/*-*- 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 "log.h" #include "util.h" #include "mkdir.h" #include "audit.h" #include "missing.h" #include "cgroup-util.h" #include "strv.h" #include "path-util.h" #include "loopback-setup.h" #include "sd-id128.h" #include "dev-setup.h" typedef enum LinkJournal { LINK_NO, LINK_AUTO, LINK_HOST, LINK_GUEST } LinkJournal; static char *arg_directory = NULL; static char *arg_user = NULL; static char **arg_controllers = NULL; static char *arg_uuid = 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); 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" " -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" " -C --controllers=LIST Put the container in specified comma-separated cgroup hierarchies\n" " --uuid=UUID Set a specific machine UUID for the container\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 capability\n" " --link-journal=MODE Link up guest journal, one of no, auto, guest, host\n" " -j Equivalent to --link-journal=host\n", program_invocation_short_name); return 0; } static int parse_argv(int argc, char *argv[]) { enum { ARG_PRIVATE_NETWORK = 0x100, ARG_UUID, ARG_READ_ONLY, ARG_CAPABILITY, ARG_LINK_JOURNAL }; static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "directory", required_argument, NULL, 'D' }, { "user", required_argument, NULL, 'u' }, { "controllers", required_argument, NULL, 'C' }, { "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 }, { "link-journal", required_argument, NULL, ARG_LINK_JOURNAL }, { NULL, 0, NULL, 0 } }; int c; assert(argc >= 0); assert(argv); while ((c = getopt_long(argc, argv, "+hD:u:C:bj", options, NULL)) >= 0) { switch (c) { case 'h': help(); return 0; case 'D': free(arg_directory); arg_directory = canonicalize_file_name(optarg); if (!arg_directory) { log_error("Failed to canonicalize root directory."); return -ENOMEM; } break; case 'u': free(arg_user); if (!(arg_user = strdup(optarg))) { log_error("Failed to duplicate user name."); return -ENOMEM; } break; case 'C': strv_free(arg_controllers); arg_controllers = strv_split(optarg, ","); if (!arg_controllers) { log_error("Failed to split controllers list."); return -ENOMEM; } strv_uniq(arg_controllers); break; case ARG_PRIVATE_NETWORK: arg_private_network = true; break; case 'b': arg_boot = true; break; case ARG_UUID: arg_uuid = optarg; break; case ARG_READ_ONLY: arg_read_only = true; break; case ARG_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); 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 '?': return -EINVAL; default: log_error("Unknown option code %c", c); return -EINVAL; } } 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 }, { "/dev/pts", "/dev/pts", NULL, NULL, MS_BIND, 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; char *where; for (k = 0; k < ELEMENTSOF(mount_table); k++) { int t; if (asprintf(&where, "%s/%s", dest, mount_table[k].where) < 0) { log_oom(); if (r == 0) r = -ENOMEM; break; } 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)); free(where); 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_label(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; } free(where); } return r; } static int setup_timezone(const char *dest) { char *where; assert(dest); /* Fix the timezone, if possible */ where = strappend(dest, "/etc/localtime"); if (!where) return log_oom(); if (mount("/etc/localtime", where, "bind", MS_BIND, NULL) >= 0) mount("/etc/localtime", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL); free(where); where = strappend(dest, "/etc/timezone"); if (!where) return log_oom(); if (mount("/etc/timezone", where, "bind", MS_BIND, NULL) >= 0) mount("/etc/timezone", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL); free(where); return 0; } static int setup_resolv_conf(const char *dest) { char *where; assert(dest); if (arg_private_network) return 0; /* Fix resolv.conf, if possible */ where = strappend(dest, "/etc/resolv.conf"); if (!where) return log_oom(); if (mount("/etc/resolv.conf", where, "bind", MS_BIND, NULL) >= 0) mount("/etc/resolv.conf", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL); free(where); return 0; } static int setup_boot_id(const char *dest) { 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"); if (!from) { r = log_oom(); goto finish; } to = strappend(dest, "/proc/sys/kernel/random/boot_id"); if (!to) { r = log_oom(); goto finish; } r = sd_id128_randomize(&rnd); if (r < 0) { log_error("Failed to generate random boot id: %s", strerror(-r)); goto finish; } 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_one_line_file(from, as_uuid); if (r < 0) { log_error("Failed to write boot id: %s", strerror(-r)); goto finish; } if (mount(from, to, "bind", MS_BIND, NULL) < 0) { log_error("Failed to bind mount boot id: %m"); r = -errno; } else mount(from, to, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL); unlink(from); finish: free(from); free(to); 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" "ptmx\0"; const char *d; int r = 0; mode_t u; assert(dest); u = umask(0000); NULSTR_FOREACH(d, devnodes) { struct stat st; char *from = NULL, *to = NULL; asprintf(&from, "/dev/%s", d); asprintf(&to, "%s/dev/%s", dest, d); if (!from || !to) { log_error("Failed to allocate devnode path"); free(from); free(to); from = to = NULL; if (r == 0) r = -ENOMEM; break; } if (stat(from, &st) < 0) { if (errno != ENOENT) { log_error("Failed to stat %s: %m", from); if (r == 0) r = -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); if (r == 0) r = -EIO; } else if (mknod(to, st.st_mode, st.st_rdev) < 0) { log_error("mknod(%s) failed: %m", dest); if (r == 0) r = -errno; } free(from); free(to); } umask(u); return r; } static int setup_dev_console(const char *dest, const char *console) { struct stat st; char *to = NULL; int r; mode_t u; assert(dest); assert(console); u = umask(0000); if (stat(console, &st) < 0) { log_error("Failed to stat %s: %m", console); r = -errno; goto finish; } else if (!S_ISCHR(st.st_mode)) { log_error("/dev/console is not a char device."); r = -EIO; goto finish; } r = chmod_and_chown(console, 0600, 0, 0); if (r < 0) { log_error("Failed to correct access mode for TTY: %s", strerror(-r)); goto finish; } if (asprintf(&to, "%s/dev/console", dest) < 0) { r = log_oom(); goto finish; } /* 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"); r = -errno; goto finish; } if (mount(console, to, "bind", MS_BIND, NULL) < 0) { log_error("Bind mount for /dev/console failed: %m"); r = -errno; goto finish; } finish: free(to); umask(u); return r; } static int setup_kmsg(const char *dest, int kmsg_socket) { char *from = NULL, *to = NULL; int r, fd, k; mode_t u; union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(int))]; } control; struct msghdr mh; 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) { r = log_oom(); goto finish; } if (asprintf(&to, "%s/proc/kmsg", dest) < 0) { r = log_oom(); goto finish; } if (mkfifo(from, 0600) < 0) { log_error("mkfifo() for /dev/kmsg failed: %m"); r = -errno; goto finish; } r = chmod_and_chown(from, 0600, 0, 0); if (r < 0) { log_error("Failed to correct access mode for /dev/kmsg: %s", strerror(-r)); goto finish; } if (mount(from, to, "bind", MS_BIND, NULL) < 0) { log_error("Bind mount for /proc/kmsg failed: %m"); r = -errno; goto finish; } fd = open(from, O_RDWR|O_NDELAY|O_CLOEXEC); if (fd < 0) { log_error("Failed to open fifo: %m"); r = -errno; goto finish; } zero(mh); zero(control); mh.msg_control = &control; mh.msg_controllen = sizeof(control); 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"); r = -errno; goto finish; } /* And now make the FIFO unavailable as /dev/kmsg... */ unlink(from); finish: free(from); free(to); umask(u); return r; } static int setup_hostname(void) { char *hn; int r = 0; hn = path_get_file_name(arg_directory); if (hn) { hn = strdup(hn); if (!hn) return -ENOMEM; hostname_cleanup(hn); if (!isempty(hn)) if (sethostname(hn, strlen(hn)) < 0) r = -errno; free(hn); } return r; } static int setup_journal(const char *directory) { sd_id128_t machine_id; char *p = NULL, *b = NULL, *l, *q = NULL, *d = NULL; int r; if (arg_link_journal == LINK_NO) return 0; p = strappend(directory, "/etc/machine-id"); if (!p) { r = log_oom(); goto finish; } r = read_one_line_file(p, &b); if (r == -ENOENT && arg_link_journal == LINK_AUTO) { r = 0; goto finish; } else if (r < 0) { log_error("Failed to read machine ID: %s", strerror(-r)); return r; } l = strstrip(b); if (isempty(l) && arg_link_journal == LINK_AUTO) { r = 0; goto finish; } /* Verify validaty */ r = sd_id128_from_string(l, &machine_id); if (r < 0) { log_error("Failed to parse machine ID: %s", strerror(-r)); goto finish; } free(p); p = strappend("/var/log/journal/", l); q = strjoin(directory, "/var/log/journal/", l, NULL); if (!p || !q) { r = log_oom(); goto finish; } if (path_is_mount_point(p, false) > 0 || path_is_mount_point(q, false) > 0) { if (arg_link_journal != LINK_AUTO) { log_error("Journal already a mount point, refusing."); r = -EEXIST; goto finish; } r = 0; goto finish; } 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)) { mkdir_p(q, 0755); r = 0; goto finish; } if (unlink(p) < 0) { log_error("Failed to remove symlink %s: %m", p); r = -errno; goto finish; } } else if (r == -EINVAL) { if (arg_link_journal == LINK_GUEST && rmdir(p) < 0) { if (errno == ENOTDIR) log_error("%s already exists and is neither symlink nor directory.", p); else { log_error("Failed to remove %s: %m", p); r = -errno; } goto finish; } } else if (r != -ENOENT) { log_error("readlink(%s) failed: %m", p); goto finish; } if (arg_link_journal == LINK_GUEST) { if (symlink(q, p) < 0) { log_error("Failed to symlink %s to %s: %m", q, p); r = -errno; goto finish; } mkdir_p(q, 0755); r = 0; goto finish; } if (arg_link_journal == LINK_HOST) { r = mkdir_p(p, 0755); if (r < 0) { log_error("Failed to create %s: %m", p); goto finish; } } else if (access(p, F_OK) < 0) { r = 0; goto finish; } if (dir_is_empty(q) == 0) { log_error("%s not empty.", q); r = -ENOTEMPTY; goto finish; } r = mkdir_p(q, 0755); if (r < 0) { log_error("Failed to create %s: %m", q); goto finish; } if (mount(p, q, "bind", MS_BIND, NULL) < 0) { log_error("Failed to bind mount journal from host into guest: %m"); r = -errno; goto finish; } r = 0; finish: free(p); free(q); free(d); free(b); return r; } static int drop_capabilities(void) { return capability_bounding_set_drop(~arg_retain, false); } static int is_os_tree(const char *path) { int r; char *p; /* We use /bin/sh as flag file if something is an OS */ if (asprintf(&p, "%s/bin/sh", path) < 0) return -ENOMEM; r = access(p, F_OK); free(p); return r < 0 ? 0 : 1; } static int process_pty(int master, sigset_t *mask) { char in_buffer[LINE_MAX], out_buffer[LINE_MAX]; size_t in_buffer_full = 0, out_buffer_full = 0; struct epoll_event stdin_ev, stdout_ev, master_ev, signal_ev; bool stdin_readable = false, stdout_writable = false, master_readable = false, master_writable = false; int ep = -1, signal_fd = -1, r; fd_nonblock(STDIN_FILENO, 1); fd_nonblock(STDOUT_FILENO, 1); fd_nonblock(master, 1); signal_fd = signalfd(-1, mask, SFD_NONBLOCK|SFD_CLOEXEC); if (signal_fd < 0) { log_error("signalfd(): %m"); r = -errno; goto finish; } ep = epoll_create1(EPOLL_CLOEXEC); if (ep < 0) { log_error("Failed to create epoll: %m"); r = -errno; goto finish; } zero(stdin_ev); stdin_ev.events = EPOLLIN|EPOLLET; stdin_ev.data.fd = STDIN_FILENO; zero(stdout_ev); stdout_ev.events = EPOLLOUT|EPOLLET; stdout_ev.data.fd = STDOUT_FILENO; zero(master_ev); master_ev.events = EPOLLIN|EPOLLOUT|EPOLLET; master_ev.data.fd = master; zero(signal_ev); signal_ev.events = EPOLLIN; signal_ev.data.fd = signal_fd; if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0 || epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 || epoll_ctl(ep, EPOLL_CTL_ADD, master, &master_ev) < 0 || epoll_ctl(ep, EPOLL_CTL_ADD, signal_fd, &signal_ev) < 0) { log_error("Failed to regiser fds in epoll: %m"); r = -errno; goto finish; } for (;;) { struct epoll_event ev[16]; ssize_t k; int i, nfds; nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), -1); if (nfds < 0) { if (errno == EINTR || errno == EAGAIN) continue; log_error("epoll_wait(): %m"); r = -errno; goto finish; } assert(nfds >= 1); for (i = 0; i < nfds; i++) { if (ev[i].data.fd == STDIN_FILENO) { if (ev[i].events & (EPOLLIN|EPOLLHUP)) stdin_readable = true; } else if (ev[i].data.fd == STDOUT_FILENO) { if (ev[i].events & (EPOLLOUT|EPOLLHUP)) stdout_writable = true; } else if (ev[i].data.fd == master) { if (ev[i].events & (EPOLLIN|EPOLLHUP)) master_readable = true; if (ev[i].events & (EPOLLOUT|EPOLLHUP)) master_writable = true; } else if (ev[i].data.fd == signal_fd) { struct signalfd_siginfo sfsi; ssize_t n; n = read(signal_fd, &sfsi, sizeof(sfsi)); if (n != sizeof(sfsi)) { if (n >= 0) { log_error("Failed to read from signalfd: invalid block size"); r = -EIO; goto finish; } if (errno != EINTR && errno != EAGAIN) { log_error("Failed to read from signalfd: %m"); r = -errno; goto finish; } } else { if (sfsi.ssi_signo == SIGWINCH) { struct winsize ws; /* The window size changed, let's forward that. */ if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0) ioctl(master, TIOCSWINSZ, &ws); } else { r = 0; goto finish; } } } } while ((stdin_readable && in_buffer_full <= 0) || (master_writable && in_buffer_full > 0) || (master_readable && out_buffer_full <= 0) || (stdout_writable && out_buffer_full > 0)) { if (stdin_readable && in_buffer_full < LINE_MAX) { k = read(STDIN_FILENO, in_buffer + in_buffer_full, LINE_MAX - in_buffer_full); if (k < 0) { if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) stdin_readable = false; else { log_error("read(): %m"); r = -errno; goto finish; } } else in_buffer_full += (size_t) k; } if (master_writable && in_buffer_full > 0) { k = write(master, in_buffer, in_buffer_full); if (k < 0) { if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) master_writable = false; else { log_error("write(): %m"); r = -errno; goto finish; } } else { assert(in_buffer_full >= (size_t) k); memmove(in_buffer, in_buffer + k, in_buffer_full - k); in_buffer_full -= k; } } if (master_readable && out_buffer_full < LINE_MAX) { k = read(master, out_buffer + out_buffer_full, LINE_MAX - out_buffer_full); if (k < 0) { if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) master_readable = false; else { log_error("read(): %m"); r = -errno; goto finish; } } else out_buffer_full += (size_t) k; } if (stdout_writable && out_buffer_full > 0) { k = write(STDOUT_FILENO, out_buffer, out_buffer_full); if (k < 0) { if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) stdout_writable = false; else { log_error("write(): %m"); r = -errno; goto finish; } } else { assert(out_buffer_full >= (size_t) k); memmove(out_buffer, out_buffer + k, out_buffer_full - k); out_buffer_full -= k; } } } } finish: if (ep >= 0) close_nointr_nofail(ep); if (signal_fd >= 0) close_nointr_nofail(signal_fd); return r; } int main(int argc, char *argv[]) { pid_t pid = 0; int r = EXIT_FAILURE, k; char *oldcg = NULL, *newcg = NULL; char **controller = NULL; int master = -1; const char *console = NULL; struct termios saved_attr, raw_attr; sigset_t mask; bool saved_attr_valid = false; struct winsize ws; int kmsg_socket_pair[2] = { -1, -1 }; log_parse_environment(); log_open(); r = parse_argv(argc, argv); if (r <= 0) 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"); goto finish; } path_kill_slashes(arg_directory); 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 (path_equal(arg_directory, "/")) { log_error("Spawning container on root directory not supported."); goto finish; } if (is_os_tree(arg_directory) <= 0) { log_error("Directory %s doesn't look like an OS root directory. Refusing.", arg_directory); goto finish; } k = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 0, &oldcg); if (k < 0) { log_error("Failed to determine current cgroup: %s", strerror(-k)); goto finish; } if (asprintf(&newcg, "%s/nspawn-%lu", oldcg, (unsigned long) getpid()) < 0) { log_error("Failed to allocate cgroup path."); goto finish; } k = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, newcg, 0); if (k < 0) { log_error("Failed to create cgroup: %s", strerror(-k)); goto finish; } STRV_FOREACH(controller, arg_controllers) { k = cg_create_and_attach(*controller, newcg, 0); if (k < 0) log_warning("Failed to create cgroup in controller %s: %s", *controller, strerror(-k)); } 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 namespace container on %s (console is %s).", arg_directory, console); if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0) ioctl(master, TIOCSWINSZ, &ws); if (unlockpt(master) < 0) { log_error("Failed to unlock tty: %m"); goto finish; } if (tcgetattr(STDIN_FILENO, &saved_attr) < 0) { log_error("Failed to get terminal attributes: %m"); goto finish; } saved_attr_valid = true; raw_attr = saved_attr; cfmakeraw(&raw_attr); raw_attr.c_lflag &= ~ECHO; if (tcsetattr(STDIN_FILENO, TCSANOW, &raw_attr) < 0) { log_error("Failed to set terminal attributes: %m"); goto finish; } if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) { log_error("Failed to create kmsg socket pair"); goto finish; } assert_se(sigemptyset(&mask) == 0); sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1); assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0); 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; const char *envp[] = { "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "container=systemd-nspawn", /* LXC sets container=lxc, so follow the scheme here */ NULL, /* TERM */ NULL, /* HOME */ NULL, /* USER */ NULL, /* LOGNAME */ NULL, /* container_uuid */ NULL }; envp[2] = strv_find_prefix(environ, "TERM="); close_nointr_nofail(master); close_nointr(STDIN_FILENO); close_nointr(STDOUT_FILENO); close_nointr(STDERR_FILENO); close_all_fds(&kmsg_socket_pair[1], 1); reset_all_signal_handlers(); assert_se(sigemptyset(&mask) == 0); assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); if (open_terminal(console, O_RDWR) != STDIN_FILENO || dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO || dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) 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; 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]); 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 (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) { 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; } } if ((asprintf((char**)(envp + 3), "HOME=%s", home ? home: "/root") < 0) || (asprintf((char**)(envp + 4), "USER=%s", arg_user ? arg_user : "root") < 0) || (asprintf((char**)(envp + 5), "LOGNAME=%s", arg_user ? arg_user : "root") < 0)) { log_oom(); goto child_fail; } if (arg_uuid) { if (asprintf((char**)(envp + 6), "container_uuid=%s", arg_uuid) < 0) { log_oom(); goto child_fail; } } setup_hostname(); 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, (char**) envp); a[0] = (char*) "/lib/systemd/systemd"; execve(a[0], a, (char**) envp); a[0] = (char*) "/sbin/init"; execve(a[0], a, (char**) envp); } else if (argc > optind) execvpe(argv[optind], argv + optind, (char**) envp); else { chdir(home ? home : "/root"); execle("/bin/bash", "-bash", NULL, (char**) envp); } log_error("execv() failed: %m"); child_fail: _exit(EXIT_FAILURE); } if (process_pty(master, &mask) < 0) goto finish; if (saved_attr_valid) { tcsetattr(STDIN_FILENO, TCSANOW, &saved_attr); saved_attr_valid = false; } r = wait_for_terminate_and_warn(argc > optind ? argv[optind] : "bash", pid); if (r < 0) r = EXIT_FAILURE; finish: if (saved_attr_valid) tcsetattr(STDIN_FILENO, TCSANOW, &saved_attr); if (master >= 0) close_nointr_nofail(master); close_pipe(kmsg_socket_pair); if (oldcg) cg_attach(SYSTEMD_CGROUP_CONTROLLER, oldcg, 0); if (newcg) cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, newcg, true); free(arg_directory); strv_free(arg_controllers); free(oldcg); free(newcg); return r; }