To not bloat util.h or image.h the protobuf.h introduced to handle all PB needs.

We represent our PB objects as pairs of records

  | 4 bytes for object packed size
  +---
  | X bytes -- object itself

v3:
 - Use plain read/write calls
 - Use local buffers for small objects

v4:
 - Add pb_pksize helper to calculate object
   size with header
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

After previous patch they are no longer required.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Before this patch a transport socket was created on-demand for each operation
requiring it. It will be problematic, when we start supporting net namespaces.
That said -- create a transport sockets and interconnect them early.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

No need to keep it in header, sk_packet used solely in one C file.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Need for PB transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

For PB transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The kernel threats them as interger values so
we should declare them this way. Moreover, explicitly
clean them up to eliminate side effects.

Initially I hit a problem where high bits of long "size"
variable was containing some crap from stack and in result
I've got errors like

 | Error (sk-queue.c:102): dump_sk_queue: Can't allocate 171798904800 bytes
 | Error (cr-dump.c:1289): Dump files (pid: 2505) failed with -1
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

debugfs isn't virtualized and never will be

jira #PCLIN-31059
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Andrey Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Otherwise the show result depends on the loglevel :\
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

1. Seeking should be done for real files only , for fifos using the
   same code -- shouldn't. Thus -- move the lseek to proper place;
2. It's nice to print error on file open error;
3. It's nice to handle lseek error.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

For PB transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Need it for PB transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This serves two things -- kills annoying data offset management
which makes protobuf switch too ugly. And removes the need to
seek the pipe data image, which in turn is the prerequisity for
streaming migration.

Memory usage is still optimal, since we still use splice on dump
path and on restore stage we F_GIFT pipe buffers to the kernel.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Using do { } while (0) for statemets macro like this is a good practice.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Need it for PB transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Strictly speaking the fd link can point to PATH_MAX string, but for the sake of
is_anonfd_link 32 bytes is enough -- even if the target string is longer it will not
match the required anon_inode:xxx string.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

To open /proc/self/fd/%d PATH_MAX array is too long :) We can use shorter.
Plus fix the snprintf size argument.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Just to explicitly state that a pipe ID is its inode number.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Now it is EBADF for bogus descriptor we pass
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

With this the code looks clearer and finally a ground for "check" code is prepared.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

And prepare it for inotify (oh my...)
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This makes tests that finish some time run smoother -- no tons of Waiting... messages
on the screen
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Make it in two stages.

First -- collect pipe data into hash without checking for pipe/fifo existance.
Next -- when pipe/fifo gets restored walk the hash and search where the pipe data
is.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The existing code checks for ID to be already dumped. But pipe and fifo may have the same ID
since they reside on different filesystems.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This routine checks for pipe data being dumped based on pipe ID, but the arg in questoin
is the pipe's end ID which makes code reading confusing.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The ret var is set to -1 at the beginning and the very first loop
will break and report it to the caller thus stopping the restore :(
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We need it for protobuf transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We need it for protobuf transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We will need it for protobuf transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We will need it for protobuf transition.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We will need to use pointer here (to PB object) anyway
so better to make it in a separate patch for bisectability sake.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Address Andrew's comments

 - use TEST_VALUE macro instead of open coded value
 - use WIFx macros for child status testing
 - kill child/parent on error

Note that it was not clear from an initiall patch
change log -- the difference between fifo_wronly
test case and this one is that we use fork() call
here which allow us to make sure that fifo restoration
code logic will be tested more widely.

Basically the flowchart of the test case:

parent				child
------				-----
open RW fifo (slave)
open RO fifo (master)
				open WO fifo (master)
				dup parent slave to slave1

				... waiting c/r to happen ...
				... waking up from c/r ...

				send bytes to master
				send bytes to slave1

				finish
... initiating c/r ...
... waking up from c/r ...

read bytes from master
read bytes from slave

PASS :D
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>