gistfile1.sh

#!/bin/sh

set -e

log() {
  str="alpbs: $1\n"
  shift
  printf "$str" "$@" >&2
}

confirm() {
  printf 'confirmed? (y/*) ' >&2
  read
  [ ay == "a$REPLY" ] || exit 1
}

bootstrap() {
  apk.static -U --allow-untrusted \
  --root "$1" -X "$2" \
  --initdb add $3
}

devices() {
  mknod -m 666 "$1"/dev/full    c 1 7
  mknod -m 666 "$1"/dev/ptmx    c 5 2
  mknod -m 644 "$1"/dev/random  c 1 8
  mknod -m 644 "$1"/dev/urandom c 1 9
  mknod -m 666 "$1"/dev/zero    c 1 5
  mknod -m 666 "$1"/dev/tty     c 5 0
}

repo() {
  mkdir -p "$1"/etc/apk
  echo "$2" > "$1"/etc/apk/repositories
}

keys() {
  wget -O - "$2"/x86_64/alpine-base-2.5.4-r0.apk | tar xzC "$1" etc/
}

install() {
  log 'bootstrapping...'
  bootstrap "$1" "$2" "$3"

  log 'resolv.conf...'
  cp /etc/resolv.conf "$1"/etc/resolv.conf

  log 'devices...'
  devices "$1"

  log 'repo config...'
  repo "$1" "$2"

  log 'keys...'
  keys "$1" "$2"
}

main() {
  ROOT=${ALP_ROOT:-.}
  REPO=${ALP_REPO:-http://dl-4.alpinelinux.org/alpine/v2.5/main}
  PKG=${ALP_PKG:-apk-tools alpine-baselayout}

  log 'root:\t%s' "$ROOT"
  log 'repo:\t%s' "$REPO"
  log 'pkgs:\t%s' "$PKG"

  confirm

  install "$ROOT" "$REPO" "$PKG"
}

main