Allow xrealloc to act as a free() when size=0, per SuS2.

 -Erik


git-svn-id: svn://busybox.net/trunk/busybox@2945 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 11 insertions, 1 deletions

diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index f3b294be2..eb93bf139 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -44,7 +44,17 @@ extern void *xmalloc(size_t size)
 
 extern void *xrealloc(void *old, size_t size)
 {
-        void *ptr = realloc(old, size);
+        void *ptr;
+
+        /* SuS2 says "If size is 0 and ptr is not a null pointer, the
+         * object pointed to is freed."  Do that here, in case realloc
+         * returns a NULL, since we don't want to choke in that case. */
+        if (size==0 && old) {
+                free(old);
+                return NULL;
+        }
+
+        ptr = realloc(old, size);
         if (!ptr)
                 error_msg_and_die(memory_exhausted);
         return ptr;