functions/detect_virt: use container env variable

[CameronNemo]

No description provided.

[benaryorg]

Mostly fine, except for it does not catch the case of container= (empty string as value), and I'm not sure about removing the check for existance of /proc/self/environ.

[benaryorg]

This only checks whether the variable is not empty, not whether it is set.
I'd recommend using the (deleted) approach of grepping:

grep -zq ^container= /proc/self/environ 2>/dev/null && export VIRTUALIZATION=1

[CameronNemo]

not gonna work with busybox

/ # busybox grep -z
grep: invalid option -- 'z'

are there any container runtimes that set the var to empty?

[benaryorg]

On one hand I doubt so, on the other hand I've seen enough not to be particularly inclined to trust that assumption.
Anyways, which version of busybox are you using, the one I tested on my voidlinux installation and the one on my Gentoo box both have a -z flag.
The Gentoo box running BusyBox v1.31.1.

[CameronNemo]

cameronnemo@cn-mbook ~> docker run --rm -it voidlinux/voidlinux sh
# xbps-install -Syu ; xbps-install -yu ; xbps-install -y busybox
[...]
# busybox grep -zq ^container= /proc/self/environ
grep: invalid option -- 'z'
BusyBox v1.30.1 (2019-08-02 18:59:22 UTC) multi-call binary.

Usage: grep [-HhnlLoqvsriwFE] [-m N] [-A/B/C N] PATTERN/-e PATTERN.../-f FILE [FILE]...

[leahneukirchen]

What's the purpose of this? Why not use [ "${container+x}" ]

[benaryorg]

@leahneukirchen entirely forgot about that construct.
Right, that seems more reasonable.

[benaryorg]

Also, I think if your comment starts with fix #6 it will automatically close the related #6 issue.