#!/bin/sh
# -*- mode: sh; tab-width: 8; encoding: utf-8-unix -*-

prog=$( basename $0 .bash )
ROLE=base
# export PATH=$PATH:/usr/local/bin
. /usr/local/bin/usr_local_tput.bash
# MUST be silent
error () { retval=$1 ; shift; ERROR $prog $* >&2 ; exit $retval ; }
usage () { echo "USAGE: $prog chroot-dir [command args] -" $* >&2 ; exit 1 ; }
warn () { : ; }
info () { : ; }
debug () { : ; }

# must be run as root
[ "$( id -u )" -ne "0" ] && error 1 "must be run as root"

[ -x /bin/chroot ] && EXE=/bin/chroot
[ -x /usr/sbin/chroot ] && EXE=/usr/sbin/chroot # debian

setcap CAP_SYS_PTRACE=+ep $EXE

if [ "$#" -eq "0" ] ; then
    usage "give an absolute directory name as argument"
fi

LARGS=""
CMD=""
while true; do
        case "$1" in
            '-'*)
		LARGS="$1"
                shift
                ;;
            *)
                break
                ;;
        esac
done
[ -z "$LARGS" ] && LARGS="--userspec=0:0"
root=$1
shift

if [ ! -d "$root" ] ; then
    error 1 "directory not found - $root"
  fi

# unix partition
[ -d $root/lost+found ] || WARN "No $root/lost+found"
# linux partition
[ -e $root/usr/src/ ] || WARN "No $root/usr/src"

# check for /dev/loop devices - up to 255 on android
[ -e /dev/loop1 ] || \
    ( cd /dev  && \
	    for i in 0 1 2 3 4 5 6 7 ; do
		[ -e loop$i ] && continue
		mknod loop$i b 7 $i
		chmod 660 loop$i
		chgrp disk loop$i
	    done )

cd $root || error 6 "Can't cd to $root"

# sbin/boostrap_chroot.bash
for file in .bashrc .bash_profile .bash_logout .emacs ; do
    [ -f $root/root/$file ] && continue
    cp -p /root/$file $root/root/
done

for file in tmp usr/tmp var/tmp ; do
    [ -d $file ] && continue
    mkdir $file || error 8 " missing directory $file"
    chmod 1777 $file
  done
# df /var/tmp | grep -q sd.12 || mount /var/tmp

for file in proc sys dev dev/pts dev/shm usr ; do
    [ -d $file ] && continue
    mkdir $file || error 9 "Cant mkdir $file"
    chmod 755 $file
  done

if false ; then
    [ -e proc/self ] || mount -o bind /proc $root/proc || error 10
    # https://forums.gentoo.org/viewtopic-t-1061422-start-0.html
    [ -e dev/null  ] || mount -o bind /dev $root/dev || error 11
    # what happens to dev/shm ? its own memory?
    # required for ansible and firefox
    df -a | grep -q $root/dev/shm || mount -t tmpfs -o noexec,size=5% tmpfs $root/dev/shm || error 12
    [ -e dev/pts/ptmx ] || \
      mount -t devpts -o rw,relatime,gid=5,mode=620,ptmxmode=000 devpts $root/dev/pts || error 13
  else
    # https://wiki.gentoo.org/wiki/Chroot
    [ -e dev/loop0 ] || \
      { mount --rbind /dev $root/dev ; mount --make-rslave $root/dev ; } \
      || error 10 mount --rbind /dev $root/dev
    [ -e proc/self ] || mount -t proc /proc $root/proc \
      || error 11 mount -t proc /proc
    [ -e sys/block ] || \
      { mount --rbind /sys $root/sys ; mount --make-rslave $root/sys ; } \
      || error 12 --rbind /sys $root/sys
    df -a | grep -q $root/dev/shm || \
	mount -t tmpfs -o noexec,size=5% tmpfs $root/dev/shm || error 14 $root/dev/shm
    df -a | grep -q $root/tmp || mount --rbind /tmp $root/tmp \
      || error 13 mount --rbind /tmp $root/tmp
    # https://wiki.gentoo.org/wiki/Project:X86/Chroot_Guide
    [ -e dev/pts/ptmx ] || \
      mount -o bind /dev/pts $root/dev/pts || error 14 mount -o bind /dev/pts $root/dev/pts
  fi

# user
if [ -d $root/$HOME -a -f ~/.Xauthority ] ; then
    cp ~/.Xauthority $root/$HOME
    cp ~/.xauth* $root/$HOME
  fi

base=$( basename $root )
[ -e ./start.rc ] || cat > ./start.rc << EOF
# env-update && . /etc/profile
export PS1='\${tty}\\u@${base}:\\W\\$ '
EOF

[ -z "$DISPLAY" ] || grep -q DISPLAY ./start.rc || \
  echo export DISPLAY=\"$DISPLAY\" >> ./start.rc

# openpty failed: 'out of pty devices'
# root@Flati:11# d /dev/pts/
# total 6
# 2 ./  4 ../

#   You'll also want to copy over resolv.conf in order to have proper DNS name
#      resolution from inside the chroot:
cp -L /etc/resolv.conf etc || error 16 "Cant cp -L /etc/resolv.conf"

EARGS="CHROOT=$root PATH=/usr/sbin:/usr/bin:/sbin:/bin"
#? set these to root or derive them? what about -l?
EELTS="$EELTS TERM DISPLAY HOME LANG LC_ALL"
[ -z "$LC_COLLATE" ] && EELTS="$EELTS LC_COLLATE" || EARGS="$EARGS LC_COLLATE=C"

. /usr/local/bin/proxy_export.bash >/dev/null

EELTS="$EELTS http_proxy https_proxy socks_proxy no_proxy"
for elt in $EELTS ; do
    EARGS="$EARGS $( env|grep ^${elt}= )"
  done

# mesg: ttyname failed: Success
tty=$( tty 2>/dev/null )
[ $? -eq 0 -a -n "$tty" ] && EARGS="$EARGS TTY=$tty"

# was /bin/bash -l
[ "$#" -eq 0 ] && set -- /bin/bash -i -l

# Now you can chroot into your new system. Use env before chroot to ensure that no
# environment variables from the installation media are used by your new system:
#?  PATH=$PATH
# info chroot $LARGS $root /usr/bin/env -i $EARGS "$@"
exec $EXE $LARGS $root /usr/bin/env -i $EARGS "$@"