udevd already limits its number of workers/children: the max number is actually
twice the number of CPUs the system is using.
(The limit can also be raised with udev.children-max= kernel command line
option BTW).
On some servers, this limit can easily exceed the maximum number of tasks that
systemd put on all services, which is 512 by default.
Since udevd has already its limitation logic, simply disable the static
limitation done by TasksMax.
Specifically "machinectl shell" (or its OpenShell() bus call) is implemented by
entering the file system namespace of the container and opening a TTY there.
In order to enter the file system namespace, chroot() is required, which is
filtered by SystemCallFilter='s @mount group. Hence, let's make this work again
and drop @mount from the filter list.
Quoting @cgwalters:
Just uploading this as an RFC. Now I know reading the code that systemd says
`Welcome to $OS` as a generic thing, but my initial impression on seeing this
was that it was almost sarcastic =)
Let's say "You are in emergency mode" as a more neutral/less excited phrase.
This patch is based on #3556, but makes the same change for rescue mode.
In order to improve compatibility with local clients that speak DNS directly
(and do not use NSS or our bus API) listen locally on 127.0.0.53:53 and process
any queries made that way.
Note that resolved does not implement a full DNS server on this port, but
simply enough to allow normal, local clients to resolve RRs through resolved.
Specifically it does not implement queries without the RD bit set (these are
requests where recursive lookups are explicitly disabled), and neither queries
with DNSSEC DO set in combination with DNSSEC CD (i.e. DNSSEC lookups with
validation turned off). It also refuses zone transfers and obsolete RR types.
All lookups done this way will be rejected with a clean error code, so that the
client side can repeat the query with a reduced feature set.
The code will set the DNSSEC AD flag however, depending on whether the data
resolved has been validated (or comes from a local, trusted source).
Lookups made via this mechanisms are propagated to LLMNR and mDNS as necessary,
but this is only partially useful as DNS packets cannot carry IP scope data
(i.e. the ifindex), and hence link-local addresses returned cannot be used
properly (and given that LLMNR/mDNS are mostly about link-local communication
this is quite a limitation). Also, given that DNS tends to use IDNA for
non-ASCII names, while LLMNR/mDNS uses UTF-8 lookups cannot be mapped 1:1.
In general this should improve compatibility with clients bypassing NSS but
it is highly recommended for clients to instead use NSS or our native bus API.
This patch also beefs up the DnsStream logic, as it reuses the code for local
TCP listening. DnsStream now provides proper reference counting for its
objects.
In order to avoid feedback loops resolved will no silently ignore 127.0.0.53
specified as DNS server when reading configuration.
resolved listens on 127.0.0.53:53 instead of 127.0.0.1:53 in order to leave
the latter free for local, external DNS servers or forwarders.
This also changes the "etc.conf" tmpfiles snippet to create a symlink from
/etc/resolv.conf to /usr/lib/systemd/resolv.conf by default, thus making this
stub the default mode of operation if /etc is not populated.
Add a line
SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
for daemons shipped by systemd. As an exception, systemd-timesyncd
needs @clock system calls and systemd-localed is not privileged.
ptrace(2) is blocked to prevent seccomp escapes.
In the same vein as commit ac59f0c12c which added
the --wait option to the emergency service, this patch makes sure that plymouth
has exited before entering into the rescue mode.
In order to support stateless systems that support offline /usr updates
properly, let's restore the ConditionNeesUpdate=/etc line that makes sure we
are run when /usr is updated and this update needs to be propagated to the
/etc/ld.so.conf file stored in /etc.
This reverts part of #2859, which snuck this change in, but really shouldn't
have.
Add a synchronization point so that custom initramfs units can run
after the root device becomes available, before it is fsck'd and
mounted.
This is useful for custom initramfs units that may modify the
root disk partition table, where the root device is not known in
advance (it's dynamically selected by the generators).
When enabling ForwardToSyslog=yes, the syslog.socket is active when entering
emergency mode. Any log message then triggers the start of rsyslog.service (or
other implementation) along with its dependencies such as local-fs.target and
sysinit.target. As these might fail themselves (e. g. faulty /etc/fstab), this
breaks the emergency mode.
This causes syslog.socket to fail with "Failed to queue service startup job:
Transition is destructive".
Add Conflicts=syslog.socket to emergency.service to make sure the socket is
stopped when emergency.service is started.
Fixes#266
Container images from Debian or suchlike contain device nodes in /dev. Let's
make sure we can clone them properly, hence pass CAP_MKNOD to machined.
Fixes: #2867#465
That way we can be sure that local users are logged out before the network is
shut down when the system goes down, so that SSH session should be ending
cleanly before the system goes down.
Fixes: #2390
With the current "Type=forking", systemd tries to guess the PID it
should wait on at reboot (because we have no "PIDFile="). Depending on
how wrong the guess is, we can end up hanging forever at reboot.
Asking it not to do that eliminates the problem.
Also drop ConditionNeedsUpdate=|/etc. Regardless if system is updated
online or offline, updating dynamic loader cache should always be
responsibility of packaging tools/scripts.
When using `%I` for instances of `systemd-nspawn@.service`, the result
will be `systemd-nspawn` trying to launch a container named e.g.
`fedora/23` instead of `fedora-23`.
Using `%i` instead prevents escaping `-` in a container name and uses
the unmodified container name from the machine store.
This commit rips out systemd-bootchart. It will be given a new home, outside
of the systemd repository. The code itself isn't actually specific to
systemd and can be used without systemd even, so let's put it somewhere
else.
As kdbus won't land in the anticipated way, the bus-proxy is not needed in
its current form. It can be resurrected at any time thanks to the history,
but for now, let's remove it from the sources. If we'll have a similar tool
in the future, it will look quite differently anyway.
Note that stdio-bridge is still available. It was restored from a version
prior to f252ff17, and refactored to make use of the current APIs.
This reworks the coredumping logic so that the coredump handler invoked from the kernel only collects runtime data
about the crashed process, and then submits it for processing to a socket-activate coredump service, which extracts a
stacktrace and writes the coredump to disk.
This has a number of benefits: the disk IO and stack trace generation may take a substantial amount of resources, and
hence should better be managed by PID 1, so that resource management applies. This patch uses RuntimeMaxSec=, Nice=, OOMScoreAdjust=
and various sandboxing settings to ensure that the coredump handler doesn't take away unbounded resources from normally
priorized processes.
This logic is also nice since this makes sure the coredump processing and storage is delayed correctly until
/var/systemd/coredump is mounted and writable.
Fixes: #2286
Now that requiring of a masked unit results in failure again, downgrade the dependency on /tmp to Wants= again, so that
our suggested way to disable /tmp-on-tmpfs by masking doesn't result in a failing boot.
References: #2315
The user manager is still limited by its parent slice user-UID.slice,
which defaults to 4096 tasks. However, it no longer has an additional
limit of 512 tasks.
Fixes#1955.
Apparently, util-linux' mount command implicitly drops the smack-related
options anyway before passing them to the kernel, if the kernel doesn't
know SMACK, hence there's no point in duplicating this in systemd.
Fixes#1696
Otherwise we might run into deadlocks, when journald blocks on the
notify socket on PID 1, and PID 1 blocks on IPC to dbus-daemon and
dbus-daemon blocks on logging to journald. Break this cycle by making
sure that journald never ever blocks on PID 1.
Note that this change disables support for event loop watchdog support,
as these messages are sent in blocking style by sd-event. That should
not be a big loss though, as people reported frequent problems with the
watchdog hitting journald on excessively slow IO.
Fixes: #1505.
If SMACK is enabled, 'smackfsroot=*' option should be specified when
/tmp is mounted since many non-root processes use /tmp for temporary
usage. If not, /tmp is labeled as '_' and smack denial occurs when
writing.
In order to do that, 'SmackFileSystemRoot=*' is newly added into
tmp.mount.
