#!/bin/bash
# Recreate fstab entries in /etc/fstab and make /media directories
# This script is called by udev rules, see /etc/udev/rules.d/
#
# Author: Tomas M <http://slax.linux-live.org/>

# Variables available in udev environment:
# $ACTION (eg: add, remove)
# $DEVNAME (full device node name including path)
# $DEVTYPE (eg: disk)
# $ID_FS_TYPE (eg: ext3)
# $MAJOR and $MINOR numbers
# $SUBSYSTEM (eg: block)

PATH=$PATH:/usr/bin:/usr/sbin:/bin:/sbin
FSTAB=/etc/fstab
FSTABFLAG="# AutoUpdate"

# a logging function
log()
{
    mkdir -p /dev/.udev
    echo "process ID $$:" "$@" >>/dev/.udev/udev-fstab-update.log
}

# Make sure the part of a script after 'mutex_lock' call is atomic,
# that means the 'locked' part of the script can never be execuetd 
# from several processes at the same time, in parallel.
# Every script waits until it gathers the lock.
# The lock directory is saved in /dev instead of /tmp, because /tmp may be
# readonly at the time when the lock is needed (eg. when udev is starting)
# $1 = name of the lock
#
mutex_lock()
{
   while ! mkdir "/dev/ll-mutex-lock-$1" 2>/dev/null; do
      usleep 100000;
   done
}


# Unlock the lock so another waiting process can reusse it and continue
# $1 = name of the lock
#
mutex_unlock()
{
   rmdir "/dev/ll-mutex-lock-$1" 2>/dev/null
}


# Get device tag.
# $1 = device
# $2 = tag name, such as TYPE, LABEL, UUID, etc
#
device_tag()
{
   blkid -s $2 "$1" | sed -r "s/^[^=]+=//" | tr -d '"'
}


# Make sure to mount FAT12/16/32 using vfat
# in order to support long filenames
# $1 = device
#
device_bestfs()
{
   local FS

   FS="$(device_tag "$1" TYPE | tr [A-Z] [a-z])"
   if [ "$FS" = "msdos" -o "$FS" = "fat" -o "$FS" = "vfat" ]; then
      FS="vfat"
   elif [ "$FS" = "ntfs" ]; then
      FS="ntfs-3g"
   fi

   echo "$FS"
}


# Filesystem options for initial mount
# $1.. = filesystem
#
fs_options()
{
   debug_log "fs_options" "$*"

   echo -n "defaults"

   if [ "$1" = "vfat" ]; then
      echo ",check=s,shortname=mixed,iocharset=utf8"
   fi
}


# Find out if device is in fstab already
# $1 = fstab file
# $2 = device name
dev_is_in_fstab()
{
   cat "$1" | sed -r "s/#.*//" | egrep -q "^[[:space:]]*$2[[:space:]]"
}


# update given line in fstab, add new values only if the device is not found
# $1 = fstab file to parse
# $2 = device name
# $3 = mountpoint
# $4 = filesystem
# $5 = mount options
#
fstab_add_line()
{
   local DIR

   if [ "$4" != "swap" ]; then DIR="$3"; else DIR="none"; fi
   if ! dev_is_in_fstab "$1" "$2"; then
      echo "$2" "$DIR" "$4" "$5" 0 0 "$FSTABFLAG" >>$1
   fi
}

# tell us if the given filesystem is supported
# (eg. it's in /proc/filesystems or we know it)
# $1 = filesystem name
#
is_supported_filesystem()
{
   egrep -q "[[:space:]]$1\$" /proc/filesystems
}


log starting udev-fstab-update with parameters $ACTION $DEVNAME

mutex_lock udev-fstab-update


if [ "$ACTION" = "add" -o "$ACTION" = "change" ]; then
   if ! dev_is_in_fstab $FSTAB $DEVNAME; then

      # find some information about the device
      FS=$(device_bestfs $DEVNAME)
      OPT=$(fs_options $FS fstab)
      BAS=$(basename "$DEVNAME")
      MNT=/media/$BAS
      log "Found the following: FS=$FS OPT=$OPT MNT=$MNT"

      # If udev detected floppy, add it here. Thanks Quax :)
      if [ "$(echo "$DEVNAME" | grep /fd)" != "" ]; then
         mkdir -p /media/floppy
         fstab_add_line $FSTAB $DEVNAME /media/floppy auto rw,noauto,user,sync
      fi

      if [ "$FS" = "swap" ]; then
         fstab_add_line $FSTAB $DEVNAME $MNT $FS $OPT
      fi

      # If the partition has a valid filesystem, add it to fstab.
      # This probably won't handle HotAdded CDROMs with no media,
      # but that shouldn't be any problem as those devices would
      # be of no use when empty, and it will notify us when a
      # new media is inserted.
      if is_supported_filesystem "$FS"; then
         log Calling fstab_add_line $FSTAB $DEVNAME $MNT $FS $OPT
         fstab_add_line $FSTAB $DEVNAME $MNT $FS $OPT
         mkdir -p "$MNT"
         gtk-bookmarks-update
         mutex_unlock udev-fstab-update

         if [ -e /usr/bin/pcmanfm ]; then
            su - root -c "export DISPLAY=:0; mount "$MNT"; pcmanfm $MNT >/dev/null 2>/dev/null"
            #umount "$MNT"
            #rmdir "$MNT"
            #gtk-bookmarks-update
         fi
         exit
      fi
   else
      log device $DEVNAME already in fstab, skipped
   fi
fi

if [ "$ACTION" = "remove" ]; then
   sed -i -r "\\;^[[:space:]]*$DEVNAME[[:space:]].*;d" $FSTAB
fi

mutex_unlock udev-fstab-update