Using unshare and still executing original function

Question

I am trying to generalize and make a shell script out of the instructions on this page, specifically here: https://nixos.org/wiki/How_to_add_files_to_the_nix-store#Large_files because of Nix's failure to handle a 4.5 GB file, I get out of memory errors.

Hence...

My current code is:

#!/usr/bin/env bash

function do_store {
    if [ "$#" -lt 1 ]; then
      printf "Must provide the Xcode_dmg\n"
      exit 1
    fi
    unshare -m bash

    local
    sdk="$1"
    name="$(basename $sdk)"
    # Hack since the openssl sha and nix-store is super slow
    hash="a08d555c4f3fd905c53ee67720d9e6ade01e1b0b"
    store_path="$(nix-store --print-fixed-path sha1 $hash $name)"
    mount -o remount,rw /nix/store
    printf "$storepath\n\n0\n" | nix-store --register-validity --reregister
    exit
    # printf "name: %s, hash: %s, store_path: %s\n" "$name" "$hash" "$store_path"
}

do_store "$@"

...with the idea that it would be invoked with sudo -HE

And the problem is that unshare immediately starts a new bash shell and the "parent" code stops running, which of course is bad for me since I need that logic to finish. Also I need to have my current user's environment preserved since I need the paths for nix-store and such to still be valid, hence the sudo -HE usage.

score 0 · Answer 1 · answered Mar 05 '16 at 11:42

0

Try with a simple:

unshare -fm

It forks a new child (so the parent can continue execution) and without specifying the new bash, it inherit the environment variables.

answered Mar 05 '16 at 11:42

ocirocir

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Using unshare and still executing original function

1 Answers1