Re: [libvirt] [PATCH RFC 2/5] lxc: make container's init process session leader

This patch forces container's init process, to become a session leader, that is its session ID is made the same as its process ID. That might seem unnecessary in general, but if we want to checkpoint a container with CRIU, which is needed for container migration, we must ensure that the SID of each process inside the container points to a process that lives in the same PID namespace as the container. Therefore, we force that the session leader is the init. Signed-off-by: Katerina Koukiou <k.koukiou(a)gmail.com&gt; --- src/lxc/lxc_container.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 916a37b..b857431 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -2245,6 +2245,14 @@ static int lxcContainerChild(void *data) argv->npassFDs, argv->passFDs) < 0) goto cleanup; + /* Make init process of the container the leader of the new session. + * That is needed when checkpointing container. + */ + if (setsid() < 0) { + virReportSystemError(errno, "%s", + _("Unable to become session leader")); + }

+ ret = 0; cleanup: VIR_FREE(ttyPath);