./move.sh

1 files changed, 364 insertions, 0 deletions

diff --git a/src/libcore/machine-id-setup.c b/src/libcore/machine-id-setup.c
new file mode 100644
index 0000000000..812e4b038c
--- /dev/null
+++ b/src/libcore/machine-id-setup.c
@@ -0,0 +1,364 @@
+/***
+  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 <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <unistd.h>
+
+#include <systemd/sd-id128.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "io-util.h"
+#include "log.h"
+#include "machine-id-setup.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "mount-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "stat-util.h"
+#include "string-util.h"
+#include "umask-util.h"
+#include "util.h"
+#include "virt.h"
+
+static int shorten_uuid(char destination[34], const char source[36]) {
+        unsigned i, j;
+
+        assert(destination);
+        assert(source);
+
+        /* Converts a UUID into a machine ID, by lowercasing it and
+         * removing dashes. Validates everything. */
+
+        for (i = 0, j = 0; i < 36 && j < 32; i++) {
+                int t;
+
+                t = unhexchar(source[i]);
+                if (t < 0)
+                        continue;
+
+                destination[j++] = hexchar(t);
+        }
+
+        if (i != 36 || j != 32)
+                return -EINVAL;
+
+        destination[32] = '\n';
+        destination[33] = 0;
+        return 0;
+}
+
+static int read_machine_id(int fd, char id[34]) {
+        char id_to_validate[34];
+        int r;
+
+        assert(fd >= 0);
+        assert(id);
+
+        /* Reads a machine ID from a file, validates it, and returns
+         * it. The returned ID ends in a newline. */
+
+        r = loop_read_exact(fd, id_to_validate, 33, false);
+        if (r < 0)
+                return r;
+
+        if (id_to_validate[32] != '\n')
+                return -EINVAL;
+
+        id_to_validate[32] = 0;
+
+        if (!id128_is_valid(id_to_validate))
+                return -EINVAL;
+
+        memcpy(id, id_to_validate, 32);
+        id[32] = '\n';
+        id[33] = 0;
+        return 0;
+}
+
+static int write_machine_id(int fd, const char id[34]) {
+        int r;
+
+        assert(fd >= 0);
+        assert(id);
+
+        if (lseek(fd, 0, SEEK_SET) < 0)
+                return -errno;
+
+        r = loop_write(fd, id, 33, false);
+        if (r < 0)
+                return r;
+
+        if (fsync(fd) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int generate_machine_id(char id[34], const char *root) {
+        int fd, r;
+        unsigned char *p;
+        sd_id128_t buf;
+        char  *q;
+        const char *dbus_machine_id;
+
+        assert(id);
+
+        dbus_machine_id = prefix_roota(root, "/var/lib/dbus/machine-id");
+
+        /* First, try reading the D-Bus machine id, unless it is a symlink */
+        fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+        if (fd >= 0) {
+                r = read_machine_id(fd, id);
+                safe_close(fd);
+
+                if (r >= 0) {
+                        log_info("Initializing machine ID from D-Bus machine ID.");
+                        return 0;
+                }
+        }
+
+        if (isempty(root)) {
+                /* If that didn't work, see if we are running in a container,
+                 * and a machine ID was passed in via $container_uuid the way
+                 * libvirt/LXC does it */
+
+                if (detect_container() > 0) {
+                        _cleanup_free_ char *e = NULL;
+
+                        r = getenv_for_pid(1, "container_uuid", &e);
+                        if (r > 0) {
+                                r = shorten_uuid(id, e);
+                                if (r >= 0) {
+                                        log_info("Initializing machine ID from container UUID.");
+                                        return 0;
+                                }
+                        }
+
+                } else if (detect_vm() == VIRTUALIZATION_KVM) {
+
+                        /* If we are not running in a container, see if we are
+                         * running in qemu/kvm and a machine ID was passed in
+                         * via -uuid on the qemu/kvm command line */
+
+                        char uuid[36];
+
+                        fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+                        if (fd >= 0) {
+                                r = loop_read_exact(fd, uuid, 36, false);
+                                safe_close(fd);
+
+                                if (r >= 0) {
+                                        r = shorten_uuid(id, uuid);
+                                        if (r >= 0) {
+                                                log_info("Initializing machine ID from KVM UUID.");
+                                                return 0;
+                                        }
+                                }
+                        }
+                }
+        }
+
+        /* If that didn't work, generate a random machine id */
+        r = sd_id128_randomize(&buf);
+        if (r < 0)
+                return log_error_errno(r, "Failed to open /dev/urandom: %m");
+
+        for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) {
+                q[0] = hexchar(*p >> 4);
+                q[1] = hexchar(*p & 15);
+        }
+
+        id[32] = '\n';
+        id[33] = 0;
+
+        log_info("Initializing machine ID from random generator.");
+
+        return 0;
+}
+
+int machine_id_setup(const char *root, sd_id128_t machine_id) {
+        const char *etc_machine_id, *run_machine_id;
+        _cleanup_close_ int fd = -1;
+        bool writable = true;
+        char id[34]; /* 32 + \n + \0 */
+        int r;
+
+        etc_machine_id = prefix_roota(root, "/etc/machine-id");
+        run_machine_id = prefix_roota(root, "/run/machine-id");
+
+        RUN_WITH_UMASK(0000) {
+                /* We create this 0444, to indicate that this isn't really
+                 * something you should ever modify. Of course, since the file
+                 * will be owned by root it doesn't matter much, but maybe
+                 * people look. */
+
+                mkdir_parents(etc_machine_id, 0755);
+                fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
+                if (fd < 0) {
+                        int old_errno = errno;
+
+                        fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+                        if (fd < 0) {
+                                if (old_errno == EROFS && errno == ENOENT)
+                                        log_error_errno(errno,
+                                                  "System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n"
+                                                  "Booting up is supported only when:\n"
+                                                  "1) /etc/machine-id exists and is populated.\n"
+                                                  "2) /etc/machine-id exists and is empty.\n"
+                                                  "3) /etc/machine-id is missing and /etc is writable.\n");
+                                else
+                                        log_error_errno(errno, "Cannot open %s: %m", etc_machine_id);
+
+                                return -errno;
+                        }
+
+                        writable = false;
+                }
+        }
+
+        /* A machine id argument overrides all other machined-ids */
+        if (!sd_id128_is_null(machine_id)) {
+                sd_id128_to_string(machine_id, id);
+                id[32] = '\n';
+                id[33] = 0;
+        } else {
+                if (read_machine_id(fd, id) >= 0)
+                        return 0;
+
+                /* Hmm, so, the id currently stored is not useful, then let's
+                 * generate one */
+
+                r = generate_machine_id(id, root);
+                if (r < 0)
+                        return r;
+        }
+
+        if (writable)
+                if (write_machine_id(fd, id) >= 0)
+                        return 0;
+
+        fd = safe_close(fd);
+
+        /* Hmm, we couldn't write it? So let's write it to
+         * /run/machine-id as a replacement */
+
+        RUN_WITH_UMASK(0022) {
+                r = write_string_file(run_machine_id, id, WRITE_STRING_FILE_CREATE);
+                if (r < 0) {
+                        (void) unlink(run_machine_id);
+                        return log_error_errno(r, "Cannot write %s: %m", run_machine_id);
+                }
+        }
+
+        /* And now, let's mount it over */
+        if (mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL) < 0) {
+                (void) unlink_noerrno(run_machine_id);
+                return log_error_errno(errno, "Failed to mount %s: %m", etc_machine_id);
+        }
+
+        log_info("Installed transient %s file.", etc_machine_id);
+
+        /* Mark the mount read-only */
+        if (mount(NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0)
+                log_warning_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id);
+
+        return 0;
+}
+
+int machine_id_commit(const char *root) {
+        _cleanup_close_ int fd = -1, initial_mntns_fd = -1;
+        const char *etc_machine_id;
+        char id[34]; /* 32 + \n + \0 */
+        int r;
+
+        etc_machine_id = prefix_roota(root, "/etc/machine-id");
+
+        r = path_is_mount_point(etc_machine_id, 0);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", etc_machine_id);
+        if (r == 0) {
+                log_debug("%s is is not a mount point. Nothing to do.", etc_machine_id);
+                return 0;
+        }
+
+        /* Read existing machine-id */
+        fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+        if (fd < 0)
+                return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id);
+
+        r = read_machine_id(fd, id);
+        if (r < 0)
+                return log_error_errno(r, "We didn't find a valid machine ID in %s.", etc_machine_id);
+
+        r = fd_is_temporary_fs(fd);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine whether %s is on a temporary file system: %m", etc_machine_id);
+        if (r == 0) {
+                log_error("%s is not on a temporary file system.", etc_machine_id);
+                return -EROFS;
+        }
+
+        fd = safe_close(fd);
+
+        /* Store current mount namespace */
+        r = namespace_open(0, NULL, &initial_mntns_fd, NULL, NULL, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Can't fetch current mount namespace: %m");
+
+        /* Switch to a new mount namespace, isolate ourself and unmount etc_machine_id in our new namespace */
+        if (unshare(CLONE_NEWNS) < 0)
+                return log_error_errno(errno, "Failed to enter new namespace: %m");
+
+        if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) < 0)
+                return log_error_errno(errno, "Couldn't make-rslave / mountpoint in our private namespace: %m");
+
+        if (umount(etc_machine_id) < 0)
+                return log_error_errno(errno, "Failed to unmount transient %s file in our private namespace: %m", etc_machine_id);
+
+        /* Update a persistent version of etc_machine_id */
+        fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
+        if (fd < 0)
+                return log_error_errno(errno, "Cannot open for writing %s. This is mandatory to get a persistent machine-id: %m", etc_machine_id);
+
+        r = write_machine_id(fd, id);
+        if (r < 0)
+                return log_error_errno(r, "Cannot write %s: %m", etc_machine_id);
+
+        fd = safe_close(fd);
+
+        /* Return to initial namespace and proceed a lazy tmpfs unmount */
+        r = namespace_enter(-1, initial_mntns_fd, -1, -1, -1);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to switch back to initial mount namespace: %m.\nWe'll keep transient %s file until next reboot.", etc_machine_id);
+
+        if (umount2(etc_machine_id, MNT_DETACH) < 0)
+                return log_warning_errno(errno, "Failed to unmount transient %s file: %m.\nWe keep that mount until next reboot.", etc_machine_id);
+
+        return 0;
+}