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The [[cmd/restore|restore]] command has several options how to restore the tree.
== Types of restore ==
; Default
: CRIU just forks the root task and all other tasks, restores the tasks, then waits for it to exit and after it exits itself. The process tree right after restore is shown on the picture below.
[[Image:Criu-restore-dflt.svg|300px|Default restore]]
; Detached
: An option <code>--restore-detached</code> makes CRIU exit right after restoring the tree thus causing it to get reparented to the init process.
[[Image:Criu-restore-detached.svg|300px|Detached restore]]
; Sibling
: An option <code>--restore-sibling</code> makes CRIU create root task as its own sibling and thus as caller's child. After restore is complete CRIU also exits thus leaving the restored tree being a pure child of the caller.
[[Image:Criu-restore-sibling.svg|300px|Sibling restore]]
== Doing execv() in CRIU ==
In the default restore case it's possible to replace CRIU hanging between the caller process and the root one with something more useful. The <code>--exec-cmd</code> option makes CRIU call execv() with arguments that are to be given at the very end of the CLI after <code>--</code> argument. E.g. like this
<pre>
criu restore --images-dir img/ --exec-cmd -v4 -o restore.log -- my_waiter --my-waiter-arg
</pre>
In this case the restored tree will look like in default case, but with the custom binary instead of CRIU processes.
[[Image:Criu-restore-n-exec.svg|300px|Restore with execv()]]
== Getting pid of the tree ==
In case the process tree lives in [[namespaces]] or is [[C/R in namespace|restored in new namespaces]], the real pid of the root task can become any. Knowing it depends on the [[API]] used.
; [[CLI]]
: When using the <code>--pidfile $path</code> option CRIU writes the PID of the root task in the <code>$path</code> file.
; [[RPC]]
: In case of RPC the real pid of restored root task is reported back in the <code>criu_resp.restore.pid</code> field of the message.
== See also ==
== See also ==
* [[Final states]]
* [[Final states]]
* [[C/R in namespace]]
[[Category:Empty articles]]
[[Category:Empty articles]]