Before only one comparison was allowed. Let's make this more flexible:
ConditionKernelVersion = ">=4.0" "<=4.5"
Fixes#12881.
This also fixes expressions like "ConditionKernelVersion=>" which would
evaluate as true.
These services are likely to coredump, and we expect that but aren't
interested in the coredump. Hence let's turn off processing by setting
RLIMIT_CORE to 0/0.
Those interfaces are created automatically when ip6_tunnel and ip6_gre loaded.
They break the test with exec-privatenetwork-yes.service.
C.f. 6b08180ca6.
... when no mount options are passed.
Change the code, to avoid the following failure in the newly added tests:
exec-temporaryfilesystem-rw.service: Executing: /usr/bin/sh -x -c
'[ "$(stat -c %a /var)" == 755 ]'
++ stat -c %a /var
+ '[' 1777 == 755 ']'
Received SIGCHLD from PID 30364 (sh).
Child 30364 (sh) died (code=exited, status=1/FAILURE)
(And I spotted an opportunity to use TAKE_PTR() at the end).
We can't remount the underlying superblocks, if we are inside a user
namespace and running Linux <= 4.17. We can only change the per-mount
flags (MS_REMOUNT | MS_BIND).
This type of mount() call can only change the per-mount flags, so we
don't have to worry about passing the right string options now.
Fixes#9914 ("Since 1beab8b was merged, systemd has been failing to start
systemd-resolved inside unprivileged containers" ... "Failed to re-mount
'/run/systemd/unit-root/dev' read-only: Operation not permitted").
> It's basically my fault :-). I pointed out we could remount read-only
> without MS_BIND when reviewing the PR that added TemporaryFilesystem=,
> and poettering suggested to change PrivateDevices= at the same time.
> I think it's safe to change back, and I don't expect anyone will notice
> a difference in behaviour.
>
> It just surprised me to realize that
> `TemporaryFilesystem=/tmp:size=10M,ro,nosuid` would not apply `ro` to the
> superblock (underlying filesystem), like mount -osize=10M,ro,nosuid does.
> Maybe a comment could note the kernel version (v4.18), that lets you
> remount without MS_BIND inside a user namespace.
This makes the code longer and I guess this function is still ugly, sorry.
One obstacle to cleaning it up is the interaction between
`PrivateDevices=yes` and `ReadOnlyPaths=/dev`. I've added a test for the
existing behaviour, which I think is now the correct behaviour.
This corresponds nicely with the specifiers we already pass for
/var/lib, /var/cache, /run and so on.
This is particular useful to update the test-path service files to
operate without guessable files, thus allowing multiple parallel
test-path invocations to pass without issues (the idea is to set $TMPDIR
early on in the test to some private directory, and then only use the
new %T or %V specifier to refer to it).
