It's so similar to copy_access(), hence let's move it over and rename it
in similar style to the rest of the functions.
No change in behaviour, just moving things over.
REMOVE_CHMOD is necessary to remove files/dirs that are owned by us but
have an access mode that would not allow us to remove them. In generic
destructor calls for use with `_cleanup_` that are "fire-and-forget"
style we should make use of that, to maximize the chance we can actually
remove the files/dirs.
(Also, add in REMOVE_MISSING_OK. Just because prettier, we ignore the
return codes anyway, but it' a bit nicer to ignore a bit fewer errors.)
Let's fine-tune the path_extract_filename() interface: on succes return
O_DIRECTORY as indicator that the input path was slash-suffixed, and
regular 0 otherwise. This is useful since in many cases it is useful to
filter out paths that must refer to dirs early on.
I opted for O_DIRECTORY instead of the following other ideas:
1. return -EISDIR: I think the function should return an extracted
filename even when referring to an obvious dir, so this is not an
option.
2. S_ISDIR, this was a strong contender, but I think O_DIRECTORY is a
tiny bit nicer since quite likely we will go on and open the thing,
maybe with openat(), and hence it's quite nice to be able to OR in
the return value into the flags argument of openat().
3. A new enum defined with two values "dont-know" and
"definitely-directory". But I figured this was unnecessary, given we
have other options too, that reuse existing definitions for very
similar purposes.
These two together are a lot like dirname() + basename() but have the
benefit that they return clear errors when one passes a special case
path to them where the extraction doesn't make sense, i.e. "", "/",
"foo", "foo/" and so on.
Sooner or later we should probably port all our uses of
dirname()/basename() over to this, to catch these special cases more
safely.
This addresses the issue described in https://lwn.net/Articles/846403/
and makes sure we will be able to stream bytes from procfs/sysfs via
copy_bytes() if people ask us to.
Our coding style dictates we should not clobber return parameters on
failure, and always initialize them on success. Do so here.
This changes getenv_path_list() to return ENXIO if the env var is not
set, which is similar to how we handle this in getenv_bool().
This drops debug logging from parse_env_extension_hierarchies(), since
it's done anyway in getenv_path_list()
Follow-up for: #18018
Clean up ignore_signals() + default_signals() + sigaction_many() a bit:
make it unnecessary to explicitly terminate the signal list with -1.
Merge all three calls into a single function that is just called with
slightly different parameters. And eliminate an unnecessary extra
iteration in its inner for() loop.
No change in behaviour.
This provides a fairly comprehensible fix for
https://bugzilla.redhat.com/show_bug.cgi?id=1893417.
This adds yet-another level of configuration:
- /etc/hostname
- transient hostname
- $SYSTEMD_DEFAULT_HOSTNAME
- DEFAULT_HOSTNAME is os-release
- -Dfallback-hostname=
- "linux"
It's a lot of layers, but each has it's own justification.
See https://bugzilla.redhat.com/show_bug.cgi?id=1893417 for the back story:
the fallback hostname matters a lot in certain environments. Right now the only
way to configure the fallback hostname is by recompiling systemd, which is
obviously problematic in case when the fallback hostname shall differ between
different editions of the same distro that share a single compiled rpm.
By making this overridable through an envvar, we're providing an escape hatch
without making this a top-level api. Later on a way to set this through
os-release is added, but I think the approach with the variable is still
useful. It it very convenient for testing, or to override settings only in a
particular service, etc.
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Lennart Poettering
Luca Boccassi
Xℹ Ruoyao
Joerg Behrmann
Annika Wickert