libc: add limited FORTIFY_SOURCE support for clang
In 829c089f83ddee37203b52bcb294867a9ae7bdbc, we disabled all
FORTIFY_SOURCE support when compiling under clang. At the time,
we didn't have proper test cases, and couldn't easily create targeted
clang tests.
This change re-enables FORTIFY_SOURCE support under clang for a
limited set of functions, where we have explicit unittests available.
The functions are:
* memcpy
* memmove
* strcpy
* strncpy
* strcat
* strncat
* memset
* strlen (with modifications)
* strchr (with modifications)
* strrchr (with modifications)
It may be possible, in the future, to enable other functions. However,
I need to write unittests first.
For strlen, strchr, and strrchr, clang unconditionally calls the
fortified version of the relevant function. If it doesn't know the
size of the buffer it's dealing with, it passes in ((size_t) -1),
which is the largest possible size_t.
I added two new clang specific unittest files, primarily copied
from fortify?_test.cpp.
I've also rebuild the entire system with these changes, and didn't
observe any obvious problems.
Change-Id: If12a15089bb0ffe93824b485290d05b14355fcaa
diff --git a/libc/include/fcntl.h b/libc/include/fcntl.h
index 67fd597..94322fd 100644
--- a/libc/include/fcntl.h
+++ b/libc/include/fcntl.h
@@ -49,7 +49,7 @@
extern int fcntl(int fd, int command, ...);
extern int creat(const char* path, mode_t mode);
-#if defined(__BIONIC_FORTIFY)
+#if defined(__BIONIC_FORTIFY) && !defined(__clang__)
__errordecl(__creat_error, "called with O_CREAT, but missing mode");
__errordecl(__too_many_args_error, "too many arguments");
extern int __open_real(const char *pathname, int flags, ...)
@@ -98,7 +98,7 @@
return __openat_real(dirfd, pathname, flags, __builtin_va_arg_pack());
}
-#endif /* defined(__BIONIC_FORTIFY) */
+#endif /* defined(__BIONIC_FORTIFY) && !defined(__clang__) */
__END_DECLS