id128: add format which treats "uninitialized" like an empty id

Add a new ID128_PLAIN_OR_UNINIT format which treats the string
"uninitialized" like the file was empty and return -ENOMEDIUM.  This
format should be used when reading an /etc/machine-id file from an image
that is not currently running.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/libsystemd/sd-id128/id128-util.h b/src/libsystemd/sd-id128/id128-util.h
index 1901bf119f..1453c00f2f 100644
--- a/src/libsystemd/sd-id128/id128-util.h
+++ b/src/libsystemd/sd-id128/id128-util.h
@@ -17,6 +17,10 @@ bool id128_is_valid(const char *s) _pure_;
 typedef enum Id128Format {
         ID128_ANY,
         ID128_PLAIN,  /* formatted as 32 hex chars as-is */
+        ID128_PLAIN_OR_UNINIT,  /* formatted as 32 hex chars as-is; allow special "uninitialized"
+                                 * value when reading from file (id128_read() and id128_read_fd()).
+                                 *
+                                 * This format should be used when reading a machine-id file. */
         ID128_UUID,   /* formatted as 36 character uuid string */
         _ID128_FORMAT_MAX,
 } Id128Format;