Add basic ATF tests for Capability mode .. lookups

[cem]

Summary

To accompany https://reviews.freebsd.org/D8746 .

Test Plan

Could also use symlink tests. Anything else?

[ngie]

tests/sys/vfs/lookup_cap_dotdot.c

42

Why is this hardcoded to /tmp ? This violates the kyua test sandbox and makes this test impossible to cleanup after if it's interrupted or killed mid-test :(.

Honestly, it seems like you should be able to create a directory under the sandbox, 2 elements deep, which would fulfill your requirements.

57–61

ATF_CHECK(mkdirat(testdir_fd, "b", 0700) == 0);

is simpler.

85–98

This should be replaced with this simpler logic (which uses the feature_present(3) API):

#include "freebsd_test_suite/macros.h"

/* ... */

ATF_REQUIRE_FEATURE("security_capabilities");
ATF_REQUIRE_FEATURE("security_capability_mode");

Be sure to add:

CFLAGS+= ${SRCTOP}/tests

to the Makefile.

[ngie]

Could also use symlink tests. Anything else?

Tests that cross mount points, perhaps?

[kib]

I think it would be useful to include all tests from the original ed program, including non-capsicum kinds.
https://github.com/emaste/snippets/blob/master/test_openat.c

[cem]

In D8748#181282, @kib wrote:

I think it would be useful to include all tests from the original ed program, including non-capsicum kinds.
https://github.com/emaste/snippets/blob/master/test_openat.c

Will do, thanks.

tests/sys/vfs/lookup_cap_dotdot.c

42

I'm unfamiliar with kyua sandboxing. How do I use it? Is it just the current directory during test body?

I'm not attached to /tmp, just not aware of anything better.

57–61

Ok.

85–98

Thanks. That's in HEAD or BODY?

[cem]

Address ngie@ review feedback.

• Use cwd (assuming that's the sandbox) instead of tmp, drop cleanup code
• Use ATF_CHECK/ATF_REQUIRE for simplicity
• Use ATF_REQUIRE_FEATURE macro instead of raw sysctls

[cem]

Actually fix commit and push changes.

[cem]

Bring in Ed's openat tests, adapted to ATF. Includes symlink tests.

[oshogbo]

We don't want to put it under tools/regression/capsicum ?

[cem]

In D8748#181353, @oshogbo wrote:

We don't want to put it under tools/regression/capsicum ?

As an ATF test the logical place is under tests/. I don't know any good reason to prefer tools/regression over tests or vice versa, so as this is already implemented, I'm inclined to keep it as-is (if it isn't broken, don't fix it).

[kib]

tests/sys/vfs/lookup_cap_dotdot.c

193

We use c89-style /* */ comments in FreeBSD source code.