return 0;
}
+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;
etc_machine_id = "/etc/machine-id";
run_machine_id = "/run/machine-id";
} else {
- etc_machine_id = strappenda(root, "/etc/machine-id");
- path_kill_slashes((char*) etc_machine_id);
+ char *x;
+
+ x = strappenda(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
- run_machine_id = strappenda(root, "/run/machine-id");
- path_kill_slashes((char*) run_machine_id);
+ x = strappenda(root, "/run/machine-id");
+ run_machine_id = path_kill_slashes(x);
}
RUN_WITH_UMASK(0000) {
}
}
- if (fstat(fd, &st) < 0) {
- log_error_errno(errno, "fstat() failed: %m");
- return -errno;
- }
+ if (fstat(fd, &st) < 0)
+ return log_error_errno(errno, "fstat() failed: %m");
- if (S_ISREG(st.st_mode))
- if (loop_read(fd, id, 33, false) == 33 && id[32] == '\n') {
- id[32] = 0;
-
- if (id128_is_valid(id))
- return 0;
- }
+ 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 */
if (r < 0)
return r;
- if (S_ISREG(st.st_mode) && writable) {
- lseek(fd, 0, SEEK_SET);
-
- if (loop_write(fd, id, 33, false) == 33)
+ if (S_ISREG(st.st_mode) && writable)
+ if (write_machine_id(fd, id) == 0)
return 0;
- }
fd = safe_close(fd);
~ianmdlvl / elogind.git / blobdiff