bind_functions.sh

declare -f -F trap_push > /dev/null || \
  source trap_stack.sh
#The trap_stack lets us nest multiple trap statments. See:
# https://stackoverflow.com/questions/16115144/save-and-restore-trap-state-easy-way-to-manage-multiple-handlers-for-traps
# https://stackoverflow.com/questions/3338030/multiple-bash-traps-for-the-same-signal


unmount_vfs(){
  if [ -z "$MMT_MOUNT_POINTS" ]; then #Wild guess in case MMT_MOUNT_POINTS is not defined
   for a_rootfs in "$rootfs" "root_fs" #The loop here is probably redundant
     if [ ! ${a_rootfs:0:1} = "/" ]; then
       if [ "${a_rootfs:0:1}" = "." ]; then
          a_rootfs=`pwd`/"${a_rootfs:1:}"
       else
          a_rootfs="$curdir/$a_rootfs"
       fi
     if [ ! -z "$a_rootfs" ]; then
       unmount_if_mounted "$a_rootfs/dev" 2>/dev/null
       unmount_if_mounted "$a_rootfs/sys" 2>/dev/null
       unmount_if_mounted "$a_rootfs/proc" 2>/dev/null
     fi
     if [ ! "$a_rootfs" = "/" ]; then
       umount --recursive "$a_rootfs"
     fi
   done
 #umount /mnt/wktaz 2>/dev/null
 #umount /mnt/wksfs 2>/dev/null
  elif [ -z "MNT_PT_ARRAYS" ] #This is the prefered branch
    for a_mp in "$MMT_MOUNT_POINTS"; then
      umount -l $a_mp 2>/dev/null
    fi
  else
    for arry_name in ${MNT_PT_ARRAYS[@]}; then
      arry_names_name=${1:-ALL_ArrNames}
      for a_mp in $(eval 'echo "${'$arry_names_name'[@]}"'); then
        umount -l $a_mp 2>/dev/null
      fi
    fi
  fi

#if we source trap_stack.sh then
 declare -f -F trap_push > /dev/null || \
   close_file_descriptors
}


#safe_add_mount_points(){
#  mountpoint -q /home || \
#    add_mount_point
#}
unmount_vfs_and_maybe_close_fd(){
 unmount_vfs

#if we source trap_stack.sh then we cose the file descriptor in a second
#trap statment. Otherwise one trap statment has to clean up everything.
#The declare statment checks whether or not trap_stack.sh is sourced.
 declare -f -F trap_push > /dev/null || \
   close_file_descriptors

}
close_file_descriptors(){
  exec 10>&-
}
unmount_if_mounted(){
  if [ "$(mount | grep ""$1"")" != "" ]; then
    if [ LAZY_UMOUNT -eq 1 ]; then
      umount -l "$1" 2>/dev/null
    else
     umount -f "$1" 2>/dev/null
    fi
  fi
fi
set_proc_mp_options(){
   PROC_MP_ACTION=${PROC_MP_ACTION:-"-t proc none"}
   case $PROC_MP_ACTION in
   "-t proc none")
     mp_options=( "-t" "proc" )
     if [ -z "$mp_source" ]; then
       mp_source="none"
     fi
     ;;
   "-t proc /proc")
     mp_options=( "-t" "proc" )
     if [ -z "$mp_source" ]; then
       mp_source="/proc"
     fi
     ;;
   "--rbind"|"-o rbind")
     mp_options=( "-o" "rbind" )
     if [ -z "$mp_source" ]; then
         mp_source="/proc"
     fi
     ;;
   "--bind"|"-o bind")
     mp_options=( "-o" "bind" )
     if [ -z "$mp_source" ]; then
         mp_source="/proc"
     fi
     ;;
   *)
     echo "Option PROC_MP_ACTION=\"$PROC_MP_ACTION\" not yet supported"
     read -p "Press enter to continue"
     ;;
   esac
}
set_sys_mp_options(){
   SYS_MP_ACTION=${SYS_MP_ACTION:-"-t sysfs none"}
   case $SYS_MP_ACTION in
   "-t sys none")
     mp_options=( "-t" "sysfs" )
     mp_source="none"
     ;;
   "-t sys /sys")
     mp_options=( "-t" "sysfs" )
     if [ -z "$mp_source" ]; then
       mp_source="/sys"
     fi
     ;;
   "--rbind"|"-o rbind")
     mp_options=( "-o" "rbind" )
     if [ -z "$mp_source" ]; then
         mp_source="/sys"
     fi
     ;;
   "--bind"|"-o bind")
     mp_options=( "-o" "bind" )
     if [ -z "$mp_source" ]; then
         mp_source="/sys"
     fi
     ;;
   *)
     echo "Option SYS_MP_ACTION=\"$SYS_MP_ACTION\" not yet supported"
     read -p "Press enter to continue"
     ;;
   esac
}
set_dev_mp_options(){
   DEV_MP_ACTION=${DEV_MP_ACTION:-"-o rbind"}
   case $DEV_MP_ACTION in
   "--rbind"|"-o rbind")
     mp_options=( "-o" "rbind" )
     if [ -z "mp_source" ]; then
         mp_source="/dev"
     fi
     ;;
   "--bind"|"-o bind") #Maybe also bind /dev/pts and /dev/shm if you do this
     mp_options=( "-o" "bind" )
     if [ -z "mp_source" ]; then
         mp_source="/dev"
     fi
     ;;
   *)
     echo "Option DEV_MP_ACTION=\"$DEV_MP_ACTION\" not yet supported"
     read -p "Press enter to continue"
     ;;
   esac
}
set_dev_pts_mp_options(){
   DEV_PTS_MP_ACTION=${DEV_PTS_MP_ACTION:-"-o bind"}
   case $DEV_PTS_MP_ACTION in
   "--bind"|"-o bind") #Maybe also bind /dev/pts and /dev/shm if you do this
     mp_options=( "-o" "bind" )
     if [ -z "mp_source" ]; then
         mp_source="/dev/pts"
     fi
     ;;
   *)
     echo "Option DEV_PTS_MP_ACTION=\"$DEV_PTS_MP_ACTION\" not yet supported"
     read -p "Press enter to continue"
     ;;
   esac
}
set_dev_pts_shm_options(){
   DEV_SHM_MP_ACTION=${DEV_SHM_MP_ACTION:-"-o bind"}
   case $DEV_PTS_MP_ACTION in
   "--bind"|"-o bind") #Maybe also bind /dev/pts and /dev/shm if you do this
     mp_options=( "-o" "bind" )
     if [ -z "mp_source" ]; then
         mp_source="/dev/shm"
     fi
     ;;
   *)
     echo "Option not yet supported"
     read -p "Press enter to continue"
     ;;
   esac
}
add_mp_and_check_path(){
  arg_count=$#
  mp_path=${@[-1]}
  #https://stackoverflow.com/questions/16860877/remove-an-element-from-a-bash-array
  unset '@[-1]' #Delete the last element of the array
  if [ $arg_count >1 ]; then
    mp_source=${@[-1]}
    unset '@[-1]'
  fi
  mp_options=( "$@" )
  if [ -z "$option" ]; then
    case "basename $mp_path" in
    "proc")
       set_proc_mp_options #The default is: option=( "-t" "proc" ); mp_source="none"
       ;;
    "sys")
       set_sys_mp_options #The default is: option=( "-t" "sysfs" ); mp_source="none"
       ;;
    "dev")
       #example said: https://unix.stackexchange.com/questions/24140/return-only-the-portion-of-a-line-after-a-matching-pattern
       #sed -n -e 's/^\(.*\)\(stalled: \)\(.*\)$/\3\2\1/p'
       #How I might use sed but I have a better idea
       #sed -n -e 's/^\(.*\)\/dev\/\(.*\)$/\3\2\1/p'
       case mp_path in
       */dev/shm)
         set_dev_pts_shm_options #The default is: option=( "-o" "bind" ); mp_source="/dev/shm"
         ;;
       */dev/pts)
         set_dev_pts_mp_options #The default is: option=( "-o" "bind" ); mp_source="/dev/pts"
         ;;
       */dev)
         #TODO add check to see if we have either mounted or plan to moun
         #/dev/shm /dev/pts and if so change option from rbind to bind.
         set_dev_mp_options
       ;;
       esac
  fi
  already_mounted=0
  mountpoint -q "$mp_path" && already_mounted=1
  if [ $already_mounted -eq 1 ]; then
    MMT_MOUNT_POINTS+=( "$mp_path" )
    mount "${mp_options[@]}" "$mp_source" "$mp_path"
  fi


}
bind_dirs(){
  local a_curd="`pwd`"
  for a_dir in $@; do
    #This step isn't necessary be is a percauation in case a "cd" accidently
    #gets inserted on a function called by this function.
    if [ ! "${a_dir:0:1" = "/" ]; then
      "$a_curd/$a_dir"
    fi
    add_mp_and_check_path "$a_dir"
  done
}