For the other verbs turning off JSON mode makes sense, but for "call"
not so much, after all the contents of a method call reply is JSON we
couldn't really show any other way.
Hence, when JSON output was not configured otherwise in "call", default
to the same as -j.
fresh otherwise
Currently, exec_setup_credential() always rewrite all credentials
upon exec_invoke(), i.e. invocation of each ExecCommand, and within
a single tmpfs instance. This is problematic though:
* When writing each tmp cred file, we essentially double the size
of the credential. Therefore, if one cred is bigger than half
of CREDENTIALS_TOTAL_SIZE_MAX, confusing ENOSPC occurs (see also
https://github.com/systemd/systemd/pull/24734#issuecomment-1925440546)
* Credential is a unit-wide thing and thus should not change
during the whole lifetime of main process. However, if e.g.
a on-disk credential or SetCredential= in unit file
changes between ExecStart= and ExecStartPost=,
the credentials are overwritten when the latter gets to run,
and the already-running main process is suddenly seeing
completely different creds.
So, let's try to reuse final cred dir if the main process has started
and the tmpfs has been populated, so that the creds used is stable
across all ExecStart= and ExecStartPost=-s. We still want to retain
the ability of updating creds through ExecStartPre= though, therefore
we forcibly use a fresh cred dir for those. 'Fresh' means to actually
unmount the old tmpfs first, so the first problem goes away, too.
This extends the test framework a bit, and allows adding additional
initrds to the qemu invocation, which we use here to place credentials
in the new /run/systemd/@initrd/ credentials dir which are then passed
to the host.
ImportCredential= takes a credential name and searches for a matching
credential in all the credential stores we know about it. It supports
globs which are expanded so that all matching credentials are loaded.
Let's make the dropin, to make the build dir writable for gcov, a bit
more generic, so it can be used by all units starting with prefix test-.
This should help with a bunch of recent reports about missing coverage I
got, as well as with existing test units using DynamicUser=true.
This might feel a bit like a magic trick from behind the curtains, but I
want to touch the actual tests as little as possible, since it makes them
unnecessarily messy (see the various workarounds for sanitizers), and
the coverage reports are generated only in a specific CI job anyway.
(The one case that is left unchanged is '< <(subcommand)'.)
This way, the style with no gap was already dominant. This way, the reader
immediately knows that ' < ' is a comparison operator and ' << ' is a shift.
In a few cases, replace custom EOF replacement by just EOF. There is no point
in using someting like "_EOL" unless "EOF" appears in the text.
This imports credentials also via SMBIOS' "OEM vendor string" section,
similar to the existing import logic from fw_cfg.
Functionality-wise this is very similar to the existing fw_cfg logic,
both of which are easily settable on the qemu command line.
Pros and cons of each:
SMBIOS OEM vendor strings:
- pro: fast, because memory mapped
- pro: somewhat VMM independent, at least in theory
- pro: qemu upstream sees this as the future
- pro: no additional kernel module needed
- con: strings only, thus binary data is base64 encoded
fw_cfg:
- pro: has been supported for longer in qemu
- pro: supports binary data
- con: slow, because IO port based
- con: only qemu
- con: requires qemu_fw_cfg.ko kernel module
- con: qemu upstream sees this as legacy
Daan De Meyer
Frantisek Sumsal
Lennart Poettering
Mike Yuan
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Luca Boccassi
Albert Brox