I tested this on my ZBook Studio G5. I'm not sure if this works for other ZBook studio machines.
I have two more notes on this PR:
- some keys send multiple scancodes. I matched only on one of them, because I couldn't figure out how to match
on all of them. This results in the others still being visible:
Event: time 1604520228.146226, -------------- SYN_REPORT ------------
Event: time 1604520228.151533, type 4 (EV_MSC), code 4 (MSC_SCAN), value db
Event: time 1604520228.151533, type 1 (EV_KEY), code 125 (KEY_LEFTMETA), value 1
Event: time 1604520228.151533, -------------- SYN_REPORT ------------
Event: time 1604520228.259862, type 4 (EV_MSC), code 4 (MSC_SCAN), value 38
Event: time 1604520228.259862, type 1 (EV_KEY), code 56 (KEY_LEFTALT), value 0
Event: time 1604520228.259862, -------------- SYN_REPORT ------------
Event: time 1604520228.259944, type 4 (EV_MSC), code 4 (MSC_SCAN), value 66
Event: time 1604520228.259944, type 1 (EV_KEY), code 218 (KEY_CONNECT), value 0
Event: time 1604520228.259944, -------------- SYN_REPORT ------------
Event: time 1604520228.266513, type 4 (EV_MSC), code 4 (MSC_SCAN), value db
Event: time 1604520228.266513, type 1 (EV_KEY), code 125 (KEY_LEFTMETA), value 0
Event: time 1604520228.266513, -------------- SYN_REPORT ------------
I wanted to set the display key to switchvideomode, but another key is already set to that, so I set it to displaytoggle instead.
There are downsides to using fexecve:
when fexecve is used (for normal executables), /proc/pid/status shows Name: 3,
which means that ps -C foobar doesn't work. pidof works, because it checks
/proc/self/cmdline. /proc/self/exe also shows the correct link, but requires
privileges to read. /proc/self/comm also shows "3".
I think this can be considered a kernel deficiency: when O_CLOEXEC is used, this
"3" is completely meaningless. It could be any number. The kernel should use
argv[0] instead, which at least has *some* meaning.
I think the approach with fexecve/execveat is instersting, so let's provide it
as opt-in.
For scripts, when we call fexecve(), on new kernels glibc calls execveat(),
which fails with ENOENT, and then we fall back to execve() which succeeds:
[pid 63039] execveat(3, "", ["/home/zbyszek/src/systemd/test/test-path-util/script.sh", "--version"], 0x7ffefa3633f0 /* 0 vars */, AT_EMPTY_PATH) = -1 ENOENT (No such file or directory)
[pid 63039] execve("/home/zbyszek/src/systemd/test/test-path-util/script.sh", ["/home/zbyszek/src/systemd/test/test-path-util/script.sh", "--version"], 0x7ffefa3633f0 /* 0 vars */) = 0
But on older kernels glibc (some versions?) implement a fallback which falls
into the same trap with bash $0:
[pid 13534] execve("/proc/self/fd/3", ["/home/test/systemd/test/test-path-util/script.sh", "--version"], 0x7fff84995870 /* 0 vars */) = 0
We don't want that, so let's call execveat() ourselves. Then we can do the
execve() fallback as we want.
Previously it was very likely, when multiple contenders for the symlink
appear in parallel, that algorithm would select wrong symlink (i.e. one
with lower-priority).
Now the algorithm is much more defensive and when we detect change in
set of contenders for the symlink we reevaluate the selection. Same
happens when new symlink replaces already existing symlink that points
to different device node.
Note that st_mtime member of struct stat is defined as follows,
#define st_mtime st_mtim.tv_sec
Hence we omitted checking nanosecond part of the timestamp (struct
timespec) and possibly would miss modifications that happened within the
same second.
FixedRandomDelay=yes will use
`siphash24(sd_id128_get_machine() || MANAGER_IS_SYSTEM(m) || getuid() || u->id)`,
where || is concatenation, instead of a random number to choose a value between
0 and RandomizedDelaySec= as the timer delay.
This essentially sets up a fixed, but seemingly random, offset for each timer
iteration rather than having a random offset recalculated each time it fires.
Closes#10355
Co-author: Anita Zhang <the.anitazha@gmail.com>
Lennart Poettering
onlybugreports
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
fwSmit
Michal Sekletár
Ronan Pigott
Jian-Hong Pan
Kristijan Gjoshev