Previously the mkdir_label() family of calls was implemented in
src/shared/mkdir-label.c but its functions partly declared ins
src/shared/label.h and partly in src/basic/mkdir.h (!!). That's weird
(and wrong).
Let's clean this up, and add a proper mkdir-label.h matching the .c
file.
When using "capture : true" in custom_target()s the mode of the source
file is not preserved when the generated file is not installed and so
needs to be tweaked manually. Switch from output capture to creating the
target file and copy the permissions from the input file.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
rearrange_stdio() invalidates specified fds even on failure, which means
we should always invalidate the fds we pass in no matter what. Let's
make this explicit by using TAKE_FD() for that everywhere.
Note that in many places we such invalidation doesnt get us much
behaviour-wise, since we don't use the variables anymore later. But
TAKE_FD() in a way is also documentation, it encodes explicitly that the
fds are invalidated here, so I think it's a good thing to always make
this explicit here.
Most sd_notify() calls are like log_info() — the result is only informative
and if they fail, it's best ignore this. But if a call with READY=1 fails,
the unit may enter a failed state, so we should warn about this. Similarly
for FSTOREREMOVE=1: the manager may be left with a stale fd, at least wasting
resources.
Those devices show up as /sys/devices/vif-N, let's use that number
to name them enXN.
Without this, all schemes fail and they keep the kernel names, which can
be racy.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Let's define two helpers strdupa_safe() + strndupa_safe() which do the
same as their non-safe counterparts, except that they abort if called
with allocations larger than ALLOCA_MAX.
This should ensure that all our alloca() based allocations are subject
to this limit.
afaics glibc offers three alloca() based APIs: alloca() itself,
strndupa() + strdupa(). With this we have now replacements for all of
them, that take the limit into account.
udev: use netlink more aggressively
I'm pasting the comment from https://github.com/systemd/systemd/pull/20744#issuecomment-934485287
which is quite informative. The code wasn't changed significantly since then:
atenart commented 6 days ago:
> I ran tests without (93caec7) and with this PR (06735f2) on Fedora, having a few udev rules
> using attributes eligible to be cached and creating 50 veth on 4 CPUs. Although the time spent
> running the test is variable between runs, I generally saw an improvement when using this PR, e.g:
>
> 249-910-g93caec7:
> real 0m3.691s
> user 0m0.022s
> sys 0m1.338s
>
> 249-920-g06735f2:
> real 0m2.950s
> user 0m0.005s
> sys 0m0.399s
>
> On a different system than the one used above, I even saw a 40% improvement; results depend
> on many parameters (distro, udev rules, concurrent daemons accessing sysfs, etc.).
>
> Because it's quite hard to measure the improvement here (as the kernel behave differently between
> the two test cases), I also ran tests using a modified kernel not hitting the trylock logic. There was
> an improvement with this PR as well. (Take this with a grain of salt though, as the kernel was
> modified not using patches approved upstream).
LLVM 13 introduced `-Wunused-but-set-variable` diagnostic flag, which
trips over some intentionally set-but-not-used variables or variables
attached to cleanup handlers with side effects (`_cleanup_umask_`,
`_cleanup_(notify_on_cleanup)`, `_cleanup_(restore_sigsetp)`, etc.):
```
../src/basic/process-util.c:1257:46: error: variable 'saved_ssp' set but not used [-Werror,-Wunused-but-set-variable]
_cleanup_(restore_sigsetp) sigset_t *saved_ssp = NULL;
^
1 error generated.
```
Previously, the devlink was created based on the priority saved in udev
database. So, we needed to reevaluate devlinks after database is saved.
But now the priority is stored in the symlink under /run/udev/links, and
the loop of devlink creation is controlled with the timestamp of the
directory. So, the double evaluation is not necessary anymore.
By the previous commit, it is not necessary to distinguish if the devlink
already exists. Also, I cannot find any significant advantages of the
previous complecated logic, that is, first try to create directly, and then
fallback to atomically creation. Moreover, such logic increases the chance
of conflicts between multiple udev workers.
This makes devlinks always created atomically. Hopefully, this reduces the
conflicts between the workers.
During creating a symlink to a device node, if another device node which
requests the same symlink is added/removed, `stat_inode_unmodified()`
should always detects that. We do not need to continue the loop
unconditionally.
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Emily Gonyer
Christian Brauner
Luca Boccassi
Benjamin Herrenschmidt
Frantisek Sumsal
Anita Zhang