Also: rename Handover → Handoff. I think it makes it clearer that this
is not really about handing over any resources, but that the executor is
out off the game from that point on.
With 1df4b21abd we started to default to
enrolling into the LUKS device backing the root fs if none was specified
(and no wipe operation is used). This changes to look for /var/ instead.
On most systems /var/ is going to be on the root fs, hence this change
is with little effect.
However, on systems where / and /var/ is separate it makes more sense to
default to /var/ because that's where the persistent and variable data
is placed (i.e. where LUKS should be used) while / doesn't really have
to be variable, could as well be immutable, or ephemeral. Hence /var/
should be a safer default.
Or to say this differently: I think it makes sense to support systems
with /var/ being on / well. I also think it makes sense to support
systems with them being separate, and /var/ being variable and
persistent. But any other kind of system I find much less interesting to
support, and in that case people should just specify the device name.
Also, while we are at it, tighten the checks a bit, insist on a dm-crypt
+ LUKS superblock before continuing.
And finally, let's print a short message indicating the device we
operate on.
The log files defined using file:, append: or truncate: inherit the owner and other privileges from the effective user running systemd.
The log files are NOT created using the "User", "Group" or "UMask" defined in the service.
When starting a container with --user, the new uid will be resolved and switched to
only in the inner child, at the end of the setup, by spawning getent. But the
credentials are set up in the outer child, long before the user is resolvable,
and the directories/files are made only readable by root and read-only, which
means they cannot be changed later and made visible to the user.
When this particular combination is specified, it is obvious the caller wants
the single-process container to be able to use credentials, so make them world
readable only in that specific case.
Fixes https://github.com/systemd/systemd/issues/31794
Enable the exec_fd logic for Type=notify* services too, and change it
to send a timestamp instead of a '1' byte. Record the timestamp in a
new ExecMainHandoverTimestamp property so that users can track accurately
when control is handed over from systemd to the service payload, so
that latency and startup performance can be trivially and accurately
tracked and attributed.
When an IO event source owns relevant fd, replacing with a new fd leaks
the previously assigned fd.
===
sd_event_add_io(event, &s, fd, ...);
sd_event_source_set_io_fd_own(s, true);
sd_event_source_set_io_fd(s, new_fd); <-- The previous fd is not closed.
sd_event_source_unref(s); <-- new_fd is closed as expected.
===
Without the change, valgrind reports the leak:
==998589==
==998589== FILE DESCRIPTORS: 4 open (3 std) at exit.
==998589== Open file descriptor 4:
==998589== at 0x4F119AB: pipe2 (in /usr/lib64/libc.so.6)
==998589== by 0x408830: test_sd_event_source_set_io_fd (test-event.c:862)
==998589== by 0x403302: run_test_table (tests.h:171)
==998589== by 0x408E31: main (test-event.c:935)
==998589==
==998589==
==998589== HEAP SUMMARY:
==998589== in use at exit: 0 bytes in 0 blocks
==998589== total heap usage: 33,305 allocs, 33,305 frees, 1,283,581 bytes allocated
==998589==
==998589== All heap blocks were freed -- no leaks are possible
==998589==
==998589== For lists of detected and suppressed errors, rerun with: -s
==998589== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Follow-ups for 74c4231ce5.
Previously, the path is obtained from the fd, but it is closed in
sd_event_loop() to unpin the filesystem.
So, let's save the path when the event source is created, and make
sd_event_source_get_inotify_path() simply read it.
We look for the root fs on the device of the booted ESP, and for the
other partitions on the device of the root fs. On EFI systems this
generally boils down to the same, but there are cases where this doesn't
hold, hence document this properly.
Fixes: #31199
