Add tests for stpcpy

1 files changed, 10 insertions, 3 deletions

diff --git a/include/string.h b/include/string.h
index f416a51..f738901 100644
--- a/include/string.h
+++ b/include/string.h
@@ -85,9 +85,16 @@ __access(write_only, 1)
 __access(read_only, 2)
 _FORTIFY_FN(stpcpy) char *stpcpy(char *__d, const char *__s)
 {
-        size_t __b = __bos(__d, 0);
+        size_t __n = strlen(__s) + 1;
 
-        if (strlen(__s) + 1 > __b)
+        /* trap if pointers are overlapping but not if dst == src.
+         * gcc seems to like to generate code that relies on dst == src */
+        if ((__d < __s && __d + __n > __s) ||
+            (__s < __d && __s + __n > __d))
+                __builtin_trap();
+
+        size_t __b = __bos(__d, 0);
+        if (__n > __b)
                 __builtin_trap();
         return __orig_stpcpy(__d, __s);
 }
@@ -129,7 +136,7 @@ _FORTIFY_FN(strcpy) char *strcpy(char *__d, const char *__s)
                 __builtin_trap();
 
         size_t __b = __bos(__d, 0);
-        if (strlen(__s) + 1 > __b)
+        if (__n > __b)
                 __builtin_trap();
         return __orig_strcpy(__d, __s);
 }