This pulls out the hwdb managment from udevadm into an independent tool.
The old code is left in place for backwards compatibility, and easy of
testing, but all documentation is dropped to encourage use of the new
tool instead.
In next_beyond_location() when the JournalFile's location type is
LOCATION_SEEK, it means there's nothing to do, because we already have
the location of the candidate entry. Do an early return. Note that now
next_beyond_location() does not anymore guarantee on return that the
entry is mapped, but previous patches made sure the caller does not
care.
This optimization is at least as good as "journal: optimize iteration:
skip files that cannot improve current candidate entry" was.
Timing results on my workstation, using:
$ time ./journalctl -q --since=2014-06-01 --until=2014-07-01 > /dev/null
Before "Revert "journal: optimize iteration: skip files that cannot
improve current candidate entry":
real 0m5.349s
user 0m5.166s
sys 0m0.181s
Now:
real 0m3.901s
user 0m3.724s
sys 0m0.176s
If from a previous iteration we know we are at the end of a journal
file, don't bother looking into the file again. This is complicated by
the fact that the EOF does not have to be permanent (think of
"journalctl -f"). So we also check if the number of entries in the
journal file changed.
This optimization has a similar effect as "journal: optimize iteration:
skip whole files behind current location" had.
set_location() is called from real_journal_next() when a winning entry
has been picked from among the candidates in journal files.
The location type is always set to LOCATION_DISCRETE. No need to pass
it as a parameter.
The per-JournalFile location information is already updated at this
point. No need for having the direction and offset here.
In next_beyond_location() when we find a candidate entry in a journal
file, save its location information in struct JournalFile.
The purpose of remembering the locations of candidate entries is to be
able to save work in the next iteration. This patch does only the
remembering part.
LOCATION_SEEK means the location identifies a candidate entry.
When a winner is picked from among candidates, it becomes
LOCATION_DISCRETE.
LOCATION_TAIL here signifies we've iterated the file to the end (or the
beginning in the case of reversed direction).
fork() is not async-signal-safe and calling it from the signal handler
could result in a deadlock when at_fork() handlers are called. Using
the raw clone() syscall sidesteps that problem.
The tricky part is that raise() does not work, since getpid() does not
work. Add raw_getpid() to get the real pid, and use kill() instead of
raise().
https://bugs.freedesktop.org/show_bug.cgi?id=86604
If child supports, but the parent does not, or when the child does
not support, but the parent does, assume the child is a mount point.
Only if neither supports use the fallback.
dup3() allows setting O_CLOEXEC which we are not interested in. However,
it also fails if called with the same fd as input and output, which is
something we don't want. Hence use dup2().
Also, we need to explicitly turn off O_CLOEXEC for the fds, in case the
input fd was O_CLOEXEC and < 3.
[zj: When we lstat the target path, symlinks above the last component
will be followed by both stat and lstat. So when we look at the
parent, we should follow symlinks.]
'systemctl cat' now works for templates too.
'systemctl edit' does not refuse to edit units that have changed on
disk. That restriction didn't seem useful, actually editing units that
have changed on disk before they are started is very reasonable.
'edit' with instances and templates works again:
Now:
$ build/systemctl edit getty@
Failed to copy /etc/systemd/system/getty@.service.d/override.conf to /etc/systemd/system/getty@.service.d/.override.confdff6290408c86369: Permission denied
$ build/systemctl edit getty@tty3
Failed to create directories for /etc/systemd/system/getty@tty3.service.d/override.conf: Permission denied
$ build/systemctl edit --full getty@tty3
Failed to copy /usr/lib/systemd/system/getty@.service to /etc/systemd/system/.getty@tty3.serviced3d175087e7e439b: Permission denied
Failed to create temporary file for /etc/systemd/system/getty@tty3.service: Permission denied
$ build/systemctl edit --full getty@
Failed to copy /usr/lib/systemd/system/getty@.service to /etc/systemd/system/.getty@.servicea3caad491c0f2f3d: Permission denied
Failed to create temporary file for /etc/systemd/system/getty@.service: Permission denied
Note that the MS receivers likely work like the Logitech ones, i.e. all
devices connected show up with the same vid/pid/name. Full evidence remains to
be gathered.
