sulogin-shell: Use force if SYSTEMD_SULOGIN_FORCE set
When the root account is locked sulogin will either inform you of
this and not allow you in or if --force is used it will hand
you passwordless root (if using a recent enough version of util-linux).
Not being allowed a shell is ofcourse inconvenient, but at the same
time handing out passwordless root unconditionally is probably not
a good idea everywhere.
This patch thus allows to control which behaviour you want by
setting the SYSTEMD_SULOGIN_FORCE environment variable to true
or false to control the behaviour, eg. via adding this to
'systemctl edit rescue.service' (or emergency.service):
[Service]
Environment=SYSTEMD_SULOGIN_FORCE=1
Distributions who used locked root accounts and want the passwordless
behaviour could thus simply drop in the override file in
/etc/systemd/system/rescue.service.d/override.conf
main: bump fs.nr_open + fs.max-file to their largest possible values
After discussions with kernel folks, a system with memcg really
shouldn't need extra hard limits on file descriptors anymore, as they
are properly accounted for by memcg anyway. Hence, let's bump these
values to their maximums.
This also adds a build time option to turn thiss off, to cover those
users who do not want to use memcg.
units: bump the RLIMIT_NOFILE soft limit for all services that access the journal
This updates the unit files of all our serviecs that deal with journal
stuff to use a higher RLIMIT_NOFILE soft limit by default. The new value
is the same as used for the new HIGH_RLIMIT_NOFILE we just added.
With this we ensure all code that access the journal has higher
RLIMIT_NOFILE. The code that runs as daemon via the unit files, the code
that is run from the user's command line via C code internal to the
relevant tools. In some cases this means we'll redundantly bump the
limits as there are tools run both from the command line and as service.
core: raise the RLIMIT_NOFILE hard limit for all services by default
Following the discussions with the kernel folks, let's substantially
increase the hard limit (but not the soft limit) of RLIMIT_NOFILE to
256K for all services we start.
Note that PID 1 itself bumps the limit even further, to the max the
kernel allows. We can deal with that after all.
tree-wide: uniformly bump RLIMIT_NOFILE in all our tools that access the journal
This makes use of rlimit_nofile_bump() in all tools that access the
journal. In some cases this replaces older code to achieve this, and
others we add it in where it was missing.
core: add a new call for bumping RLIMIT_NOFILE to "high" values
Following discussions with some kernel folks at All Systems Go! it
appears that file descriptors are not really as expensive as they used
to be (both memory and performance-wise) and it should thus be OK to allow
programs (including unprivileged ones) to have more of them without ill
effects.
Unfortunately we can't just raise the RLIMIT_NOFILE soft limit
globally for all processes, as select() and friends can't handle fds
>= 1024, and thus unexpecting programs might fail if they accidently get
an fd outside of that range. We can however raise the hard limit, so
that programs that need a lot of fds can opt-in into getting fds beyond
the 1024 boundary, simply by bumping the soft limit to the now higher
hard limit.
This is useful for all our client code that accesses the journal, as the
journal merging logic might need a lot of fds. Let's add a unified
function for bumping the limit in a robust way.
This simply adds a new constant we can use for bumping RLIMIT_NOFILE to
a "high" value. It default to 256K for now, which is pretty high, but
smaller than the kernel built-in limit of 1M.
Previously, some tools that needed a higher RLIMIT_NOFILE bumped it to
16K. This new define goes substantially higher than this, following the
discussion with the kernel folks.
tree-wide: add a single version of "static const int one = 1"
All over the place we define local variables for the various sockopts
that take a bool-like "int" value. Sometimes they are const, sometimes
static, sometimes both, sometimes neither.
Let's clean this up, introduce a common const variable "const_int_one"
(as well as one matching "const_int_zero") and use it everywhere, all
acorss the codebase.
sd-bus: rework how we initialize struct sockaddr_un
Let's use structured initialization, but more importantly, let's
increase salen by 1, if we reference AF_UNIX sockets in the file system,
so that they also contain the trailing NUL byte. This is what unix(7)
suggests to do, hence follow it.
sd-bus: make parsing of AF_UNIX socket addresses more strict
Insist on NUL termination, just to be safe rather than sorry. The kernel
doesn't require it, but it's really annoying if people rely on this,
hence refuse this early.
systemctl: clean up start_unit_one() error handling
Let's split exit code handling in two: "r" is only used for errno-style
errors, and "ret" is used for exit() codes. Then, let's use EXIT_SUCCESS
for checking whether the latter is already used.
This way it should always be clear what kind of error we are processing,
and when we propaate one into the other.
Moreover this allows us to drop "q" form all inner loops, avoiding
confusion when to use "q" and when "r" to store received errors.
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.
So far we always used "yes" instead of "true" in all our unit files,
except for one outlier. Let's do this here too. No change in behaviour
whatsoever, except that it looks prettier ;-)
logind: automatically GC lingering users for who now user@.service (nor slice, not runtime dir service) is running anymore
This heavily borrows from @intelfx' PR #5546, but watches all three
units that are associated with a user now: the slice, the user@.service
and user-runtime-dir@.service.
The logic and reasoning behind it is the same though: there's no value
in keeping lingering users around if all their three services are gone.
logind: add a RequiresMountsFor= dependency from the session scope unit to the home directory of the user
This is useful so that during shutdown scope units are always terminated
before the mounts necessary for the home directory.
(Ideally we'd also add a similar dependency from the user@.service
instance to the home directory, but this isn't as easy as that service
is defined statically and not dynamically, and hence not easy to modify
dynamically, in particular when it comes to deps)
logind: change user-runtime-dir to query runtime dir size from logind via the bus
I think this is a slightly cleaner approach than parsing the
configuration file at multiple places, as this way there's only a single
reload cycle for logind.conf, and that's systemd-logind.service's
runtime.
This means that logind and dbus become a requirement of
user-runtime-dir, but given that XDG_RUNTIME_DIR is not set anyway
without logind and dbus around this isn't really any limitation.
This also simplifies linking a bit as this means user-runtime-dir
doesn't have to link against any code of logind itself.