Update the timeout warnings for remount and unmount. For consistency with
mount, for accuracy, and for consistency with their equivalents in
service.c.
manager_connect_bus() is called *before* manager_coldplug(). As a last
thing in service_coldplug() we set service state to
s->deserialized_state, and thus before we do that all services are
inactive and try_connect always evaluates to false. To fix that we must
look at deserialized state instead of current unit state.
Fixes#7146
Using `kill()` with a signal of 0 is a slightly more documented idiom for
checking whether a process still exists. It is mentioned explicitly in
man pages. This avoids the need to comment the call as "misuse".
A comment is still necessary - in fact this idiom is even more confusing if
you don't know how it works. But it's easy enough to explain.
This augments %t which already resolves to the runtime directory root, and
should be useful for units that want to pass any of these paths in
command line arguments.
Example:
ExecStart=/usr/bin/mydaemon --datadir=%S/mydaemon
Why not expose a specifier resolving directly to the configured
state/runtime/cache/log dir? Three reasons:
1. Specifiers should be independent of configuration of the unit itself,
and StateDirectory= and friends are unit configuration. See
03fc9c723c and related work.
2. We permit multiple StateDirectory= values per unit, and it hence
wouldn't be clear which one is passed.
3. We already have %t for the runtime directory root, and we should
continue with the same scheme.
After previous output from systemd-shutdown indicated a bug, my attention
was drawn to redundant output lines. Did they indicate an anomaly?
It turns out to be an expected, harmless result of the current code. But
we don't have much justification to run such redundant operations. Let's
remove the confusing redundant message.
We can stop trying to remount a directory read-only once its mount entry
has successfully been changed to "ro". We can simply let the kernel keep
track of this for us. I don't bother to try and avoid re-parsing the
mountinfo. I appreciate snappy shutdowns, but this code is already
intricate and buggy enough (see issue 7131).
(Disclaimer: At least for the moment, you can't _rely_ on always seeing
suspicious output from systemd-shutdown. By default, you can expect the
kernel to truncate the log output of systemd-shutdown. Ick ick ick!
Because /dev/kmsg is rate-limited by default. Normally it prints a message
"X lines supressed", but we tend to shut down before the timer expires
in this case).
Before:
systemd-shutdown[1]: Remounting '/' read-only with options 'seclabel...
EXT4-fs (vda3): re-mounted. Opts: data=ordered
systemd-shutdown[1]: Remounting '/' read-only with options 'seclabel, ...
EXT4-fs (vda3): re-mounted. Opts: data=ordered
After:
systemd-shutdown[1]: Remounting '/' read-only with options 'seclabel, ...
EXT4-fs (vda3): re-mounted. Opts: data=ordered
I also tested with `systemctl reboot --force`, plus a loopback mount to
cause one of the umounts to fail initially. In this case another 2 lines
of output are removed (out of a larger number of lines).
When a user logs in, systemd-pam will wait for the user manager instance to
report readiness. We don't need to wait for all the jobs to finish, it
is enough if the basic startup is done and the user manager is responsive.
systemd --user will now send out a READY=1 notification when either of two
conditions becomes true:
- basic.target/start job is gone,
- the initial transaction is done.
Also fixes#2863.
The assumption was that nothing changes in the final attempt. This
would be confusing if a filesystem with a process in uninterruptible
sleep suddenly became un-stuck for the final attempt, but we still give
up and don't try to e.g. unmount any parent mounts.
I don't know how possible that is. But the code will be easier to read
without an assumption that it does not attempt to justify.
The units that are not loaded don't have dropin_paths set. This
currently results in units that have fragments to always have
NeedDaemonReload=true when masked:
$ find {/usr/lib,/run/user/8086}/systemd/user/meh.service* |xargs ls -ld
lrwxrwxrwx. 1 lkundrak lkundrak 9 Oct 11 11:19 /run/user/8086/systemd/user/meh.service -> /dev/null
-rw-rw-r--. 1 root root 49 Oct 11 10:16 /usr/lib/systemd/user/meh.service
drwxrwxr-x. 2 root root 4096 Oct 11 10:50 /usr/lib/systemd/user/meh.service.d
-rw-rw-r--. 1 root root 666 Oct 11 10:50 /usr/lib/systemd/user/meh.service.d/override.conf
$ systemctl --user daemon-reload
$ busctl --user get-property org.freedesktop.systemd1 \
/org/freedesktop/systemd1/unit/meh_2eservice \
org.freedesktop.systemd1.Unit NeedDaemonReload
b true
The error message corresponds to EILSEQ is "Invalid or incomplete
multibyte or wide character", and is not suitable in this case.
So, let's show a custom error message when the function
dynamic_creds_realize() returns -EILSEQ.
In the past we introduced this property just for tmp.mount. However on
todays systems usually there are many more tmpfs mounts. Most notably
mounts backing XDG_RUNTIME_DIR for each user.
Let's generalize what we already have for tmp.mount and implement the
ordering After=swap.target for all tmpfs based mounts.
This makes systemd supports the case that DynamicUser=yes and
static user and group exist such that uid and gid of them are different.
We only refuse the operation when user does not exist but the group
with the same name exists.
Fixes#7013.
We generally use the casing "Namespace" for the word, and that's visible
in a number of user-facing interfaces, including "RestrictNamespace=" or
"JoinsNamespaceOf=". Let's make sure to use the same casing internally
too.
As discussed in #7024
We added JobRunningTimeoutSec= late, and Dracut configured only
JobTimeoutSec= to turn of root device timeouts before. With this change
we'll propagate a reset of JobTimeoutSec= into JobRunningTimeoutSec=,
but only if the latter wasn't set explicitly.
This should restore compatibility with older systemd versions.
Fixes: #6402
This fixes a mostly theoretical potential security hole: if for some
reason we failed to remove IPC objects created for a dynamic user (maybe
because a MAC/SElinux erronously prohibited), then we should not hand
out the same UID again until they are successfully removed.
With this commit we'll enumerate the IPC objects currently existing, and
step away from using a UID for the dynamic UID logic if there are any
matching it.
The advantage is that is the name is mispellt, cpp will warn us.
$ git grep -Ee "conf.set\('(HAVE|ENABLE)_" -l|xargs sed -r -i "s/conf.set\('(HAVE|ENABLE)_/conf.set10('\1_/"
$ git grep -Ee '#ifn?def (HAVE|ENABLE)' -l|xargs sed -r -i 's/#ifdef (HAVE|ENABLE)/#if \1/; s/#ifndef (HAVE|ENABLE)/#if ! \1/;'
$ git grep -Ee 'if.*defined\(HAVE' -l|xargs sed -i -r 's/defined\((HAVE_[A-Z0-9_]*)\)/\1/g'
$ git grep -Ee 'if.*defined\(ENABLE' -l|xargs sed -i -r 's/defined\((ENABLE_[A-Z0-9_]*)\)/\1/g'
+ manual changes to meson.build
squash! build-sys: use #if Y instead of #ifdef Y everywhere
v2:
- fix incorrect setting of HAVE_LIBIDN2
This reverts commit ee043777be.
It broke almost everywhere it touched. The places that
handn't been converted, were mostly followed by special
handling for the invalid PID `0`. That explains why they
tested for `pid < 0` instead of `pid <= 0`.
I think that one was the first commit I reviewed, heh.
Let's optimize dynamic UID allocation a bit: if a StateDirectory= (or
suchlike) is configured, we start our allocation loop from that UID and
use it if it currently isn't used otherwise. This is beneficial as it
saves us from having to expensively recursively chown() these
directories in the typical case (which StateDirectory= does when it
notices that the owner of the directory doesn't match the UID picked).
With this in place we now have the a three-phase logic for allocating a
dynamic UID:
a) first, we try to use the owning UID of StateDirectory=,
CacheDirectory=, LogDirectory= if that exists and is currently
otherwise unused.
b) if that didn't work out, we hash the UID from the service name
c) if that didn't yield an unused UID either, randomly pick new ones
until we find a free one.
Let's clean up the interaction of StateDirectory= (and friends) to
DynamicUser=1: instead of creating these directories directly below
/var/lib, place them in /var/lib/private instead if DynamicUser=1 is
set, making that directory 0700 and owned by root:root. This way, if a
dynamic UID is later reused, access to the old run's state directory is
prohibited for that user. Then, use file system namespacing inside the
service to make /var/lib/private a readable tmpfs, hiding all state
directories that are not listed in StateDirectory=, and making access to
the actual state directory possible. Mount all directories listed in
StateDirectory= to the same places inside the service (which means
they'll now be mounted into the tmpfs instance). Finally, add a symlink
from the state directory name in /var/lib/ to the one in
/var/lib/private, so that both the host and the service can access the
path under the same location.
Here's an example: let's say a service runs with StateDirectory=foo.
When DynamicUser=0 is set, it will get the following setup, and no
difference between what the unit and what the host sees:
/var/lib/foo (created as directory)
Now, if DynamicUser=1 is set, we'll instead get this on the host:
/var/lib/private (created as directory with mode 0700, root:root)
/var/lib/private/foo (created as directory)
/var/lib/foo → private/foo (created as symlink)
And from inside the unit:
/var/lib/private (a tmpfs mount with mode 0755, root:root)
/var/lib/private/foo (bind mounted from the host)
/var/lib/foo → private/foo (the same symlink as above)
This takes inspiration from how container trees are protected below
/var/lib/machines: they generally reuse UIDs/GIDs of the host, but
because /var/lib/machines itself is set to 0700 host users cannot access
files in the container tree even if the UIDs/GIDs are reused. However,
for this commit we add one further trick: inside and outside of the unit
/var/lib/private is a different thing: outside it is a plain,
inaccessible directory, and inside it is a world-readable tmpfs mount
with only the whitelisted subdirs below it, bind mounte din. This
means, from the outside the dir acts as an access barrier, but from the
inside it does not. And the symlink created in /var/lib/foo itself
points across the barrier in both cases, so that root and the unit's
user always have access to these dirs without knowing the details of
this mounting magic.
This logic resolves a major shortcoming of DynamicUser=1 units:
previously they couldn't safely store persistant data. With this change
they can have their own private state, log and data directories, which
they can write to, but which are protected from UID recycling.
With this change, if RootDirectory= or RootImage= are used it is ensured
that the specified state/log/cache directories are always mounted in
from the host. This change of semantics I think is much preferable since
this means the root directory/image logic can be used easily for
read-only resource bundling (as all writable data resides outside of the
image). Note that this is a change of behaviour, but given that we
haven't released any systemd version with StateDirectory= and friends
implemented this should be a safe change to make (in particular as
previously it wasn't clear what would actually happen when used in
combination). Moreover, by making this change we can later add a "+"
modifier to these setings too working similar to the same modifier in
ReadOnlyPaths= and friends, making specified paths relative to the
container itself.
When putting together the namespace, always create the file or directory
we are supposed to bind mount on, the same way we do it for most other
stuff, for example mount units or systemd-nspawn's --bind= option.
This has the big benefit that we can use namespace bind mounts on dirs
in /tmp or /var/tmp even in conjunction with PrivateTmp=.
Before this patch we had an ordering problem: if we have no namespacing
enabled except for two bind mounts that intend to swap /a and /b via
bind mounts, then we'd execute the bind mount binding /b to /a, followed
by thebind mount from /a to /b, thus having the effect that /b is now
visible in both /a and /b, which was not intended.
With this change, as soon as any bind mount is configured we'll put
together the service mount namespace in a temporary directory instead of
operating directly in the root. This solves the problem in a
straightforward fashion: the source of bind mounts will always refer to
the host, and thus be unaffected from the bind mounts we already
created.
Alan Jenkins
Michal Sekletar
Matija Skala
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Lubomir Rintel