Michael Salerno  108512298
Paul    Campbell 108481554

This is the 60 pt OS final project.

How to test binaries:
  1) make sure the binary is in the rootfs/bin/ folder
  2) go into the sys/kmain.c and call the binary by using
        void exec_tarfs_elf_args(const char *path, int argc, char *argv[], char *envp[])
        or
        void exec_tarfs_elf(const char *path)

Included binaries:
  - args [arg1] [arg2] ...
      This program tests that args are placed on the stack correctly
  - malloc
      Attempts to test the malloc
  - open
      It asks for a file name in tarfs and then writes out its contents
  - ps
      lists all of the processes running on the os
  - kill
      kills a process
  - echo
      echos text passed as arguments


Working system calls:
  - fork
    * Bug with using exec after forking.
  - execve
  - sleep
  - open 
  - read
  - write
  - lseek
  - close
  - brk
  - exit
  - getpid
  - getppid
  - kill
  - getcwd
  - chdir

Other noteable features:
  - fast syscall and sysretq are used
  - on demand malloc
  - auto growing stack

The provided Makefile:
  1) builds a kernel
  2) copies it into rootfs/boot/kernel/kernel
  3) creates an ISO CD image with the rootfs/ contents

To boot the system in QEMU, run:
  qemu-system-x86_64 -curses -cdrom $USER.iso -drive id=disk,file=$USER.img,if=none -device ahci,id=ahci
  -device ide-drive,drive=disk,bus=ahci.0 -net nic -net user,hostfwd=tcp::10080-:80 -net user,
  hostfwd=tcp::10023-:23 --no-reboot -gdb tcp::9998

  Explanation of parameters:
  -curses         use a text console (omit this to use default SDL/VNC console)
  -cdrom x.iso    connect a CD-ROM and insert CD with x.iso disk
  --no-reboot     exit when guest reboots
  -gdb tcp::9998  listen for "remote" debugging connections on port 9998

  connect a hard drive with x.img disk:
  -drive id=disk,file=$USER.img,if=none -device ahci,id=ahci -device ide-drive,drive=disk,bus=ahci.0
  connect a NIC and forward local port 10080 into port 80 and local port 10023 to port 23
  -net nic -net user,hostfwd=tcp::10080-:80 -net user,hostfwd=tcp::10023-:23

When using the -curses mode, switch to the qemu> console with ESC-2.

To connect a remote debugger to the running qemu VM:
  gdb ./kernel
  target remote localhost:9998