#!/bin/bash
# Create devices
# Author: Igor Pechtchanski <pechtcha@cs.nyu.edu>
# Version: 1.2
#
# Note: This version creates *real* device files using mknod and mkfifo
#

# Script parameters
# Number of devices of a certain type to be created - change if more needed
# ttys
CREATE_TTY=32
# serial ttys
CREATE_TTYS=16
# floppy drives
CREATE_FD=3
# compact disks
CREATE_SCD=3
# hard drives
CREATE_SD=3
# hard drive partitions
CREATE_SD_PART=3
# tape drives
CREATE_ST=3
# Parameters end here -- you shouldn't have to change anything below this line

usage() {
  echo "Usage: $0 [--verbose|-v]"
  echo "    or $0 --debug|-n"
  echo "    or $0 --help|-h"
  echo "    or $0 --version|-V"
  echo ""
  echo "--verbose, -v	Print commands as they are executed"
  echo "--debug, -n	Don't execute commands, just print what will be done"
  echo "--help, -h	Print this message and exit"
  echo "--version, -V	Print the program version and exit"
}

if [ "x$1" = "x--debug" -o "x$1" = "x-n" ]; then
  mknod() { echo mknod "$@"; }
  mkfifo() { echo mkfifo "$@"; }
  ln() { echo ln "$@"; }
  mkdir() { echo mkdir "$@"; }
  cd() { echo cd "$@"; }
  shift
elif [ "x$1" = "x--help" -o "x$1" = "x-h" ]; then
  usage
  exit 0
elif [ "x$1" = "x--version" -o "x$1" = "x-V" ]; then
  echo -n "$0, "
  sed -n '/^# Version: /{s/^# // p}' "$0"
  exit 0
elif [ "x$1" = "x--verbose" -o "x$1" = "x-v" ]; then
  set -x
elif [ "x$1" != "x" ]; then
  echo "Invalid parameter: $1"
  usage
  exit 1
fi

error() { echo "$@" && exit 1; }

# Maximum number of tty devices
NUM_TTY=64
[ -z "$CREATE_TTY" ] && CREATE_TTY="$NUM_TTY"
[ "$CREATE_TTY" -le "$NUM_TTY" ] || error "Too many ttys: $CREATE_TTY"
# Maximum number of ttyS (serial tty) devices
NUM_TTYS=16
[ -z "$CREATE_TTYS" ] && CREATE_TTYS="$NUM_TTYS"
[ "$CREATE_TTYS" -le "$NUM_TTYS" ] || \
  error "Too many serial ttys: $CREATE_TTYS"
# Maximum number of st (tape) devices
NUM_ST=16
[ -z "$CREATE_ST" ] && CREATE_ST="$NUM_ST"
[ "$CREATE_ST" -le "$NUM_ST" ] || error "Too many tape devices: $CREATE_ST"
# Maximum number of fd (floppy drive) devices
NUM_FD=16
[ -z "$CREATE_FD" ] && CREATE_FD="$NUM_FD"
[ "$CREATE_FD" -le "$NUM_FD" ] || error "Too many floppy drives: $CREATE_FD"
# Maximum number of scd (compact disk) devices
NUM_SCD=16
[ -z "$CREATE_SCD" ] && CREATE_SCD="$NUM_SCD"
[ "$CREATE_SCD" -le "$NUM_SCD" ] || error "Too many compact disks: $CREATE_SCD"
# Maximum number of sd (hard disk) physical devices
NUM_SD=16
[ -z "$CREATE_SD" ] && CREATE_SD="$NUM_SD"
[ "$CREATE_SD" -le "$NUM_SD" ] || error "Too many hard drives: $CREATE_SD"
# Maximum number of sd (hard disk) partition devices
NUM_SD_PART=16
[ -z "$CREATE_SD_PART" ] && CREATE_SD_PART="$NUM_SD_PART"
[ "$CREATE_SD_PART" -le "$NUM_SD_PART" ] || \
  error "Too many hard drive partitions: $CREATE_SD_PART"
# Sequence of numbers from $2(0) to $1-1
NUMS() {
  [ -z "$2" ] && set -- "$1" 0;
  seq -s " " $2 1 $(expr $1 - 1) 2>/dev/null;
}
# Sequence of letters from 'a' to 'a'+$1-1
LTRS() {
  /bin/echo -e $(printf '\\%o ' $(seq -s " " 97 1 $(expr 96 + $1) 2>/dev/null));
}

# Actual /dev directory
[ -z "$DEVDIR" ] && DEVDIR="/dev"
[ -e "$DEVDIR" -a ! -d "$DEVDIR" ] && \
   error "$DEVDIR exists and is not a directory"
[ ! -e "$DEVDIR" ] && \
   (mkdir "$DEVDIR" || error "Unable to create $DEVDIR")
[ ! -e "$DEVDIR" -o -w "$DEVDIR" ] || \
   error "$DEVDIR exists, but isn't writeable"
cd "$DEVDIR" || error "Unable to cd to $DEVDIR"

# Major device numbers
DEVNO_FIFO=0
DEVNO_MEM=1
DEVNO_FD=2
DEVNO_CONSOLE=5
DEVNO_SD=8
DEVNO_ST=9
DEVNO_SCD=11
DEVNO_WINDOWS=13
DEVNO_DSP=14
DEVNO_TTYS=117
DEVNO_TTYM=128
DEVNO_TTY=136

# - (0,252): fifo
mknod -m666 fifo c $DEVNO_FIFO 252
# - (1,*): mem kmem null zero port random urandom
mknod -m666 mem c $DEVNO_MEM 1
mknod -m666 kmem c $DEVNO_MEM 2
mknod -m666 null c $DEVNO_MEM 3
mknod -m666 zero c $DEVNO_MEM 4
mknod -m666 port c $DEVNO_MEM 5
mknod -m666 random c $DEVNO_MEM 8
mknod -m666 urandom c $DEVNO_MEM 9
# - (2,*): floppies
for i in $(NUMS $CREATE_FD); do
  mknod -m666 "fd$i" b $DEVNO_FD $i
done
# - (5,*): tty console ptmx conout conin
mknod -m666 tty c $DEVNO_CONSOLE 0
mknod -m666 console c $DEVNO_CONSOLE 1
mknod -m666 ptmx c $DEVNO_CONSOLE 2
mknod -m666 conout c $DEVNO_CONSOLE 254
mknod -m666 conin c $DEVNO_CONSOLE 255
# - (8,*): hard disks
MINOR=0
for j in $(LTRS $CREATE_SD); do
  mknod -m666 "sd$j" b $DEVNO_SD $MINOR
  for i in $(NUMS $CREATE_SD_PART 1); do
    mknod -m666 "sd$j$i" b $DEVNO_SD $(($MINOR+$i))
  done
  MINOR=$(($MINOR+16))
done
# - (9,*) tape drives (rewind/no rewind)
for i in $(NUMS $CREATE_ST); do
  mknod -m666 "st$i" c $DEVNO_ST $i
  mknod -m666 "nst$i" c $DEVNO_ST $((128+$i))
done
# - (11,*) compact disks
for i in $(NUMS $CREATE_SCD); do
  mknod -m666 "scd$i" b $DEVNO_SCD $i
  ln -s "scd$i" "sr$i"
done
# - (13,*) clipboard windows
mknod -m666 clipboard c $DEVNO_WINDOWS 254
mknod -m666 windows c $DEVNO_WINDOWS 255
# - (14,3) dsp
mknod -m666 dsp c $DEVNO_DSP 3
# - (117,*) serial
for i in $(NUMS $CREATE_TTYS); do
  mknod -m666 "ttyS$i" c $DEVNO_TTYS $(($i+1))
  # TODO: how do we deal with com*?
  #mknod -m666 "com$i" c $DEVNO_TTYS $i
done
# TODO: how do we deal with the other com*?
mknod -m666 com0 c $DEVNO_TTYS 0
# - (128,0) tty master
mknod -m666 ttym c $DEVNO_TTYM 0
# - (136,*) tty
for i in $(NUMS $CREATE_TTY); do
  mknod -m666 "tty$i" c $DEVNO_TTY $i
done

# Create pipes
# TODO: UNIMPLEMENTED
mkfifo -m666 pipe

# Create symbolic links
[ ! -e floppy ]  && ln -s fd0 ./floppy
[ ! -e cdrom ]   && ln -s scd0 ./cdrom
[ ! -e tape ]    && ln -s st0 ./tape
[ ! -e audio ]   && ln -s dsp ./audio
[ ! -e stdin ]   && ln -s /proc/self/fd/0 ./stdin
[ ! -e stdout ]  && ln -s /proc/self/fd/1 ./stdout
[ ! -e stderr ]  && ln -s /proc/self/fd/2 ./stderr