Libc-997.1.1.tar.gz

[apple/libc.git] / secure / strlcat_chk.c

diff --git a/secure/strlcat_chk.c b/secure/strlcat_chk.c
new file mode 100644 (file)
index 0000000..5eb434e
--- /dev/null
+++ b/secure/strlcat_chk.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2012-2013 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "secure.h"
+
+size_t
+__strlcat_chk (char *restrict dest, char *restrict src,
+              size_t len, size_t dstlen)
+{
+  size_t initial_srclen;
+  size_t initial_dstlen;
+
+  if (__builtin_expect (dstlen < len, 0))
+    __chk_fail_overflow ();
+
+  initial_srclen = strlen(src);
+  initial_dstlen = strnlen(dest, len);
+
+  if (initial_dstlen == len)
+    return len+initial_srclen;
+
+  if (initial_srclen < len - initial_dstlen) {
+    __chk_overlap(dest, initial_srclen + initial_dstlen + 1, src, initial_srclen + 1);
+    memcpy(dest+initial_dstlen, src, initial_srclen + 1);
+  } else {
+    __chk_overlap(dest, initial_srclen + initial_dstlen + 1, src, len - initial_dstlen - 1);
+    memcpy(dest+initial_dstlen, src, len - initial_dstlen - 1);
+    dest[len-1] = '\0';
+  }
+
+  return initial_srclen + initial_dstlen;
+}