This patch converts PID 1 to libsystemd-bus and thus drops the
dependency on libdbus. The only remaining code using libdbus is a test
case that validates our bus marshalling against libdbus' marshalling,
and this dependency can be turned off.
This patch also adds a couple of things to libsystem-bus, that are
necessary to make the port work:
- Synthesizing of "Disconnected" messages when bus connections are
severed.
- Support for attaching multiple vtables for the same interface on the
same path.
This patch also fixes the SetDefaultTarget() and GetDefaultTarget() bus
calls which used an inappropriate signature.
As a side effect we will now generate PropertiesChanged messages which
carry property contents, rather than just invalidation information.
We want to emphasize bus connections as per-thread communication
primitives, hence introduce a concept of a per-thread default bus, and
make use of it everywhere.
Try to emphasize a bit that there should be a mapping between event
loops and threads, hence introduce a logic that there's one "default"
event loop for each thread, that can be queried via
"sd_event_default()".
liblogind-core.la was underlinked, missing a few functions
defined in logind.c. They are moved to a new file, logind-core.c,
and this file is linked into liblogind-core.la.
In addition, logind-acl.c is attached to the liblogind-core.la,
instead of systemd-logind directly.
The seat->vtconsole member always points to the default seat seat0. Even
if VTs are disabled, it's used as default seat. Therefore, rename it to
seat0 to correctly state what it is.
This also changes the seat files in /run from IS_VTCONSOLE to IS_SEAT0. It
wasn't used by any code, yet, so this seems fine.
While we are at it, we also remove every "if (s->vtconsole)" as this
pointer is always valid!
A session usually has only a single compositor or other application that
controls graphics and input devices on it. To avoid multiple applications
from hijacking each other's devices or even using the devices in parallel,
we add session controllers.
A session controller is an application that manages a session. Specific
API calls may be limited to controllers to avoid others from getting
unprivileged access to restricted resources. A session becomes a
controller by calling the RequestControl() dbus API call. It can drop it
via ReleaseControl().
logind tracks bus-names to release the controller once an application
closes the bus. We use the new bus-name tracking to do that. Note that
during ReleaseControl() we need to check whether some other session also
tracks the name before we remove it from the bus-name tracking list.
Currently, we only allow one controller at a time. However, the public API
does not enforce this restriction. So if it makes sense, we can allow
multiple controllers in parallel later. Or we can add a "scope" parameter,
which allows a different controller for graphics-devices, sound-devices
and whatever you want.
Note that currently you get -EBUSY if there is already a controller. You
can force the RequestControl() call (root-only) to drop the current
controller and recover the session during an emergency. To recover a seat,
this is not needed, though. You can simply create a new session or
force-activate it.
To become a session controller, a dbus caller must either be root or the
same user as the user of the session. This allows us to run a session
compositor as user and we no longer need any CAP_SYS_ADMIN.
If we want to track bus-names to allow exclusive resource-access, we need
a way to get notified when a bus-name is gone. We make logind watch for
NameOwnerChanged dbus events and check whether the name is currently
watched. If it is, we remove it from the watch-list (notification for
other objects can be added in follow-up patches).
Session compositors need access to fbdev, DRM and evdev devices if they
control a session. To make logind pass them to sessions, we need to
listen for them actively.
However, we avoid creating new seats for non master-of-seat devices. Only
once a seat is created, we start remembering all other session devices. If
the last master-device is removed (even if there are other non-master
devices still available), we destroy the seat. This is the current
behavior, but we need to explicitly implement it now as there may be
non-master devices in the seat->devices list.
Unlike master devices, we don't care whether our list of non-master
devices is complete. We don't export this list but use it only as cache if
sessions request these devices. Hence, if a session requests a device that
is not in the list, we will simply look it up. However, once a session
requested a device, we must be notified of "remove" udev events. So we
must link the devices somehow into the device-list.
Regarding the implementation, we now sort the device list by the "master"
flag. This guarantees that master devices are at the front and non-master
devices at the tail of the list. Thus, we can easily test whether a seat
has a master device attached.
When PID 1 reloads the units logind/machined will see UnitRemoved
signals for all units. Instead of trusting these immediately, let's
check the actual unit state before considering a unit gone, so that
reloading PID 1 is not mistaken as the end of all sessions.
Embedded folks don't need the machine registration stuff, hence it's
nice to make this optional. Also, I'd expect that machinectl will grow
additional commands quickly, for example to join existing containers and
suchlike, hence it's better keeping that separate from loginctl.
In order to prepare things for the single-writer cgroup scheme, let's
make logind use systemd's own primitives for cgroup management.
Every login user now gets his own private slice unit, in which his sessions
live in a scope unit each. Also, add user@$UID.service to the same
slice, and implicitly start it on first login.
- This changes all logind cgroup objects to use slice objects rather
than fixed croup locations.
- logind can now collect minimal information about running
VMs/containers. As fixed cgroup locations can no longer be used we
need an entity that keeps track of machine cgroups in whatever slice
they might be located. Since logind already keeps track of users,
sessions and seats this is a trivial addition.
- nspawn will now register with logind and pass various bits of metadata
along. A new option "--slice=" has been added to place the container
in a specific slice.
- loginctl gained commands to list, introspect and terminate machines.
- user.slice and machine.slice will now be pulled in by logind.service,
since only logind.service requires this slice.
The information about the unit for which files are being parsed
is passed all the way down. This way messages land in the journal
with proper UNIT=... or USER_UNIT=... attribution.
'systemctl status' and 'journalctl -u' not displaying those messages
has been a source of confusion for users, since the journal entry for
a misspelt setting was often logged quite a bit earlier than the
failure to start a unit.
Based-on-a-patch-by: Oleksii Shevchuk <alxchk@gmail.com>
Containers will now carry a label (normally derived from the root
directory name, but configurable by the user), and the container's root
cgroup is /machine/<label>. This label is called "machine name", and can
cover both containers and VMs (as soon as libvirt also makes use of
/machine/).
libsystemd-login can be used to query the machine name from a process.
This patch also includes numerous clean-ups for the cgroup code.
Before, we would initialize many fields twice: first
by filling the structure with zeros, and then a second
time with the real values. We can let the compiler do
the job for us, avoiding one copy.
A downside of this patch is that text gets slightly
bigger. This is because all zero() calls are effectively
inlined:
$ size build/.libs/systemd
text data bss dec hex filename
before 897737 107300 2560 1007597 f5fed build/.libs/systemd
after 897873 107300 2560 1007733 f6075 build/.libs/systemd
… actually less than 1‰.
A few asserts that the parameter is not null had to be removed. I
don't think this changes much, because first, it is quite unlikely
for the assert to fail, and second, an immediate SEGV is almost as
good as an assert.
Strictly speaking this isn't necessary for the /run/systemd/seats/
directory, since that is created anyway as the first seat is found, and
seat0 is always found. But let's be explicit here, and also create the
sessions/ and users/ directories, so that people can always install
inotify watches from very early on, even when nobody logged in yet.
We currently enforce that seats are to be named in the form of
"seatXXX", i.e. need to begin with the 4 characters "seat". Thus,
"seat-master" would qualify as a seat name. As seat names are frequently
used as tags on devices, the "seat-master" tag might hence confuse
logind if the user decides to name a seat "seat-master".
Hence, avoid any ambuigity: let's rename the "seat-master" tag to
"master-of-seat".
- Don't allow any locks to be taken while we are in the process of
executing the specific operation, so that apps are not surprised if a
suspend/shutdown happens while they rely on their inhibitor.
- Get rid of the Resumed signal, it was a bad idea, and redundant due to
PrepareForSleep(false), see below.
- Always send out PrepareFor{Shutdown,Sleep} signals, instead of only if
a delay lock is taken.
- Move PrepareForSleep(false) after we come back from the suspend, so
that apps can use this as "Resumed" notification. This also has the
benefit that apps know when to take a new lock.
Previously, if X allocated all 6 TTYs (for multi-session for example) no
getty would be available anymore to guarantee console-based logins.
With the new ReserveVT= switch in logind.conf we can now choose one VT
(6 by default) that will always be subject to autovt-style activation,
i.e. we'll always have a getty on TTY6, and X will never take possession
of it.
also a number of minor fixups and bug fixes: spelling, oom errors
that didn't print errors, not properly forwarding error codes,
few more consistency issues, et cetera
glibc/glib both use "out of memory" consistantly so maybe we should
consider that instead of this.
Eliminates one string out of a number of binaries. Also fixes extra newline
in udev/scsi_id
Restore the check that was removed in commit 74afee9c. Its removal
caused a regression on some s390x systems where for whatever reason the
device node /dev/tty0 exists and makes the preceding access() check
pass.
This takes handling of chassis power and sleep keys as well as the lid
switch over from acpid.
This logic is enabled by default for power and sleep keys, but not for
the lid switch.
If a graphical session is in the foreground no action is taken under the
assumption that the graphical session does this.
