Bash completion

[Aneurin Price]

Hello all,

I spent a bit of time this afternoon writing a bash completion script
for zfs and zpool since I didn't really like the only one I could
find. It's something I've just hacked together quickly so it's far
from complete, and I haven't spent much time testing it. That said, I
think it covers all the options I use with any frequency, and a fair
bit more, so I thought I'd post it now rather than wait until it's
finished - since that may never happen.

I hope this is of some use to someone. If you do try it, let me know
if there are any problems.

Nye

[Seth Heeren]

Aneurin,

this is very good stuff. I spot a number of omissions

- datasets now need "-t all" since a while
- split is missing
- some of the commands listed are not actually supported

But overall the experience is just Rolls Royce!

>  zfs_completion.bash
> 8KViewDownload

[Seth Heeren]

Oh, and lest i forget: it has been pushed to 'testing' as a very
welcome new feature to support our users!

[Aneurin Price]

On Thu, May 27, 2010 at 20:18, Seth Heeren <sghe...@hotmail.com> wrote:
> Aneurin,
>
> this is very good stuff. I spot a number of omissions
>
> - datasets now need "-t all" since a while

Thanks for pointing that out.

> - split is missing

Completely missing? It doesn't have explicit support, so the
completions for it aren't great, but you should get the 'split'
command itself plus the default poolname completion if you are using a
version of zpool which includes 'split' in its usage instructions. I
actually didn't write the specific completion for split purely because
I hadn't installed the updated manpage, so I'd missed the command
completely :-).

Taking a second look, I guess it's the <device> part that you need
adding like with 'zpool add' etc. It's not quite the same as 'split'
requires a new poolname in between the two, but I'll look into it.

> - some of the commands listed are not actually supported

This is because the script parses the usage instructions from the zfs
and zpool commands to determine what completions should be available.
I could add a filter to remove commands that are unsupported in
zfs-fuse, but it didn't seem worth the effort :P.

>
> But overall the experience is just Rolls Royce!
>

Thanks for the feedback! I am hoping to add more support for
command-specific options, plus complete the relevant switches if you
have typed the leading dash, but not otherwise (assuming this doesn't
prove technically difficult). However if I find it works well enough
for my needs then I may take an indefinite length of time get around
to it...

Nye

[Leho Kraav]

Hi

I'm trying to get zfs-fuse bash completion working with sudo. This presents a problem because calls to zfs and zpool to get completions are apparently not made with sudo, but instead the regular user. Any thoughts on how to solve this? Manually put sudo into the zfs-fuse bash completion file? I would rather not change to complete root shell, mistakes are expensive.

[Emmanuel Anne]

Errr... use zsh ? ;-)
Actually I use zsh, and zfs completions work with sudo without doing anything ! :)

2011/4/6 Leho Kraav <le...@kraav.com>

Hi

I'm trying to get zfs-fuse bash completion working with sudo. This presents a problem because calls to zfs and zpool to get completions are apparently not made with sudo, but instead the regular user. Any thoughts on how to solve this? Manually put sudo into the zfs-fuse bash completion file? I would rather not change to complete root shell, mistakes are expensive.

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[sgheeren]

On 04/06/2011 06:41 PM, Emmanuel Anne wrote:

Errr... use zsh ? ;-)
Actually I use zsh, and zfs completions work with sudo without doing anything ! :)

I use bash and it works as well.

Perhaps you haven't installed all related completion packages;
Perhaps the simplest is to alias zfs='sudo zfs' etc

Please post
  . what distro is this
  . what is output of

    (cd /etc/bash_completion_d && find)|egrep 'zfs|bash|sudo'

On Stackoverflow there is this [1]: "although bash-completion is installed. purge and reinstall solved the problem"

Good luck

[Leho Kraav]

I'm on Gentoo, my bash completion quite likely is in working condition, I think this is a problem level deeper. Googling this was in vain, all results seem to be for the first level of sudo completion, which also works for me. But nothing for the scenario when sudo is needed to retrieve bash-completion options.

\/ leho@server:2067 src  $ (cd ~/.bash_completion.d && find)|egrep 'zfs|bash|sudo'
./zfs-fuse
\/ leho@server:2069 src  $ (cd /etc/bash_completion.d && find)|egrep 'zfs|bash|sudo'
<empty>

I don't think I'm supposed to have a separate sudo bash-completion file. Do you have one? What is in that?

I just manually put sudo in front of calls in zfs-fuse b-c file and that does work as expected.

[sgheeren]

On 04/06/2011 07:52 PM, Leho Kraav wrote:
> sudo is needed to retrieve bash-completion options

aha, now I got the problem. Don't you think this can only be solved by
being root or modifying the completion scripts to use sudo throughout?

Now you mention it, my proposed method to

alias zfs="sudo zfs"
alias zpool="sudo zpool"

might work like a charm. Can/did you try it?

[Leho Kraav]

Argh, forgot to write that. I did. Unfortunately bash aliases don't get expanded inside scripts. At least it's not the default behavior and I'm not entirely sure whether this would break anything else anywhere.
 

[Stefan G. Weichinger]

Am 06.04.2011 19:52, schrieb Leho Kraav:
> I'm on Gentoo, my bash completion quite likely is in working condition,

This reminds me that my current local ebuild (with the lzo-patch)
doesn't yet have bash-completion.

Will try to add that now.

Stefan

[Stefan G. Weichinger]

done.
Unsure what to do w/ my ebuild (apart from testing it ;-) ).

File a bug at bugs.gentoo.org?
Anyone wants to test it?

Right now I call it zfs-fuse-0.7.1_beta2.ebuild here, it pulls the
"compress"-branch from Emanuels repo (has lzo, yes) and does
bash-completion now.

Stefan

[Leho Kraav]

On Wednesday, April 6, 2011 10:44:02 PM UTC+3, sgw wrote:

Unsure what to do w/ my ebuild (apart from testing it ;-) ).

File a bug at bugs.gentoo.org?
Anyone wants to test it?

Right now I call it zfs-fuse-0.7.1_beta2.ebuild here, it pulls the
"compress"-branch from Emanuels repo (has lzo, yes) and does
bash-completion now.

Definitely shoot it up on b.g.o, with perhaps a note to the 0.7.0 ebuild bug.

[Stefan G. Weichinger]

Am 07.04.2011 07:46, schrieb Leho Kraav:

> Definitely shoot it up on b.g.o, with perhaps a note to the 0.7.0 ebuild
> bug.

forgot about the note, will add now:

http://bugs.gentoo.org/show_bug.cgi?id=362431

[Aneurin Price]

The reason behind this is that (as I'm sure you're aware, but just to
make sure we're all on the same page) zfs needs to be called in order
to determine what the completions are, and as far as I can tell zfs
requires full access to /var/run/zfs/zfs_socket even to read the
relevant information.

Manually[0] putting sudo before every call would be one option,
although that could lead to a situation where you need to put in a
password when you press tab which would be strange given that you's
usually only expect the password prompt when actually entering a
command. Another option would be to use zfs only when in a root shell
so that it's no longer necessary - but I'm sure you don't want to do
that.

What I actually do is 'sudo chmod g+w /var/run/zfs/zfs_socket' and
'sudo chgrp users /var/run/zfs/zfs_socket' so that anyone in the
'users' group (ie. just me in this case) can use zfs without becoming
root. This does allow destructive operations (zpool destroy and so on)
as a normal user so might also not be desirable.

The problem boils down to the fact that there's no way to my knowledge
to query ZFS in order to get completion information, without *also*
having full control over ZFS. If there *is* a way, then that would
lead us to the ideal solution...

Hope that helps,
Nye

[0] When I say 'manually', what I would actually do is change all
calls to zfs (and zpool) to use a variable $ZFS/$ZPOOL and define that
at the top of the file so that it can be set in one place. This option
would potentially allow for automatically determining if sudo is
necessary and doing the right thing. The thing that concerns me is
that I normally do that in shell scripts as a matter of course so I'm
not sure if I didn't here simply out of laziness or if there was a
good reason not to.

[sgheeren]

On 04/07/2011 03:41 PM, Aneurin Price wrote:

The problem boils down to the fact that there's no way to my knowledge
to query ZFS in order to get completion information, without *also*
having full control over ZFS. If there *is* a way,

confirmed

[Leho Kraav]

On Thursday, April 7, 2011 4:41:27 PM UTC+3, Aneurin Price wrote:

[0] When I say 'manually', what I would actually do is change all
calls to zfs (and zpool) to use a variable $ZFS/$ZPOOL and define that
at the top of the file so that it can be set in one place. This option
would potentially allow for automatically determining if sudo is
necessary and doing the right thing. The thing that concerns me is
that I normally do that in shell scripts as a matter of course so I'm
not sure if I didn't here simply out of laziness or if there was a
good reason not to.

Good breakdown. I think if upstream did this, i.e. at least as a first step replaced vanilla calls to zfs/zpool with $ZFS and $ZPOOL, I think that would be a good base to work keep working. Default configuration can very well stay just ZFS=zfs and ZPOOL=zpool, so nothing changes for regular usage, but people like me would have lower maintenance on upgrades.

But OTOH, is there a way to detect in bash-completion whether you are completing against sudo? In that case the script could automatically prefix commands with sudo as well, since bash itself apparently can't be configured to do so?

[Seth Heeren]

On 8 apr, 17:17, Leho Kraav <l...@kraav.com> wrote:
> But OTOH, is there a way to detect in bash-completion whether you are
> completing against sudo? In that case the script could automatically prefix
> commands with sudo as well, since bash itself apparently can't be configured
> to do so?

You don't really want to do that. If something is amiss in the
completion (accidental or malicious), it would run with root
permissions, where the user is _not_ using sudo _yet_.
The impact of this is enormous: the completioni scripts usually depend
on dozens of tiny moving parts and ad-hoc scripts, opening heaps and
heaps of attack vectors for malicious code.
The security of indirect dependencies is hard to verify, which is why
on most systems, bash_completion is completely disabled for the root
user anyway.

Just because a user is typing sudo on the commandline is no reason to
assume that he will want to run all that completion stuff as root as
well.