In various tools and services we have a per-system and per-user concept.
So far we sometimes used a boolean indicating whether we are in system
mode, or a reversed boolean indicating whether we are in user mode, or
the LookupScope enum used by the lookup path logic.
Let's address that, in introduce a common enum for this, we can use all
across the board.
This is mostly just search/replace, no actual code changes.
Although this slightly more verbose it makes it much easier to reason
about. The code that produces the tests heavily benefits from this.
Test lists are also now sorted by test name.
All users were setting this to some static string (usually "-"), so let's
simplify things by not doing strdup, but instead limiting callers to a fixed
set of values. In preparation for the next commit, the function is renamed from
"empty" to "replacement", because it'll be used for more than empty fields. I
didn't do the whole string-table setup, because it's all used internally in one
file and this way we can immediately assert if an invalid value is passed in.
Some callers were (void)ing the error, others were ignoring it, and others
propagating. It's nicer to remove the boilerplate.
D-Bus interfaces can have multiple methods with the same name, as long
as they have different arguments (signature). Currently busctl can call
those methods but when introspecting the interface it just displays
"Duplicate method"
This PR fixes the behavior, by also adding the signature to the hash for
the members set.
Before this patch:
$ busctl introspect org.asamk.Signal /org/asamk/Signal
Invalid introspection data: duplicate method 'sendMessage' on interface 'org.asamk.Signal'.
After this patch:
$ busctl introspect org.asamk.Signal /org/asamk/Signal
NAME TYPE SIGNATURE RESULT/VALUE FLAGS
org.asamk.Signal interface - - -
.sendMessage method as x -
.sendMessage method s x -
Calling the methods already works as expected, as the user must specify
the signature explicitely:
busctl --user call org.asamk.Signal /org/asamk/Signal org.asamk.Signal sendMessage "as" 2 foo bar
busctl --user call org.asamk.Signal /org/asamk/Signal org.asamk.Signal sendMessage "s" foo
$ busctl --xml introspect org.asamk.Signal /org/asamk/Signal
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node name="/org/asamk/Signal">
<interface name="org.asamk.Signal">
<method name="sendMessage" >
<arg type="as" direction="in"/>
<arg type="x" direction="out"/>
</method>
<method name="sendMessage" >
<arg type="s" direction="in"/>
<arg type="x" direction="out"/>
</method>
<interface name="org.freedesktop.DBus.Introspectable">
<method name="Introspect">
<arg type="s" direction="out"/>
</method>
</interface>
<interface name="org.freedesktop.DBus.Peer">
<method name="Ping">
</method>
</interface>
</node>
This patch changes busctl capture to generate pcapng format
instead of the legacy pcap format files. It includes basic
meta-data in the file and still uses microsecond time
resolution. In future, more things can be added such as
high resolution timestams, statistics, etc.
PCAP Next Generation capture file format is what tshark uses
and is in process of being standardized in IETF. It is also
readable with libpcap.
$ capinfos /tmp/new.pcapng
File name: /tmp/new.pcapng
File type: Wireshark/... - pcapng
File encapsulation: D-Bus
File timestamp precision: microseconds (6)
Packet size limit: file hdr: (not set)
Packet size limit: inferred: 4096 bytes
Number of packets: 22
File size: 21kB
Data size: 20kB
Capture duration: 0.005694 seconds
First packet time: 2021-12-11 11:57:42.788374
Last packet time: 2021-12-11 11:57:42.794068
Data byte rate: 3,671kBps
Data bit rate: 29Mbps
Average packet size: 950.27 bytes
Average packet rate: 3,863 packets/s
SHA256: b85ed8b094af60c64aa6d9db4a91404e841736d36b9e662d707db9e4096148f1
RIPEMD160: 81f9bac7ec0ec5cd1d55ede136a5c90413894e3a
SHA1: 8400822ef724b934d6000f5b7604b9e6e91be011
Strict time order: True
Capture oper-sys: Linux 5.14.0-0.bpo.2-amd64
Capture application: systemd 250 (250-rc2-33-gdc79ae2+)
Number of interfaces in file: 1
Interface #0 info:
Encapsulation = D-Bus (146 - dbus)
Capture length = 4096
Time precision = microseconds (6)
Time ticks per second = 1000000
Number of stat entries = 0
Number of packets = 22
(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.
These functions are used pretty much independently of locale, i.e. the
only info relevant is whether th locale is UTF-8 or not. Hence let's
give this its own pair of .c/.h files.
In general we almost never hit those asserts in production code, so users see
them very rarely, if ever. But either way, we just need something that users
can pass to the developers.
We have quite a few of those asserts, and some have fairly nice messages, but
many are like "WTF?" or "???" or "unexpected something". The error that is
printed includes the file location, and function name. In almost all functions
there's at most one assert, so the function name alone is enough to identify
the failure for a developer. So we don't get much extra from the message, and
we might just as well drop them.
Dropping them makes our code a tiny bit smaller, and most importantly, improves
development experience by making it easy to insert such an assert in the code
without thinking how to phrase the argument.
We recently started making more use of malloc_usable_size() and rely on
it (see the string_erase() story). Given that we don't really support
sytems where malloc_usable_size() cannot be trusted beyond statistics
anyway, let's go fully in and rework GREEDY_REALLOC() on top of it:
instead of passing around and maintaining the currenly allocated size
everywhere, let's just derive it automatically from
malloc_usable_size().
I am mostly after this for the simplicity this brings. It also brings
minor efficiency improvements I guess, but things become so much nicer
to look at if we can avoid these allocation size variables everywhere.
Note that the malloc_usable_size() man page says relying on it wasn't
"good programming practice", but I think it does this for reasons that
don't apply here: the greedy realloc logic specifically doesn't rely on
the returned extra size, beyond the fact that it is equal or larger than
what was requested.
(This commit was supposed to be a quick patch btw, but apparently we use
the greedy realloc stuff quite a bit across the codebase, so this ends
up touching *a*lot* of code.)
With some versions of the compiler, the _cleanup_ attr makes it think
the variable might be freed/closed when uninitialized, even though it
cannot happen. The added cost is small enough to be worth the benefit,
and optimized builds will help reduce it even further.
This nicely covers the case when optarg is optional. The same parser can be
used when the option string passed to getopt_long() requires a parameter and
when it doesn't.
The error messages are made consistent.
Also fixes a log error c&p in --crash-reboot message.
I started working on this because I wanted to change how
DEFINE_TRIVIAL_CLEANUP_FUNC is defined. Even independently of that change, it's
nice to make make things more consistent and predictable.
I think this formatting was originally used because it simplified
adding new options to the help messages. However, these days, most
tools their help message end with "\nSee the %s for details.\n" so
the final line almost never has to be edited which eliminates the
benefit of the custom formatting used for printf() help messages.
Let's make things more consistent and use the same formatting for
printf() help messages that we use everywhere else.
Prompted by https://github.com/systemd/systemd/pull/18355#discussion_r567241580
This is unfortunately harder to implement than it sounds. The user's bus
is bound a to the user's lifecycle after all (i.e. only exists as long
as the user has at least one PAM session), and the path dynamically (at
least theoretically, in practice it's going to be the same always)
generated via $XDG_RUNTIME_DIR in /run/.
To fix this properly, we'll thus go through PAM before connecting to a
user bus. Which is hard since we cannot just link against libpam in the
container, since the container might have been compiled entirely
differently. So our way out is to use systemd-run from outside, which
invokes a transient unit that does PAM from outside, doing so via D-Bus.
Inside the transient unit we then invoke systemd-stdio-bridge which
forwards D-Bus from the user bus to us. The systemd-stdio-bridge makes
up the PAM session and thus we can sure tht the bus exists at least as
long as the bus connection is kept.
Or so say this differently: if you use "systemctl -M lennart@foobar"
now, the bus connection works like this:
1. sd-bus on the host forks off:
systemd-run -M foobar -PGq --wait -pUser=lennart -pPAMName=login systemd-stdio-bridge
2. systemd-run gets a connection to the "foobar" container's
system bus, and invokes the "systemd-stdio-bridge" binary as
transient service inside a PAM session for the user "lennart"
3. The systemd-stdio-bridge then proxies our D-Bus traffic to
the user bus.
sd-bus (on host) → systemd-run (on host) → systemd-stdio-bridge (in container)
Complicated? Well, to some point yes, but otoh it's actually nice in
various other ways, primarily as it makes the -H and -M codepaths more
alike. In the -H case (i.e. connect to remote host via SSH) a very
similar three steps are used. The only difference is that instead of
"systemd-run" the "ssh" binary is used to invoke the stdio bridge in a
PAM session of some other system. Thus we get similar implementation and
isolation for similar operations.
Fixes: #14580
Lennart Poettering
Jan Janssen
Yu Watanabe
David Tardon
Zbigniew Jędrzejewski-Szmek
Sebastian Scheibner
Michael Biebl
Stephen Hemminger
Luca Boccassi
Daan De Meyer
d032747