/*-*- 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 #if HAVE_SELINUX #include #endif #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 char *arg_process_label = NULL; static char *arg_file_label = 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 bool arg_quiet = false; 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" " -L --file-label=LABEL Set the MAC file label to be used by tmpfs file\n" " systems in the container\n" " -Z --process-label=LABEL Set the MAC label to be used by processes in\n" " 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\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" " -q --quiet Do not show status information\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 }, { "process-label", required_argument, NULL, 'Z' }, { "file-label", required_argument, NULL, 'L' }, { "quiet", no_argument, NULL, 'q' }, {} }; int c, r; assert(argc >= 0); assert(argv); while ((c = getopt_long(argc, argv, "+hD:u:bL:M:jS:Z:q", 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 'L': arg_file_label = optarg; break; case 'Z': arg_process_label = optarg; 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 'q': arg_quiet = true; 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; #ifdef HAVE_SELINUX _cleanup_free_ char *options = NULL; #endif const char *o; 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); #ifdef HAVE_SELINUX if (arg_file_label && (streq_ptr(mount_table[k].what, "tmpfs") || streq_ptr(mount_table[k].what, "devpts"))) { options = strjoin(mount_table[k].options, ",context=\"", arg_file_label, "\"", NULL); if (!options) return log_oom(); o = options; } else #endif o = mount_table[k].options; if (mount(mount_table[k].what, where, mount_table[k].type, mount_table[k].flags, o) < 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_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", "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; } if (!arg_quiet) 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 HAVE_SELINUX if (arg_process_label) if (setexeccon(arg_process_label) < 0) log_error("setexeccon(\"%s\") failed: %m", arg_process_label); #endif 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; } if (!arg_quiet) 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; } if (!arg_quiet) log_debug("Container %s exited successfully.", arg_machine); break; } else if (status.si_code == CLD_KILLED && status.si_status == SIGINT) { if (!arg_quiet) log_info("Container %s has been shut down.", arg_machine); r = 0; break; } else if (status.si_code == CLD_KILLED && status.si_status == SIGHUP) { if (!arg_quiet) 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; }