.bin/custom-chroot

   1 #!/bin/bash -e
   2
   3 [[ -w / ]] || exec sudo env HOME="$HOME" "$0" "$@"
   4
   5 if [[ -z ${UNSHARE} ]] ; then
   6         mount_args=
   7         if type -P unshare >&/dev/null ; then
   8                 UNSHARE=true exec unshare -m -- "$0" "$@"
   9         fi
  10 else
  11         mount_args='-n'
  12 fi
  13 unset UNSHARE
  14
  15 mounts="proc sys tmp dev dev/pts usr/portage usr/portage/distfiles usr/local/src"
  16
  17 chroot=${0%/*}
  18 case ${chroot} in
  19         .) chroot=${PWD} ;;
  20         ./*) chroot=${PWD}/${chroot#./} ;;
  21 esac
  22 cd "${chroot}"
  23
  24 do_umount() {
  25         local m mounts=$(mount | grep ${chroot} | awk '{print $3}' | tac)
  26         for m in ${mounts} ; do
  27                 echo "unmounting ${m}"
  28                 umount "${m}"
  29         done
  30         if [[ -z ${mounts} ]] ; then
  31                 echo "nothing mounted in ${chroot}"
  32         fi
  33         exit 0
  34 }
  35
  36 while [[ -n $1 ]] ; do
  37         case $1 in
  38         -u) do_umount ;;
  39         -m) mounts+=" $2"; shift ;;
  40         -*) echo "unknown option $1"; exit 1 ;;
  41         *)  break ;;
  42         esac
  43         shift
  44 done
  45
  46 maybe_mount() {
  47         local src=/$1 dst=${chroot}/${2:-$1}
  48         [[ -d ${src} ]] || return 0
  49         mkdir -p "${dst}"
  50         grep -sq "${dst}" /proc/mounts || mount ${mount_args} --bind "${src}" "${dst}"
  51 }
  52 for m in ${mounts} ; do
  53         maybe_mount ${m}
  54 done
  55
  56 get_type() {
  57         case $(file "$1") in
  58                 *x86-64*)         echo x86_64;;
  59                 *"Intel 80386"*)  echo i386;;
  60                 *32-bit*PowerPC*) echo ppc;;
  61                 *64-bit*PowerPC*) echo ppc64;;
  62         esac
  63 }
  64 bin_dst=$(get_type bin/bash)
  65 setarch=
  66 if [[ -n ${bin_dst} ]] && type -P setarch &>/dev/null ; then
  67         setarch="setarch ${bin_dst}"
  68 fi
  69
  70 if [[ ! -L etc/mtab ]] ; then
  71         rm -f etc/mtab
  72         ln -sf /proc/mounts etc/mtab
  73 fi
  74 etc="
  75         hosts
  76         locale.gen
  77         localtime
  78         resolv.conf
  79 "
  80 home="
  81         .inputrc
  82         .gdbinit
  83         .gitconfig
  84         .nanorc
  85 "
  86 for f in \
  87         $(printf 'etc/%s ' ${etc}) \
  88 ; do
  89         if [ -e "/${f}" ] ; then
  90                 cp /${f} ${f}
  91         fi
  92 done
  93 for f in ${home} ; do
  94         cp ~/${f} root/${f}
  95 done
  96
  97 unset LS_COLORS # format changes over time
  98 [[ $# -eq 0 ]] && set -- env HOME=/root /bin/bash -l
  99 exec \
 100         ${setarch} \
 101         chroot "${chroot}" \
 102         "$@"