This adds a function sd_bus_slot_set_destroy_callback() to set a function
which can free userdata or perform other cleanups.
sd_bus_slot_get_destory_callback() queries the callback, and is included
for completeness.
Without something like this, for floating asynchronous callbacks, which might
be called or not, depending on the sequence of events, it's hard to perform
resource cleanup. The alternative would be to always perform the cleanup from
the caller too, but that requires more coordination and keeping of some shared
state. It's nicer to keep the cleanup contained between the callback and the
function that requests the callback.
This shows a minor memleak:
==1883== 24 bytes in 1 blocks are definitely lost in loss record 1 of 1
==1883== at 0x4C2DBAB: malloc (vg_replace_malloc.c:299)
==1883== by 0x4E9D385: malloc_multiply (alloc-util.h:69)
==1883== by 0x4EA2959: bus_request_name_async_may_reload_dbus (bus-util.c:1841)
==1883== by ...
The exchange of messages is truncated at two different points: once right
after the first callback is requested, and the second time after the full
sequence has run (usually resulting in an error because of policy).
The only difference is that functions are not individually listed by name,
but that seems completely pointless, since all functions that are documented
are always exported, so the generic text tells the user all she or he needs
to know.
LOG_MESSAGE is just a wrapper, but it keeps the arguments indented together
with the format string, so put the argument inside of the macro invocation.
(No functional change.)
Also use lowercase for "trust anchor" — it should either be all capitaled or not
at all, and it's not a proper name, so let's make it all lowercase.
Also, add a newline, to make the string more readable. "%s" can expand to
something that is quite long.
There are different Cube i7 Stylus generations.
Those are identified with the printed serial code sticker on motherboard (Printed serial code on casing is not always true)
Order of Model (Old - New):
W
WA
WWA
WN(I8WN)
I8L(With W on casing)
I own a I8L generation so the hw identification for my model does not work.
# cat /sys/class/dmi/id/sys_vendor
Cube
# сat /sys/class/dmi/id/product_name
i8-L
The test is heavily dependent on timeouts, and if we are run in
potentially very slow QEMU instances there's a good chance we'll miss
some which we normally wouldn't miss. Hence, let's test this one in
nspawn only. Given that the test is purely in service management it
shouldn't matter whether it runs in nspawn or qemu, hence keep running
it in nspawn, but don't bother with qemu.
Similar, do this for TEST-03-JOBS, too, which operates with relatively
short sleep times internally.
Fixes: #9123
It's a bit prettier that day as the function won't silently overwrite
any possibly pre-initialized field, and destroy it right before we
allocate a new event source.
This tests a couple of corner cases of the sd-event API including
changing priorities of existing event sources, as well as overflow
conditions of the inotify queue.
This adds a new call sd_event_add_inotify() which allows watching for
inotify events on specified paths.
sd-event will try to minimize the number of inotify fds allocated, and
will try to add file watches to the same inotify fd objects as far as
that's possible. Doing this kind of inotify object should optimize
behaviour in programs that watch a limited set of mostly independent
files as in most cases a single inotify object will suffice for watching
all files.
Traditionally, this kind of coalescing logic (i.e. that multiple event
sources are implemented on top of a single inotify object) was very hard
to do, as the inotify API had serious limitations: it only allowed
adding watches by path, and would implicitly merge watches installed on
the same node via different path, without letting the caller know about
whether such merging took place or not.
With the advent of O_PATH this issue can be dealt with to some point:
instead of adding a path to watch to an inotify object with
inotify_add_watch() right away, we can open the path with O_PATH first,
call fstat() on the fd, and check the .st_dev/.st_ino fields of that
against a list of watches we already have in place. If we find one we
know that the inotify_add_watch() will update the watch mask of the
existing watch, otherwise it will create a new watch. To make this
race-free we use inotify_add_watch() on the /proc/self/fd/ path of the
O_PATH fd, instead of the original path, so that we do the checking and
watch updating with guaranteed the same inode.
This approach let's us deal safely with inodes that may appear under
various different paths (due to symlinks, hardlinks, bind mounts, fs
namespaces). However it's not a perfect solution: currently the kernel
has no API for changing the watch mask of an existing watch -- unless
you have a path or fd to the original inode. This means we can "merge"
the watches of the same inode of multiple event sources correctly, but
we cannot "unmerge" it again correctly in many cases, as access to the
original inode might have been lost, due to renames, mount/unmount, or
deletions. We could in theory always keep open an O_PATH fd of the inode
to watch so that we can change the mask anytime we want, but this is
highly problematics, as it would consume too many fds (and in fact the
scarcity of fds is the reason why watch descriptors are a separate
concepts from fds) and would keep the backing mounts busy (wds do not
keep mounts busy, fds do). The current implemented approach to all this:
filter in userspace and accept that the watch mask on some inode might
be higher than necessary due to earlier installed event sources that
might have ceased to exist. This approach while ugly shouldn't be too
bad for most cases as the same inodes are probably wacthed for the same
masks in most implementations.
In order to implement priorities correctly a seperate inotify object is
allocated for each priority that is used. This way we get separate
per-priority event queues, of which we never dequeue more than a few
events at a time.
Fixes: #3982
