qvm-run -p should redirect stdin and stdout separately

[3hhh]

Every call to qvm-run -p redirects both stdin and stdout.

Especially stdin is usually not necessary and may lead to unexpected behavior or even unexpected leaks from dom0 code.

Simple example:

#!/bin/bash

list="super"$'\n'"secret"

while IFS= read -r item ; do
        echo "item: $item"
        qvm-run -p -u root sys-usb "true"
done <<< "$list"

This will break after the first run and make qvm-run read the entire list during the first iteration (I'm not sure whether it is actually passed to sys-usb?). It works without -p.

I'd recommend to introduce different flags for stdin and stdout or at least support a flag to disable the stdin redirect (ssh e.g. uses -n).

Similar issue with ssh: https://stackoverflow.com/questions/346445/bash-while-read-loop-breaking-early

Affects both 3.2 and 4.0rc1.

[marmarek]

If you don't want either stdin or stdout, use standard shell features: </dev/null or >/dev/null.

[marmarek]

If you don't want either stdin or stdout, use standard shell features: </dev/null or >/dev/null.

[3hhh]

True, but that makes e.g. bash aliases impossible.

In general I'd also recommend to opt-in to functionality rather than having to opt-out, but well...

[3hhh]

True, but that makes e.g. bash aliases impossible.

In general I'd also recommend to opt-in to functionality rather than having to opt-out, but well...