Add `strlen`

1 files changed, 17 insertions, 0 deletions

diff --git a/include/string.h b/include/string.h
index e681181..ab7ac43 100644
--- a/include/string.h
+++ b/include/string.h
@@ -35,6 +35,7 @@ extern "C" {
 #undef memset
 #undef strcat
 #undef strcpy
+#undef strlen
 #undef strncat
 #undef strncpy
 
@@ -237,6 +238,22 @@ _FORTIFY_FN(strcpy) char *strcpy(char * _FORTIFY_POS0 __d, const char *__s)
 #endif
 }
 
+__access (read_only, 1)
+#if __has_builtin(__builtin_strlen)
+__diagnose_as_builtin(__builtin_strlen, 1)
+#endif
+_FORTIFY_FN(strlen) size_t strlen(const char * _FORTIFY_POS0 __s)
+{
+#if __has_builtin(__builtin___strlen_chk) && USE_NATIVE_CHK
+        return __builtin___strlen_chk(__s, __bos(__s, 0));
+#else
+        size_t ret = __orig_strlen(__s);
+        if (ret > __bos(__s, 0) - 1)
+                __builtin_trap();
+        return ret;
+#endif
+}
+
 __access (read_write, 1)
 __access (read_only, 2, 3)
 #if __has_builtin(__builtin_strncat)