.bin/custom-chroot

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