libblkid: fix and cleanup blkid_safe_string()

* Don't use 'size_t len' variable for utf8_encoded_valid_unichar()
  return code as it returns negative numbers on invalid utf8 sequence.

* Don't rely only on \0, but check the current position against output
  buffer size.

* Accept hex encoding like the original version.

* Use else-if to avoid unnecessary 'continue'.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libblkid/src/encode.c b/libblkid/src/encode.c
index 80bca176bd978574f67328489ae44a82d887c174..8213873eeae5e0ff5cc60759abab7d5e67b8d458 100644 (file)
--- a/libblkid/src/encode.c
+++ b/libblkid/src/encode.c
@@ -230,30 +230,34 @@ int blkid_safe_string(const char *str, char *str_safe, size_t len)
        if (!str || !str_safe || !len)
                return -1;
 
-       len = strnlen(str, len);
-       __normalize_whitespace((const unsigned char *) str, len,
-                              (unsigned char *) str_safe, len + 1);
+       __normalize_whitespace(
+                       (const unsigned char *) str, strnlen(str, len),
+                       (unsigned char *) str_safe, len);
 
-       while (str_safe[i] != '\0') {
-               /* accept ASCII from '<space>' to '~' */
-               if (str_safe[i] > 0x20 && str_safe[i] <= 0x7E) {
+       while (i < len && str_safe[i] != '\0') {
+               int seqsz;
+
+               /* accept ASCII from ' ' to '~' */
+               if (str_safe[i] > 0x20 && str_safe[i] <= 0x7E)
                        i++;
-                       continue;
-               }
+
+               /* accept hex encoding */
+               else if (str_safe[i] == '\\' && str_safe[i+1] == 'x')
+                       i += 2;
+
                /* replace whitespace */
-               if (isspace(str_safe[i])) {
-                       str_safe[i] = '_';
-                       i++;
-                       continue;
-               }
-               len = utf8_encoded_valid_unichar(&str_safe[i]);
-               if (len >= 1) {
-                       i += len;
-                       continue;
-               }
+               else if (isspace(str_safe[i]))
+                       str_safe[i++] = '_';
+
+               /* accept valid utf8 */
+               else if ((seqsz = utf8_encoded_valid_unichar(&str_safe[i])) >= 1)
+                       i += seqsz;
+
                /* everything else is replaced with '_' */
-               str_safe[i] = '_';
-               i++;
+               else
+                       str_safe[i++] = '_';
        }
+
+       str_safe[len - 1] = '\0';
        return 0;
 }