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-rw-r--r--src/core/machine-id-setup.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c
index 62f80833dd..423d4ff69d 100644
--- a/src/core/machine-id-setup.c
+++ b/src/core/machine-id-setup.c
@@ -295,9 +295,13 @@ int machine_id_setup(const char *root, sd_id128_t machine_id) {
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 */
+ sd_id128_t id;
int r;
+ /* Replaces a tmpfs bind mount of /etc/machine-id by a proper file, atomically. For this, the umount is removed
+ * in a mount namespace, a new file is created at the right place. Afterwards the mount is also removed in the
+ * original mount namespace, thus revealing the file that was just created. */
+
etc_machine_id = prefix_roota(root, "/etc/machine-id");
r = path_is_mount_point(etc_machine_id, 0);
@@ -313,10 +317,6 @@ int machine_id_commit(const char *root) {
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);
@@ -325,6 +325,10 @@ int machine_id_commit(const char *root) {
return -EROFS;
}
+ r = id128_read_fd(fd, ID128_PLAIN, &id);
+ if (r < 0)
+ return log_error_errno(r, "We didn't find a valid machine ID in %s.", etc_machine_id);
+
fd = safe_close(fd);
/* Store current mount namespace */
@@ -343,15 +347,9 @@ int machine_id_commit(const char *root) {
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);
+ r = id128_write(etc_machine_id, ID128_PLAIN, id, true);
if (r < 0)
- return log_error_errno(r, "Cannot write %s: %m", etc_machine_id);
-
- fd = safe_close(fd);
+ return log_error_errno(r, "Cannot write %s. This is mandatory to get a persistent machine ID: %m", etc_machine_id);
/* Return to initial namespace and proceed a lazy tmpfs unmount */
r = namespace_enter(-1, initial_mntns_fd, -1, -1, -1);