strutils: fix double free in strrealloc() [coverity scan]

* fix double free
* keep strrealloc() semantic compatible with classic realloc() (do not
  free original pointer on failed memory allocation).
* remove unnecessary goto

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

diff --git a/include/strutils.h b/include/strutils.h
index fc3bb0c1c79e8cddfc78417dc5bc88a80b44669e..4b3182f85c66aa8d8ea11357ba0e69930183bf77 100644 (file)
--- a/include/strutils.h
+++ b/include/strutils.h
@@ -93,7 +93,9 @@ static inline char *mem2strcpy(char *dest, const void *src, size_t n, size_t nma
        return dest;
 }
 
-/* Reallocate @str according to @newstr and copy @newstr to @str; returns new @str */
+/* Reallocate @str according to @newstr and copy @newstr to @str; returns new @str.
+ * The @str is not modified if reallocation failed (like classic realloc()).
+ */
 static inline char * __attribute__((warn_unused_result))
 strrealloc(char *str, const char *newstr)
 {
@@ -101,27 +103,17 @@ strrealloc(char *str, const char *newstr)
 
        if (!str)
                return newstr ? strdup(newstr) : NULL;
-       if (!newstr) {
-               free(str);
-               goto nothing;
-       }
+       if (!newstr)
+               return NULL;
 
        osz = strlen(str);
        nsz = strlen(newstr);
 
-       if (nsz > osz) {
-               char *tmp = realloc(str, nsz + 1);
-               if (!tmp)
-                       goto nothing;
-               str = tmp;
-       }
-
-       memcpy(str, newstr, nsz + 1);
+       if (nsz > osz)
+               str = realloc(str, nsz + 1);
+       if (str)
+               memcpy(str, newstr, nsz + 1);
        return str;
-
-nothing:
-       free(str);
-       return NULL;
 }
 
 /* Copy string @str to struct @stru to member addressed by @offset */