The desktop file specification allows entries like ";;;;;;", full of empty strings.
But looking at the actual list of supported keys [1], empty entries are meaningless
(unless we would allow e.g. the desktop name to be the empty string. But that doesn't
seem very useful either). So let's just simplify our life and skip any empty substrings
entirely.
This would also resolve the fuzzer case:
$ valgrind build/fuzz-xdg-desktop test/fuzz/fuzz-xdg-desktop/oss-fuzz-22812
test/fuzz/fuzz-xdg-desktop/oss-fuzz-22812... ok
==2899241== HEAP SUMMARY:
==2899241== in use at exit: 0 bytes in 0 blocks
==2899241== total heap usage: 484,385 allocs, 484,385 frees, 12,411,330 bytes allocated
↓
==2899650== HEAP SUMMARY:
==2899650== in use at exit: 0 bytes in 0 blocks
==2899650== total heap usage: 1,325 allocs, 1,325 frees, 1,463,602 bytes allocated
The fuzzer test case has a giant line with ";;;;;;;;;;;..." which is turned into
a strv of empty strings. Unfortunately, when pushing each string, strv_push() needs
to walk the whole array, which leads to quadratic behaviour. So let's use
greedy_allocation here and also keep location in the string to avoid iterating.
build/fuzz-xdg-desktop test/fuzz/fuzz-xdg-desktop/oss-fuzz-22812 51.10s user 0.01s system 99% cpu 51.295 total
↓
build/fuzz-xdg-desktop test/fuzz/fuzz-xdg-desktop/oss-fuzz-22812 0.07s user 0.01s system 96% cpu 0.083 total
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=22812.
Other minor changes:
- say "was already defined" instead of "defined multiple times" to make it
clear that we're ignoring this second definition, and not all definitions
of the key
- unescaping needs to be done also for the last entry
If an autostart file for GNOME has a phase specified, then this implies
it is a session service that needs to be started at a specific time.
We have no way of handling the ordering, and while it does make sense
to explicitly hide these services with X-systemd-skip, there is no point
in even trying to handle them.
This is a follow-up for 9f83091e3c.
Instead of reading the mtime off the configuration files after reading,
let's do so before reading, but with the fd we read the data from. This
is not only cleaner (as it allows us to save one stat()), but also has
the benefit that we'll detect changes that happen while we read the
files.
This also reworks unit file drop-ins to use the common code for
determining drop-in mtime, instead of reading system clock for that.
This generator can be used by desktop environments to launch autostart
applications and services. The feature is an opt-in, triggered by
xdg-desktop-autostart.target being activated.
Also included is the new binary xdg-autostart-condition. This binary is
used as an ExecCondition to test the OnlyShowIn and NotShowIn XDG
desktop file keys. These need to be evaluated against the
XDG_CURRENT_DESKTOP environment variable which may not be known at
generation time.
Co-authored-by: Henri Chain <henri.chain@enioka.com>
Zbigniew Jędrzejewski-Szmek