Terminal goes crazy when I use sudo/su

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

So yesterday I upgraded my system and today when I rebooted - craziness. When I open a terminal and I try to use sudo, it works but once the sudo'ed command starts execution, it gets into a weird loop where the shell prompt keeps repeating over and over - it's like the enter key is blocked or being pressed constantly. I've also noticed that the same happens with su (root prompt appears in a loop), and I can't use the 'exec' command (I need it to start my WM).

I'd post logs - but they don't actually show anything unusual of any kind! And once the terminal starts acting up, the keyboard blocks and I can't do anything, so I'm unable to take screenshots.

Has anyone ever seen anything like this before?

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

Added weirdness: this only seems to happen when I'm using a terminal with a login shell! So for example, if I start my terminal with 'urxvt -e zsh' the terminal works perfectly, if I just run 'urxvt' without extra arguments - boom.

Ant P. · Watchman Joined: 18 Apr 2009 Posts: 6920

Does your urxvt have any plugins enabled? Does it work without those?

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

I only had the URL matcher plugin enabled. Disabling it didn't help. I've been digging and messing around a bit, and now it seems like the problem appears only if the following conditions are all met:

- I'm running a terminal emulator under X (using sudo in the tty works just fine).
- I'm running a login shell in this terminal emulator (using 'urxvt -e zsh' allows me to sudo).

I tried a blank .zshrc and .zprofile - no luck there either, and afterwards I discovered that bash had the same problem.

I've also been facing a few problems with X which are related to the upgrade to Xorg 1.16 (was made stable this Thursday, just before I upgraded my system). Think DM's not working properly any more. I'm not sure if that's directly related but since the problem only appears in X terminals ...

khayyam · Posted: Sun Feb 22, 2015 12:44 am Post subject:

sinopeus ...

on this update did you updater perl, and subsequently run 'perl-cleaner --all'? urxvt links to perl, and given the odd behavior seems to be localised to the terminal this may be the issue. In my case x11-terms/rxvt-unicode was re-merged with perl-cleaner.

BTW, rather than use "a blank .zshrc" you can do the following: 'env -i zsh -f' (or just 'zsh -f' ... if you don't want to make sure the env is absoultely free of any variables).

best ... khay

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

My last Perl upgrade was on the 12th of February and the system has been fully functional up to Thursday the 19th. I ran perl-cleaner anyway and it didn't find anything to unmerge or rebuild ... So I'm thinking it has nothing to do with perl. What I did notice is: if I use a different graphical terminal (I've tried st and terminator), sudo does work, so I'm now thinking that it does have something to do with urxvt specifically. BUT: it only works if I use some kind of launcher to run them - if I open urxvt, run the command 'st' or 'terminator', and try sudo in the resulting window, the same problem occurs.

I tried out the env command as well. It seems that doing sudo in the shell resulting from 'env -i zsh -f' works perfectly! So it's probably something to do with my environment, since I've already tried running without a .zshrc? But I'd find that a bit strange. I used the env command to print out the environment variables for both a login shell and non-login shell in urxvt and they're exactly the same ...

EDIT: I've now excluded ZSH being at fault. 'env -i sudo' works within any shell. So how do I start digging through my environment to find the culprit?

khayyam · Posted: Sun Feb 22, 2015 3:21 pm Post subject:

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

I'm not. Using grml-zsh, which is a lot less broken than oh-my-zsh in my experience. Note that running 'env -i sudo -i' works perfectly (i.e. the problem is not with zsh, since sudo -i starts a zsh login shell from another zsh login shell). The problem also appears in other shells if used in the same manner. So setting bash or tcsh (I tested those two) as my login shell and trying to use sudo in urxvt caused the exact same problem. Also - the configuration was working perfectly and hasn't changed a lot in the past six months (except adding an alias here or there). So I don't think my zsh config can be the cause.

It's just very weird behaviour. At first sight it seems like a problem with the shell because of the shell prompt appearing in a loop, but if I run for ex. 'sudo emerge <package>' the emerge command goes through fine, except there's a line break after every character - it's like the enter key is being pressed continuously.

khayyam · Posted: Sun Feb 22, 2015 7:55 pm Post subject:

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

sinopeus · n00b Joined: 20 Feb 2015 Posts: 7

Found the solution.

https://bbs.archlinux.org/viewtopic.php?id=185398

I was running urxvtd as a systemd user service as well. Now I've put it into xinitrc and it works just fine. It's only since the xorg 1.16 upgrade that this happened and I haven't got a clue why. I'll report to the thread on the Arch BBS that I have had the same problem. This explains why urxvt worked perfectly ...