SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

machine-id-setup: rework --commit based on chase()

Browse Source
This commit is contained in:
Lennart Poettering
2025-01-20 11:32:01 +01:00
parent 4d0fb50e9e
commit efabf4e044
1 changed files with 34 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/shared/machine-id-setup.c
+34 -14
View File
@@ -250,8 +250,6 @@ finish:
}
int machine_id_commit(const char *root) {
_cleanup_close_ int fd = -EBADF, initial_mntns_fd = -EBADF;
const char *etc_machine_id;
sd_id128_t id;
int r;
@@ -274,9 +272,17 @@ int machine_id_commit(const char *root) {
* 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");
_cleanup_close_ int etc_fd = -EBADF;
_cleanup_free_ char *etc = NULL;
r = chase("/etc/", root, CHASE_PREFIX_ROOT, &etc, &etc_fd);
if (r < 0)
return log_error_errno(r, "Failed to open /etc/: %m");
r = path_is_mount_point(etc_machine_id);
_cleanup_free_ char *etc_machine_id = path_join(etc, "machine-id");
if (!etc_machine_id)
return log_oom();
r = fd_is_mount_point(etc_fd, "machine-id", /* flags= */ 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) {
@@ -285,9 +291,12 @@ int machine_id_commit(const char *root) {
}
/* Read existing machine-id */
fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
_cleanup_close_ int fd = xopenat_full(etc_fd, "machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, XO_REGULAR, MODE_INVALID);
if (fd < 0)
return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id);
return log_error_errno(fd, "Cannot open %s: %m", etc_machine_id);
etc_fd = safe_close(etc_fd);
r = fd_is_temporary_fs(fd);
if (r < 0)
@@ -301,10 +310,8 @@ int machine_id_commit(const char *root) {
if (r < 0)
return log_error_errno(r, "We didn't find a valid machine ID in %s: %m", etc_machine_id);
fd = safe_close(fd);
/* Store current mount namespace */
initial_mntns_fd = namespace_open_by_type(NAMESPACE_MOUNT);
_cleanup_close_ int initial_mntns_fd = namespace_open_by_type(NAMESPACE_MOUNT);
if (initial_mntns_fd < 0)
return log_error_errno(initial_mntns_fd, "Can't fetch current mount namespace: %m");
@@ -313,15 +320,23 @@ int machine_id_commit(const char *root) {
if (r < 0)
return log_error_errno(r, "Failed to set up new mount namespace: %m");
r = umount_verbose(LOG_ERR, etc_machine_id, 0);
/* Open /etc/ again after we transitioned into our own private mount namespace */
_cleanup_close_ int etc_fd_again = -EBADF;
r = chase("/etc/", root, CHASE_PREFIX_ROOT, /* ret_path= */ NULL, &etc_fd_again);
if (r < 0)
return log_error_errno(r, "Failed to open /etc/: %m");
r = umountat_detach_verbose(LOG_ERR, etc_fd_again, "machine-id");
if (r < 0)
return r;
/* Update a persistent version of etc_machine_id */
r = id128_write(etc_machine_id, ID128_FORMAT_PLAIN | ID128_SYNC_ON_WRITE, id);
r = id128_write_at(etc_fd_again, "machine-id", ID128_FORMAT_PLAIN | ID128_SYNC_ON_WRITE, id);
if (r < 0)
return log_error_errno(r, "Cannot write %s. This is mandatory to get a persistent machine ID: %m", etc_machine_id);
etc_fd_again = safe_close(etc_fd_again);
/* Return to initial namespace and proceed a lazy tmpfs unmount */
r = namespace_enter(/* pidns_fd = */ -EBADF,
initial_mntns_fd,
@@ -329,10 +344,15 @@ int machine_id_commit(const char *root) {
/* userns_fd = */ -EBADF,
/* root_fd = */ -EBADF);
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);
return log_warning_errno(r,
"Failed to switch back to initial mount namespace: %m.\n"
"We'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);
r = umountat_detach_verbose(LOG_DEBUG, fd, /* filename= */ NULL);
if (r < 0)
return log_warning_errno(r,
"Failed to unmount transient %s file: %m.\n"
"We keep that mount until next reboot.", etc_machine_id);
return 0;
}