This reverts commit 69bd76f2b9.
$DBUS_SESSION_BUS_ADDRESS is again set only if the socket exists.
Quoting https://github.com/systemd/systemd/pull/11327#issuecomment-452019027:
> [setting $DBUS_SESSION_BUS_ADDRESS unconditionally] makes pam_systemd
> incompatible with installations and distributions where dbus was not
> configured with --enable-user-session, and the session dbus-daemon is started
> by autolaunching or dbus-launch (as opposed to dbus.socket). I don't think
> that's wise: using autolaunching or dbus-launch, and disabling or not
> installing dbus.socket and dbus.service on the systemd user instance, is our
> compatibility story for people who still need a D-Bus session bus per X11
> session for whatever reason.
>
> For example, Debian can currently do either way, with a dbus-user-session
> package strongly recommended but not actually mandatory. dbus-user-session
> requires libpam-systemd; if pam_systemd now requires dbus.socket (which is in
> the dbus-user-session package), that's a circular dependency, which we
> normally try hard to avoid.
For systems that use dbus.socket this doesn't matter much, because the
user session is ordered after the user managaer, which pulls in dbus.socket
very early. For example, when logging over ssh:
sshd[20796]: pam_systemd(sshd:session): pam-systemd initializing
sshd[20796]: pam_systemd(sshd:session): Asking logind to create session: uid=1001 pid=20796 service=sshd type=tty class=user desktop= seat= vtnr=0 tty= display= remote=yes remote_user= remote_host=::1
sshd[20796]: pam_systemd(sshd:session): Session limits: memory_max=n/a tasks_max=n/a cpu_weight=n/a io_weight=n/a
systemd[1]: Created slice User Slice of UID 1001.
systemd[1]: Starting User Runtime Directory /run/user/1001...
systemd-logind[1210]: New session 3796 of user guest.
systemd[1]: Started User Runtime Directory /run/user/1001.
systemd[1]: Starting User Manager for UID 1001...
systemd[20805]: pam_systemd(systemd-user:session): pam-systemd initializing
systemd[20805]: Starting D-Bus User Message Bus Socket.
...
systemd[20805]: Reached target Sockets.
systemd[20805]: Reached target Basic System.
systemd[1]: Started User Manager for UID 1001.
systemd[1]: Started Session 3796 of user guest.
sshd[20796]: pam_systemd(sshd:session): Reply from logind: id=3796 object_path=/org/freedesktop/login1/session/_33796 runtime_path=/run/user/1001 session_fd=13 seat= vtnr=0 original_uid=1001
sshd[20796]: pam_unix(sshd:session): session opened for user guest by (uid=0)
Hence, everything in the ssh session is ordered after the user instance.
And in the user instance, services should be orderd after dbus.socket using
inter-unit dependencies. dbus.socket in turns does
systemctl --user set-environment DBUS_SESSION_BUS_ADDRESS=unix:path=%t/bus.
So there should be no race between starting of the dbus socket and our check
if it exists.
The alternative would be to set the "DBUS_SESSION_BUS_ADDRESS=unix:path=%s/bus;autolaunch:".
AFAICT, this would work as well. But I don't see any case where it actually works
better. Since this is an area with many compatiblity concerns, let's stick to
the previous setup which seems to work well.
The message is changed from
Cannot create session: Already running in a session...
to
Not creating session: Already running in a session...
This is more neutral and avoids suggesting a problem.
"Will not create session: ..." was suggested, but it sounds like the action
would have yet to be performed. I think Using present continuous is better.
Fixes#10822 (for good now, I hope).
There's very little lost if the variable is set for a socket that isn't
connectible, but a lot lost (races, ...) if it's not set but the socket exists.
Also, drop the FIXME note, since we don't plan to revert this revert any time
soon.
This reverts commit 2b2b7228bf.
Fixes#11293.
Removing the environment variable causes problems, e.g. Xfce and Chromium and
... don't communicate with the running dbus instance. If they attempt to start their
own instance, things become even more confusing. Those packages could be fixed
one by one, but removing the variable right now is causing too many problems.
In the PAM module we need to suppress LOG_DEBUG messages manually, if
debug logging is not on, as PAM won't do this for us. We did this
correctly for most log messages already, but two were missing. Let's fix
those too.
Fixes: #10822
Let's be safe than sorry, in particular as logind doesn't set it up
anymore, but user-runtime-dir@.service does, and logind doesn't really
track success of that.
We so far had various placed we'd parse percentages with
parse_percent(). Let's make them use parse_permille() instead, which is
downward compatible (as it also parses percent values), and increases
the granularity a bit. Given that on the wire we usually normalize
relative specifications to something like UINT32_MAX anyway changing
from base-100 to base-1000 calculations can be done easily without
breaking compat.
This commit doesn't document this change in the man pages. While
allowing more precise specifcations permille is not as commonly
understood as perent I guess, hence let's keep this out of the docs for
now.
We likely get the data from the env block, but we might also determine
it from elsewhere (such as PAM module parameters). Let's set the env
vars on the env block explicitly, so that they are available always, and
apps can rely on it.
Let's make this symmetric with XDG_SESSION_CLASS and XDG_SESSION_TYPE,
so that PAM stacks can configure this easily without involving env vars,
in case there are PAM session managers which only support a single
desktop anyway.
Since D-Bus 1.9.14 (2015-03-02) dbus looks in $XDG_RUNTIME_DIR/bus for
the system bus on its own, hence we can finally drop setting this
environment variable. gdbus since glib 2.45.3 (June 2015) also supports
it.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Let's directly reference /run instead, so that we can work without /var
being around, or with /var/run being incorrectly set up.
Note that we keep the old socket path in place when referencing the
system bus of containers, as they might be foreign operating systems,
that still don't have adopted /run, and where it makes sense to use the
standardized name instead. On local systems, we insist on /run being set
up properly however, hence this limitation does not apply.
Also, get rid of the UNIX_SYSTEM_BUS_ADDRESS and
UNIX_USER_BUS_ADDRESS_FMT defines. They had a purpose when we still did
kdbus, as we then had to support two different backends. But since
that's gone, we don't need this indirection anymore, hence settle on a
one define only.
Apparently, PAM documents that the PAM_TTY should come with a /dev
prefix, but we don't expect it so far, except that Wayland ends up
setting it after all, the way the docs suggest. Hence, let's simply drop
the /dev prefix if it is there.
Fixes: #6516
This moves pretty much all uses of getpid() over to getpid_raw(). I
didn't specifically check whether the optimization is worth it for each
replacement, but in order to keep things simple and systematic I
switched over everything at once.
We don't have plural in the name of any other -util files and this
inconsistency trips me up every time I try to type this file name
from memory. "formats-util" is even hard to pronounce.
Delete the dbus1 generator and some critical wiring. This prevents
kdbus from being loaded or detected. As such, it will never be used,
even if the user still has a useful kdbus module loaded on their system.
Sort of fixes#3480. Not really, but it's better than the current state.
The macro determines the right length of a AF_UNIX "struct sockaddr_un" to pass to
connect() or bind(). It automatically figures out if the socket refers to an
abstract namespace socket, or a socket in the file system, and properly handles
the full length of the path field.
This macro is not only safer, but also simpler to use, than the usual
offsetof() + strlen() logic.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
Lets not pretend we support changing XDG_RUNTIME_DIR via logind state
files. There is no reason to ever write the string into /run, as we
allocate it statically based on the UID, anyway. Lets stop that and just
allocate the runtime_path in "struct User" at all times.
We keep writing it into the /run state to make sure pam_systemd of
previous installs can still read it. However, pam_systemd is now fixed to
allocate it statically as well, so we can safely remove that some time in
the future.
Last but not least: If software depends on systemd, they're more than free
to assume /run/user/$uid is their runtime dir. Lets not require sane
applications to query the environment to get their runtime dir. As long as
applications know their login-UID, they should be safe to deduce the
runtime dir.
The files are named too generically, so that they might conflict with
the upstream project headers. Hence, let's add a "-util" suffix, to
clarify that this are just our utility headers and not any official
upstream headers.
dbus-1.10 was just released, including systemd units to run
`dbus-daemon --session` as systemd user unit. This allows using a
user-bus with dbus1, just like we do per default with kdbus.
All the dbus libraries have already been fixed long ago to use the
user-bus as default. Hence, there's no need to set
DBUS_SESSION_BUS_ADDRESS= if we use the user-bus. However, gdm and
friends continue to spawn a session bus if this variable is not set
(instead of checking for the existence of the user-bus). Hence, we force
the user-bus, if it is available, in pam_systemd. Once gdm and friends
are fixed, we can continue to drop this again. However, that might take
a while.
With this in place, all that is needed to make the user-bus work is:
`systemctl --global enable dbus.socket`
If dbus.socket is not enabled, the legacy session-bus is still used.
Based on a patch by: Jan Alexander Steffens <jan.steffens@gmail.com>
Right now, if you're already in a session and call CreateSession, we
return information about the current session of yours. This is highy
confusing and a nasty hack. Avoid that, and instead return a commonly
known error, so the caller can detect that.
This has the side-effect, that we no longer override XDG_VTNR and XDG_SEAT
in pam_systemd, if you're already in a session. But this sounds like the
right thing to do, anyway.
