fix umount2 syscall flags type, add conversion helper function

[oheifetz]

• change the flags (param 1) from u32 to s32
• add a userspace to scap flag conversion helper routine

Reported by: github issue #515

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

/kind cleanup

/kind design

/kind documentation

/kind failing-test

/kind feature

Any specific area of the project related to this PR?

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/area API-version

/area build

/area CI

/area driver-kmod

/area driver-bpf

/area driver-modern-bpf

/area libscap-engine-bpf

/area libscap-engine-gvisor

/area libscap-engine-kmod

/area libscap-engine-modern-bpf

/area libscap-engine-nodriver

/area libscap-engine-noop

/area libscap-engine-source-plugin

/area libscap-engine-savefile

/area libscap-engine-udig

/area libscap

/area libpman

/area libsinsp

/area tests

/area proposals

Does this PR require a change in the driver versions?

/version driver-API-version-major

/version driver-API-version-minor

/version driver-API-version-patch

/version driver-SCHEMA-version-major

/version driver-SCHEMA-version-minor

/version driver-SCHEMA-version-patch

What this PR does / why we need it: change the flags (param 1) from u32 to s32 and add a userspace to scap flag conversion helper routine

Which issue(s) this PR fixes: issue 515 umount2 bullet

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

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[github-actions]

Please double check driver/SCHEMA_VERSION file. See versioning.

[incertum]

@oheifetz just wanted to let you know, we are discussing in the other PR #1192 (comment) how to make the executive decision on when we absolutely need to bump the event given it's rather a long list of minor type miss casts. We will keep you updated, for now we are holding all these PRs until we have clarified the open questions.

[oheifetz]

Hi @incertum,
Saw that some CI builds failed even though my builds and tests passed. I ran:

cmake -DUSE_BUNDLED_DEPS=On -DBUILD_LIBSCAP_GVISOR=Off \
      -DENABLE_DRIVERS_TESTS=On -DCREATE_TEST_TARGETS=On \
      -DBUILD_BPF=On -DBUILD_LIBSCAP_MODERN_BPF=On -DMODERN_BPF_DEBUG_MODE=On ..
make drivers_test
make driver bpf
make unit-test-libsinsp; make run-unit-test-libsinsp;
make unit-test-libscap; sudo libscap/test/unit-test-libscap;
sudo ./test/drivers/drivers_test -b driver/bpf/probe.o;
sudo ./test/drivers/drivers_test -m
sudo ./test/drivers/drivers_test -k

If there are some additional builds I can run to confirm that it will not fail on CI it would be great

[Andreagit97]

hey @oheifetz yes if you want to reproduce the failure locally you have to put -DBUILD_LIBSCAP_GVISOR=On the fix here seems to put ifdefs around the flag you added, so:

#ifdef MNT_FORCE
	if (flags & MNT_FORCE)
		res |= PPM_MNT_FORCE;
#endif
#ifdef MNT_DETACH
	if (flags & MNT_DETACH)
		res |= PPM_MNT_DETACH;
#endif

    ...
	return res;

The ifdef __NR_umount2 is not enough because the syscall numbers are defined in another header with respect to the flags

[FedeDP]

/milestone driver-backlog

[oheifetz]

Hi @incertum,
When pushing code now I get: `! [remote rejected] issue_515_umount2 -> issue_515_umount2 (refusing to allow a Personal Access Token to create or update workflow ``
Is there some explanation on the workflow changes that needs to be done to make a push work?

[incertum]

@oheifetz probably not, I just pushed myself onto my branch. I have had such issues in the past and likely something in your settings changed or you need to setup a new ssh key or something. Please let us know if you keep having these issues after checking everything.