chase_symlinks() can return its last O_PATH fd to us. Let's use that and
make the access() check a bit tighter by going via faccessat() on the
O_PATH fd.
This doesn't really change too much, but is nice in context of the next
commit, which uses the O_PATH fd in one other way.
Simplify generated sysfs paths, since we might get data passed that
includes extra // in the middle.
Also, let's not assume /sys/ prefix without verification.
GIT_VERSION is not available as a config.h variable, because it's rendered
into version.h during builds. Let's rework jinja2 rendering to also
parse version.h. No functional change, the new variable is so far unused.
I guess this will make partial rebuilds a bit slower, but it's useful
to be able to use the full version string.
This can be problematic especially when there's no more free disk
space. Consider the following:.
When disk space becomes sparse, writting to the system journal can lead to
error. In this case journald attempts to make room by rotating the journals,
which consists in archiving online journals and opening new ones.
However opening new files is likely to fail too and in this case
journal_file_open() leaves half initialized file around but in online
state. Then the error is propagated and journald switches into volatile mode.
Next time a new message is received by journald, it tries to open the
persistent system journal file to switch automatically back to persistent
mode.
When opening the system journal, journal_file_open(), called by
managed_journal_file_open_reliably(), finds the persistent system journal left
previously and assumes that it was uncleanly closed and considers it as
corrupted. The error is reported to managed_journal_file_open_reliably(), which
backs the file up and attempts to create a new system file, which fails and
leaves a corrupted system file again.
Since this is done for each message received by journald, /var/log/message can
be filled with backup files pretty quickly.
To prevent this, the patch makes sure to delete the newly created file in case
of error.
We usually open() device node obtained by sd_device_get_devname().
However, the device node corresponds to the sd-device object may be
already removed, and another device node with the same path may be
created, hence an unexpected device may be opened.
The sd_device_open() opens device node, and checks the devnum and
diskseq of opened devnum, to avoid the above possibility.
Prompted by https://github.com/systemd/systemd/issues/22906#issuecomment-1082736443.
Let's raise our supported baseline a bit: CLOCK_BOOTTIME started to work
with timerfd in kernel 3.15 (i.e. back in 2014), let's require support
for it now.
This will raise our baseline only modestly from 3.13 → 3.15.
Same idea as 03677889f0.
No functional change intended. The type of the iterator is generally changed to
be 'const char*' instead of 'char*'. Despite the type commonly used, modifying
the string was not allowed.
I adjusted the naming of some short variables for clarity and reduced the scope
of some variable declarations in code that was being touched anyway.
When sorting paths it actually matters to use the right comparison
function. Example:
```
a/x
a-b/y
a_/z
```
I think people would probably expect this:
```
a/x
a-b/y
a_a/z
```
but if you use strcmp() instead of path_compare() you'd instead get:
```
a-b/y
a/x
a_a/z
```
That's because `/` is between `-` and `a` in the ascii table. I think
that's quite confusing, and we shouldn#t order that way hence.
As discussed: https://github.com/systemd/systemd/pull/22662#discussion_r831174776
Lennart Poettering
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Franck Bui