halfer53 / winix

A UNIX-style Operating System for the Waikato RISC Architecture Microprocessor (WRAMP)

WINIX OS

Winix is a minimal, hobbyistic, educational and UNIX-style Operating System for the Waikato RISC Architecture Microprocessor (WRAMP).

Inspired by the Minix1 operating system, Winix includes a full-featured kernel with features such as process and memory management, in-memory file system, exception control, and a user space bourne shell with interactive command line. And, for a bit of fun, you can even play the classic game of snake by simply typing snake in the command line.

Demo

Playing Snake

Using Pipe in shell

Features

• Kernel Memory Management: virtual memory, page mapping
• Process Management: Kernel thread, process creation
• Exception control and interrupt handler
• In-memory file system that supports most of the POSIX api
• A Bourne shell supporting multiple pipes and redirection
• User memory management: malloc() free()
• User coroutine with ucontext.h support
• Stacktrace dump, segfault analysis

Supported Commands

• snake
• shell
• cat
• cp
• echo
• grep
• history
• ls
• mkdir
• mv
• ps
• pwd
• rm
• stat
• test
• touch
• uptime
• wc
• df
• du
• ln
• tail

Unit Test

tests

How to Run

Download the latest Rexsimulator from Here

N.B. mono is required to run in Linux/MacOS environment, Download Instruction

Download the latest WINIX binary winix.srec from Here

Run Rexsimulator.exe

Click Quick Load, select winix.srec

Loading Winix

How to Compile

N.B. Linux environment is required for compilation

Prerequisite

Debian / Ubuntu

sudo apt-get install xutils-dev gcc

Clone and Compile

git clone https://github.com/halfer53/winix.git
cd winix
make -j$((`nproc`+2))

Debug tips

Debug Makefile

Similar to linux kbuild, Winix supports verbose option, you can debug Makefile by setting verbose to 1

make V=1

Debug Kernel

kprintf(): is your friend.

trace: type trace in shell to print all the syscalls in serial port 2

Supported System Call

• times
• exit
• fork
• vfork
• execve
• brk
• alarm
• sigaction
• sigret
• waitpid
• kill
• getpid
• winfo
• strerror
• dprintf
• sysconf
• sigsuspend
• sigpending
• sigprocmask
• setpgid
• getpgid
• open
• read
• write
• close
• creat
• pipe
• mknod
• chdir
• chown
• chmod
• stat
• fstat
• dup
• dup2
• link
• unlink
• getdent
• access
• mkdir
• sync
• lseek
• umask
• fcntl
• ioctl
• setsid
• nanosleep
• getppid
• signal
• sbrk
• statfs
• getcwd
• tfork
• setitimer

Credits

Paul Monigatti

winix's Issues

Note about kernel mocking

Variables to mock

• RexSp1
• RexSp2
• TEXT_BEGIN, etc
• mm.c
  • PAGE_TO_PADDR
  • PAGE_TO_PADDR
  • ram table
• get_physical_addr
• get_virtual_addr

Check length of long long in wcc

run test in tty2

Build dependencies of srec into makedepend

e.g. if stdio is modified, all srec relying on stdio should be recompiled

Fix concurrency bug

if(is_debugging_ipc()){
                KDEBUG(("IPC: SEND to %d from %d blocked\n",
                            dest, src->proc_nr));
            }
            // Otherwise, block current process and add it to
            // head of sending queue of the destination.
            src->state |= STATE_SENDING;
            src->next_sender = pDest->sender_q;
            pDest->sender_q = src;

This part could trigger undefined behavior if the sender is already receiving

Check use of open and creat in unit tests, namely mode and file flag

return in tty read immediately if new line is in buffer

    if(filp->filp_flags & O_NONBLOCK){
        return __tty_read(state, data, count);
    }

Fix memory leak

bug: Bash crashes after command `ls -lah bin | grep snake | cat | cat`

Fix fork() after tfork()

>Calls shell "bash"

It is not bash.

What did they meant with this.

Check pointer address of wait

improvement: Change ptr_t, vptr_t, reg_t to unsigned long

Remove memset in user get pages

bug: Kernel crashes in branch feature/change-block-size

copy string using memcpy instead of strlcpy

if(count > 0 && state->bptr > state->read_ptr){
        *state->bptr = '\0';
        strlcpy(data, state->read_ptr, count);
        buffer_count -= count;
        state->read_ptr += count;
        // KDEBUG(("count %d buffer %d, ptr %x %x\n", count, buffer_count, state->bptr, state->read_ptr));
        return count;
    }

Implement CLOSE on EXEC in open(2)

Set flag of ARCH_INODE in inode flag instead of using ARCH_INODE_MAP

Make bash compatible with linux

Implement poll(2)

Fix bug of command `test deadlock`