Perform dumping but with preliminary iterations. Each
time an iteration ends the ->more callback is called.
The callback's return value is
- positive -- one more iteration starts
- zero -- final dump is performed and call exits
- negative -- dump is aborted, the value is returned
back from criu_dump_iters
Inside callback one may (well, should) call criu_set_
function to alter the details of next iterations. In
particluar, then prev and next images directories should
be changed.
The @pi argument is an opaque value that caller may
use to request pre-dump statistics (not yet implemented).
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
After a bit more thinking I found a way to fetch arguments
from notifications -- pass opaque value into callback and
provide a set of calls for exploring one.
With this we can
a) provide more data if service supplies additional fields
in the future
b) not check the action name to decide whether or not the
requested argument is available
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This is achieved by supplying the callback. Every time a notification
arrives the callback is called. Return value of 0 means continue,
any other value aborst the request and the value is reported back
to the caller (from criu_dump/criu_restore calls).
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
It fully uses the swrk action of criu. The problems, that caller may
have is that the restored tasks die _before_ libcriu's call returns.
v2:
* rename _sub to _child
* unblock sigchild before execl-ing criu
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The --exec-cmd option specifies a command that will be execvp()-ed on successful
restore. This way the command specified here will become the parent process of
the restored process tree.
Waiting for the restored processes to finish is responsibility of this command.
All service FDs are closed before we call execvp(). Standad output and error of
the command are redirected to the log file when we are restoring through the RPC
service.
This option will be used when restoring LinuX Containers and it seems helpful
for perf or other use cases when restored processes must be supervised by a
parent.
Two directions were researched in order to integrate CRIU and LXC:
1. We tell to CRIU, that after restoring container is should execve()
lxc properly explaining to it that there's a new container hanging
around.
2. We make LXC set himself as child subreaper, then fork() criu and ask
it to detach (-d) from restore container afterwards. Being a subreaper,
it should get the container's init into his child list after it.
The main reason for choosing the first option is that the second one can't work
with the RPC service. If we call restore via the service then criu service will
be the top-most task in the hierarchy and will not be able to reparent the
restore trees to any other task in the system. Calling execve from service
worker sub-task (and daemonizing it) should solve this.
Signed-off-by: Deyan Doychev <deyandoichev@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
As we've added work_dir_fd to RPC, lets add support for it to libcriu.
Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
These functions are to be used to check criu, dump process and restore process.
Signed-off-by: Ruslan Kuprieiev <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
