This tries to add information about when each option was added. It goes
back to version 183.
The version info is included from a separate file to allow generating it,
which would allow more control on the formatting of the final output.
But the directories are changed from /dev/loop/by-ref/ -> /dev/disk/by-loop-ref/
and /dev/loop/by-inode/ -> /dev/disk/by-loop-inode/.
As /dev/loop/ is used by losetup command for other purpose.
See issue #28475.
This effectively reverts commits 9915cc6086,
5022fab15f, and
c0d998248e.
--copy-to, --copy-from, --list and --mtree are useful for image directories
as well as image files, so for those verbs, let's check if we were passed
a directory and skip all the image file setup if that's the case.
The /usr/lib/extensions/ location for systemd-sysext images is not
supported anymore. In https://github.com/systemd/systemd/pull/26013
systemd-confext images got introduced and we can list its path under
/usr instead.
This allows unprivileged validation of DDIs. Only superficial structure,
i.e. not mounting or so. This becomes particularly handy in the
integration tests, and to validate image policies.
When attaching a loopback file this allows us to set an explicit name
for it. This is useful since it allows a caller to pre-select a string
that is directly attached to the loopback file. Via udev rules we'l
later make the device accessible through this name.
Note that "lo_file_name" is supposed to carry a file name of the backing
file, but the kernel actually does not care or enforce any of that, it
just stores the filename and returns it later. This makes it so useful,
as userspace has total control of that field.
"lo_file_name" should not be confused with the sysattr
"loop/backing_file" which is actually maintained by the kernel itself,
and always shows the file to the backing inode without userspace having
direct control over the returned string. Because the sysattr is
generated by the kernel it is subject to file system namespacing and
everything, while "lo_file_name" is not, it's really just a string
passed through the kernel.
Sometimes it is useful attaching DDIs without mounting them. We could
use "losetup" for that, but doing this in systemd-dissect has various
benefits:
1. we superficially validate the DDI first
2. we set the sector size depending on what we determine
3. we synchronously create the per-partition block devices
(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.
During the call today we agreed to work towards -rc1 in January. Nevertheless,
I already started writing this up and I'll push it so it doesn't get lost.
I didn't include all the changes to systemd-repart, because those are still in
flux.
This command takes a mountpoint, unmounts it and makes sure the
underlying partition devices and block device are removed before
exiting.
To mirror the --mount operation, we also add a --rmdir option which
does the opposite of --mkdir, and a -U option which is a shortcut
for --umount --rmdir.
This doesn't actually port systemd-dissect to table_print_with_pager()
but at least rearranges things so that similar behaviour is exposed. The
reason it's not ported over 1:1 is that systemd-dissect actually adjusts
the JSON output of the table with additional info, and doesn't print the
table 1:1 as JSON.
