Reset terminal on erroneous console exit

[mcktr]

This ensures that the terminal is reset on an erroneous exit when using the Icinga 2 console. The problematic state only occurs if Icinga 2 is compiled with libedit support.

Test

1. Start the Icinga 2 console and choose an invalid port.

metis ~/Coding/icinga/icinga2/build_debug (fix/erroneous-console-exit) # /home/michael/bin/icinga2/sbin/icinga2 console --connect https://localhost:9999/
Icinga 2 (version: v2.9.1-50-g51b900b30)
Type $help to view available commands.
<1> =>

2. Now hit the tab key. The console (correctly) terminates with an critical error because of the invalid port.

metis ~/Coding/icinga/icinga2/build_debug (fix/erroneous-console-exit) # /home/michael/bin/icinga2/sbin/icinga2 console --connect https://localhost:9999/
Icinga 2 (version: v2.9.1-50-g51b900b30)
Type $help to view available commands.
<1> => critical/TcpSocket: Invalid socket: Connection refused
critical/ConsoleCommand: HTTP query failed: std::exception

3. Hit the return key.

metis ~/Coding/icinga/icinga2/build_debug (fix/erroneous-console-exit) # /home/michael/bin/icinga2/sbin/icinga2 console --connect https://localhost:9999/
Icinga 2 (version: v2.9.1-50-g51b900b30)
Type $help to view available commands.
<1> => critical/TcpSocket: Invalid socket: Connection refused
critical/ConsoleCommand: HTTP query failed: std::exception
metis ~/Coding/icinga/icinga2/build_debug (fix/erroneous-console-exit) #

4. The terminal stays intact.

fixes #6382

[Crunsher]

Nice, this has always been bugging me but never enough to fix it myself ^_^

[Crunsher]

While testing this I noticed I can't reproduce this anymore. Meaning the result with the master and your PR is the same. So I went and looked up rl_deprep_terminal:
Function: void rl_deprep_terminal (void)
Undo the effects of rl_prep_terminal(), leaving the terminal in the state in which it was before the most recent call to rl_prep_terminal().

Is rl_prep_terminal called somehow by the library? Because we don't do so explicitly.

[mcktr]

I just tested the master on Debian 9 and I can reproduce #6382.

root@testing-deb9-icinga2:~# /tmp/icinga2/sbin/icinga2 console --connect https://localhost:9999/
Icinga 2 (version: v2.9.1-55-g33492420f)
Type $help to view available commands.
<1> => critical/TcpSocket: Invalid socket: Connection refused
critical/ConsoleCommand: HTTP query failed: std::exception
root@testing-deb9-icinga2:~# root@testing-deb9-icinga2:~# root@testing-deb9-icinga2:~# root@testing-deb9-icinga2:~#

Notice that this only occurse if you press the tab key.

The function rl_reset_terminal seems to fit better here. Unfortunately this works for /tmp/icinga2/lib/icinga2/sbin/icinga2 console --connect https://localhost:9999/ but not for /tmp/icinga2/sbin/icinga2 console --connect https://localhost:9999/.

From a look I into the library I guess rl_prep_terminal is not called by the library. Basicly the two functions set the tty mode (rl_prep_terminal for raw mode and rl_deprep_terminal for cooked mode). I can't rule out that the raw mode getting set during the readline call, but in an other fashion.

[dnsmichi]

Current

Fixed

[dnsmichi]

(Ok you cannot set it, but terminal 1 is broken, terminal 2 works)

[dnsmichi]

Thanks 👍