Now:
- we don't open the PID file in main() anymore
- PID file and AF_UNIX socket are opened by pidfile_open() and
  tap_sock_unix_open()
- write_pidfile() becomes pidfile_write()

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>

For some unknown reason "owner" makes it impossible to open bind mounted
netns references as apparmor denies it. In the kernel denied log entry
we see ouid=0 but it is not clear why that is as the actual file is
owned by the real (rootless) user id.

In abstractions/pasta there is already `@{run}/user/@{uid}/**` without
owner set for the same reason as this path contains the netns path by
default when running under Podman.

Fixes: 72884484b00d ("apparmor: allow read access on /tmp for pasta")
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

The podman CI on debian runs tests based on /tmp but pasta is failing
there because it is unable to open the netns path as the open for read
access is denied.

Link: https://github.com/containers/podman/issues/22625
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

If pasta and pasta.avx2 are hard links to passt and passt.avx2,
AppArmor will attach their own profiles on execution, and we can
restrict passt's profile to what it actually needs. Note that pasta
needs to access all the resources that passt needs, so the pasta
abstraction still includes passt's one.

I plan to push the adaptation required for the Debian package in
commit 5bb812e79143 ("debian/rules: Override pasta symbolic links
with hard links"), on Salsa. If other distributions need to support
AppArmor profiles they can follow a similar approach.

The profile itself will be installed, there, via dh_apparmor, in a
separate commit, b52557fedcb1 ("debian/rules: Install new pasta
profile using dh_apparmor").

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

AppArmor resolves executable links before profile attachment rules
are evaluated, so, as long as pasta is installed as a link to passt,
there's no way to differentiate the two cases. Merge the two profiles
and leave a TODO note behind, explaining two possible ways forward.

Update the rules so that passt and pasta are actually usable, once
the profile is installed. Most required changes are related to
isolation and sandboxing features.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

These should cover any reasonably common use case in distributions.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>