chiark / gitweb /
nspawn: fix error message when mknod fails
[elogind.git] / src / nspawn / nspawn.c
index 1bfc99d5fcaa37129fcd6e85304caa54e8fa959c..e5a24dda70c0460ea6fb7931de869f87c3cd9e27 100644 (file)
@@ -31,7 +31,6 @@
 #include <stdio.h>
 #include <errno.h>
 #include <sys/prctl.h>
-#include <sys/capability.h>
 #include <getopt.h>
 #include <termios.h>
 #include <sys/signalfd.h>
 #include "base-filesystem.h"
 #include "barrier.h"
 #include "event-util.h"
+#include "capability.h"
 #include "cap-list.h"
 #include "btrfs-util.h"
+#include "machine-image.h"
 
 #ifdef HAVE_SECCOMP
 #include "seccomp-util.h"
@@ -477,15 +478,19 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
 
                 case ARG_LINK_JOURNAL:
-                        if (streq(optarg, "auto"))
+                        if (streq(optarg, "auto")) {
                                 arg_link_journal = LINK_AUTO;
-                        else if (streq(optarg, "no"))
+                                arg_link_journal_try = false;
+                        } else if (streq(optarg, "no")) {
                                 arg_link_journal = LINK_NO;
-                        else if (streq(optarg, "guest"))
+                                arg_link_journal_try = false;
+                        } else if (streq(optarg, "guest")) {
                                 arg_link_journal = LINK_GUEST;
-                        else if (streq(optarg, "host"))
+                                arg_link_journal_try = false;
+                        } else if (streq(optarg, "host")) {
                                 arg_link_journal = LINK_HOST;
-                        else if (streq(optarg, "try-guest")) {
+                                arg_link_journal_try = false;
+                        } else if (streq(optarg, "try-guest")) {
                                 arg_link_journal = LINK_GUEST;
                                 arg_link_journal_try = true;
                         } else if (streq(optarg, "try-host")) {
@@ -683,6 +688,11 @@ static int parse_argv(int argc, char *argv[]) {
                 return -EINVAL;
         }
 
+        if (arg_ephemeral && !IN_SET(arg_link_journal, LINK_NO, LINK_AUTO)) {
+                log_error("--ephemeral and --link-journal= may not be combined.");
+                return -EINVAL;
+        }
+
         if (arg_volatile != VOLATILE_NO && arg_read_only) {
                 log_error("Cannot combine --read-only with --volatile. Note that --volatile already implies a read-only base hierarchy.");
                 return -EINVAL;
@@ -859,6 +869,112 @@ static int mount_binds(const char *dest, char **l, bool ro) {
         return 0;
 }
 
+static int mount_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) {
+        char *to;
+        int r;
+
+        to = strappenda(dest, "/sys/fs/cgroup/", hierarchy);
+
+        r = path_is_mount_point(to, false);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine if %s is mounted already: %m", to);
+        if (r > 0)
+                return 0;
+
+        mkdir_p(to, 0755);
+
+        if (mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV|(read_only ? MS_RDONLY : 0), controller) < 0)
+                return log_error_errno(errno, "Failed to mount to %s: %m", to);
+
+        return 1;
+}
+
+static int mount_cgroup(const char *dest) {
+        _cleanup_set_free_free_ Set *controllers = NULL;
+        _cleanup_free_ char *own_cgroup_path = NULL;
+        const char *cgroup_root, *systemd_root, *systemd_own;
+        int r;
+
+        controllers = set_new(&string_hash_ops);
+        if (!controllers)
+                return log_oom();
+
+        r = cg_kernel_controllers(controllers);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine cgroup controllers: %m");
+
+        r = cg_pid_get_path(NULL, 0, &own_cgroup_path);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine our own cgroup path: %m");
+
+        cgroup_root = strappenda(dest, "/sys/fs/cgroup");
+        if (mount("tmpfs", cgroup_root, "tmpfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, "mode=755") < 0)
+                return log_error_errno(errno, "Failed to mount tmpfs to /sys/fs/cgroup: %m");
+
+        for (;;) {
+                _cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL;
+
+                controller = set_steal_first(controllers);
+                if (!controller)
+                        break;
+
+                origin = strappend("/sys/fs/cgroup/", controller);
+                if (!origin)
+                        return log_oom();
+
+                r = readlink_malloc(origin, &combined);
+                if (r == -EINVAL) {
+                        /* Not a symbolic link, but directly a single cgroup hierarchy */
+
+                        r = mount_cgroup_hierarchy(dest, controller, controller, true);
+                        if (r < 0)
+                                return r;
+
+                } else if (r < 0)
+                        return log_error_errno(r, "Failed to read link %s: %m", origin);
+                else {
+                        _cleanup_free_ char *target = NULL;
+
+                        target = strjoin(dest, "/sys/fs/cgroup/", controller, NULL);
+                        if (!target)
+                                return log_oom();
+
+                        /* A symbolic link, a combination of controllers in one hierarchy */
+
+                        if (!filename_is_valid(combined)) {
+                                log_warning("Ignoring invalid combined hierarchy %s.", combined);
+                                continue;
+                        }
+
+                        r = mount_cgroup_hierarchy(dest, combined, combined, true);
+                        if (r < 0)
+                                return r;
+
+                        if (symlink(combined, target) < 0)
+                                return log_error_errno(errno, "Failed to create symlink for combined hiearchy: %m");
+                }
+        }
+
+        r = mount_cgroup_hierarchy(dest, "name=systemd", "systemd", false);
+        if (r < 0)
+                return r;
+
+        /* Make our own cgroup a (writable) bind mount */
+        systemd_own = strappenda(dest, "/sys/fs/cgroup/systemd", own_cgroup_path);
+        if (mount(systemd_own, systemd_own,  NULL, MS_BIND, NULL) < 0)
+                return log_error_errno(errno, "Failed to turn %s into a bind mount: %m", own_cgroup_path);
+
+        /* And then remount the systemd cgroup root read-only */
+        systemd_root = strappenda(dest, "/sys/fs/cgroup/systemd");
+        if (mount(NULL, systemd_root, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0)
+                return log_error_errno(errno, "Failed to mount cgroup root read-only: %m");
+
+        if (mount(NULL, cgroup_root, NULL, MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755") < 0)
+                return log_error_errno(errno, "Failed to remount %s read-only: %m", cgroup_root);
+
+        return 0;
+}
+
 static int mount_tmpfs(const char *dest) {
         char **i, **o;
 
@@ -1175,7 +1291,7 @@ static int copy_devnodes(const char *dest) {
                         }
 
                         if (mknod(to, st.st_mode, st.st_rdev) < 0)
-                                return log_error_errno(errno, "mknod(%s) failed: %m", dest);
+                                return log_error_errno(errno, "mknod(%s) failed: %m", to);
                 }
         }
 
@@ -1313,6 +1429,10 @@ static int setup_journal(const char *directory) {
         char *id;
         int r;
 
+        /* Don't link journals in ephemeral mode */
+        if (arg_ephemeral)
+                return 0;
+
         p = strappend(directory, "/etc/machine-id");
         if (!p)
                 return log_oom();
@@ -1341,8 +1461,7 @@ static int setup_journal(const char *directory) {
                          "Host and machine ids are equal (%s): refusing to link journals", id);
                 if (arg_link_journal == LINK_AUTO)
                         return 0;
-                return
-                        -EEXIST;
+                return -EEXIST;
         }
 
         if (arg_link_journal == LINK_NO)
@@ -2070,6 +2189,27 @@ finish:
 
 }
 
+static int setup_propagate(const char *root) {
+        const char *p, *q;
+
+        (void) mkdir_p("/run/systemd/nspawn/", 0755);
+        (void) mkdir_p("/run/systemd/nspawn/propagate", 0600);
+        p = strappenda("/run/systemd/nspawn/propagate/", arg_machine);
+        (void) mkdir_p(p, 0600);
+
+        q = strappenda(root, "/run/systemd/nspawn/incoming");
+        mkdir_parents(q, 0755);
+        mkdir_p(q, 0600);
+
+        if (mount(p, q, NULL, MS_BIND, NULL) < 0)
+                return log_error_errno(errno, "Failed to install propagation bind mount.");
+
+        if (mount(NULL, q, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0)
+                return log_error_errno(errno, "Failed to make propagation mount read-only");
+
+        return 0;
+}
+
 static int setup_image(char **device_path, int *loop_nr) {
         struct loop_info64 info = {
                 .lo_flags = LO_FLAGS_AUTOCLEAR|LO_FLAGS_PARTSCAN
@@ -2849,21 +2989,43 @@ static int on_orderly_shutdown(sd_event_source *s, const struct signalfd_siginfo
 }
 
 static int determine_names(void) {
+        int r;
 
         if (!arg_image && !arg_directory) {
-                if (arg_machine)
-                        arg_directory = strappend("/var/lib/container/", arg_machine);
-                else
+                if (arg_machine) {
+                        _cleanup_(image_unrefp) Image *i = NULL;
+
+                        r = image_find(arg_machine, &i);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to find image for machine '%s': %m", arg_machine);
+                        else if (r == 0) {
+                                log_error("No image for machine '%s': %m", arg_machine);
+                                return -ENOENT;
+                        }
+
+                        if (i->type == IMAGE_GPT)
+                                r = set_sanitized_path(&arg_image, i->path);
+                        else
+                                r = set_sanitized_path(&arg_directory, i->path);
+                        if (r < 0)
+                                return log_error_errno(r, "Invalid image directory: %m");
+
+                        arg_read_only = arg_read_only || i->read_only;
+                } else
                         arg_directory = get_current_dir_name();
 
-                if (!arg_directory) {
-                        log_error("Failed to determine path, please use -D.");
+                if (!arg_directory && !arg_machine) {
+                        log_error("Failed to determine path, please use -D or -i.");
                         return -EINVAL;
                 }
         }
 
         if (!arg_machine) {
-                arg_machine = strdup(basename(arg_image ?: arg_directory));
+                if (arg_directory && path_equal(arg_directory, "/"))
+                        arg_machine = gethostname_malloc();
+                else
+                        arg_machine = strdup(basename(arg_image ?: arg_directory));
+
                 if (!arg_machine)
                         return log_oom();
 
@@ -2872,6 +3034,21 @@ static int determine_names(void) {
                         log_error("Failed to determine machine name automatically, please use -M.");
                         return -EINVAL;
                 }
+
+                if (arg_ephemeral) {
+                        char *b;
+
+                        /* Add a random suffix when this is an
+                         * ephemeral machine, so that we can run many
+                         * instances at once without manually having
+                         * to specify -M each time. */
+
+                        if (asprintf(&b, "%s-%016" PRIx64, arg_machine, random_u64()) < 0)
+                                return log_oom();
+
+                        free(arg_machine);
+                        arg_machine = b;
+                }
         }
 
         return 0;
@@ -2879,13 +3056,12 @@ static int determine_names(void) {
 
 int main(int argc, char *argv[]) {
 
-        _cleanup_free_ char *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL;
+        _cleanup_free_ char *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL, *console = NULL;
         bool root_device_rw = true, home_device_rw = true, srv_device_rw = true;
         _cleanup_close_ int master = -1, image_fd = -1;
         _cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 };
         _cleanup_fdset_free_ FDSet *fds = NULL;
         int r, n_fd_passed, loop_nr = -1;
-        const char *console = NULL;
         char veth_name[IFNAMSIZ];
         bool secondary = false, remove_subvol = false;
         sigset_t mask, mask_chld;
@@ -2930,8 +3106,8 @@ int main(int argc, char *argv[]) {
         if (arg_directory) {
                 assert(!arg_image);
 
-                if (path_equal(arg_directory, "/")) {
-                        log_error("Spawning container on root directory not supported.");
+                if (path_equal(arg_directory, "/") && !arg_ephemeral) {
+                        log_error("Spawning container on root directory is not supported. Consider using --ephemeral.");
                         r = -EINVAL;
                         goto finish;
                 }
@@ -2952,7 +3128,21 @@ int main(int argc, char *argv[]) {
                 } else if (arg_ephemeral) {
                         char *np;
 
-                        r = tempfn_random(arg_directory, &np);
+                        /* If the specified path is a mount point we
+                         * generate the new snapshot immediately
+                         * inside it under a random name. However if
+                         * the specified is not a mount point we
+                         * create the new snapshot in the parent
+                         * directory, just next to it. */
+                        r = path_is_mount_point(arg_directory, false);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to determine whether directory %s is mount point: %m", arg_directory);
+                                goto finish;
+                        }
+                        if (r > 0)
+                                r = tempfn_random_child(arg_directory, &np);
+                        else
+                                r = tempfn_random(arg_directory, &np);
                         if (r < 0) {
                                 log_error_errno(r, "Failed to generate name for snapshot: %m");
                                 goto finish;
@@ -3028,9 +3218,9 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        console = ptsname(master);
-        if (!console) {
-                r = log_error_errno(errno, "Failed to determine tty name: %m");
+        r = ptsname_malloc(master, &console);
+        if (r < 0) {
+                r = log_error_errno(r, "Failed to determine tty name: %m");
                 goto finish;
         }
 
@@ -3048,10 +3238,6 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        sd_notify(false,
-                  "READY=1\n"
-                  "STATUS=Container running.");
-
         assert_se(sigemptyset(&mask) == 0);
         sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
         assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
@@ -3088,9 +3274,9 @@ int main(int argc, char *argv[]) {
                         goto finish;
                 }
 
-                pid = syscall(__NR_clone, SIGCHLD|CLONE_NEWNS|
-                                          (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)|
-                                          (arg_private_network ? CLONE_NEWNET : 0), NULL);
+                pid = raw_clone(SIGCHLD|CLONE_NEWNS|
+                                (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)|
+                                (arg_private_network ? CLONE_NEWNET : 0), NULL);
                 if (pid < 0) {
                         if (errno == EINVAL)
                                 r = log_error_errno(errno, "clone() failed, do you have namespace support enabled in your kernel? (You need UTS, IPC, PID and NET namespacing built in): %m");
@@ -3215,6 +3401,9 @@ int main(int argc, char *argv[]) {
 
                         dev_setup(arg_directory);
 
+                        if (setup_propagate(arg_directory) < 0)
+                                _exit(EXIT_FAILURE);
+
                         if (setup_seccomp() < 0)
                                 _exit(EXIT_FAILURE);
 
@@ -3226,6 +3415,11 @@ int main(int argc, char *argv[]) {
 
                         kmsg_socket_pair[1] = safe_close(kmsg_socket_pair[1]);
 
+                        /* Tell the parent that we are ready, and that
+                         * it can cgroupify us to that we lack access
+                         * to certain devices and resources. */
+                        (void) barrier_place(&barrier);
+
                         if (setup_boot_id(arg_directory) < 0)
                                 _exit(EXIT_FAILURE);
 
@@ -3247,10 +3441,12 @@ int main(int argc, char *argv[]) {
                         if (mount_tmpfs(arg_directory) < 0)
                                 _exit(EXIT_FAILURE);
 
-                        /* Tell the parent that we are ready, and that
-                         * it can cgroupify us to that we lack access
-                         * to certain devices and resources. */
-                        (void)barrier_place(&barrier);
+                        /* Wait until we are cgroup-ified, so that we
+                         * can mount the right cgroup path writable */
+                        (void) barrier_sync_next(&barrier);
+
+                        if (mount_cgroup(arg_directory) < 0)
+                                _exit(EXIT_FAILURE);
 
                         if (chdir(arg_directory) < 0) {
                                 log_error_errno(errno, "chdir(%s) failed: %m", arg_directory);
@@ -3389,10 +3585,13 @@ int main(int argc, char *argv[]) {
                 fdset_free(fds);
                 fds = NULL;
 
-                /* wait for child-setup to be done */
-                if (barrier_place_and_sync(&barrier)) {
+                /* Wait for the most basic Child-setup to be done,
+                 * before we add hardware to it, and place it in a
+                 * cgroup. */
+                if (barrier_sync_next(&barrier)) {
                         _cleanup_event_unref_ sd_event *event = NULL;
                         _cleanup_(pty_forward_freep) PTYForward *forward = NULL;
+                        char last_char = 0;
                         int ifi = 0;
 
                         r = move_network_interfaces(pid);
@@ -3429,7 +3628,14 @@ int main(int argc, char *argv[]) {
                         /* Notify the child that the parent is ready with all
                          * its setup, and that the child can now hand over
                          * control to the code to run inside the container. */
-                        (void)barrier_place(&barrier);
+                        (void) barrier_place(&barrier);
+
+                        /* And wait that the child is completely ready now. */
+                        (void) barrier_place_and_sync(&barrier);
+
+                        sd_notify(false,
+                                  "READY=1\n"
+                                  "STATUS=Container running.");
 
                         r = sd_event_new(&event);
                         if (r < 0) {
@@ -3450,7 +3656,7 @@ int main(int argc, char *argv[]) {
                         /* simply exit on sigchld */
                         sd_event_add_signal(event, NULL, SIGCHLD, NULL, NULL);
 
-                        r = pty_forward_new(event, master, &forward);
+                        r = pty_forward_new(event, master, true, &forward);
                         if (r < 0) {
                                 log_error_errno(r, "Failed to create PTY forwarder: %m");
                                 goto finish;
@@ -3462,9 +3668,11 @@ int main(int argc, char *argv[]) {
                                 goto finish;
                         }
 
+                        pty_forward_get_last_char(forward, &last_char);
+
                         forward = pty_forward_free(forward);
 
-                        if (!arg_quiet)
+                        if (!arg_quiet && last_char != '\n')
                                 putc('\n', stdout);
 
                         /* Kill if it is not dead yet anyway */
@@ -3526,6 +3734,13 @@ finish:
                         log_warning_errno(k, "Cannot remove subvolume '%s', ignoring: %m", arg_directory);
         }
 
+        if (arg_machine) {
+                const char *p;
+
+                p = strappenda("/run/systemd/nspawn/propagate", arg_machine);
+                (void) rm_rf(p, false, true, false);
+        }
+
         free(arg_directory);
         free(arg_template);
         free(arg_image);