[CRIU] [PATCH v2 0/5] Restore of "/proc/self/ns/net" fixes

[Kirill Tkhai]

The main goal of this series was to fix the problem, when
opened by dumpee "/proc/self/ns/net" restores wrong. It's
in [4/5].

But at the same time I saw, that we do not restore "/proc/self/ns/user"
at all. So, [1-3/5] are preparations for that:
[1/5] is preparation for using open_proc() instead of raw "/proc/self/ns/user",
[2/5] is refactoring,
[3/5] is small change for uniformity,
[5/5] is a test for user ns (it requires the test, as it's also set manually,
                             not during clone(), like net ns)

https://travis-ci.org/tkhai/criu/builds/216266532

v2: Rebased on fresh criu-dev. Added comment.
---

Kirill Tkhai (5):
      user_ns: Close pid proc in create_user_ns_hierarhy_fn()
      ns: Pack functionality of storing ns fd to store_self_ns()
      user_ns: Keep root_user_ns ns fd in fdstore
      ns: Fix wrong opened net ns file
      zdtm: Add proc-self01 test


 criu/include/namespaces.h      |    1 +
 criu/namespaces.c              |   55 +++++++++++++++++++++++++++++++---------
 test/zdtm/static/Makefile      |    2 +
 test/zdtm/static/proc-self.c   |    4 +++
 test/zdtm/static/proc-self01.c |    1 +
 5 files changed, 50 insertions(+), 13 deletions(-)
 create mode 120000 test/zdtm/static/proc-self01.c

--
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>