds(const char *dest, char **l, unsigned long flags) {
char **x, **y;
STRV_FOREACH_PAIR(x, y, l) {
char *where;
struct stat source_st, dest_st;
int r;
if (stat(*x, &source_st) < 0) {
log_error("failed to stat %s: %m", *x);
return -errno;
}
where = strappenda(dest, *y);
r = stat(where, &dest_st);
if (r == 0) {
if ((source_st.st_mode & S_IFMT) != (dest_st.st_mode & S_IFMT)) {
log_error("The file types of %s and %s do not match. Refusing bind mount",
*x, where);
return -EINVAL;
}
} else if (errno == ENOENT) {
r = mkdir_parents_label(where, 0755);
if (r < 0) {
log_error("Failed to bind mount %s: %s", *x, strerror(-r));
return r;
}
} else {
log_error("Failed to bind mount %s: %s", *x, strerror(errno));
return -errno;
}
/* Create the mount point, but be conservative -- refuse to create block
* and char devices. */
if (S_ISDIR(source_st.st_mode))
mkdir_label(where, 0755);
else if (S_ISFIFO(source_st.st_mode))
mkfifo(where, 0644);
else if (S_ISSOCK(source_st.st_mode))
mknod(where, 0644 | S_IFSOCK, 0);
else if (S_ISREG(source_st.st_mode))
touch(where);
else {
log_error("Refusing to create mountpoint for file: %s", *x);
return -ENOTSUP;
}
if (mount(*x, where, "bind", MS_BIND, NULL) < 0) {
log_error("mount(%s) failed: %m", where);
return -errno;
}
if (flags && mount(NULL, where, NULL, MS_REMOUNT|MS_BIND|flags, NULL) < 0) {
log_error("mount(%s) failed: %m", where);
return -errno;
}
}
return 0;
}
static int setup_timezone(const char *dest) {
_cleanup_free_ char *where = NULL, *p = NULL, *q = NULL, *check = NULL, *what = NULL;
char *z, *y;
int r;
assert(dest);
/* Fix the timezone, if possible */
r = readlink_malloc("/etc/localtime", &p);
if (r < 0) {
log_warning("/etc/localtime is not a symlink, not updating container timezone.");
return 0;
}
z = path_startswith(p, "../usr/share/zoneinfo/");
if (!z)
z = path_startswith(p, "/usr/share/zoneinfo/");
if (!z) {
log_warning("/etc/localtime does not point into /usr/share/zoneinfo/, not updating container timezone.");
return 0;
}
where = strappend(dest, "/etc/localtime");
if (!where)
return log_oom();
r = readlink_malloc(where, &q);
if (r >= 0) {
y = path_startswith(q, "../usr/share/zoneinfo/");
if (!y)
y = path_startswith(q, "/usr/share/zoneinfo/");
/* Already pointing to the right place? Then do nothing .. */
if (y && streq(y, z))
return 0;
}
check = strjoin(dest, "/usr/share/zoneinfo/", z, NULL);
if (!check)
return log_oom();
if (access(check, F_OK) < 0) {
log_warning("Timezone %s does not exist in container, not updating container timezone.", z);
return 0;
}
what = strappend("../usr/share/zoneinfo/", z);
if (!what)
return log_oom();
unlink(where);
if (symlink(what, where) < 0) {
log_error("Failed to correct timezone of container: %m");
return 0;
}
return 0;
}
static int setup_resolv_conf(const char *dest) {
char _cleanup_free_ *where = NULL;
assert(dest);
if (arg_private_network)
return 0;
/* Fix resolv.conf, if possible */
where = strappend(dest, "/etc/resolv.conf");
if (!where)
return log_oom();
/* We don't really care for the results of this really. If it
* fails, it fails, but meh... */
copy_file("/etc/resolv.conf", where, O_TRUNC|O_NOFOLLOW);
return 0;
}
static int setup_boot_id(const char *dest) {
_cleanup_free_ char *from = NULL, *to = NULL;
sd_id128_t rnd;
char as_uuid[37];
int r;
assert(dest);
/* Generate a new randomized boot ID, so that each boot-up of
* the container gets a new one */
from = strappend(dest, "/dev/proc-sys-kernel-random-boot-id");
to = strappend(dest, "/proc/sys/kernel/random/boot_id");
if (!from || !to)
return log_oom();
r = sd_id128_randomize(&rnd);
if (r < 0) {
log_error("Failed to generate random boot id: %s", strerror(-r));
return r;
}
snprintf(as_uuid, sizeof(as_uuid),
"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
SD_ID128_FORMAT_VAL(rnd));
char_array_0(as_uuid);
r = write_string_file(from, as_uuid);
if (r < 0) {
log_error("Failed to write boot id: %s", strerror(-r));
return r;
}
if (mount(from, to, "bind", MS_BIND, NULL) < 0) {
log_error("Failed to bind mount boot id: %m");
r = -errno;
} else if (mount(from, to, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL))
log_warning("Failed to make boot id read-only: %m");
unlink(from);
return r;
}
static int copy_devnodes(const char *dest) {
static const char devnodes[] =
"null\0"
"zero\0"
"full\0"
"random\0"
"urandom\0"
"tty\0";
const char *d;
int r = 0;
_cleanup_umask_ mode_t u;
assert(dest);
u = umask(0000);
NULSTR_FOREACH(d, devnodes) {
_cleanup_free_ char *from = NULL, *to = NULL;
struct stat st;
from = strappend("/dev/", d);
to = strjoin(dest, "/dev/", d, NULL);
if (!from || !to)
return log_oom();
if (stat(from, &st) < 0) {
if (errno != ENOENT) {
log_error("Failed to stat %s: %m", from);
return -errno;
}
} else if (!S_ISCHR(st.st_mode) && !S_ISBLK(st.st_mode)) {
log_error("%s is not a char or block device, cannot copy", from);
return -EIO;
} else if (mknod(to, st.st_mode, st.st_rdev) < 0) {
log_error("mknod(%s) failed: %m", dest);
return -errno;
}
}
return r;
}
static int setup_ptmx(const char *dest) {
_cleanup_free_ char *p = NULL;
p = strappend(dest, "/dev/ptmx");
if (!p)
return log_oom();
if (symlink("pts/ptmx", p) < 0) {
log_error("Failed to create /dev/ptmx symlink: %m");
return -errno;
}
return 0;
}
static int setup_dev_console(const char *dest, const char *console) {
struct stat st;
_cleanup_free_ char *to = NULL;
int r;
_cleanup_umask_ mode_t u;
assert(dest);
assert(console);
u = umask(0000);
if (stat(console, &st) < 0) {
log_error("Failed to stat %s: %m", console);
return -errno;
} else if (!S_ISCHR(st.st_mode)) {
log_error("/dev/console is not a char device");
return -EIO;
}
r = chmod_and_chown(console, 0600, 0, 0);
if (r < 0) {
log_error("Failed to correct access mode for TTY: %s", strerror(-r));
return r;
}
if (asprintf(&to, "%s/dev/console", dest) < 0)
return log_oom();
/* We need to bind mount the right tty to /dev/console since
* ptys can only exist on pts file systems. To have something
* to bind mount things on we create a device node first, that
* has the right major/minor (note that the major minor
* doesn't actually matter here, since we mount it over
* anyway). */
if (mknod(to, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0) {
log_error("mknod() for /dev/console failed: %m");
return -errno;
}
if (mount(console, to, "bind", MS_BIND, NULL) < 0) {
log_error("Bind mount for /dev/console failed: %m");
return -errno;
}
return 0;
}
static int setup_kmsg(const char *dest, int kmsg_socket) {
_cleanup_free_ char *from = NULL, *to = NULL;
int r, fd, k;
_cleanup_umask_ mode_t u;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
} control = {};
struct msghdr mh = {
.msg_control = &control,
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
assert(dest);
assert(kmsg_socket >= 0);
u = umask(0000);
/* We create the kmsg FIFO as /dev/kmsg, but immediately
* delete it after bind mounting it to /proc/kmsg. While FIFOs
* on the reading side behave very similar to /proc/kmsg,
* their writing side behaves differently from /dev/kmsg in
* that writing blocks when nothing is reading. In order to
* avoid any problems with containers deadlocking due to this
* we simply make /dev/kmsg unavailable to the container. */
if (asprintf(&from, "%s/dev/kmsg", dest) < 0 ||
asprintf(&to, "%s/proc/kmsg", dest) < 0)
return log_oom();
if (mkfifo(from, 0600) < 0) {
log_error("mkfifo() for /dev/kmsg failed: %m");
return -errno;
}
r = chmod_and_chown(from, 0600, 0, 0);
if (r < 0) {
log_error("Failed to correct access mode for /dev/kmsg: %s", strerror(-r));
return r;
}
if (mount(from, to, "bind", MS_BIND, NULL) < 0) {
log_error("Bind mount for /proc/kmsg failed: %m");
return -errno;
}
fd = open(from, O_RDWR|O_NDELAY|O_CLOEXEC);
if (fd < 0) {
log_error("Failed to open fifo: %m");
return -errno;
}
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
mh.msg_controllen = cmsg->cmsg_len;
/* Store away the fd in the socket, so that it stays open as
* long as we run the child */
k = sendmsg(kmsg_socket, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
close_nointr_nofail(fd);
if (k < 0) {
log_error("Failed to send FIFO fd: %m");
return -errno;
}
/* And now make the FIFO unavailable as /dev/kmsg... */
unlink(from);
return 0;
}
static int setup_hostname(void) {
if (sethostname(arg_machine, strlen(arg_machine)) < 0)
return -errno;
return 0;
}
static int setup_journal(const char *directory) {
sd_id128_t machine_id, this_id;
_cleanup_free_ char *p = NULL, *b = NULL, *q = NULL, *d = NULL;
char *id;
int r;
p = strappend(directory, "/etc/machine-id");
if (!p)
return log_oom();
r = read_one_line_file(p, &b);
if (r == -ENOENT && arg_link_journal == LINK_AUTO)
return 0;
else if (r < 0) {
log_error("Failed to read machine ID from %s: %s", p, strerror(-r));
return r;
}
id = strstrip(b);
if (isempty(id) && arg_link_journal == LINK_AUTO)
return 0;
/* Verify validity */
r = sd_id128_from_string(id, &machine_id);
if (r < 0) {
log_error("Failed to parse machine ID from %s: %s", p, strerror(-r));
return r;
}
r = sd_id128_get_machine(&this_id);
if (r < 0) {
log_error("Failed to retrieve machine ID: %s", strerror(-r));
return r;
}
if (sd_id128_equal(machine_id, this_id)) {
log_full(arg_link_journal == LINK_AUTO ? LOG_WARNING : LOG_ERR,
"Host and machine ids are equal (%s): refusing to link journals", id);
if (arg_link_journal == LINK_AUTO)
return 0;
return
-EEXIST;
}
if (arg_link_journal == LINK_NO)
return 0;
free(p);
p = strappend("/var/log/journal/", id);
q = strjoin(directory, "/var/log/journal/", id, NULL);
if (!p || !q)
return log_oom();
if (path_is_mount_point(p, false) > 0) {
if (arg_link_journal != LINK_AUTO) {
log_error("%s: already a mount point, refusing to use for journal", p);
return -EEXIST;
}
return 0;
}
if (path_is_mount_point(q, false) > 0) {
if (arg_link_journal != LINK_AUTO) {
log_error("%s: already a mount point, refusing to use for journal", q);
return -EEXIST;
}
return 0;
}
r = readlink_and_make_absolute(p, &d);
if (r >= 0) {
if ((arg_link_journal == LINK_GUEST ||
arg_link_journal == LINK_AUTO) &&
path_equal(d, q)) {
r = mkdir_p(q, 0755);
if (r < 0)
log_warning("failed to create directory %s: %m", q);
return 0;
}
if (unlink(p) < 0) {
log_error("Failed to remove symlink %s: %m", p);
return -errno;
}
} else if (r == -EINVAL) {
if (arg_link_journal == LINK_GUEST &&
rmdir(p) < 0) {
if (errno == ENOTDIR) {
log_error("%s already exists and is neither a symlink nor a directory", p);
return r;
} else {
log_error("Failed to remove %s: %m", p);
return -errno;
}
}
} else if (r != -ENOENT) {
log_error("readlink(%s) failed: %m", p);
return r;
}
if (arg_link_journal == LINK_GUEST) {
if (symlink(q, p) < 0) {
log_error("Failed to symlink %s to %s: %m", q, p);
return -errno;
}
r = mkdir_p(q, 0755);
if (r < 0)
log_warning("failed to create directory %s: %m", q);
return 0;
}
if (arg_link_journal == LINK_HOST) {
r = mkdir_p(p, 0755);
if (r < 0) {
log_error("Failed to create %s: %m", p);
return r;
}
} else if (access(p, F_OK) < 0)
return 0;
if (dir_is_empty(q) == 0) {
log_error("%s not empty.", q);
return -ENOTEMPTY;
}
r = mkdir_p(q, 0755);
if (r < 0) {
log_error("Failed to create %s: %m", q);
return r;
}
if (mount(p, q, "bind", MS_BIND, NULL) < 0) {
log_error("Failed to bind mount journal from host into guest: %m");
return -errno;
}
return 0;
}
static int setup_kdbus(const char *dest, const char *path) {
const char *p;
if (!path)
return 0;
p = strappenda(dest, "/dev/kdbus");
if (mkdir(p, 0755) < 0) {
log_error("Failed to create kdbus path: %m");
return -errno;
}
if (mount(path, p, "bind", MS_BIND, NULL) < 0) {
log_error("Failed to mount kdbus domain path: %m");
return -errno;
}
return 0;
}
static int drop_capabilities(void) {
return capability_bounding_set_drop(~arg_retain, false);
}
static int register_machine(pid_t pid) {
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_bus_unref_ sd_bus *bus = NULL;
int r;
r = sd_bus_open_system(&bus);
if (r < 0) {
log_error("Failed to open system bus: %s", strerror(-r));
return r;
}
r = sd_bus_call_method(
bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"CreateMachine",
&error,
NULL,
"sayssusa(sv)",
arg_machine,
SD_BUS_MESSAGE_APPEND_ID128(arg_uuid),
"nspawn",
"container",
(uint32_t) pid,
strempty(arg_directory),
!isempty(arg_slice), "Slice", "s", arg_slice);
if (r < 0) {
log_error("Failed to register machine: %s", bus_error_message(&error, r));
return r;
}
return 0;
}
static int terminate_machine(pid_t pid) {
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
_cleanup_bus_unref_ sd_bus *bus = NULL;
const char *path;
int r;
r = sd_bus_default_system(&bus);
if (r < 0) {
log_error("Failed to open system bus: %s", strerror(-r));
return r;
}
r = sd_bus_call_method(
bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"GetMachineByPID",
&error,
&reply,
"u",
(uint32_t) pid);
if (r < 0) {
/* Note that the machine might already have been
* cleaned up automatically, hence don't consider it a
* failure if we cannot get the machine object. */
log_debug("Failed to get machine: %s", bus_error_message(&error, r));
return 0;
}
r = sd_bus_message_read(reply, "o", &path);
if (r < 0)
return bus_log_parse_error(r);
r = sd_bus_call_method(
bus,
"org.freedesktop.machine1",
path,
"org.freedesktop.machine1.Machine",
"Terminate",
&error,
NULL,
NULL);
if (r < 0) {
log_debug("Failed to terminate machine: %s", bus_error_message(&error, r));
return 0;
}
return 0;
}
static bool audit_enabled(void) {
int fd;
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
if (fd >= 0) {
close_nointr_nofail(fd);
return true;
}
return false;
}
int main(int argc, char *argv[]) {
pid_t pid = 0;
int r = EXIT_FAILURE, k;
_cleanup_close_ int master = -1, kdbus_fd = -1, sync_fd = -1;
int n_fd_passed;
const char *console = NULL;
sigset_t mask;
_cleanup_close_pipe_ int kmsg_socket_pair[2] = { -1, -1 };
_cleanup_fdset_free_ FDSet *fds = NULL;
_cleanup_free_ char *kdbus_domain = NULL;
const char *ns;
log_parse_environment();
log_open();
k = parse_argv(argc, argv);
if (k < 0)
goto finish;
else if (k == 0) {
r = EXIT_SUCCESS;
goto finish;
}
if (arg_directory) {
char *p;
p = path_make_absolute_cwd(arg_directory);
free(arg_directory);
arg_directory = p;
} else
arg_directory = get_current_dir_name();
if (!arg_directory) {
log_error("Failed to determine path, please use -D.");
goto finish;
}
path_kill_slashes(arg_directory);
if (!arg_machine) {
arg_machine = strdup(basename(arg_directory));
if (!arg_machine) {
log_oom();
goto finish;
}
hostname_cleanup(arg_machine, false);
if (isempty(arg_machine)) {
log_error("Failed to determine machine name automatically, please use -M.");
goto finish;
}
}
if (geteuid() != 0) {
log_error("Need to be root.");
goto finish;
}
if (sd_booted() <= 0) {
log_error("Not running on a systemd system.");
goto finish;
}
if (arg_boot && audit_enabled()) {
log_warning("The kernel auditing subsystem is known to be incompatible with containers.\n"
"Please make sure to turn off auditing with 'audit=0' on the kernel command\n"
"line before using systemd-nspawn. Sleeping for 5s...\n");
sleep(5);
}
if (path_equal(arg_directory, "/")) {
log_error("Spawning container on root directory not supported.");
goto finish;
}
if (path_is_os_tree(arg_directory) <= 0) {
log_error("Directory %s doesn't look like an OS root directory (/etc/os-release is missing). Refusing.", arg_directory);
goto finish;
}
log_close();
n_fd_passed = sd_listen_fds(false);
if (n_fd_passed > 0) {
k = fdset_new_listen_fds(&fds, false);
if (k < 0) {
log_error("Failed to collect file descriptors: %s", strerror(-k));
goto finish;
}
}
fdset_close_others(fds);
log_open();
master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
if (master < 0) {
log_error("Failed to acquire pseudo tty: %m");
goto finish;
}
console = ptsname(master);
if (!console) {
log_error("Failed to determine tty name: %m");
goto finish;
}
log_info("Spawning container %s on %s. Press ^] three times within 1s to abort execution.", arg_machine, arg_directory);
if (unlockpt(master) < 0) {
log_error("Failed to unlock tty: %m");
goto finish;
}
ns = strappenda("machine-", arg_machine);
kdbus_fd = bus_kernel_create_domain(ns, &kdbus_domain);
if (r < 0)
log_debug("Failed to create kdbus domain: %s", strerror(-r));
else
log_debug("Successfully created kdbus domain as %s", kdbus_domain);
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) {
log_error("Failed to create kmsg socket pair: %m");
goto finish;
}
sd_notify(0, "READY=1");
assert_se(sigemptyset(&mask) == 0);
sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
for (;;) {
siginfo_t status;
sync_fd = eventfd(0, EFD_CLOEXEC);
if (sync_fd < 0) {
log_error("Failed to create event fd: %m");
goto finish;
}
pid = syscall(__NR_clone, SIGCHLD|CLONE_NEWIPC|CLONE_NEWNS|CLONE_NEWPID|CLONE_NEWUTS|(arg_private_network ? CLONE_NEWNET : 0), NULL);
if (pid < 0) {
if (errno == EINVAL)
log_error("clone() failed, do you have namespace support enabled in your kernel? (You need UTS, IPC, PID and NET namespacing built in): %m");
else
log_error("clone() failed: %m");
goto finish;
}
if (pid == 0) {
/* child */
const char *home = NULL;
uid_t uid = (uid_t) -1;
gid_t gid = (gid_t) -1;
unsigned n_env = 2;
const char *envp[] = {
"PATH=" DEFAULT_PATH_SPLIT_USR,
"container=systemd-nspawn", /* LXC sets container=lxc, so follow the scheme here */
NULL, /* TERM */
NULL, /* HOME */
NULL, /* USER */
NULL, /* LOGNAME */
NULL, /* container_uuid */
NULL, /* LISTEN_FDS */
NULL, /* LISTEN_PID */
NULL
};
char **env_use;
eventfd_t x;
envp[n_env] = strv_find_prefix(environ, "TERM=");
if (envp[n_env])
n_env ++;
close_nointr_nofail(master);
master = -1;
close_nointr(STDIN_FILENO);
close_nointr(STDOUT_FILENO);
close_nointr(STDERR_FILENO);
close_nointr_nofail(kmsg_socket_pair[0]);
kmsg_socket_pair[0] = -1;
reset_all_signal_handlers();
assert_se(sigemptyset(&mask) == 0);
assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
k = open_terminal(console, O_RDWR);
if (k != STDIN_FILENO) {
if (k >= 0) {
close_nointr_nofail(k);
k = -EINVAL;
}
log_error("Failed to open console: %s", strerror(-k));
goto child_fail;
}
if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
log_error("Failed to duplicate console: %m");
goto child_fail;
}
if (setsid() < 0) {
log_error("setsid() failed: %m");
goto child_fail;
}
if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0) {
log_error("PR_SET_PDEATHSIG failed: %m");
goto child_fail;
}
/* Mark everything as slave, so that we still
* receive mounts from the real root, but don't
* propagate mounts to the real root. */
if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
log_error("MS_SLAVE|MS_REC failed: %m");
goto child_fail;
}
/* Turn directory into bind mount */
if (mount(arg_directory, arg_directory, "bind", MS_BIND|MS_REC, NULL) < 0) {
log_error("Failed to make bind mount.");
goto child_fail;
}
if (arg_read_only)
if (mount(arg_directory, arg_directory, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY|MS_REC, NULL) < 0) {
log_error("Failed to make read-only.");
goto child_fail;
}
if (mount_all(arg_directory) < 0)
goto child_fail;
if (copy_devnodes(arg_directory) < 0)
goto child_fail;
if (setup_ptmx(arg_directory) < 0)
goto child_fail;
dev_setup(arg_directory);
if (setup_dev_console(arg_directory, console) < 0)
goto child_fail;
if (setup_kmsg(arg_directory, kmsg_socket_pair[1]) < 0)
goto child_fail;
close_nointr_nofail(kmsg_socket_pair[1]);
kmsg_socket_pair[1] = -1;
if (setup_boot_id(arg_directory) < 0)
goto child_fail;
if (setup_timezone(arg_directory) < 0)
goto child_fail;
if (setup_resolv_conf(arg_directory) < 0)
goto child_fail;
if (setup_journal(arg_directory) < 0)
goto child_fail;
if (mount_binds(arg_directory, arg_bind, 0) < 0)
goto child_fail;
if (mount_binds(arg_directory, arg_bind_ro, MS_RDONLY) < 0)
goto child_fail;
if (setup_kdbus(arg_directory, kdbus_domain) < 0)
goto child_fail;
if (chdir(arg_directory) < 0) {
log_error("chdir(%s) failed: %m", arg_directory);
goto child_fail;
}
if (mount(arg_directory, "/", NULL, MS_MOVE, NULL) < 0) {
log_error("mount(MS_MOVE) failed: %m");
goto child_fail;
}
if (chroot(".") < 0) {
log_error("chroot() failed: %m");
goto child_fail;
}
if (chdir("/") < 0) {
log_error("chdir() failed: %m");
goto child_fail;
}
umask(0022);
loopback_setup();
if (drop_capabilities() < 0) {
log_error("drop_capabilities() failed: %m");
goto child_fail;
}
if (arg_user) {
/* Note that this resolves user names
* inside the container, and hence
* accesses the NSS modules from the
* container and not the host. This is
* a bit weird... */
if (get_user_creds((const char**)&arg_user, &uid, &gid, &home, NULL) < 0) {
log_error("get_user_creds() failed: %m");
goto child_fail;
}
if (mkdir_parents_label(home, 0775) < 0) {
log_error("mkdir_parents_label() failed: %m");
goto child_fail;
}
if (mkdir_safe_label(home, 0775, uid, gid) < 0) {
log_error("mkdir_safe_label() failed: %m");
goto child_fail;
}
if (initgroups((const char*)arg_user, gid) < 0) {
log_error("initgroups() failed: %m");
goto child_fail;
}
if (setresgid(gid, gid, gid) < 0) {
log_error("setregid() failed: %m");
goto child_fail;
}
if (setresuid(uid, uid, uid) < 0) {
log_error("setreuid() failed: %m");
goto child_fail;
}
} else {
/* Reset everything fully to 0, just in case */
if (setgroups(0, NULL) < 0) {
log_error("setgroups() failed: %m");
goto child_fail;
}
if (setresgid(0, 0, 0) < 0) {
log_error("setregid() failed: %m");
goto child_fail;
}
if (setresuid(0, 0, 0) < 0) {
log_error("setreuid() failed: %m");
goto child_fail;
}
}
if ((asprintf((char**)(envp + n_env++), "HOME=%s", home ? home: "/root") < 0) ||
(asprintf((char**)(envp + n_env++), "USER=%s", arg_user ? arg_user : "root") < 0) ||
(asprintf((char**)(envp + n_env++), "LOGNAME=%s", arg_user ? arg_user : "root") < 0)) {
log_oom();
goto child_fail;
}
if (!sd_id128_equal(arg_uuid, SD_ID128_NULL)) {
if (asprintf((char**)(envp + n_env++), "container_uuid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(arg_uuid)) < 0) {
log_oom();
goto child_fail;
}
}
if (fdset_size(fds) > 0) {
k = fdset_cloexec(fds, false);
if (k < 0) {
log_error("Failed to unset O_CLOEXEC for file descriptors.");
goto child_fail;
}
if ((asprintf((char **)(envp + n_env++), "LISTEN_FDS=%u", n_fd_passed) < 0) ||
(asprintf((char **)(envp + n_env++), "LISTEN_PID=1") < 0)) {
log_oom();
goto child_fail;
}
}
setup_hostname();
eventfd_read(sync_fd, &x);
close_nointr_nofail(sync_fd);
sync_fd = -1;
if (!strv_isempty(arg_setenv)) {
char **n;
n = strv_env_merge(2, envp, arg_setenv);
if (!n) {
log_oom();
goto child_fail;
}
env_use = n;
} else
env_use = (char**) envp;
if (arg_boot) {
char **a;
size_t l;
/* Automatically search for the init system */
l = 1 + argc - optind;
a = newa(char*, l + 1);
memcpy(a + 1, argv + optind, l * sizeof(char*));
a[0] = (char*) "/usr/lib/systemd/systemd";
execve(a[0], a, env_use);
a[0] = (char*) "/lib/systemd/systemd";
execve(a[0], a, env_use);
a[0] = (char*) "/sbin/init";
execve(a[0], a, env_use);
} else if (argc > optind)
execvpe(argv[optind], argv + optind, env_use);
else {
chdir(home ? home : "/root");
execle("/bin/bash", "-bash", NULL, env_use);
}
log_error("execv() failed: %m");
child_fail:
_exit(EXIT_FAILURE);
}
fdset_free(fds);
fds = NULL;
r = register_machine(pid);
if (r < 0)
goto finish;
eventfd_write(sync_fd, 1);
close_nointr_nofail(sync_fd);
sync_fd = -1;
k = process_pty(master, &mask, arg_boot ? pid : 0, SIGRTMIN+3);
if (k < 0) {
r = EXIT_FAILURE;
break;
}
putc('\n', stdout);
/* Kill if it is not dead yet anyway */
terminate_machine(pid);
/* Redundant, but better safe than sorry */
kill(pid, SIGKILL);
k = wait_for_terminate(pid, &status);
pid = 0;
if (k < 0) {
r = EXIT_FAILURE;
break;
}
if (status.si_code == CLD_EXITED) {
r = status.si_status;
if (status.si_status != 0) {
log_error("Container %s failed with error code %i.", arg_machine, status.si_status);
break;
}
log_debug("Container %s exited successfully.", arg_machine);
break;
} else if (status.si_code == CLD_KILLED &&
status.si_status == SIGINT) {
log_info("Container %s has been shut down.", arg_machine);
r = 0;
break;
} else if (status.si_code == CLD_KILLED &&
status.si_status == SIGHUP) {
log_info("Container %s is being rebooted.", arg_machine);
continue;
} else if (status.si_code == CLD_KILLED ||
status.si_code == CLD_DUMPED) {
log_error("Container %s terminated by signal %s.", arg_machine, signal_to_string(status.si_status));
r = EXIT_FAILURE;
break;
} else {
log_error("Container %s failed due to unknown reason.", arg_machine);
r = EXIT_FAILURE;
break;
}
}
finish:
if (pid > 0)
kill(pid, SIGKILL);
free(arg_directory);
free(arg_machine);
free(arg_setenv);
return r;
}