sd-id128: be more liberal when reading files with 128bit IDs

Accept both files with and without trailing newlines. Apparently some rkt
releases generated them incorrectly, missing the trailing newlines, and we
shouldn't break that.

1 files changed, 21 insertions, 9 deletions

diff --git a/src/libsystemd/sd-id128/id128-util.c b/src/libsystemd/sd-id128/id128-util.c
index aaac838b59..c3f527d657 100644
--- a/src/libsystemd/sd-id128/id128-util.c
+++ b/src/libsystemd/sd-id128/id128-util.c
@@ -100,33 +100,45 @@ int id128_read_fd(int fd, Id128Format f, sd_id128_t *ret) {
         assert(f < _ID128_FORMAT_MAX);
 
         /* Reads an 128bit ID from a file, which may either be in plain format (32 hex digits), or in UUID format, both
-         * followed by a newline and nothing else. */
+         * optionally followed by a newline and nothing else. ID files should really be newline terminated, but if they
+         * aren't that's OK too, following the rule of "Be conservative in what you send, be liberal in what you
+         * accept". */
 
-        l = loop_read(fd, buffer, sizeof(buffer), false); /* we expect a short read of either 33 or 37 chars */
+        l = loop_read(fd, buffer, sizeof(buffer), false); /* we expect a short read of either 32/33 or 36/37 chars */
         if (l < 0)
                 return (int) l;
         if (l == 0) /* empty? */
                 return -ENOMEDIUM;
 
-        if (l == 33) {
-                if (f == ID128_UUID)
-                        return -EINVAL;
+        switch (l) {
 
+        case 33: /* plain UUID with trailing newline */
                 if (buffer[32] != '\n')
                         return -EINVAL;
 
+                /* fall through */
+        case 32: /* plain UUID without trailing newline */
+                if (f == ID128_UUID)
+                        return -EINVAL;
+
                 buffer[32] = 0;
+                break;
 
-        } else if (l == 37) {
-                if (f == ID128_PLAIN)
+        case 37: /* RFC UUID with trailing newline */
+                if (buffer[36] != '\n')
                         return -EINVAL;
 
-                if (buffer[36] != '\n')
+                /* fall through */
+        case 36: /* RFC UUID without trailing newline */
+                if (f == ID128_PLAIN)
                         return -EINVAL;
 
                 buffer[36] = 0;
-        } else
+                break;
+
+        default:
                 return -EINVAL;
+        }
 
         return sd_id128_from_string(buffer, ret);
 }