The system call open can add O_LARGEFILE.

A point is reopend for unsharing a file descriptor. So here are two
types of points. One is returned by pipe() and all other ones are
got via opening /proc/PID/fd.

Currently I know only one difference between these types, it's
O_LARGEFILE.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Tested-by: Alexander Kartashov <alekskartashov@parallels.com
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Use decode_pointer() to convert a virtual address into a native pointer.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

I'm really lucky.

prepare_ctl_tty:
	e->fd           = get_service_fd(CTL_TTY_OFF); // -1 as fd is not set

send_fd_to_self:
if (dup2(fd, dfd) != dfd) { // tries to install sfd, but -1 == -1

tty_restore_ctl_terminal:
	if (!is_service_fd(fd, CTL_TTY_OFF))
		return fd == get_service_fd(type); // -1 = -1
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Otherwise we will get nil dereference in shared_fdt_prepare
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Here is updated one.

0001-ids-Make-sure-kIDs-is-present-in-image.patch

>From dee67b483f0ed1a6f81ebe95ae9bdf74d3ab2ad7 Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@openvz.org>
Date: Fri, 15 Mar 2013 00:43:30 +0400
Subject: [PATCH 1/2] ids: Make sure kIDs is present in image

Otherwise yield error instead of nil dereference
if we meet a broken image.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This mode was introduced less than year ago:

commit 9883035ae7edef3ec62ad215611cb8e17d6a1a5d
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Apr 29 13:12:42 2012 -0700

    pipes: add a "packetized pipe" mode for writing
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

mnt_entry::fstype is a part of image ABI, thus we need
to provide some "common" encoding outside tools would
know about this field encoding.

Thus we instorduce fstype enum in .proto file and use it
in source code as well.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This patch generalizes format strings in the file page-xfer.c
to prevent format string warnings on ARM.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Andrey Vagin <avagin@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>

Otherwise

 | (00.002843)      1: Error (files-reg.c:522): Can't find regfile for 0
 | : Success

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

Actually rt_sigset_t and k_rtsigset_t are the same
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Otherwise ppage_bitmap and page_bitmap will be updated for wrong VMA
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The iov array for 1-page mapping would be zero. Fix this silly mistake.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

This makes it easier to merge with anon vmas dumping and makes use of
page server for shared memory.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

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

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

Need to have proper fake-item state to make this code work ok:

get_task_ids
if (item->state != TASK_DEAD) {
	ret = dump_task_kobj_ids(item);
	if (ret)
		goto err_free;
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Without patch

 | Error (cr-restore.c:414): Unable to reserve memory: Invalid argument

with applied

 | Error (cr-restore.c:414): Unable to reserve memory (0 bytes): Invalid argument

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

 - Free unpacked PB data
 - Close file descriptor
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

In Fedora /var/run is on tmpfs, so all directories should be
recreated each times.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Currently shmem generates page images in parallel
with page server and IDs may intersect. Fix this by
making page server create larger IDs.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

When -p is used, launch page server in the same dir as
crtools dump is to get fill dump in it.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The page server is a process, that is about to get pages over
the network and put them into pagemap- + pages- images. Right
now what it does is simply get the data and puts it into the
image files. When we have dirty set tracking in the kernel the
page server will have to collect "page changes" and properly
integrate them into images.

Running crtools with page server is like this:

dst_node# crtools page-server --port <port> -D dump/ ...
src_node# crtools dump -t <pid> --page-server --address <dst_node> --port <port> -D dump/ ...

After this images from dst_node/dump/ and src_node/dump/ should
be put into one place and tasks can be restored out of it.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We'll send them over network soon, so prepare abstraction layer for
this. Shmem is not on this scheme yet.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Since now we drain pages out of parasite, we can invent any format for
page dumps. Let is be ... prorobuf one! :)

Another thing to keep in mind, is that we're about to use splices and
implement iterative migration, so it's better to have actual pages be
page-aligned in the image.

And -- backward compatibility. That said the new format is:

1. pagemap-... file which contains a header (currently with a ID of
   the image with pages, see below) and an array of <nr_pages:vaddr>
   pairs. The first value means "how many pages to take from the
   file with pages (see below)" and the second -- where in the task
   address space to put them. Simple.

2. pages-... file which containes only pages one by one (thus aligned
   as we want).

This patch breaks backward compatibility (old images with pages wil
be restored and then crash). Need to do it before v0.5 release.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Generate random data only for buffers with sizes less than FAST_SIZE
If a size of buffer is more that FAST_SIZE, the first FAST_SIZE bytes
are filled by random generator and then this chunk is used as pattern
for all other chunks.

With out this patch:
$ time bash -x test/zdtm.sh static/maps04
real	0m16.777s
user	0m0.054s
sys	0m0.724s

With this patch:
$ time bash -x test/zdtm.sh static/maps04
real	0m1.865s
user	0m0.128s
sys	0m0.745s
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Otherwise
 | 11:03:13.524: 19446: ERR: ipc_namespace.c:212: Can't write 0 into /proc/sys/fs/mqueue/msg_max (errno = 22 (Invalid argument))
 | 11:03:13.524: 19446: ERR: ipc_namespace.c:273: Failed to randomize ipc namespace tunables (errno = 22 (Invalid argument))
 | 11:03:13.524: 19446: ERR: ipc_namespace.c:336: Failed to randomize ipc ns before migration (errno = 22 (Invalid argument))
 | 11:03:13.527: 19445: ERR: test.c:298: Test exited with unexpectedly with code 1 (errno = 4 (Interrupted system call))

https://bugzilla.openvz.org/show_bug.cgi?id=2530Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

A signal can be handled by non-leader thread and sigsuspend
will not be woken up.

kill can send signals to a specified thread, so a futex is used for
synchronization.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

It's leftover from early times.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This allows to reuse magic numbers outside of crtools code.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

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

The ARM parasite head uses a pad of 228 bytes
to make the offset of the symbol __export_parasite_stack
representable in the ARM instruction set. This value
needs to be changed every time the value of the macro
PARASITE_STACK_SIZE changes.

This patch makes this manual interference redundant.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

Currently we dump pages directly from parasite into image files. This
is bad for several reasons:

1. We cannot use any more-or-less custom format for pages easily, since
   parasite code cannot be linked with any libraries;
2. We will not be able to optimize migration with preliminary memory
   migration (a.k.a. iterative migration) with it -- if we send pages
   from parasite over network we are not able to let the task we dump
   continue running.

That said, what is done is -- pages from target task are put into a
page-pipe in one go, then (not in this patch) parasite can be released
and we can do with pages whatever we want. For now pages are just
spliced from pipe into image file.

Some numbers:
In order to drain 1Gb of memory from task we need 1.5M of shared map
in args (for iovecs) and 4 pipes (8 descriptors) each referencing 128Mb
of pages, which int turn requires 4 x 640K chunks of sequential kernel
memory (for pipe_buffer). Not that big I guess.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>