Re: [PATCH 14/15] selftests/clone3: Avoid OS-defined clone_args

Christian Brauner
2020-09-15T22:22:43Z

On Sat, Sep 12, 2020 at 04:08:19AM -0700, Kees Cook wrote:
> As the UAPI headers start to appear in distros, we need to avoid
> outdated versions of struct clone_args to be able to test modern
> features. Additionally pull in the syscall numbers correctly.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---

Hm, with this patch applied I'm getting:

gcc -g -I../../../../usr/include/ clone3_set_tid.c /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest_harness.h /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest.h -lcap -o /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid
In file included from clone3_set_tid.c:24:
clone3_selftests.h:37:8: error: redefinition of ‘struct clone_args’
37 | struct clone_args {
| ^~~~~~~~~~
In file included from clone3_set_tid.c:12:
/usr/include/linux/sched.h:92:8: note: originally defined here
92 | struct clone_args {
| ^~~~~~~~~~
make: *** [../lib.mk:140: /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid] Error 1

One trick to avoid this could be:

#ifndef CLONE_ARGS_SIZE_VER0
#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
#endif

#ifndef CLONE_ARGS_SIZE_VER1
#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
#endif

#ifndef CLONE_ARGS_SIZE_VER2
#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
#endif

struct __clone_args {
__aligned_u64 flags;
__aligned_u64 pidfd;
__aligned_u64 child_tid;
__aligned_u64 parent_tid;
__aligned_u64 exit_signal;
__aligned_u64 stack;
__aligned_u64 stack_size;
__aligned_u64 tls;
__aligned_u64 set_tid;
__aligned_u64 set_tid_size;
__aligned_u64 cgroup;
};

static pid_t sys_clone3(struct __clone_args *args, size_t size)
{
return syscall(__NR_clone3, args, size);
}

Christian