This augments the drm/input device management by adding a single method
call for setting the brightness of an "leds" or "backlight" kernel class
device.
This method call requires no privileges to call, but a caller can only
change the brightness on sessions that are currently active, and they
must own the session.
This does not do enumeration of such class devices, feature or range
probing, chnage notification; it doesn't help associating graphics or
input devices with their backlight or leds devices. For all that clients
should go directly to udev/sysfs. The SetBrightness() call is just for
executing the actual change operation, that is otherwise privileged.
Example line:
busctl call org.freedesktop.login1 /org/freedesktop/login1/session/self org.freedesktop.login1.Session SetBrightness ssu "backlight" "intel_backlight" 200
The parameter the SetBrightness() call takes are the kernel subsystem
(i.e. "leds" or "backlight"), the device name, and the brightness
value.
On some hw setting the brightness is slow, and implementation and write
access to the sysfs knobs exposes this slowness. Due to this we'll fork
off a writer process in the background so that logind doesn't have to
block. Moreover, write requestes are coalesced: when a write request is
enqueued while one is already being executed it is queued. When another
write reques is then enqueued the earlier one is replaced by the newer
one, so that only one queued write request per device remains at any
time. Method replies are sent as soon as the first write request that
happens after the request was received is completed.
It is recommended that bus clients turn off the "expect_reply" flag on
the dbus messages they send though, that relieves logind from sending
completion notification and is particularly a good idea if clients
implement reactive UI sliders that send a quick secession of write
requests.
Replaces: #12413
This adds support for user to set & get reboot parameter for reboot.
As callee would be next issuing Reboot call same policy checks are being used.
If unit file issuing the reboot action defines RebootArgument (or similar) that
setting takes precedence.
This behaves similar to the "boot into firmware" logic, and also allows
either direct EFI operation (which sd-boot supports and others might
support eventually too) or override through env var.
Suspend to Hibernate is a new sleep method that invokes suspend
for a predefined period of time before automatically waking up
and hibernating the system.
It's similar to HybridSleep however there isn't a performance
impact on every suspend cycle.
It's intended to use with systems that may have a higher power
drain in their supported suspend states to prevent battery and
data loss over an extended suspend cycle.
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
This adds new method calls Halt() and CanHalt() to the logind bus APIs.
They aren't overly useful (as the whole concept of halting isn't really
too useful), however they clean up one major asymmetry: currently, using
the "shutdown" legacy commands it is possibly to enqueue a "halt"
operation through logind, while logind officially doesn't actually
support this. Moreover, the path through "shutdown" currently ultimately
fails, since the referenced "halt" action isn't actually defined in
PolicyKit.
Finally, the current logic results in an unexpected asymmetry in
systemctl: "systemctl poweroff", "systemctl reboot" are currently
asynchronous (due to the logind involvement) while "systemctl halt"
isnt. Let's clean this up, and make all three APIs implemented by
logind natively, and all three hence asynchronous in "systemctl".
Moreover, let's add the missing PK action.
Fixes: #6957
Enable unprivileged users to set wall message on a shutdown
operation. When the message is set via the --message option,
it is logged together with the default shutdown message.
$ systemctl reboot --message "Applied kernel updates."
$ journalctl -b -1
...
systemd-logind[27]: System is rebooting. (Applied kernel updates.)
...
A while back we opened up all of logind's bus calls to unprivileged
users, via PK. However, the dbus1 policy wasn't updated accordingly.
With this change, the dbus1 policy is opened up for all bus calls that
should be available to unprivileged clients.
(also rearranges some calls in the vtable, to make more sense, and be in
line with the order in the bus policy file)
Fixes#471.
Introduces a new concept of "trusted" vs. "untrusted" busses. For the
latter libsystemd-bus will automatically do per-method access control,
for the former all access is automatically granted. Per-method access
control is encoded in the vtables: by default all methods are only
accessible to privileged clients. If the SD_BUS_VTABLE_UNPRIVILEGED flag
is set for a method it is accessible to unprivileged clients too. By
default whether a client is privileged is determined via checking for
its CAP_SYS_ADMIN capability, but this can be altered via the
SD_BUS_VTABLE_CAPABILITY() macro that can be ORed into the flags field
of the method.
Writable properties are also subject to SD_BUS_VTABLE_UNPRIVILEGED and
SD_BUS_VTABLE_CAPABILITY() for controlling write access to them. Note
however that read access is unrestricted, as PropertiesChanged messages
might send out the values anyway as an unrestricted broadcast.
By default the system bus is set to "untrusted" and the user bus is
"trusted" since per-method access control on the latter is unnecessary.
On dbus1 busses we check the UID of the caller rather than the
configured capability since the capability cannot be determined without
race. On kdbus the capability is checked if possible from the attached
meta-data of a message and otherwise queried from the sending peer.
This also decorates the vtables of the various daemons we ship with
these flags.
The session-device/control API was introduced for unprivileged device
access from within a session. Add the required dbus policy to the default
logind policies.
Note: logind validates that only root and the user of a session can
use the API. Furthermore, only a single API user gets access at a time.
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
