Wrong last user in tomb list

[arthaud]

Hi,

When I'm using tomb list, the last visited user is wrong.

It's because you are looking for :$uid: in /etc/passwd. Actually, my /etc/passwd looks like:

maxima:x:1000:100:maxima:/home/maxima:/bin/zsh
skype:x:1001:1000::/home/skype:/bin/false

and therefore, looking for :1000:, user skype is found instead of me.

This happens here: https://github.com/dyne/Tomb/blob/master/tomb#L1821-L1824 and there: https://github.com/dyne/Tomb/blob/master/tomb#L1986-L1989

You could probably use getent passwd $uid

[hellekin]

Right, is getent available for *BSD?

Otherwise using awk could work as well:

tombuser=$(awk -F: '/^[^:]+:x:'$tombuid':/ {print $1}' /etc/passwd)

Using getent:

tombuser=$(getent passwd $tombuid | awk -F: '{print $1}')

[arthaud]

I don't know. Your example using awk seems good.

[hellekin]

Minimal patch, replace:

[[ "$ee" =~ ":${tombuid}:" ]] && {

with

[[ "$ee" =~ ":x:${tombuid}:" ]] && {

(Both my proposals assume use of shadow passwords.)

[boyska]

On Tue, Apr 14, 2015 at 01:40:28PM -0700, hellekin wrote:

Otherwise using awk could work as well:

tombuser=$(awk -F: '/^[^:]+:x:'$tombuid':/ {print $1}' /etc/passwd)

I'd prefer

awk -F: '$4 == '$tombuid' { print $1 }'

tombuser=$(getent passwd $tombuid | awk -F: '{print $1}')

this is maybe clearer with cut:

getent passwd $tombuid | cut -d: -f1

[hellekin]

Fair enough.

[hellekin]

@jaromil I put the fix into a branch. Please ack and close the issue.

[jaromil]

ACK. Thanks @arthaud, well spotted. Three observations:

1) Tomb is not compabible with BSD. If we aim for that, we need some BSD expert to join our team first, then we can target use of tcplay instead of cryptsetup (hence modularize that part of the code) and then finalize. Until we take this route the only concern against using getent is about avoiding the spawn of a new binary (hence depending from its integrity, yet this isn't a critical role for it in the script and its not suid when run).

2) ZSh has native support for simple string-token operations, which is preferable than spawning extra processes. In this case an half native formula would be:

getent passwd $tombuid | sysread tombuser
tombuser=${tombuser[(ws@:@)1]}

or without the zmodule zsh/system (which I think we aren't using in Tomb, perhaps we should)

tombuser=$(getent passwd $tombuid)
tombuser=${tombuser[(ws@:@)1]}

@hellekin if you like to update your pull request with the latter, I agree to merge it.

3) We may want to avoid using getent and have a fully native ZSh approach to parsing passwd

[boyska]

point 3 is conceptually wrong. getent does not just read /etc/passwd, it

get entries from Name Service Switch libraries

so if you want to reimplement it (but why?) you should actually reimplement a parser for /etc/nsswitch.conf; good luck with that.

[jaromil]

Eventually, in 3) I mention we may parse /etc/passwd natively, not cover all getent functionalities.

[boyska]

So you might not found the user. Not every user is in /etc/passwd.

[jaromil]

You are right. Lets resort to solution 2). Wait for hellekin to respond so we don't waste his branch, he is on another timezone.