#!/bin/sh

# Functions library :: for Linux Live Kit scripts
# Original author: Tomas M. <http://www.linux-live.org>
# Modified by: 'JohnDaH4x0r' <terencedoesmc12 AT gmail DOT com>

# related to build script
# get_exclude: Generate exclude arguments for 'mksquashfs'
# $1: the exclude list ("$EXCLUDE", if you use .config)

get_exclude()
{
    EXCLUDE_LIST="$1"
    PARENT_DIR="$(echo "$2" | tr -s "/")"

    if [ -z "$PARENT_DIR" ]; then
        return 1
    elif [ "$PARENT_DIR" = "/" ]; then
        return 1
    fi

    echo "$EXCLUDE_LIST" | tr " " "\n" | grep "$PARENT_DIR" \
    | while read KEY; do
        echo -n "-e $KEY "
    done
}

# NOTE: DO NOT TOUCH THE ESCAPE CHARACTERS!
BLUE=""
YELLOW=""
ORANGE=""
GREEN=""
BOLD=""
RED=""
NC=""

# debug related
debug_start()
{
    if grep -q debug /proc/cmdline; then
        DEBUG_IS_ENABLED=1
    else
        DEBUG_IS_ENABLED=
    fi
}

dbg_shell_start()
{
    if grep -q 'dbg_shell' /proc/cmdline; then
        DBG_SHELL=1
    else
        DBG_SHELL=
    fi
}

debug_log()
{
    if [ "$DEBUG_IS_ENABLED" ]; then
        echo "[${GREEN}"' debug '"${NC}]: $@" >&2
        log "debug_log: $*"
    fi
}

# echo related functions

# echo fatal tag
# $1 = text to show
echo_fatal()
{
    echo "[${RED}"' fatal '"${NC}] $@" >&2
}

# echo bold
# $1 = text to show
#
echo_bold()
{
    echo "$BOLD""$@""$NC"
}

# echo livekit tag
echo_livekit()
{
    echo "[${BLUE}"'livekit'"${NC}] "
}

echo_livekit_msg()
{
    echo "[${BLUE}"'livekit'"${NC}] $@"
}

# echo error
echo_err()
{
    echo "[${RED}"' error '"${NC}] $@" >&2
}

# echo warn
echo_warn()
{
    echo "[${YELLOW}"' warn! '"${NC}] $@" >&2
}

# echo signature
echo_sign()
{
    echo "${BOLD}"' Linux Live Kit Improved v1.0 - '"$* ${NC}"
}

# log - store given text in /var/log/livedbg
log()
{
    echo "$@" 2>/dev/null >>/var/log/livekit-log
}

echolog()
{
    echo "$@"
    log "echolog: $@"
}

# show information about the debug shell
show_debug_banner()
{
   echo_sign "DEBUGGING MODE"
   echo "The root shell is prepared for you!" >&2
   echo "Type your desired commands or press Ctrl-D to continue booting." >&2
   echo >&2
}

# debug_shell
# executed when debug boot parameter is present
#
debug_shell()
{
    if [ "$DBG_SHELL" ]; then
        show_debug_banner
        setsid sh -c 'exec sh < /dev/tty1 >/dev/tty1 2>&1'
        echo
    fi
}

fatal()
{
    log "FatalError: $@"
    echo_fatal "$@"
    echo_sign "EMERGENCY MODE" >&2
    echo_bold "Please consult /var/log/livekit-log for more info." >&2
    setsid sh -c 'exec sh < /dev/tty1 >/dev/tty1 2>&1'
}


# test if the script is started by root user. If not, exit
#
allow_only_root()
{
    if [ "0$UID" -ne 0 ]; then
        echo_err "Only root can run $(basename $0)"; exit 1
    fi
}

# Make bundle
# call mksquashfs with apropriate arguments
# $1 = directory which will be compressed to squashfs bundle
# $2 = output file
# $3..$9 = optional arguments like -keep-as-directory or -b 123456789
#
mkbund()
{
    debug_log "mkbund" "$*"

    if [ -e "$2" ]; then
        echo_warn "mkbund: `basename $2`: File already exists!"
        echo_warn "mkbund: `basemane $2`: Deleting file..."
        rm -f "$2"
    else
        echo_livekit_msg "mkbund: `basename $2`: Making new bundle..."
    fi

    echo_livekit_msg "mkbund: SquashFS compression: 1024k - XZ" >&2
    echo_livekit_msg "mkbund: `basename $2`: Compressing bundle..." >&2
    mksquashfs "$1" "$2" -comp xz -b 1024k $3 $4 $5 $6 $7 $8 $9 >/dev/null || \
    (echo_err "mkbund: Failed to make bundle!" && exit 1)
}

# Now, for the Live Kit system-related stuff

# get value of kernel cmdline parameter $1
# $1 = parameter to search for
#
cmdline_value()
{
   cat /proc/cmdline | egrep -o "(^|[[:space:]])$1=[^[:space:]]+" | \
   tr -d " " | cut -d "=" -f 2- | tail -n 1
}


# Move entire initramfs tree to tmpfs mount.
# It's a bit tricky but is necessray to enable pivot_root
# even for initramfs boot image
#
transfer_initramfs()
{
   if [ ! -r /lib/initramfs_escaped ]; then
      echo_livekit
      echo "Switching from initramfs to tmpfs..."
      SWITCH=/m # one letter directory
      mkdir -p $SWITCH
      mount -t tmpfs -o size="100%" tmpfs $SWITCH
      cp -a /??* $SWITCH 2>/dev/null # only copy two-and-more-letter directories
      cd $SWITCH
      echo "This file indicates that we successfully escaped initramfs" > $SWITCH/lib/initramfs_escaped
      exec switch_root -c /dev/console . $0
   fi
}

# mount virtual filesystems like proc, sys and such
#
init_proc_sysfs()
{
   debug_log "init_proc_sysfs" "$*"
   mkdir -p /proc /sys /etc $MEMORY
   mount -n -t proc proc /proc
   echo "0" >/proc/sys/kernel/printk
   mount -n -t sysfs sysfs /sys
   mount -n -o remount,rw rootfs /
   ln -sf /proc/mounts /etc/mtab
}


# modprobe all modules found in initial ramdisk
modprobe_everything()
{
   debug_log "modprobe_everything" "$*"

   echo_livekit_msg "Probing for hardware..." >&2

   find /lib/modules/ | fgrep '.ko' | xargs -n 1 modprobe 2>/dev/null
   refresh_devs
}


refresh_devs()
{
   debug_log "refresh_devs" "$*"
   if [ -r /proc/sys/kernel/hotplug ]; then
      echo /sbin/mdev > /proc/sys/kernel/hotplug
   fi
   mdev -s
}

# make sure some devices are there
init_devs()
{
   debug_log "init_devs" "$*"
   modprobe zram 2>/dev/null
   modprobe loop 2>/dev/null
   modprobe squashfs 2>/dev/null
   modprobe fuse 2>/dev/null
   refresh_devs
}

# Activate zram (auto-compression of RAM)
# Compressed RAM consumes 1/2 or even 1/4 of original size
# Setup static size of 500MB
#
init_zram()
{
   debug_log "init_zram" "$*"
   echo_livekit_msg "Setting up ZRAM as swap if available..."
   if [ -r /sys/block/zram0/disksize ]; then
      echo 536870912 > /sys/block/zram0/disksize # 512MB
      mkswap /dev/zram0 >/dev/null
      swapon /dev/zram0 -p 32767
      echo 100 > /proc/sys/vm/swappiness
   fi
}

# load the AUFS kernel module if needed
#
init_aufs()
{
    debug_log "init_aufs" "$*"
    # TODO maybe check here if aufs support is working at all
    # and produce useful error message if user has no aufs
    modprobe aufs 2>/var/log/livekit-log

    # TODO ACCOMPLISHED:
    # If aufs module failed to load, panic immidiately
    if [ $? -ne 0 ]; then
        fatal "Failed to load AUFS module!"
    fi

    # finally, refresh all devices
    refresh_devs
}

# Setup empty union
# $1 = changes directory (ramfs or persistent changes)
# $2 = union directory where to mount the union
#
init_union()
{
   debug_log "init_union" "$*"

   echo_livekit_msg "Initialising AUFS union..."
   mkdir -p "$1"
   mkdir -p "$2"
   mount -t aufs -o xino="/.xino",trunc_xino,br="$1" aufs "$2"
}

# Return device mounted for given directory
# $1 = directory
#
mounted_device()
{
   debug_log "mounted_device" "$*"

   local MNT TARGET
   MNT="$1"
   while [ "$MNT" != "/" -a "$MNT" != "." -a "$MNT" != "" ]; do
      TARGET="$(grep -F " $MNT " /proc/mounts | cut -d " " -f 1)"
      if [ "$TARGET" != "" ]; then
         echo "$TARGET"
         return
      fi
      MNT="$(dirname "$MNT")"
   done
}

# Return mounted dir for given directory
# $1 = directory
#
mounted_dir()
{
   debug_log "mounted_dir" "$*"

   local MNT
   MNT="$1"
   while [ "$MNT" != "/" -a "$MNT" != "." -a "$MNT" != "" ]; do
      if mountpoint -q "$MNT" 2>/dev/null; then
         echo "$MNT"
         return
      fi
      MNT="$(dirname "$MNT")"
   done
}

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

    FS="$(blkid "$1" | sed -r "s/.*TYPE=//" | tr -d '"' | \
    tr "[A-Z]" "[a-z]" | cut -d ' ' -f 1)"
    if [ "$FS" = "msdos" -o "$FS" = "fat" ]; then
        FS="vfat"
    elif [ "$FS" = "ntfs" ]; then
        FS="ntfs-3g"
    else
        FS="$FS"
    fi
    echo "-t $FS"
}

# Filesystem options for mount
# $1 = filesystem or '-t filesystem'
#
fs_options()
{
   debug_log "fs_options" "$*"

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


# Modprobe network kernel modules until a working driver is found.
# These drivers are (or used to be) probed in Slackware's initrd.
# The function returns the first device found, yet it doesn't have
# to be a working one, eg. if the computer has two network interfaces
# and ethernet cable is plugged only to one of them.
#
init_network_dev()
{
   debug_log "init_network_dev" "$*"
   echo_livekit_msg "Preparing networking device(s)..." >&2
   local MODULE ETH

   for MODULE in 3c59x acenic de4x5 e1000 e1000e e100 epic100 hp100 \
   ne2k-pci pcnet32 8139too 8139cp tulip via-rhine r8169 atl1e yellowfin \
   tg3 dl2k ns83820 atl1 b44 bnx2 skge sky2 tulip depca 3c501 3c503 \
   3c505 3c507 3c509 3c515 ac3200 at1700 cosa cs89x0 de600 de620 e2100 \
   eepro eexpress eth16i ewrk3 forcedeth hostess_sv11 hp-plus hp ni52 \
   ni65 sb1000 sealevel smc-ultra sis900 smc9194 wd; do
      modprobe $MODULE 2>/dev/null
      ETH="$(cat /proc/net/dev | grep : | grep -v lo: | cut -d : -f 1 | tr -d " " | head -n 1)"
      if [ "$ETH" != "" ]; then
         echo $ETH
         return 0
      fi
      rmmod $MODULE 2>/dev/null
   done

   # If we are here, none of the above specified modules worked.
   # As a last chance, try to modprobe everything.
   echo_warn "No networking kernel module found!"
   modprobe_everything
   cat /proc/net/dev | grep : | grep -v lo: | cut -d : -f 1 | tr -d " " | head -n 1
}


# Download data from tftp
# $1 = target (store downloaded files there)
#
download_data_pxe()
{
   debug_log "download_data_pxe" "$*"
   local CMD CLIENT SERVER GW MASK PORT ETH PROTOCOL

   mkdir -p "$1/$LIVEKITNAME"

   cmdline_value ip | while IFS=":" read CLIENT SERVER GW MASK PORT; do
      echo_livekit_msg "Downloading files from $SERVER ..." >&2

      ETH=$(init_network_dev)
      if [ "$PORT" = "" ]; then PORT="7529"; fi

      # set IP address as given by boot paramter
      if [ "$CLIENT" != "" -a "$MASK" != "" ]; then
         ifconfig $ETH "$CLIENT" netmask "$MASK"
         route add default gw "$GW"
      else
         # if client ip is unknown, try to get a DHCP lease
         udhcpc -i $ETH -f -q
      fi

      # well known IP address of Google public DNS service
      echo nameserver 8.8.8.8 >> /etc/resolv.conf

      PROTOCOL=http
      wget -q -O "$1/PXEFILELIST" "http://$SERVER:$PORT/PXEFILELIST?$(uname -r):$(uname -m)"
      if [ $? -ne 0 ]; then
         echo_warn "Failed to download from http://$SERVER:$PORT, trying TFTP..."
         PROTOCOL=tftp
         tftp -g -r PXEFILELIST -l "$1/PXEFILELIST" $SERVER
      fi

      cat "$1/PXEFILELIST" | while read FILE; do
         if [ "$PROTOCOL" = "http" ]; then
            wget -O "$1/$LIVEKITNAME/$FILE" "http://$SERVER:$PORT/$FILE"
         else
            echo_livekit_msg "PXE: ${FILE}..." >&2
            tftp -g -r $FILE -l "$1/$LIVEKITNAME/$FILE" $SERVER
         fi
      done
   done

   echo "$1/$LIVEKITNAME"
}

# Find LIVEKIT data by mounting all devices
# If found, keep mounted, else unmount
# $1 = data directory target (mount here)
# $2 = data directory which contains compressed bundles
#
find_data_try()
{
    debug_log "find_data_try" "$*"

    local DEVICE FS FROM OPTIONS

    mkdir -p "$1"
    blkid | sort | cut -d: -f 1 | grep -E -v "/loop|/ram|/zram" | while read DEVICE; do
        FROM="$2"
        FS="$(device_bestfs "$DEVICE")"
        OPTIONS="$(fs_options $FS)"
        mount -r "$DEVICE" "$1" $FS $OPTIONS 2>/dev/null

        # if the FROM parameter is actual file, mount it again as loop (eg. iso)
        if [ -f "$1/$FROM" ]; then
            mount -o remount,rw "$DEVICE" "$1" 2>/dev/null
            mkdir -p "$1/../file"
            mount -o loop,ro "$1/$FROM" "$1/../file" 2>/dev/null
            FROM="../file/$LIVEKITNAME"
        fi

        # search for bundles in the mounted directory
        if [ "$(find "$1/$FROM" -maxdepth 1 -name "*.$BEXT" 2>/dev/null)" != "" ]; then
            # we found at least one bundle/module here
            mount -o remount,rw "$DEVICE" "$1" 2>/dev/null
            echo "$1/$FROM" | tr -s "/" | sed -r "s:/[^/]+/[.][.]/:/:g"
            return
        fi

        # unmount twice, since there could be mounted ISO as loop too. If not, it doesn't hurt
        umount "$1" 2>/dev/null
        umount "$1" 2>/dev/null
    done
    }

# Retry finding LIVEKIT data several times,
# until timeouted or until data is found
# $1 = timeout
# $2 = data directory target (mount here)
#
find_data()
{
    debug_log "find_data" "$*"

    local DATA FROM

    if [ "$(cmdline_value ip)" != "" ]; then
        download_data_pxe "$2"
        return
    fi

    FROM="$(cmdline_value from)"
    if [ "$FROM" = "" ]; then FROM="$LIVEKITNAME"; fi
    echo_livekit >&2
    echo "Looking for $LIVEKITNAME data in /$FROM .." | tr -s "/" >&2
    for timeout in $(seq 1 $1); do
      echo -n "." >&2
      refresh_devs
      DATA="$(find_data_try "$2" "$FROM")"
    if [ "$DATA" != "" ]; then
        echo
        echo_livekit_msg "$LIVEKITNAME data found on $(mounted_device "$2")" >&2
        echo "$DATA"
        return
    fi
      sleep 1
   done
   echo "" >&2

   if [ "$DATA" = "" ]; then
      fatal "$LIVEKITNAME data not found"
   fi

}

# Activate persistent changes
# $1 = data directory
# $2 = target changes directory
#
persistent_changes()
{
    debug_log "persistent_changes" "$*"

    local CHANGES T1 T2

    CHANGES="$1/$(basename "$2")"
    T1="$CHANGES/.perch-test.dat"
    T2="${T1}-clone.dat"

    # Setup the directory anyway, it will be used in all cases
    mkdir -p "$2"

    # If persistent changes are not requested, end here
    if grep -vq perch /proc/cmdline; then
        return
    fi

    # check if changes directory exists and is writable
    touch "$T1" 2>/dev/null && rm -f "$T1" 2>/dev/null

    # if not, simply return back
    if [ $? -ne 0 ]; then
        echo_warn "Persistent changes not writable or not used."
        return
    fi
    echo_livekit_msg "Testing persistent changes for POSIX compatibility..." >&2
    touch "$T1" && ln -sf "$T1" "$T2" 2>/dev/null && \
    chmod +x "$T1" 2>/dev/null && test -x "$T1" && \
    chmod -x "$T1" 2>/dev/null && test ! -x "$T1" && \
    rm "$T1" "$T2" 2>/dev/null

    if [ $? -ne 0 ]; then
        echo_warn "File system is not POSIX-compatible!" >&2
        echo_livekit_msg "Activating DynFileFS persistent changes..." >&2
        rm "$T1" "$T2" 2>/dev/null

        mount.dynfilefs "$CHANGES/changes.dat" 4000 "$2"
        if [ "$(device_bestfs "$2/loop.fs" | tr -d " ")" = "-t" ]; then
            mke2fs -F "$2/loop.fs" >/dev/null
        fi
        mount -o loop,sync "$2/loop.fs" "$2"
        rmdir "$2/lost+found" 2>/dev/null
    else
        echo_livekit_msg "Activating native persistent changes..." >&2
        mount --bind "$CHANGES" "$2"
    fi
}

# Copy content of rootcopy directory to union
# $1 = data directory
# $2 = union directory
copy_rootcopy_content()
{
    debug_log "copy_rootcopy_content" "$*"

    if [ "$(ls -1 "$1/rootcopy/" 2>/dev/null)" != "" ]; then
        echo_livekit
        echo "Copying content of rootcopy directory..."
        cp -a "$1"/rootcopy/* "$2"
    fi
}

# Copy data to RAM if requested
# $1 = live data directory
# $2 = changes directory
#
copy_to_ram()
{
    debug_log "copy_to_ram" "$*"

    local MDIR MDEV RAM CHANGES

    if grep -vq 'copy2ram' /proc/cmdline; then
        echo "$1"
        return
    fi

    echo_livekit_msg "Copying $LIVEKITNAME data to RAM..." >&2
    RAM="$(dirname "$2")"/copy_to_ram
    mkdir  -p "$RAM"
    cp -a "$1"/* "$RAM"
    echo "$RAM"

    MDIR="$(mounted_dir "$1")"
    MDEV="$(mounted_device "$1")"
    MDEV="$(losetup $MDEV 2>/dev/null | cut -d " " -f 3)"
    umount "$MDIR" 2>/dev/null

    if [ "$MDEV" ]; then # iso was mounted here, try to unmount the FS it resides on too
        MDEV="$(mounted_device "$MDEV")"
        umount "$MDEV" 2>/dev/null
    fi
}

# load filter
#
filter_load()
{
    local FILTER
    FILTER=$(cmdline_value load)
    if [ "$FILTER" = "" ]; then
        cat -
    else
        cat - | egrep "$FILTER"
    fi
}

# noload filter
#
filter_noload()
{
    local FILTER
    FILTER=$(cmdline_value noload)
    if [ "$FILTER" = "" ]; then
        cat -
    else
        cat - | egrep -v "$FILTER"
    fi
}

# sort modules by number even if they are in subdirectory
#
sortmod()
{
    cat - | sed -r "s,(.*/(.*)),\\2:\\1," | sort -n | cut -d : -f 2-
}

# Mount squashfs filesystem bundles
# and add them to union
# $1 = directory where to search for bundles
# $2 = directory where to mount bundles
# $3 = directory where union is mounted
#
union_append_bundles()
{
    debug_log "union_append_bundles" "$*"

    local BUN

    echo_livekit >&2
    echo "Appending bundles to union..." >&2

    # Just tell me why! Why be compact?!?
    ( ls -1 "$1" | sort -n ; cd "$1" ; find modules/ 2>/dev/null | \
    sortmod | filter_load) | grep '[.]'$BEXT'$' |\
    filter_noload | \
    while read BUNDLE; do
        echo_livekit_msg "Appending: $BUNDLE" >&2

        BUN="$(basename "$BUNDLE")"
        mkdir -p "$2/$BUN"

        # It now depends on your kernel!
        mount -o loop -t squashfs "$1/$BUNDLE" "$2/$BUN"
        mount -o remount,add:1:"$2/$BUN" aufs "$3"
    done
}

# Create empty fstab properly
# $1 = root directory
#
fstab_create()
{
    debug_log "fstab_create" "$*"

    local FSTAB
    FSTAB="$1/etc/fstab"
    echo aufs / aufs defaults 0 0 > $FSTAB
    echo proc /proc proc defaults 0 0 >> $FSTAB
    echo sysfs /sys sysfs defaults 0 0 >> $FSTAB
    echo devpts /dev/pts devpts gid=5,mode=620 0 0 >> $FSTAB
    echo tmpfs /dev/shm tmpfs defaults 0 0 >> $FSTAB
}


# Change root and execute init
# $1 = where to change root
#
change_root()
{
    debug_log "change_root" "$*"
    echo_livekit_msg "Changing root..." >&2
    umount /proc
    umount /sys

    cd "$1"

    # make sure important device files and directories are in union
    mkdir -p boot dev proc sys tmp mnt run
    chmod 1777 tmp
    if [ ! -e dev/console ]; then mknod dev/console c 5 1; fi
    if [ ! -e dev/tty ]; then mknod dev/tty c 5 0; fi
    if [ ! -e dev/tty0 ]; then mknod dev/tty0 c 4 0; fi
    if [ ! -e dev/tty1 ]; then mknod dev/tty1 c 4 1; fi
    if [ ! -e dev/null ]; then mknod dev/null c 1 3; fi
    if [ ! -e sbin/fsck.aufs ]; then ln -s /bin/true sbin/fsck.aufs; fi

    # find chroot and init
    if [ -x bin/chroot -o -L bin/chroot ]; then  CHROOT=bin/chroot; fi
    if [ -x sbin/chroot -o -L sbin/chroot ]; then  CHROOT=sbin/chroot; fi
    if [ -x usr/bin/chroot -o -L usr/bin/chroot ]; then  CHROOT=usr/bin/chroot; fi
    if [ -x usr/sbin/chroot -o -L usr/sbin/chroot ]; then CHROOT=usr/sbin/chroot; fi
    if [ "$CHROOT" = "" ]; then fatal "chroot: Executable not found!"; fi

    if [ -x bin/init -o -L bin/init ]; then INIT=bin/init; fi
    if [ -x sbin/init -o -L sbin/init  ]; then INIT=sbin/init; fi
    if [ "$INIT" = "" ]; then fatal "init: Executable not found!"; fi

    mkdir -p mnt/live
    mount -n -o remount,ro aufs .
    pivot_root . mnt/live
    exec $CHROOT . $INIT < dev/console > dev/console 2>&1
}