Bug#841935: pbuilder: incorrect permissions on /dev/ptmx breaks openpty()

[Thorsten Glaser]

@debootstrap maintainers, look near the end for a tl;dr

James Clarke dixit:

>> # ls -l /dev/ptmx
>> lrwxrwxrwx 1 root root 8 Oct  4 06:43 /dev/ptmx -> pts/ptmx
>> # ls -l /dev/pts/ptmx
>> c--------- 1 root root 5, 2 Oct 24 14:46 /dev/pts/ptmx

>> For comparison this is from my regular system:
>> $ ls -l /dev/ptmx /dev/pts/ptmx
>> crw-rw-rw- 1 root tty  5, 2 okt 24 17:03 /dev/ptmx
>> c--------- 1 root root 5, 2 okt 11 12:35 /dev/pts/ptmx

>for std{in,out,err}. I tried many months ago and couldn’t get it to work,
>but would love to be proved wrong.

So, the real problem is the symlink, I guess? This has also
been annoying me for mksh, whose testsuite uses script(1)
since forever (so I’m happy util-linux now uses it too).

I see that in all “old” and “old and upgraded” chroots I
have (sid started during lenny times), I have this setup…

ls: cannot access 'base.cow-sid-i386/dev/pts/ptmx': No such file or directory
crw-rw-rw- 1 root tty 5, 2 Okt 23 00:40 base.cow-sid-i386/dev/ptmx

… whereas all “new” chroots look like…

ls: cannot access 'base.cow-xenial-amd64/dev/pts/ptmx': No such file or directory
lrwxrwxrwx 1 root root 8 Mai 10 14:10 base.cow-xenial-amd64/dev/ptmx -> pts/ptmx

… so I assume that something in debootstrap changed so that
there is now a symlink created instead of a proper device node.

Maybe the debootstrap maintainers can comment on this?

Thanks,
//mirabilos
-- 
18:47⎜<mirabilos:#!/bin/mksh> well channels… you see, I see everything in the
same window anyway      18:48⎜<xpt:#!/bin/mksh> i know, you have some kind of
telnet with automatic pong         18:48⎜<mirabilos:#!/bin/mksh> haha, yes :D
18:49⎜<mirabilos:#!/bin/mksh> though that's more tinyirc – sirc is more comfy