diff options
Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/machine-id-setup.c | 79 | ||||
| -rw-r--r-- | src/core/machine-id-setup.h | 1 |
2 files changed, 80 insertions, 0 deletions
diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c index d8600bde2d..74582a5dcd 100644 --- a/src/core/machine-id-setup.c +++ b/src/core/machine-id-setup.c @@ -188,6 +188,85 @@ static int write_machine_id(int fd, char id[34]) { 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 wether %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; diff --git a/src/core/machine-id-setup.h b/src/core/machine-id-setup.h index b0583eefc8..f7707c3bf9 100644 --- a/src/core/machine-id-setup.h +++ b/src/core/machine-id-setup.h @@ -21,4 +21,5 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ +int machine_id_commit(const char *root); int machine_id_setup(const char *root); |