#include <fcntl.h>
#include <sys/mount.h>
-#include <systemd/sd-id128.h>
+#include "systemd/sd-id128.h"
#include "machine-id-setup.h"
#include "macro.h"
#include "log.h"
#include "virt.h"
#include "fileio.h"
+#include "path-util.h"
-static int shorten_uuid(char destination[36], const char *source) {
+static int shorten_uuid(char destination[34], const char source[36]) {
unsigned i, j;
for (i = 0, j = 0; i < 36 && j < 32; i++) {
return -EINVAL;
}
-static int generate(char id[34]) {
+static int generate(char id[34], const char *root) {
int fd, r;
unsigned char *p;
sd_id128_t buf;
- char *q;
+ char *q;
ssize_t k;
- const char *vm_id;
+ const char *vm_id, *dbus_machine_id;
assert(id);
+ if (isempty(root))
+ dbus_machine_id = "/var/lib/dbus/machine-id";
+ else
+ dbus_machine_id = strappenda(root, "/var/lib/dbus/machine-id");
+
/* First, try reading the D-Bus machine id, unless it is a symlink */
- fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd >= 0) {
+ k = loop_read(fd, id, 33, false);
+ safe_close(fd);
- k = loop_read(fd, id, 32, false);
- close_nointr_nofail(fd);
-
- if (k >= 32) {
- id[32] = '\n';
- id[33] = 0;
-
- log_info("Initializing machine ID from D-Bus machine ID.");
- return 0;
- }
- }
-
- /* If that didn't work, see if we are running in qemu/kvm and a
- * machine ID was passed in via -uuid on the qemu/kvm command
- * line */
+ if (k == 33 && id[32] == '\n') {
- r = detect_vm(&vm_id);
- if (r > 0 && streq(vm_id, "kvm")) {
- char uuid[37];
+ id[32] = 0;
+ if (id128_is_valid(id)) {
+ id[32] = '\n';
+ id[33] = 0;
- fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
- if (fd >= 0) {
- k = loop_read(fd, uuid, 36, false);
- close_nointr_nofail(fd);
-
- if (k >= 36) {
- r = shorten_uuid(id, uuid);
- if (r >= 0) {
- log_info("Initializing machine ID from KVM UUID.");
- return 0;
- }
+ log_info("Initializing machine ID from D-Bus machine ID.");
+ return 0;
}
}
}
- /* If that didn't work either, see if we are running in a
- * container, and a machine ID was passed in via
- * $container_uuid the way libvirt/LXC does it */
- r = detect_container(NULL);
- if (r > 0) {
- char *e;
-
- r = getenv_for_pid(1, "container_uuid", &e);
+ 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 */
+ r = detect_container(NULL);
if (r > 0) {
- if (strlen(e) >= 36) {
- r = shorten_uuid(id, e);
- if (r >= 0) {
- log_info("Initializing machine ID from container UUID.");
- free(e);
- return 0;
+ _cleanup_free_ char *e = NULL;
+
+ r = getenv_for_pid(1, "container_uuid", &e);
+ if (r > 0) {
+ if (strlen(e) >= 36) {
+ r = shorten_uuid(id, e);
+ if (r >= 0) {
+ log_info("Initializing machine ID from container UUID.");
+ return 0;
+ }
}
}
- free(e);
+ } else {
+ /* 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 */
+
+ r = detect_vm(&vm_id);
+ if (r > 0 && streq(vm_id, "kvm")) {
+ char uuid[37];
+
+ fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd >= 0) {
+ k = loop_read(fd, uuid, 36, false);
+ safe_close(fd);
+
+ if (k >= 36) {
+ 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) {
- log_error("Failed to open /dev/urandom: %s", strerror(-r));
- return r;
- }
+ 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);
return 0;
}
-int machine_id_setup(void) {
- int fd, r;
- bool writable;
+static int get_valid_machine_id(int fd, char id[34]) {
+ char id_to_validate[34];
+
+ assert(fd >= 0);
+ assert(id);
+
+ if (loop_read(fd, id_to_validate, 33, false) == 33 && id_to_validate[32] == '\n') {
+ id_to_validate[32] = 0;
+
+ if (id128_is_valid(id_to_validate)) {
+ memcpy(id, id_to_validate, 32);
+ id[32] = '\n';
+ id[33] = 0;
+ return 0;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static int write_machine_id(int fd, char id[34]) {
+ assert(fd >= 0);
+ assert(id);
+ lseek(fd, 0, SEEK_SET);
+
+ if (loop_write(fd, id, 33, false) == 0)
+ return 0;
+
+ return -errno;
+}
+
+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;
+
+ if (isempty(root))
+ etc_machine_id = "/etc/machine-id";
+ else {
+ char *x;
+
+ x = strappenda(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
+ }
+
+ r = path_is_mount_point(etc_machine_id, false);
+ 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 = get_valid_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 = is_fd_on_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);
+ 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);
+ 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;
+}
+
+int machine_id_setup(const char *root) {
+ const char *etc_machine_id, *run_machine_id;
+ _cleanup_close_ int fd = -1;
+ bool writable = true;
struct stat st;
char id[34]; /* 32 + \n + \0 */
+ int r;
+
+ if (isempty(root)) {
+ etc_machine_id = "/etc/machine-id";
+ run_machine_id = "/run/machine-id";
+ } else {
+ char *x;
+
+ x = strappenda(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
+
+ x = strappenda(root, "/run/machine-id");
+ run_machine_id = path_kill_slashes(x);
+ }
RUN_WITH_UMASK(0000) {
/* We create this 0444, to indicate that this isn't really
* will be owned by root it doesn't matter much, but maybe
* people look. */
- fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
- if (fd >= 0)
- writable = true;
- else {
- fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ 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) {
- log_error("Cannot open /etc/machine-id: %m");
+ if (old_errno == EROFS && errno == ENOENT)
+ log_error("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;
}
}
}
- if (fstat(fd, &st) < 0) {
- log_error("fstat() failed: %m");
- r = -errno;
- goto finish;
- }
+ if (fstat(fd, &st) < 0)
+ return log_error_errno(errno, "fstat() failed: %m");
- if (S_ISREG(st.st_mode)) {
- if (loop_read(fd, id, 32, false) >= 32) {
- r = 0;
- goto finish;
- }
- }
+ if (S_ISREG(st.st_mode) && get_valid_machine_id(fd, id) == 0)
+ return 0;
/* Hmm, so, the id currently stored is not useful, then let's
* generate one */
- r = generate(id);
+ r = generate(id, root);
if (r < 0)
- goto finish;
-
- if (S_ISREG(st.st_mode) && writable) {
- lseek(fd, 0, SEEK_SET);
+ return r;
- if (loop_write(fd, id, 33, false) == 33) {
- r = 0;
- goto finish;
- }
- }
+ if (S_ISREG(st.st_mode) && writable)
+ if (write_machine_id(fd, id) == 0)
+ return 0;
- close_nointr_nofail(fd);
- fd = -1;
+ 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);
+ r = write_string_file(run_machine_id, id);
}
if (r < 0) {
- log_error("Cannot write /run/machine-id: %s", strerror(-r));
-
- unlink("/run/machine-id");
- goto finish;
+ log_error_errno(r, "Cannot write %s: %m", run_machine_id);
+ unlink(run_machine_id);
+ return r;
}
/* And now, let's mount it over */
- r = mount("/run/machine-id", "/etc/machine-id", NULL, MS_BIND, NULL) < 0 ? -errno : 0;
+ r = mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL);
if (r < 0) {
- unlink("/run/machine-id");
- log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
- } else {
- log_info("Installed transient /etc/machine-id file.");
-
- /* Mark the mount read-only */
- if (mount(NULL, "/etc/machine-id", NULL,
- MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0)
- log_warning("Failed to make transient /etc/machine-id read-only");
+ log_error_errno(errno, "Failed to mount %s: %m", etc_machine_id);
+ unlink_noerrno(run_machine_id);
+ return -errno;
}
-finish:
+ log_info("Installed transient %s file.", etc_machine_id);
- if (fd >= 0)
- close_nointr_nofail(fd);
+ /* 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 r;
+ return 0;
}
~ianmdlvl / elogind.git / blobdiff