Fix realloc with size == 0 in dbuf_default_realloc()

mikma · saghul · commit 20b25df62c09 · 2025-10-01T08:53:46.000+02:00
If the new_size argument to realloc is zero, the behavior
is undefined since C23.
diff --git a/cutils.c b/cutils.c
@@ -102,6 +102,10 @@ int js__has_suffix(const char *str, const char *suffix)
 
 static void *dbuf_default_realloc(void *opaque, void *ptr, size_t size)
 {
+    if (unlikely(size == 0)) {
+        free(ptr);
+        return NULL;
+    }
     return realloc(ptr, size);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -102,6 +102,10 @@ int js__has_suffix(const char str, const char suffix)`
`102`	`102`
`103`	`103`	`static void dbuf_default_realloc(void opaque, void *ptr, size_t size)`
`104`	`104`	`{`
	`105`	`+ if (unlikely(size == 0)) {`
	`106`	`+ free(ptr);`
	`107`	`+ return NULL;`
	`108`	`+ }`
`105`	`109`	`return realloc(ptr, size);`
`106`	`110`	`}`
`107`	`111`