BenV's notes

This one has been on my todo list for a while, so today I took a stab at it: a fail2ban plugin for Check_MK.
My previous plugin (LMSensors plugin for Check_MK) still gets quite a few hits, so I figured you guys might like this one as well.

Why? Pretty graphs of course 😉
Another reason might be that you want to keep an eye on how many ssh bots etc fail2ban keeps out. (continue reading…)

Just ran into this one, noting it down for anyone else with this error:

Trying to compile Lua 5.2.3 (which should try to invest some in autoconf / cmake or something) gave me this lovely error:

make[2]: Entering directory `/usr/src/lua-5.2.3/src'
gcc -o lua lua.o liblua.a -lm -Wl,-E -ldl -lreadline
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tputs'
echo Stom product, Makefile editen, dan make MYLIBS="-lncurses" anders breekt ie op readline.
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgoto'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetflag'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `UP'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetent'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetnum'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `PC'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetstr'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `BC'
collect2: error: ld returned 1 exit status
make[2]: *** [lua] Error 1
make[2]: Leaving directory `/usr/src/lua-5.2.3/src'
make[1]: *** [linux] Error 2
make[1]: Leaving directory `/usr/src/lua-5.2.3/src'
make: *** [linux] Error 2


Reason: it needs to link against ncursus in Slackware (or alternatively libtermcap, but ncursus worked for me).
Solution – use make MYLIBS=”-lncursus”:

make MYLIBS="-lncurses"
cd src && make linux
make[1]: Entering directory `/usr/src/lua-5.2.3/src'
make all SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-Wl,-E -ldl -lreadline"
make[2]: Entering directory `/usr/src/lua-5.2.3/src'
gcc -o lua lua.o liblua.a -lm -Wl,-E -ldl -lreadline -lncurses
gcc -o luac luac.o liblua.a -lm -Wl,-E -ldl -lreadline -lncurses
make[2]: Leaving directory `/usr/src/lua-5.2.3/src'
make[1]: Leaving directory `/usr/src/lua-5.2.3/src'


I just ran into something funny:

root@machine:~$ slackpkg update

root@machine:~$

Huh. I didn’t do anything weird with slackpkg….
Waaait a minute…

root@machine:~$ unset GREP_OPTIONS
root@machine:~$ slackpkg update
# Cut out the fetching of Changelog.txt
No changes in ChangeLog.txt between your last update and now.
Do you really want to download all other files (y/N)?

Apparently slackpkg breaks if you set GREP_OPTIONS to “–color=always”. Good to know for when I break it this way next time 😉

Yay, another new linux kernel. Of course this broke the closed NVidia driver, I tried 331.38:

[ 110.917769] nvidia: Unknown symbol acpi_os_wait_events_complete (err 0)

The fix for this is easy, unpack the installer and then patch file kernel/nv-acpi.c hack out line 306:

// NV_ACPI_OS_WAIT_EVENTS_COMPLETE();

Run nvidia-installer and you should be good to go. Incredible that it always takes NVidia forever to fix these things, this bug has been known since at least 3.13-rc1. Oh well.

Next up, testing nftables. Looks like iptables will soon be obsolete 🙂
Here’s a nice howto to get you started – https://home.regit.org/netfilter-en/nftables-quick-howto/.
Update:
Might you be wondering (like me) where the heck the libnftables git repository went: they decided to rename the thing to libnftnl. You can find the repository here – https://git.netfilter.org/libnftnl/

Another thing: compiling nftables from git breaks on my Slackware64-current machine atm because 1. configure.ac still points to libnftables (instead of libnftl), I assume this will be fixed within the hour. 2: it tries to compile against libreadline without linking libncurses.
Fix for that is running configure like: LDFLAGS=-lncurses ./configure