A LXC container's lifecycle is regulated by the states STARTING, RUNNING,
STOPPING, STOPPED, ABORTING. These states are tracked in the LXC handler and
can be checked via approriate functions in the command socket callback system.
(The freezer stages are not part of a container's lifecycle since they are not
recorded in the LXC handler. This might change in the future but given that the
freezer controller will be removed from future cgroup implementations it is
unlikely.) So far, LXC was using an external helper to track the states of a
container (lxc-monitord). This solution was error prone. For example, the
external state server would hang in various scenarios that seemed to be caused
by either very subtle internal races or irritation of the external state server
by signals.
LXC will switch from an external state monitor (lxc-monitord) which serves as a
state server for state clients to a native implementation using the indiviual
container's command socket. This solution was discussed and outlined by Stéphane
Graber and Christian Brauner during a LX{C,D} sprint.
The LXC handler will gain an additional field to track state clients. In order
for a state client to receive state notifications from the command server he
will need to register himself via the lxc_cmd_state_server() function in the
state client list. The state client list will be served by lxc_set_state()
during the container's lifecycle. lxc_set_state() will also take care of
removing any clients from the state list in the LXC handler once the requested
state has been reached and sent to the client.
In order to prevent races between adding and serving new state clients the state
client list and the state field in the LXC handler will be protected by a lock.
This commit effectively deprecates lxc-monitord. Instead of serving states to
state clients via the lxc-monitord fifo and socket we will now send the state
of the container via the container's command socket.
lxc-monitord is still useable and will - for the sake of the lxc-monitor
command - be kept around so that non-API state clients can still monitor the
container during it's lifecycle.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Starting at version 3.6, Alpine Linux has support for ppc64le
architecture. Adding the new keys also.
Signed-off-by: Breno Leitao <breno.leitao@gmail.com>
The removed codepath was non-functional for a long time now. All mounting is
handled through bdev.{c,h} and if that fails the other codepath would
necessarily fail as well. So let's remove them. This makes it way clearer what
is going on and simplifies things massively.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
- Enable lxc_abstract_unix_{send,recv}_fd() to send and receive multiple fds at
once.
- lxc_abstract_unix_{send,recv}_fd() -> lxc_abstract_unix_{send,recv}_fds()
- Send tty fds from child to parent all at once.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This is a potentially security sensitive operation and I really want to keep an
eye on *when exactly* this is send. So add more logging on the TRACE() level.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This also fixes a bug where we caused a double mapping, when the {u,g}id for
the user was mapped to container root {g,u}id.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This adds confile_utils.{c,h} which will contain a helpers to parse lxc
configuration files.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This adds a test that checks LXC's configuration jump table whether all methods
for a given configuration item are implemented. If it is not, we'll error out.
This should provide additional safety since a) the API can now be sure that
dereferencing the pointer for a given method in the config struct is safe and
b) when users implement new configuration keys and forget to implement a
required method we'll see it right away.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Afaict, userns_exec_1() is only used to operate based on privileges for the
user's own {g,u}id on the host and for the container root's unmapped {g,u}id.
This means we require only to establish a mapping from:
- the container root {g,u}id as seen from the host -> user's host {g,u}id
- the container root -> some sub{g,u}id
The former we add, if the user did not specifiy a mapping. The latter we
retrieve from the ontainer's configured {g,u}id mappings.
Closes#1598.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Ever since 8eb62c2, systemd has not been able to cleanly stop lxc
containers (via lxc@) because it's still using SIGPWR for systemd-based
containers.
We should now use the nice logic in 330ae3d to stop the containers
instead.
Signed-off-by: JD Friedrikson <yours@decompo.site>
