When we want to just execute command (without capturing output), we must
not do it via $(cmd). With such form, shell first gets output of 'cmd',
and then evaluates it. If this is empty string, it is successfully
executed. If not empty, all breaks down.
https://jira.sw.ru/browse/PSBM-44207Signed-off-by: Eugene Kolomeetz <klm@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

When read bultin detects EOF, it sets empty string as value of specified
variable, and returns non-zero exit code. So we can rely just on exit
code, and not check variable value. This is standard approach.
https://jira.sw.ru/browse/PSBM-44207Signed-off-by: Eugene Kolomeetz <klm@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This function may catch overflow near INT_MAX, so
it becomes return strange fd, like fd = -2147483648.
Fix that.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

v2: fix compilation warning for snprintf
v3: check iptables has xtables locks support once on init
v4: switch opts to kdat
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

when run several tests simultaneousely it seem that some iptables
commands can intersect and if we do not wait xtables lock criu fails:

(00.009263)     Running iptables [iptables -t filter -A INPUT --protocol tcp --source 127.0.0.1 --sport 55074 --destination 127.0.0.1 --dport 8880 -j DROP]
Another app is currently holding the xtables lock. Perhaps you want to use the -w option?
(00.014367) Error (util.c:660): exited, status=4
(00.014416) Error (netfilter.c:88): Iptables configuration failed: Success
(00.014432) ----------------------------------------
(00.014461) Error (cr-dump.c:1297): Dump files (pid: 24) failed with -1

https://ci.openvz.org/job/CRIU/job/CRIU-virtuozzo/branch/criu-dev/3/Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Now readlink is called in host context, this is obviously wrong.
Signed-off-by: Eugene Kolomeetz <klm@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Let's use $(...) form, it is more readable, and used in other places.
Signed-off-by: Eugene Kolomeetz <klm@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Otherwise the following errors can be triggered:

/usr/libexec/criu/scripts/systemd-autofs-restart.sh: line 64: [: =: unary
operator expected
/usr/libexec/criu/scripts/systemd-autofs-restart.sh: line 77: [: =: unary
operator expected
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Restore_ns helper closes passed namepsace fd unconditionally.
Thus new_pid_ns must be invalidated in any case after calling for it.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Fily system type is not necessarily located in the column number 9.
But look like we can rely on " - " pattern: it's always located immediately
after dash.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

There can be a situation, when autofs mount is catatonic, but doesn't know
about it yet.
It wasn't possible to distinguish between such mounts and others, which are
active, but not accessible for some reason. And all of such mounts were
threated as undumpable.
Such "hidden" catatonic mounts can appear if:

1) autofs master process has exited without switching
   the mount to catatonic mode (or was killed).

2) mount point was unmounted, but not propagated to
   nested mount namespace with private mounts.

These mounts can be handled by accessing the mount point. If it's catatonic,
it will update it's internals on first failed request to the autofs master.
Then we can read options again and dump the mountpoint as catatonic.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

No not return error from autofs_find_pipe_read_end, if pipe end wasn't found,
because read_fd remains negative.
There is another explicit check in the caller of this function for read_fd and
proper messages are printed in such a case.
Return -ENOENT in case of read end of the pipe doesn't exist to distinguish
with other error types (will be used later).
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Unfortunatelly, autofs doesn't allow to discover it's type. At least without
accessing master process. That means, that stat can be used to determine
whether some other file system is mounted on top of autofs (which we need to
take a decision whether to move restore fs aside or not), because it simply
stuck.
This patch does fs type discovering by parsing CTs mountinfo.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This patch slightly changes the logic on systemd autofs service restart script:

1) It tries to bind-mount the mountpoint on top of autofs (if any) somewhere
before service restart, and replace new mount point on top of autofs (if any)
by the saved one after.

2) It doesn't exit in case of error, trying to recover as much as
possible in case of failure instead and then continue services restarting.

The reason for introducing new logic is that there can be some other,
stateful, file system on top of autofs (say, tmpfs), which state was restore
during migration.
With current script this state will be lost, while this patch allows to
preserve restored mount point after service restart.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This was a silly mistake: bind-mounts share the same superblock, thus dentry
creation on a bind-monut will fail with EEXIST.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This is essential to make sure, that we won't use the same pipe descriptor for
different pipes.
Otherwise we can run into problem with fd send via unix sockets.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This is log cleanup patch.
Pr_perror prints new line by itself.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Otherwise information about real pid is lost in case of pid_to_virt returned
zero. This is required to output the real pid in error message instead of
always outputting zero (result of pid_to_virt).
IOW, would be nice to know the process pid we failed to find in the tree.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Without correct pid namespace systemctl is not able to determine whether
autofs is active or not.
The reason is unaccessible proc due to mount namespace change without pid
namespace change.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This will be installed into $(prefix)/libexec/criu/scripts.
Signed-off-by: Cyrill Gorcunov <gorcunov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This script restarts systemd autofs services to workaround a problem, when
systemd doesn't consider autofs mount as own after restore (alien device ID
problem)

v4:
Environment variable NS_PID was renamed to CRTOOLS_INIT_PID

v2:
1) Added different checks: for process with pid, active service, systemd based
container.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This will lead to segmentation fault.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Type dev_t corresponds to "unsigned long".

v2: explicitly cast to "long"
Signed-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Type dev_t corresponds to "unsigned long".
Signed-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Otherwise dump fails.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

In file included from /home/travis/build/xemul/criu/criu/include/autofs.h:16:0,
                 from autofs.c:7:
/usr/include/linux/auto_fs.h:54:12: error: ‘NAME_MAX’ undeclared here (not in a function)
  char name[NAME_MAX+1];

In file included from /home/travis/build/xemul/criu/criu/include/autofs.h:16:0,
                 from autofs.c:7:
/usr/include/linux/auto_fs.h:54:12: error: ‘NAME_MAX’ undeclared here (not in a function)
  char name[NAME_MAX+1];
Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

The following error happens when building CRIU on Fedora 22:

  CC       autofs.o
autofs.c: In function ‘autofs_mount’:
autofs.c:892:9: error: implicit declaration of function ‘add_post_prepare_cb’ [-Werror=implicit-function-declaration]
   ret = add_post_prepare_cb(autofs_add_mount_info, mi);
         ^
cc1: all warnings being treated as errors

Adding forward declaration of add_post_prepare_cb resolves the issue.
Signed-off-by: Mike Rapoport <rapoport@il.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

The only way to check, whether autofs migration is supported  from the kernel
side is to check actual mount point options (search for "pipe_ino" option).
This checker first tries to find autofs on host. If there is no any, temporary
mounts autofs by itself.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Required for test/zdtm/static/autofs test.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

1) Support autofs kernel-user exchange protocol
2) Test mounts: direct, indirect, offset (?) (migrated and operational).
3) Test cases, when write end of the pipe is closed, and when it's not.
4) Test catatonic mounts.
5) Test nested mounts are migrated (tmpfs suits it good)
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

In case of mounting AutoFS indirect mount points, target dentry doesn't exist
and has to be created.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

AutoFS mount point is managed by user space daemon, which receives requests
from kernel via pipe, passed on mount operation.
Kernel hold write end, while user space process - read end.
Thus, for successfull AutoFS migration, this connection has to be restored.

Autofs restore is tricky. Mount point is created by init process in pair with
per-mount context to be able to fix up actual kernel-userspace pipe
connection, when all the mount points are restored.

The problems with restoring pipe connection are:

1) It has to be done from actual AutoFS mount point master process context,
because pipe and pgrp values are taken from current in kernel.
2) Actual mounts are created by "init" process, and mount point owner (master)
have to set later.
3) To update mount point master one requires an opened write end of the pipe.

To provide AutoFS mount point master with resources, mentioned above, the
following was implemented:

1) If mount master doesn't have write pipe end opened, it is created as a
clone of read pipe end file descriptor and added to master's fds list. This
end is required to reconfigure mount point master.
2) Another pipe fle is created with explicit "post_open" callback, which is
used for actual mount point reconfiguration.
3) Mount point in created by init process. Mount data, required to restore
the owner, is copied to shared memory location by post-mount callback.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

This structures and helpers are needed to simplify autofs mounts reconfiguring
during restore.
Note: taken from automount package.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>