This updates a couple of links talking about Varlink:
1. anything that refers to specific Varlink concepts now point to the
UAPI.20 spec
2. More general references to Varlink as a whole point to both the
varlink.org domain and the spec.
By chance (because I had this mistake in my own commit) I noticed
that there are a bunch of duplicated works like "the the" in the
code and man-pages.
This commit fixes them and some similar issues with "and and" etc.
With the new protocol upgrade support in varlinkctl client we can
now do the equivalent for the server side. This commit adds a new
`serve` verb that will serve any command that speaks stdin/stdout
via varlink and its protocol upgrade feature. This is the
"inetd for varlink".
This is useful for various reasons:
1. Allows to e.g. provide a heavily sandboxed io.myorg.xz.Decompress
varlink endpoint, c.f. xz CVE-2024-3094)
2. Allow sftp over varlink which is quite useful with the
varlink-http-bridge (that has more flexible auth mechanism than
plain sftp).
3. Makes testing the varlinkctl client protocol upgrade simpler.
4. Because we can.
Having support for `--exec` when using `--upgrade` is nice so this
commit adds it. It does it by extracting a shared helper called
`exec_with_listen_fds()` and then use that in the `verb_call()`
and `varlink_call_and_upgrade()` calls.
The varlink spec supports protocol upgrades and they are very
useful to e.g. transfer binary data directly via varlink. So
far varlinkctl/sd-varlink was not supporting this. This commit
adds support for it in varlinkctl by using the new code in
sd-varlink and the generalized socket-forward code.
This new switch makes it possible to process fds attached to a varlink
reply: if specified it will execute a command line specified by the
caller, will pass the response json as stdin, and any fds acquired as
fd3, fd4, …
This is generally useful, but in some cases particularly: when
implementing enumeration calls that use the "more" flag to return
multiple replies then for the first reply we need to return an error in
case the list of objects to enumerate is empty, usually so form of
"NoSuchXYZ" error. In many cases this shouldn't really be treated as
error, as an empty list probably more than not is as valid as a list
with one, two or more entries.
For putting together "varlinkctl call" command lines it's useful to
quickly enumerate all methods implemented by a service. Hence, let's add
a new "list-methods" which uses the introspection data of a service to
quickly list methods.
This is implemented as a special flavour of the "introspect" logic,
and just suppresses all output except for the method names.
let's make it easier to use the introspection functionality of
"varlinkctl": if no interface name is shown, display the introspection
data of all available interfaces. Moreover, allow that multiple
interfaces can be listed, in which case we enumerate them all.
This relieves the user from having to list interfaces first in order to
find the ones which to introspect.
It exposes the varlink_collect() call we internally provide: it collects
all responses of a method call that is issued with the "more" method
call flag. It then returns the result as a single JSON array.
This uses openssh 9.4's -W support for AF_UNIX. Unfortunately older versions
don't work with this, and I couldn#t figure a way that would work for
older versions too, would not be racy and where we'd still could keep
track of the forked off ssh process.
Unfortunately, on older versions -W will just hang (because it tries to
resolve the AF_UNIX path as regular host name), which sucks, but hopefully this
issue will go away sooner or later on its own, as distributions update.
Fedora is still stuck at 9.3 at the time of posting this (even on
Fedora), even though 9.4, 9.5, 9.6 have all already been released by
now.
Example:
varlinkctl call -j ssh:root@somehost:/run/systemd/io.systemd.Credentials io.systemd.Credentials.Encrypt '{"text":"foobar"}'
Lennart Poettering
Michael Vogt
Luca Boccassi
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Jan Engelhardt
Yu Watanabe
Antonio Alvarez Feijoo
Sam Leonard
cunshunxia
David Tardon