plugin: Explicit assign plugin hooks

So it won't depend on the order in declaration.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
proc: Don't use FILE* for reading personality

It turned out, that fdopen (used in fopen_proc) always maps
a 4k buffer for reads and this buffer gets unmap-ed later
on fclose.

Taking into account the amount of proc files we read (~20
per task plus one file per opened file descriptor) this
mmap+munmap result in quite a lot of useless CPU time.

E.g. for a container of 20 tasks we have 1000 calls taking
~8% of total dump time.

So lets first stop doing this for simple cases -- one line
proc files.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
proc: Don't use FILE * to reach children

The same reasoning as for personality file -- switch to
plan open + read + close.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
mount: skip the criu's mount namespace if tasks live in another mntns

Currently here is a bug, because when we see criu's mount namespace,
we go to the "out" mark and don't validate mounts.

Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
restore: TASK_HELPERs live until RESTORE stage ends

In order to use TASK_HELPERS to open files from dead processes, they should
persist until criu is done restoring the filesystem, which happens in the
RESTORE stage. To do this, we need to pass each helper's PIDs to the restorer
blob, so that it can wait() on them when the restore stage is done.

This commit is in preparation for the remap_dead_pid commits.

v2: wait() on helpers after restore stage is over
v3: add CR_STATE_RESTORE_FS stage
v4: CR_STATE_RESTORE_FS waits for nr_tasks + nr_helpers, not nr_threads
v5: ditch CR_STATE_RESTORE_FS in favor of passing helpers to restorer blob

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
remap: add a dead pid /proc remap

If a file like /proc/20/mountinfo is open, but 20 is a zombie (or doesn't exist
any more), we can't read this file at all, so a link remap won't work. Instead,
we add a new remap, called the dead process remap, which forks a TASK_HELPER as
that dead pid so that the restore task can open the new /proc/20/mountinfo
instead.

This commit also adds a new stage CR_STATE_RESTORE_SHARED. Since new
TASK_HELPERS are added when loading the shared resource images, we need to wait
to start forking tasks until after these resources are loaded.

v2: fix a mutex bug

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: add a test for remap_dead_pid

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
zdtm: move get_smaps_bits to separate file for reuse

Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
zdtm: test for mlocked area restores if programm have no credentials

Test maps 17 pages and mlocks them, then changes user id from root
to 18943, after c/r checks that MAP_LOCKED bit is set for that vma.

Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
parasite: send PARASITE_CMD_FINI before resuming the target process

The control socket has enough buffer for one command and the target
process will not wait a new command, so we will avoid extra context
switches.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
dump: use breakpoints instead of tracing syscalls (v2)

Currently CRIU traces syscalls to catch a moment, when sigreturn() is
called. Now we trace recv(cmd), close(logfd), close(cmdfd), sigreturn().

We can reduce a number of steps by using hw breakpoints. A breakpoint is
set before sigreturn, so we will need to trace only it.

v2: In the first version a breakpoint is set after sigreturn. In this
case we have a problem with signals. If a process has pending signals,
it will start to precess them after exiting from sigreturn(), but before
returning to userspace. So the breakpoint will not be triggered.

And at the end Here are a few numbers how we catch sigreturn.
Before this patch criu executes 36 syscalls and gets 12 signals.
With this patch criu executes 18 syscalls and gets 5 signals.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
restore: use breakpoints instead of tracing syscalls

Currently CRIU traces syscalls to catch a moment, when sigreturn() is
called. Now we trace recv(cmd), close(logfd), close(cmdfd), sigreturn().

We can reduce a number of steps by using hw breakpoints. A breakpoint is
set before sigreturn, so we will need to trace only it.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
zdtm: don't call mount_cgroups a few times concurrently

Here is a race now:
./zdtm.sh --ct -d -C -x static/cgroup02 ns/static/pipe02 &> ns_static_pipe02.log || \
{ flock Makefile cat ns_static_pipe02.log; exit 1; }
./zdtm.sh --ct -d -C -x static/cgroup02 ns/static/busyloop00 &> ns_static_busyloop00.log || \
{ flock Makefile cat ns_static_busyloop00.log; exit 1; }
make[3]: `zdtm_ct' is up to date.
mkdir: cannot create directory ‘zdtm.GgIjUS/holder’: File exists

Reported-by: Mr Jenkins
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
ptrace: say to parasite_stop_on_syscall where is we now

On restore parasite_stop_on_syscall() can be called after PTRACE_SYSCALL
and after a breakpoint. parasite_stop_on_syscall() must be called only
after PTRACE_SYSCALL, so all tests where is one process stuck.

Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
page-server: assign opts.ps_port to sin_port in autobind case

Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
service: page-server: return port back to user, v2

Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
service: page-server: allow requesting page-server without setting any ps_info

Since we now can return port to user in autobind case, it's ok to request
page-server without setting ps_info.

Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: rpc: test page-server

Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
ptrace: flush breakpoints

Unfortunately the kernel doesn't flush hw breakpoints on
detaching ptrace. If a breakpoint is triggered without ptrace, it
will be killed by SIGTRAP.

Reported-by: Mr Jenkins
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
ptrace: Factor out pie stopping code

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