The time-based cache allows starting a new unit without an expensive
daemon-reload, unless there was already a reference to it because of
a dependency or ordering from another unit.
If the cache is out of date, check again if we can load the
fragment.
Possibly fixes#15220. (There might be another leak. I'm still investigating.)
The leak would occur when the path cache was rebuilt. So in normal circumstances
it wouldn't be too bad, since usually the path cache is not rebuilt too often. But
the case in #15220, where new unit files are created in a loop and started, the leak
occurs once for each unit file:
$ for i in {1..300}; do cp ~/.config/systemd/user/test0001.service ~/.config/systemd/user/test$(printf %04d $i).service; systemctl --user start test$(printf %04d $i).service;done
sd-boot uses rdtsc to set those timestamps. There is no guarantee that the tsc
has any particular absolute value.
On my VM:
$ head /sys/firmware/efi/efivars/LoaderTime*
==> /sys/firmware/efi/efivars/LoaderTimeExecUSec-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f <==
4397904074
==> /sys/firmware/efi/efivars/LoaderTimeInitUSec-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f <==
4396386839
==> /sys/firmware/efi/efivars/LoaderTimeMenuUSec-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f <==
4396392521
$ build/test-boot-timestamps
...
LoaderTimeExecUSec=4396386839 too large, refusing.
Failed to read EFI loader data: Input/output error
Assertion 'q >= 0' failed at src/test/test-boot-timestamps.c:84, function main(). Aborting.
(with patch)
$ build/test-boot-timestamps
...
EFI Loader: start=1h 13min 16.386s exit=1h 13min 17.904s duration=1.517s
Firmware began 1h 13min 17.904074s before kernel.
Loader began 1.517235s before kernel.
Firmware began Tue 2020-05-26 11:04:13 CEST.
Loader began Tue 2020-05-26 12:17:30 CEST.
Kernel began Tue 2020-05-26 12:17:31 CEST.
Units created with "systemctl edit --full" from generator units aren't
removed with "systemctl revert" because units in the generator,
generator_early, and generator_late paths aren't considered vendor
units.
Alter path_is_vendor() to return true if the given path is a
generator unit, which in turn causes "systemctl revert" to remove units
created with "systemctl edit --full" as they now have vendor versions.
Fixes#10053
Much like systemd.condition-needs-update= this new switch allows
overriding of a unit file condition, but this time its
ConditionFirstBoot=.
Usecase is also primarily debugging, but could be useful for other
schemes too.
Condition checks shouldn't log loudly, since they run all the time.
Let's make things debuggable, by keeping the messages in LOG_DEBUG in,
but don't make more noise than necessary.
We should do this check first since it is done on the string itself
without any conditioning of system state otherwise. It is a weird to do
this test only if /etc is read-only.
For low memory machines (256MB), 10% of RAM for /run may not be enough for
re-exec of PID1 because 16MB of free space is required and /run may already
contain something.
Fixes: oss-fuzz#22208
```
test/fuzz/fuzz-calendarspec/oss-fuzz-22208... ../src/shared/calendarspec.c:666:48: runtime error: signed integer overflow: 2147000000 + 1000000 cannot be represented in type 'int'
#0 0x7f0b9f6cc56a in prepend_component ../src/shared/calendarspec.c:666
#1 0x7f0b9f6cd03a in parse_chain ../src/shared/calendarspec.c:718
#2 0x7f0b9f6cea1c in parse_calendar_time ../src/shared/calendarspec.c:845
#3 0x7f0b9f6d1397 in calendar_spec_from_string ../src/shared/calendarspec.c:1084
#4 0x401570 in LLVMFuzzerTestOneInput ../src/fuzz/fuzz-calendarspec.c:17
#5 0x401ae0 in main ../src/fuzz/fuzz-main.c:39
#6 0x7f0b9e31b1a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
#7 0x40122d in _start (/home/fsumsal/repos/systemd/build/fuzz-calendarspec+0x40122d)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../src/shared/calendarspec.c:666:48 in
```
Prompted by the discussions in #15180.
This is a bit more complex than I hoped, since for PID 1 we need to pass
in the synethetic environment block in we generate on demand.
