The expression in if () becomes quite complex and
deserves a helper with proper explanation of what's
going on.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

Use the format specifier %zu instead of %lu to print a size_t integer.
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

It's not freed anywhere. Makes code look simpler.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

All the entries with with_plugin set will be mounted by plugin.
The interesting case is when we do the pivot-root restore. In this
case we call restore callback very early (before we unmount the old
tree) and ask it to create the mountpoint at temporary location.
Later we move the mount to proper place.

The old_root argument of the callback is where it can find files
in the original mount namespace.

The is_file is return-argument. Sine files and directories cannot be
bind-mounted to each-other, the callback should create the mountpoint
itself and report whether it created file or directory.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

External bind mounts are those with source sitting outside of the
current FS view. Such are detected in validate_mounts(), so we
just go ahead and call plugins.

The plugin is provided with the mountpoint to decide whether it's
his or not (what else does the guy need?) and an ID with this it
can identify the mountpoint in /proc. The same ID will be used at
restore time to find the needed restore info.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The t and m match there, but strictly speaking we're working on the m.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We'll have to pre-mount some, so move the read_mnt_ns_img
before pivot_root call.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

To carry them with us in a local variable (next patches), not
the global mntinfo one.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We will need images at hands while we do pivot_root (see further patches),
so prepare the images reading routine.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

CID 1141016 (#1 of 1): Extra sizeof expression (SIZEOF_MISMATCH)
suspicious_pointer_arithmetic: Adding "40UL /* sizeof (FilePermsEntry)
*/" to pointer "(FownEntry *)perms" of type "FownEntry *" is suspicious
because adding an integral value to this pointer automatically scales
that value by the size, 48 bytes, of the pointed-to type, "FownEntry".
Most likely, "sizeof (FilePermsEntry)" is extraneous and should be
replaced with 1.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

CID 1141017 (#1-2 of 2): Resource leak (RESOURCE_LEAK)
14. leaked_handle: Handle variable fd going out of scope leaks the handle.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

CID 1141015 (#1 of 1): Resource leak (RESOURCE_LEAK)
8. leaked_handle: Handle variable fd going out of scope leaks the handle.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

CID 1141011 (#1 of 1): Double free (USE_AFTER_FREE)
24. double_free: Calling "free(void *)" frees pointer "ue" which has
already been freed.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The timeout can be exceeded during dumping and restoring.
When we are testing snapshots, the test is dumped three times.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

In file included from arch/x86/crtools.c:11:0:
include/ptrace.h:16:0: error: "PTRACE_LISTEN" redefined [-Werror]
 #define PTRACE_LISTEN  0x4208
 ^
In file included from include/ptrace.h:5:0,
                 from arch/x86/crtools.c:11:
/usr/include/sys/ptrace.h:150:0: note: this is the location of the previous definition
 #define PTRACE_LISTEN PTRACE_LISTEN
 ^
cc1: all warnings being treated as errors
make[1]: *** [arch/x86/crtools.o] Error 1
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

CID 1141012 (#1 of 1): Copy into fixed size buffer (STRING_OVERFLOW)
2. fixed_size_dest: You might overrun the 108 byte fixed-size string
"addr.sun_path" by copying "service_address" without checking the
length.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Just a small mistake in prev patch.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

It's a feature of PTRACE_SEIZE.  So we need to do something, only
if we want to change the state.

[xemul: If task _was_ in stopped state before dump and we want them
 to stay alive after dump, the existing code queues one more STOP
 to it. This affects subsequent dump, as we seize a stopped task
 with STOP in queue.

 One more item in TODO list -- support stopped tasks with STOP in
 queue :)
]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

Why we do several attempts to freeze tasks.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Before this patch, backslash was at 81th column which makes the text
twice longer on a standard 80 col terminal, which is quite annoying.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Remove whitespace at EOL (found by git grep '	$')
(the character before $ is real tab, typed in shell using Ctrl+V Tab)

To people using vim, I'd suggest adding the following code to ~/.vimrc:

let c_space_errors = 1
highlight FormatError ctermbg=darkred guibg=darkred
match FormatError /\s\+$\|\ \+\t\|\%80v.\|\ \{8\}/
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Since sd_listen_fds() doesn't set errno when returning a value > 1,
it doesn't make sense to use pr_perror(). Use pr_err() instead.

While at it, remove the period from the log message.

[v2: fix function names]
Signed-off-by: Kir Kolyshkin <kir@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>

Here is nothing interecting. If a file can't be dumped by criu,
plugins are called. If one of plugins knows how to dump the file,
the file entry is marked as need_callback. On restore if we see
this mark, we execute plugins for restoring the file.

v2: Callbacks are called for all files, which are not supported by CRIU.
v3: Call plugins for a file instead of file descriptor. A few file
descriptors can be associated with one file.
v4: A file descriptor is opened in a callback. It's required for
    restoring anon vmas.
v5: Add a separate type for unsupported files
v6: define FD_TYPES__UNSUPP
v7: s/unsupp/ext (external)
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Here are client, server programs and two libraries for dumping client
sockets and syslog socket.

The client can ask server to save a value and then request it later.
We suppose that after dumping and restoring the client will get
the same value.

So the dump callback requests the value and save it in a file.
The restore callback creates a new socket and ask server to save the
value from the file.

v2: open a syslog socket
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We don't know a state behind an external socket. It depends on logic
of the program, which handles this socket.

This patch adds ability to load a library with callbacks for dumping
and restoring external sockets.

This patch introduces two callbacks cr_plugin_dump_unix_sk and
cr_plugin_restore_unix_sk. If a callback can not handle a socket, it
must return -ENOTSUP.

The main questions, what kind of information should be tranfered in
these callbacks. Pls, think a few minutes about that and send me
your opinion.

v2: Use uflags instread of adding a new field
v3: clean up
v4: Unsuitable callbacks return -ENOTSUP.
v5: set USK_CALLBACK, if a socket was dumped by callback.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Unix sockets are dumped, when a peer socket is found.
We are going to dump external sockets with help plugins. For the we need
to set the USK_CALLBACK flags in unix entry. Currently a socket is
dumped immediately when it's transfered, but we can be sure that a
socket is not external, only when we have its peer.

v2: add comments in code
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>

We are going to add callback-s for dumping external sockets.
All external sockets are added into unix_list, but for dumping we need
to know all peers.

And one more thing is that a socket is not closed before its peer is
not be dumped. We are going to transfer the socket decriptor in the
callback.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We read /proc/pid/status to determine a task state, but if a task is
running in this moment, its state may be changed.

This patch stops tasks before reading their /proc/pid/status
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Before this patch crtools freezes processes and if something is changed,
it unfreezes all processes and starts again from the beginning.

If if are going to dump fork-bomb, this method doesn't work. Because a
big tree is always changed.

We don't need unfreeze processes, which have been frozen and this patch
does that.

This patch uses depth-first search (DFS) for traversing a process tree.

A root task is frozen at first turn, than a child is frozen, than a
child of child and so on.

When all children of one process are frozen, criu reads the list of
children again and check that nothing changed. This processes continues
until all of them will not be frozen. Afte that a new child can not be
appeared, because all children for children are frozen too.

v2: add comments in code
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

When we try to freeze threads, some of them can exit
and a few new ones can be born. Currently we unfreeze process free
int this case, so we have the same chance to failed in the next case.

I suggest to not unfreeze frozen threads, just try to update thread list
and freeze unfrozen threads.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

A warning catched by clang:

> > mount.c:869:71: error: variable 'progress' is uninitialized when used here
> >       [-Werror,-Wuninitialized]
> >   ...prev, MNT_WALK_NONE, fn, (struct list_head *) NULL, progress);
> >                                                          ^~~~~~~~
> > mount.c:802:4: note: expanded from macro 'MNT_TREE_WALK'
> >                         _prgs++;
> > \
> >                         ^
> > mount.c:867:14: note: initialize the variable 'progress' to silence this
> > warning
> >         int progress;
> >                     ^
> >                      = 0
> > 1 error generated.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

A thread can create another threads, if the number of threads is less
than the limit.

This test case is very useful to check criu freezer.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

Currently all task are restored as alive, but stopped tasks
must be restored as stopped.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>