I've finally gotten 'cpio' into a shape where it could be useable. This version can archive and extract directories, sockets, FIFOs, devices, symlinks, and regular files. Supported options are -iot, -H FMT (which is a dummy right now). It only writes newc, and could read newc or newcrc. This does NOT implement -d, which essentially is equivalent to mkdir -p $(dirname $FILE) for every file that needs it. Hard links are not supported, though it would be easy to add them given a hash table or something like that. I also have not implemented the "<n> blocks" output on stderr. If desired, I can add it pretty simply. There is one assumption this makes: that the mode of a file, as mode_t, is bitwise equivalent to the mode as defined for the cpio format. This is true of Linux, but is not mandated by POSIX. If it is compiled for a system where that is false, the archives will not be portable.

#!/bin/bash

[ -z "$TOPDIR" ] && TOPDIR="$(pwd)"

rm -rf testdir
mkdir -p testdir

if [ -z "$TEST_HOST" ]
then
  make install_flat PREFIX=testdir || exit 1
fi

cd testdir
PATH="$(pwd):$PATH"

. "$TOPDIR"/scripts/test/testing.sh
[ -f "$TOPDIR/generated/config.h" ] && export OPTIONFLAGS=:$(echo $(sed -nr 's/^#define CFG_(.*) 1/\1/p' "$TOPDIR/generated/config.h") | sed 's/ /:/g')

if [ $# -ne 0 ]
then
  for i in "$@"
  do
    ln -sf toybox $i
    . "$TOPDIR"/scripts/test/$i.test
  done
else
  for i in "$TOPDIR"/scripts/test/*.test
  do
    CMDNAME="$(echo "$i" | sed 's@.*/\(.*\)\.test@\1@')"
    if [ -h $CMDNAME ] || [ ! -z "$TEST_HOST" ]
    then
      . $i
    else
      echo "$CMDNAME disabled"
    fi
  done
fi