This introduces `ExitType=main|cgroup` for services.
Similar to how `Type` specifies the launch of a service, `ExitType` is
concerned with how systemd determines that a service exited.
- If set to `main` (the current behavior), the service manager will consider
the unit stopped when the main process exits.
- The `cgroup` exit type is meant for applications whose forking model is not
known ahead of time and which might not have a specific main process.
The service will stay running as long as at least one process in the cgroup
is running. This is intended for transient or automatically generated
services, such as graphical applications inside of a desktop environment.
Motivation for this is #16805. The original PR (#18782) was reverted (#20073)
after realizing that the exit status of "the last process in the cgroup" can't
reliably be known (#19385)
This version instead uses the main process exit status if there is one and just
listens to the cgroup empty event otherwise.
The advantages of a service with `ExitType=cgroup` over scopes are:
- Integrated logging / stdout redirection
- Avoids the race / synchronisation issue between launch and scope creation
- More extensive use of drop-ins and thus distro-level configuration:
by moving from scopes to services we can have drop ins that will affect
properties that can only be set during service creation,
like `OOMPolicy` and security-related properties
- It makes systemd-xdg-autostart-generator usable by fixing [1], as obviously
only services can be used in the generator, not scopes.
[1] https://bugs.kde.org/show_bug.cgi?id=433299
The LoopDevice object supports a shortcut: if the backing fd we are
supposed to create a loopback device of refers to a
block device alrady then we'll use it as is – if we can – instead of
setting up an unnecessary loopback device that would be pretty much
the same as its backing device.
Previously, when doing this we'd just dup() the original backing fd and
use that. But that's problematic in case O_DIRECT was set on the fd,
since we'll keep that flag set on our copy too, which means we can't do
simple, regular IO on it anymore.
Thus, let's reopen the inode in this case with the exact access flags
we'd apply if we'd actually allocate and open a new loopback device.
Fixes: #21176
(Or when -H is used, since -H and -M are incompatible.)
Note that the slightly unusual form with separate boolean variables (hint_vars,
hint_addr) instead of e.g. a const char* variable to hold the message, because this
way we don't trigger the warning about non-literal format.
rearrange_stdio() invalidates specified fds even on failure, which means
we should always invalidate the fds we pass in no matter what. Let's
make this explicit by using TAKE_FD() for that everywhere.
Note that in many places we such invalidation doesnt get us much
behaviour-wise, since we don't use the variables anymore later. But
TAKE_FD() in a way is also documentation, it encodes explicitly that the
fds are invalidated here, so I think it's a good thing to always make
this explicit here.
Those devices show up as /sys/devices/vif-N, let's use that number
to name them enXN.
Without this, all schemes fail and they keep the kernel names, which can
be racy.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When combined with a tmpfs on /run or /var/lib, allows to create
arbitrary and ephemeral symlinks for StateDirectory or RuntimeDirectory.
This is especially useful when sharing these directories between
different services, to make the same state/runtime directory 'backend'
appear as different names to each service, so that they can be added/removed
to a sharing agreement transparently, without code changes.
An example (simplified, but real) use case:
foo.service:
StateDirectory=foo
bar.service:
StateDirectory=bar
foo.service.d/shared.conf:
StateDirectory=
StateDirectory=shared:foo
bar.service.d/shared.conf:
StateDirectory=
StateDirectory=shared:bar
foo and bar use respectively /var/lib/foo and /var/lib/bar. Then
the orchestration layer decides to stop this sharing, the drop-in
can be removed. The services won't need any update and will keep
working and being able to store state, transparently.
To keep backward compatibility, new DBUS messages are added.
This is useful since certain shares can only be mounted with additional
mount flags. For example the SMB share in modern AVM Fritz!Boxes
requires "noserverino" to be set to work from Linux.
JSON doesn't have NaN/infinity/-infinity concepts in the spec.
Implementations vary what they do with it. JSON5 + Python simply
generate special words "NAN" and "Inifinity" from it. Others generate
"null" for it.
At this point we never actually want to output this, so let's be
conservative and generate RFC compliant JSON, i.e. convert to null.
One day should JSON5 actually become a thing we can revisit this, but in
that case we should implement things via a flag, and only optinally
process nan/infinity/-infinity.
This patch is extremely simple: whenever accepting a
nan/infinity/-infinity from outside it converts it to NULL. I.e. we
convert on input, not output.
Let's move things around a bit, and open /proc/self/mountinfo if needed
inside of bind_remount_one_with_mountinfo(). That way bind_remount_one()
can become a superthin inline wrapper around
bind_remount_one_with_mountinfo(). Main benefit is that we don't even
have to open /p/s/mi in case mount_setattr() actually worked for us.
This returns a namespace fd, and takes a uidmap/gidmap as string. This
is split out out mount-util.c's remount_idmap() logic, so that we can
allocate a userns independently.
Previously we'd possibly see POLLHUP on a varlink link, and continue to
run epoll on it even though we have nothing to read nor write anymore.
Let's fix that, and once we know that there's nothing to write anymore
(or we saw a write error already) we'll disconnect after POLLHUP.
Fixes: #20062
This is supposed to be used by package/image builders such as mkosi to
speed up building, since it allows us to suppress sync() inside a
container.
This does what Debian's eatmydata tool does, but for a container, and
via seccomp (instead of LD_PRELOAD).
The whole reason loop_device_make_internal() exists (as opposed to just
loop_device_make()) is to avoid mangling the loop flags value/call
getenv twice. Hence let's actually call it when we already mangled the
flags value.
Let's define two helpers strdupa_safe() + strndupa_safe() which do the
same as their non-safe counterparts, except that they abort if called
with allocations larger than ALLOCA_MAX.
This should ensure that all our alloca() based allocations are subject
to this limit.
afaics glibc offers three alloca() based APIs: alloca() itself,
strndupa() + strdupa(). With this we have now replacements for all of
them, that take the limit into account.
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Henri Chain
Lennart Poettering
Daan De Meyer
Luca Boccassi
Benjamin Herrenschmidt
Jan Janssen
Dimitri Papadopoulos
Dan Streetman