Based on the journalctl documentation of this option added in 23ad99b519
(#10527), but with the first reference to “fields” replaced by “journal
messages”, since I think it’s less common to show other fields with
`systemctl status` (though it’s possible with the `-o` option).
Instead of enabling it unconditionally and then using ConditionPathExists=/etc/fstab,
and possibly masking this condition if it should be enabled for auto gpt stuff,
just pull it in explicitly when required.
The current support in kernel-install for initrd images doesn't copy
over the initrd file or allow a means for it to be specified (it
requires a specific filename in a particular directory).
This patchset adds support for (optionally) providing the name of
initial ramdisk file to copied over and used by kernel-install.
From WordNet (r) 3.0 (2006) [wn]:
time-out
n 1: a brief suspension of play; "each team has two time-outs left"
From The Free On-line Dictionary of Computing (18 March 2015) [foldoc]:
timeout
A period of time after which an error condition is raised if
some event has not occured. A common example is sending a
message. If the receiver does not acknowledge the message
within some preset timeout period, a transmission error is
assumed to have occured.
RFC7766 section 4 states that in the absence of EDNS0, a response that
is too large for a 512-byte UDP packet will have the 'truncated' bit
set. The client is expected to retry the query over TCP.
Fixes#10264.
This is useful for distributions, where the stability of interface names should
be preseved after an upgrade of systemd. So when some specific release of the
distro is made available, systemd defaults to the latest & greatest naming
scheme, and subsequent updates set the same default. This default may still
be overriden through the kernel and env var options.
A special value "latest" is also allowed. Without a specific name, it is harder
to verride from meson. In case of 'combo' options, meson reads the default
during the initial configuration, and "remembers" this choice. When systemd is
updated, old build/ directories could keep the old default, which would be
annoying. Hence, "latest" is introduced to make it explicit, yet follow the
upstream. This is actually useful for the user too, because it may be used
as an override, without having to actually specify a version.
With this we can stabilize how naming works for network interfaces. A
user can request through a kernel cmdline option or an env var which
scheme to follow. The idea is that installers use this to set into stone
(a very soft stone though) the scheme used during installation so that
interface naming doesn't change afterwards anymore.
Why use env vars and kernel cmdline options, and not a config file of
its own?
Well, first of all there's no obvious existing one to use. But more
importantly: I have the feeling that this logic is kind of an incomplete
hack, and I simply don't want to do advertise this as a perfectly
working solution. So far we used env vars for the non-so-official
options and proper config files for the official stuff. Given how
incomplete this logic is (i.e. the big variable for naming remains the
kernel, which might expose sysfs attributes in newer versions that we
check for and didn't exist in older versions — and other problems like
this), I am simply not confident in giving this first-class exposure in
a primary configuration file.
Fixes: #10448
We would describe tmpfiles.d through what systemd-tmpfiles does with them, but
I think it's better to start with a geneneral statement what they are. Also,
let's make the description of volatile file systems less prominent.
Also, strenghten the advice to use RuntimeDirectory and mention
{Cache,Logs,Configuration,State}Directory=.
I think it is OK if some option is described as "similar to ..., but in
addition ...", as long as the "in addition" part is strictly additive this is
unambiguous. Otherwise, we'd have to repeat a lot of text, and then we'd
probably forget to adjust some of the descriptions when doing changes.
But when the "in addition" part is about replacing or removing parts of
functionality, it is better to avoid this pattern and describe the later option
from scratch.
Some paragraph breaks are added and minor changes made. UID/GID is changed to
user/group, since we generally expect user/group names to be used, not numeric
ids.
Fixes#11115.
This is convenient when working with device units in systemd. Instead of
converting the systemd unit name to a path to feed to udevadm, udevadm
info|trigger can be called directly on the unit name.
The man page is reworked a bit to describe the modern syntax with positional
arguments first. It's just simpler to use than the positional options.
When using networkd we currently have no way of ensuring that static
neighbor entries are set when our link comes up. This change adds a new
section to the network definition that allows multiple static neighbors
to be set on a link.
Patches are shown on github with a fixed width (no matter how wide the window
is). When line numbers are high (we have some files with 5 digit line numbers),
the diff does not fit, and horizontal scrolling must be used when viewing the
patch. This is super annoying. Let's reduce the width a bit. I think 109 is
still very wide, but at least the github issue should be alleviated.
The current use of literal + replaceable is pretty ugly as it usually
ends up with cgroup_disable= rendered in quotes, which looks really
weird, and this doesn't conform with others of a similar type (for
example, the earlier `DefaultDependencies=no` discussion in the same
file.
Some controllers (like the CPU controller) have a performance cost that
is non-trivial on certain workloads. While this can be mitigated and
improved to an extent, there will for some controllers always be some
overheads associated with the benefits gained from the controller.
Inside Facebook, the fix applied has been to disable the CPU controller
forcibly with `cgroup_disable=cpu` on the kernel command line.
This presents a problem: to disable or reenable the controller, a reboot
is required, but this is quite cumbersome and slow to do for many
thousands of machines, especially machines where disabling/enabling a
stateful service on a machine is a matter of several minutes.
Currently systemd provides some configuration knobs for these in the
form of `[Default]CPUAccounting`, `[Default]MemoryAccounting`, and the
like. The limitation of these is that Default*Accounting is overrideable
by individual services, of which any one could decide to reenable a
controller within the hierarchy at any point just by using a controller
feature implicitly (eg. `CPUWeight`), even if the use of that CPU
feature could just be opportunistic. Since many services are provided by
the distribution, or by upstream teams at a particular organisation,
it's not a sustainable solution to simply try to find and remove
offending directives from these units.
This commit presents a more direct solution -- a DisableControllers=
directive that forcibly disallows a controller from being enabled within
a subtree.
add new "systemd-run-generator" for running arbitrary commands from the kernel command line as system services using the "systemd.run=" kernel command line switch
Having systemctl disable/unmask remove all symlinks in /etc and /run is
unintuitive and breaks existing use cases.
systemctl should behave symmetrically.
A "systemctl --runtime unmask" should undo a "systemctl --runtime mask"
action.
Say you have a service, which was masked by the admin in /etc.
If you temporarily want to mask the execution of the service (say in a
script), you'd create a runtime mask via "systemctl --runtime mask".
It is is now no longer possible to undo this temporary mask without
nuking the admin changes, unless you start rm'ing files manually.
While it is useful to be able to remove all enablement/mask symlinks in
one go, this should be done via a separate command line switch, like
"systemctl --all unmask".
This reverts commit 4910b35078.
Fixes: #9393
Let's simplify things and drop the logic that /var/lib/machines is setup
as auto-growing btrfs loopback file /var/lib/machines.raw.
THis was done in order to make quota available for machine management,
but quite frankly never really worked properly, as we couldn't grow the
file system in sync with its use properly. Moreover philosophically it's
problematic overriding the admin's choice of file system like this.
Let's hence drop this, and simplify things. Deleting code is a good
feeling.
Now that regular file systems provide project quota we could probably
add per-machine quota support based on that, hence the btrfs quota
argument is not that interesting anymore (though btrfs quota is a bit
more powerful as it allows recursive quota, i.e. that the machine pool
gets an overall quota in addition to per-machine quota).
Fixes: #2728
This is also supposed to be preparation for doing #10234 eventually,
where a very similar operation is requested: instead of importing a tree
to /var/lib/machines it would need to be imported into
/var/lib/portables/.
I keep running "systemd-run -t /bin/bash" to quickly get a shell running
in service context. I suspect I am not the only one, hence let's add a
shortcut for it. While we are at it, let's make it smarter, and
automatically inherit the $SHELL of the invoking user as well as the
working directory, and let's imply --pty. --shell (or -S) is hence
equivalent to "-t -d $SHELL".
I find myself testing service management quite often with "systemd-run
-t /bin/bash". For that it is handy if the invoked shell would use the
working directory I am currently in. Hence introduce a shorthand for
that:
$ systemd-run -dt /bin/bash
This will automatically insert a WorkingDirectory= property into the
transient service, pointing to the working directory of the caller.
The way this is used drifted a bit from the original intent. Let's update
the description and add some examples to inspire people to texts that look
less bad during initial boot.
We now don't enable the CPU controller just for CPU accounting if we are
on 4.15+ and using pure unified hierarchy, as this is provided
externally to the CPU controller. This makes CPUAccounting=yes
essentially free, so enabling it by default when it's cheap seems like a
good idea.
We keep adding new features, let's advertise to the host OS what these
are in a new variable LoaderFeatures.
It works a bit like OsIndicationsSupported, but is about Loader
features.
This removes the ability to configure which cgroup controllers to mount
together. Instead, we'll now hardcode that "cpu" and "cpuacct" are
mounted together as well as "net_cls" and "net_prio".
The concept of mounting controllers together has no future as it does
not exist to cgroupsv2. Moreover, the current logic is systematically
broken, as revealed by the discussions in #10507. Also, we surveyed Red
Hat customers and couldn't find a single user of the concept (which
isn't particularly surprising, as it is broken...)
This reduced the (already way too complex) cgroup handling for us, since
we now know whenever we make a change to a cgroup for one controller to
which other controllers it applies.
The concept is redundant and predates the special chars that do the same
in ExecStar=. Let's settle on advertising just the latter, and hide
PermissionsStartOnly= from the docs (even if we continue supporting it).
Normally, we want to immediately quit on ^C. But when we are running under
less, people may set SYSTEMD_LESS without K, in which case they can use ^C to
communicate with less, and e.g. start and stop following input.
Fixes#6405.
Rebooting to set change the kernel command line to set some udev parameters is
inconvenient. Let's allow setting more stuff in the config file.
Also drop quotes from around "info" in udev.conf. We need to accept them for
compatibility, but there is no reason to use them.
In a way this is a follow-up for
a2d1fb882c, but adds a similar warning for
PIDFile=.
There's a much stronger case for doing this kind of notification in
tmpfiles.d (since it helps relating lines to each other for the purpose
of merging them). Doing this for PIDFile= is mostly about being
systematic and copying tmpfiles.d/ behaviour here.
While we are at it, let's also support relative filenames in PIDFile=
now, and prefix them with /run, to make them absolute.
Fixes: #10657
This adds a new pair of API calls sd_bus_set_close_on_exit() and
sd_bus_get_close_on_exit(). They control whether an sd_bus object
attached to a an sd-event loop shall automatically be flushed/closed
when the event loop goes down. Usually that's a good thing, except for
very few cases where the bus connection is longer living than the event
loop it is attached on. Specifically, this is the case for nspawn, where
we run the event loop only while the container is up, but afterwards
still want to be able to use the bus connection.
It's obsolete, stop mentioning it. Let's not confuse people suggests it
would be OK to use that, because it really isn't anymore, and it gives
us trouble with merging idenctical lines.
This reorganizes the systemd.timer man page so that it doesn't claim
there are no implicit dependencies right after specifying the implicit
dependencies, and so that it matches the other man pages for units. This
fixes a mistake introduced by commit aed5cb03db.
A simple copy+paste mistake, since the reference to
systemd-localed.service was added to both locale.conf(5) and
vconsole.conf(5) in the same commit (8968e36f21).
This changes the ProtectSystem= documentation to refer in more explicit
words to the restrictions of ReadOnlyPath=, as sugegsted in #9857.
THis also extends the paragraph in ReadOnlyPath= that explains the hole.
Fixes: #9857
In the documentation for ConditionXYZ= we claimed that AssertXYZ= would
have an effect on unit state (which is wrong), while at the
documentation for AssertXYZ= we said it only has an effect on the job,
but not the unit (which is right). Let's fix this contradiction, and
only claim the latter.
Also, fix a couple of other things (for example, stop talking about a
"failure state", but let's just expressly called it "the 'failed' state",
as that's the actual name of that state.
Finally, let's emphasize again when the conditions/assertions are
executed, and that they hence are not useful to conditionalize deps.
Fixes: #10433
In the default journalctl output, unprintable entries are abbreviated as
“[<amount> blob data]”; using the same term in the documentation helps
users to quickly discover the option they need to add in order to see
those entries.
The &MEMORY_ACCOUNTING_DEFAULT; resolves to "yes" or "no" while the rest
of the paragraph talked about "on" and "off". Let's adjust this and
stick to "yes" and "no"...
Quite frankly I think it's not a particularly good idea to change the
docs based configuration changes... THis can only be incomplete, and the
wording is still very awkward since we repeat the same sentence twice.
This is useful for a couple of cases, I'm mostly interested in case #1:
1. Verifying "reasonable" values in a trivially scriptable way
2. Debugging unexpected time span parsing directly
Test Plan:
```
% build/systemd-analyze timespan 20
Original: 20
μs: 20
Human: 20us
% build/systemd-analyze timespan 20ms
Original: 20ms
μs: 20000
Human: 20ms
% build/systemd-analyze timespan 20z
Failed to parse time span '20z': Invalid argument
```
Add LogRateLimitIntervalSec= and LogRateLimitBurst= options for
services. If provided, these values get passed to the journald
client context, and those values are used in the rate limiting
function in the journal over the the journald.conf values.
Part of #10230
C.f. 287419c119ef961db487a281162ab037eba70c61: 'systemctl exit 42' can be
used to set an exit value and pulls in exit.target, which pulls in systemd-exit.service,
which calls org.fdo.Manager.Exit, which calls method_exit(), which sets the objective
to MANAGER_EXIT. Allow the same to happen through SuccessAction=exit.
v2: update for 'exit' and 'exit-force'
We would accept e.g. FailureAction=reboot-force in user units and then do an
exit in the user manager. Let's be stricter, and define "exit"/"exit-force" as
the only supported actions in user units.
v2:
- rename 'exit' to 'exit-force' and add new 'exit'
- add test for the parsing function
FailureAction=/SuccessAction= were added later then StartLimitAction=, so it
was easiest to refer to the existing description. But those two settings are
somewhat simpler (they just execute the action unconditionally) while
StartLimitAction= has additional timing and burst parameters, and they are
about to take on a more prominent role, so let's move the description of
allowed values.
The term “positive” is often read to exclude 0 (though “strictly
positive” is sometimes used to clarify this), so let’s explicitly state
that --lines=0 is legal and completely disables journal output.
Motivated by an answer on StackExchange [1].
[1]: https://unix.stackexchange.com/a/475068/44049
These man pages list references to the various sd_event_add_xyz() calls
at the bottom, but sd_event_add_inotify() was never added there.
Moreover, some list references to sd_event_add_post() and
sd_event_add_exit() even though these have shared man pages with
sd_event_add_defer(), and given that the "SEE ALSO" section should
probably reference pages instead of functions let's drop this.
Then, let's always specify the sd_event_add_xyz() calls in the same
order.
Finally, in the sd_event_new(3) text explaining the basic logic,
actually mention sd_event_add_post() and sd_event_add_exit() as well, as
in that case we actually want to list functions, not man pages.
Also, while we are at it, beef it up, by adding json-seq support (i.e.
https://tools.ietf.org/html/rfc7464). This is particularly useful in
conjunction with jq's --seq switch.
A new switch "-j" or "--json=" is added which transforms dbus
marshalling into json. This is extremely useful in combination with
tools such as "jq" to process bus calls further.
Until a core dump handler is installed by systemd-sysctl, the generation of
core dump for services is turned OFF which can make the debugging of the early
boot process harder especially since there's no easy way to restore the core
dump generation.
This patch introduces a new kernel command line option which specifies an
absolute path where the kernel should write the core dump file when an early
process crashes.
This will take effect until systemd-coredump (or any other handlers) takes
over.
let's add an env var for this, as this really shouldn't be a top-level
feature, as it turning off the validity checks certainly isn't
advisable.
Fixes: #4925
/etc/systemd/sleep.conf gains four new switches:
AllowSuspend=, AllowHibernation=, AllowSuspendThenHibernate=, AllowHybridSleep=.
Disabling specific modes was already possible by masking suspend.target,
hibernate.target, suspend-then-hibernate.target, or hybrid-sleep.target.
But this is not convenient for distributions, which want to set some defaults
based on what they want to support. Having those available as configuration
makes it easy to put a config file in /usr/lib/systemd/sleep.conf.d/ that
overrides the defaults and gives instructions how to undo that override.
The behaviour described *was* observed on Fedora 28
(systemd-238-9.git0e0aa59), with and without SELinux. I don't actually
know why though! It contradicts my understanding of the code, including an
explicit comment in the code.
Testing in a VM upgraded to v239-792-g1327f272d, this behaviour goes away.
Test case:
# /etc/systemd/system/mount-test.service
[Service]
MountFlags=shared
Type=oneshot
ExecStart=/usr/bin/ls -l /proc/1/ns/mnt /proc/self/ns/mnt
ExecStart=/usr/bin/grep ext4 /proc/self/mountinfo
Weird old behaviour: new mount namespace but / is fully shared.
lrwxrwxrwx. 1 root root 0 Sep 14 11:18 /proc/1/ns/mnt -> mnt:[4026531840]
lrwxrwxrwx. 1 root root 0 Sep 14 11:48 /proc/self/ns/mnt ->
mnt:[4026532851]
968 967 253:0 / / rw,relatime shared:1 - ext4 /dev/mapper/alan_dell_2016...
Current behaviour: / is not fully shared
lrwxrwxrwx. 1 root root 0 Sep 14 11:39 /proc/1/ns/mnt -> mnt:[4026531840]
lrwxrwxrwx. 1 root root 0 Sep 14 11:41 /proc/self/ns/mnt ->
mnt:[4026532329]
591 558 8:3 / / rw,relatime shared:313 master:1 - ext4 /dev/sda3 rw,secl...
It is very useful for distributions to be able to set a primary
documentation URL in a standard location so that users and
applications on the system can identify it. For example, many
headless systems these days use the "Cockpit" admin console. It
would be ideal if we could specify this location directly in the
os-release file so that any application or service could have a
well-known location for retrieving this and displaying it
appropriately. Users could likewise examine /etc/os-release to
learn this location.
Related: https://github.com/cockpit-project/cockpit/issues/10198
Signed-off-by: Stephen Gallagher <sgallagh@redhat.com>
Let's remove redundancy and not advertise "journalctl --new-id128"
anymore, now that we have "systemd-id128 new" in a proper tool.
This allows us to reduce the overly large journalctl command set a bit.
Note that this just removes the --help and man text, the call remains
available for compat reasons.
The raison d'etre for this program is printing machine-app-specific IDs. We
provide a library function for that, but not a convenient API. We can hardly
ask people to quickly hack their own C programs or call libsystemd through CFFI
in python or another scripting language if they just want to print an ID.
Verb 'new' was already available as 'journalctl --new-id128', but this makes
it more discoverable.
v2:
- rename binary to systemd-id128
- make --app-specific= into a switch that applies to boot-id and machine-id
Allows configuring the watchdog signal (with a default of SIGABRT).
This allows an alternative to SIGABRT when coredumps are not desirable.
Appropriate references to SIGABRT or aborting were renamed to reflect
more liberal watchdog signals.
Closes#8658
This is an implementation that covers making errors encountered when writing
file content optionally fatal. If this is something that folks would want I'll
add handling of this for all the other directives. I'd appreciate suggestions
on how this might better be structured as well (use of a goto fail or such) as
I'm not super happy with the approach.
This changes the output a bit, as the previous multi-line output of each
inhibitor is changed to a single line, but it does unify the output look
with the one of our other tools. Moreover this adds proper sorting.
RFC 7084, WPD-4, requires Customer Edge end routers to behave
according to the following:
"WPD-4: By default, the IPv6 CE router MUST initiate DHCPv6 prefix
delegation when either the M or O flags are set to 1 in a
received Router Advertisement (RA) message. Behavior of the
CE router to use DHCPv6 prefix delegation when the CE router
has not received any RA or received an RA with the M and the
O bits set to zero is out of scope for this document."
Since it cannot be automatically detected whether DHCPv6 is to be
operated as an CE end router or whether to initiate an Informational
exchange to obtain other useful network information via DHCPv6 when the
Router Advertisement 'O' bit is set, a 'ForceDHCPv6PDOtherInformation'
boolean network configuration option in the '[DHCP]' section of a is
introduced. Setting this option causes DHCPv6 to be started in stateful
mode, although only the 'O' bit is seen in the Router Advertisement.
When 'ForceDHCPv6PDOtherInformation' is set and the Router Advertisement
has only the Other information 'O' bit set, disable requests for IA_NA
addresses.
Fixes#9745.
That recommendation is likely to cause more trouble and for pretty
much all end-user units is not useful. Let's recommend relying on
the implicit dependency instead.
Fixes#10015.
Dracut has a support for unlocking encrypted drives with keyfile stored
on the external drive. This support is included in the generated initrd
only if systemd module is not included.
When systemd is used in initrd then attachment of encrypted drives is
handled by systemd-cryptsetup tools. Our generator has support for
keyfile, however, it didn't support keyfile on the external block
device (keydev).
This commit introduces basic keydev support. Keydev can be specified per
luks.uuid on the kernel command line. Keydev is automatically mounted
during boot and we look for keyfile in the keydev
mountpoint (i.e. keyfile path is prefixed with the keydev mount point
path). After crypt device is attached we automatically unmount
where keyfile resides.
Example:
rd.luks.key=70bc876b-f627-4038-9049-3080d79d2165=/key:LABEL=KEYDEV
For an example where we already use it, see man:sd-login(3):
> A session is defined by the time a user is logged in until they log out.
As far as I can tell, this removes the only remaining occurrences of
referring to users by gendered pronouns in our documentation (though
some still survive in code comments and the NEWS and TODO files):
git grep '\b\(he\|him\|his\|she\|her\|hers\)\b' man/
You can only have one listitem in each varlistentry.
xmllint says:
resolvectl.xml:269: element varlistentry: validity error : Element varlistentry content does not follow the DTD, expecting (term+ , listitem), got (term term term term term term term listitem listitem listitem )
Without this fix, udev(7) munges the two items together, like so:
ATTR{filename}, SYSCTL{kernel parameter}
Match sysfs attribute values of the event device. Trailing
whitespace in the attribute values is ignored unless the specified
match value itself contains trailing whitespace. Match a kernel
parameter value.
You're not allowed to have a <term> element after a <listitem> element within a
<varlistentry>.
xmllint complains:
udev.xml:192: element varlistentry: validity error : Element varlistentry content does not follow the DTD, expecting (term+ , listitem), got (term listitem term listitem )
This work add support to generic netlink to sd-netlink.
See https://lwn.net/Articles/208755/
networkd: add support FooOverUDP support to IPIP tunnel netdev
https://lwn.net/Articles/614348/
Example conf:
/lib/systemd/network/1-fou-tunnel.netdev
```
[NetDev]
Name=fou-tun
Kind=fou
[FooOverUDP]
Port=5555
Protocol=4
```
/lib/systemd/network/ipip-tunnel.netdev
```
[NetDev]
Name=ipip-tun
Kind=ipip
[Tunnel]
Independent=true
Local=10.65.208.212
Remote=10.65.208.211
FooOverUDP=true
FOUDestinationPort=5555
```
$ ip -d link show ipip-tun
```
5: ipip-tun@NONE: <POINTOPOINT,NOARP> mtu 1472 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ipip 10.65.208.212 peer 10.65.208.211 promiscuity 0
ipip remote 10.65.208.211 local 10.65.208.212 ttl inherit pmtudisc encap fou encap-sport auto encap-dport 5555 noencap-csum noencap-csum6 noencap-remcsum numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
```
The qgroup logic (types 'q' and 'Q') only has an effect if there's no previous
setup at all, and any explicitly configured subvolumes with their qgroups are
left entirely unmodified.
The idea is that if users want a different logic than the one we set up by
default, then by all means they should do that before hand, and tmpfiles won't
override their logic.
This makes it possible to wait until boot is finished without having to poll
for this command repeatedly, instead using the syntax:
$ systemctl is-system-running --wait
Waiting is implemented by waiting for the StartupFinished signal to be posted
on the bus.
Register the matcher before checking for the property to avoid race conditions.
Tested by artificially delaying startup with a oneshot service and calling this
command, checked that it emitted `running` and exited with a 0 return code as
soon as the delay service completed startup.
Also tested that booting to degraded state unblocks the command.
Inserted a delay between getting the property and waiting for the signal and
confirmed this seems to work free of race conditions.
Updated the --help text (under --wait) and the man page to document the new
feature.
RootImage= may require the following settings
```
DeviceAllow=/dev/loop-control rw
DeviceAllow=block-loop rwm
DeviceAllow=block-blkext rwm
```
This adds the following settings implicitly when RootImage= is
specified.
Fixes#9737.
Triggered by https://bugzilla.redhat.com/show_bug.cgi?id=1609349
This adds two generic paragaphs we include via xinclude. One is the
"strict" version, which contains wording saying that we are thread
agnostic and what that means. And the other is the "safe" version, for
the cases we provide fully safety.
Let's then change most man pages to use either of these generic
paragraphs. With one exception: man/sd_journal_get_catalog.xml contains
both kinds of function, we hence use manual wording.
sd_bus_message{get_type,is_signal,is_method_call,is_method_error} get one man
page.
sd_bus_message_{set,get}_{destination,path,interface,member,sender} are put in
the second one.
Moving them out makes it easier to run them through a compiler, use automatic
indentation, and opens the possibility to provide a download link in the
future. I verified that all examples compile cleanly.
(2-space indentation is used because the examples are already significantly
indented in the man page, and we need to keep them narrow so that they display
well on standard terminals.)
