Write in C: Quesiton 2. Implementing non-blocking / non-echoing mode for xv6 console The default operation of xv6 console driver is to collect user keypresses into a line of text and to awaken the processes waiting for user input only when the user presses Enter. In addition, xv6 console automatically echoes (i.e. prints out on the display) every user keypress. While this behaviour is appropriate in many scenarios, it is not suitable for interactive gaming. Implement ioctl() system call for the console driver that switches it into non-echoingm non-blocking mode and test it using sample game supplied to you in user/game.c file This is some of the code: Console.c ---------------------------- #include #include "types.h" #include "param.h" #include "spinlock.h" #include "sleeplock.h" #include "fs.h" #include "file.h" #include "memlayout.h" #include "riscv.h" #include "defs.h" #include "proc.h" #include "console.h" #include "ioctl.h" #define BACKSPACE 0x100 #define C(x) ((x)-'@') // Control-x // // send one character to the uart. // called by printf(), and to echo input characters, // but not from write(). // void consputc(int c) { if(c==BACKSPACE){ // if the user typed backspace, overwrite with a space. uartputc_sync('\b'); uartputc_sync(''); uartputc_sync('\b'); } else { uartputc_sync(c); } } struct { structspinlocklock; // input #define INPUT_BUF_SIZE 128 charbuf[INPUT_BUF_SIZE]; uintr; // Read index uintw; // Write index uinte; // Edit index } cons; // // user write()s to the console go here. // int consolewrite(int user_src, uint64 src, int n) { inti; for(i=0; i0){ // wait until interrupt handler has put some // input into cons.buffer. while(cons.r==cons.w){ if(killed(myproc())){ release(&cons.lock); return-1; } sleep(&cons.r, &cons.lock); } c=cons.buf[cons.r++%INPUT_BUF_SIZE]; if(c==C('D')){ // end-of-file if(n

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Write in C:

Quesiton 2. Implementing non-blocking / non-echoing mode for xv6 console
The default operation of xv6 console driver is to collect user keypresses into a line of text and to
awaken the processes waiting for user input only when the user presses Enter. In addition, xv6
console automatically echoes (i.e. prints out on the display) every user keypress. While this
behaviour is appropriate in many scenarios, it is not suitable for interactive gaming.
Implement ioctl() system call for the console driver that switches it into non-echoingm non-blocking
mode and test it using sample game supplied to you in user/game.c file

This is some of the code:

Console.c

----------------------------

#include <stdarg.h>

#include "types.h"

#include "param.h"

#include "spinlock.h"

#include "sleeplock.h"

#include "fs.h"

#include "file.h"

#include "memlayout.h"

#include "riscv.h"

#include "defs.h"

#include "proc.h"

#include "console.h"

#include "ioctl.h"

#define BACKSPACE 0x100

#define C(x) ((x)-'@') // Control-x

// send one character to the uart.

// called by printf(), and to echo input characters,

// but not from write().

void

consputc(int c)

{

if(c==BACKSPACE){

// if the user typed backspace, overwrite with a space.

uartputc_sync('\b'); uartputc_sync(''); uartputc_sync('\b');

} else {

uartputc_sync(c);

}

struct {

structspinlocklock;

// input

#define INPUT_BUF_SIZE 128

charbuf[INPUT_BUF_SIZE];

uintr; // Read index

uintw; // Write index

uinte; // Edit index

} cons;

// user write()s to the console go here.

int

consolewrite(int user_src, uint64 src, int n)

{

inti;

for(i=0; i<n; i++){

charc;

if(either_copyin(&c, user_src, src+i, 1) ==-1)

break;

uartputc(c);

}

returni;

}

// user read()s from the console go here.

// copy (up to) a whole input line to dst.

// user_dist indicates whether dst is a user

// or kernel address.

int

consoleread(int user_dst, uint64 dst, int n)

{

uinttarget;

intc;

charcbuf;

target=n;

acquire(&cons.lock);

while(n>0){

// wait until interrupt handler has put some

// input into cons.buffer.

while(cons.r==cons.w){

if(killed(myproc())){

release(&cons.lock);

return-1;

}

sleep(&cons.r, &cons.lock);

}

c=cons.buf[cons.r++%INPUT_BUF_SIZE];

if(c==C('D')){ // end-of-file

if(n<target){

// Save ^D for next time, to make sure

// caller gets a 0-byte result.

cons.r--;

}

break;

}

// copy the input byte to the user-space buffer.

cbuf=c;

if(either_copyout(user_dst, dst, &cbuf, 1) ==-1)

break;

dst++;

--n;

if(c=='\n'){

// a whole line has arrived, return to

// the user-level read().

break;

}

release(&cons.lock);

returntarget-n;

}

// the console input interrupt handler.

// uartintr() calls this for input character.

// do erase/kill processing, append to cons.buf,

// wake up consoleread() if a whole line has arrived.

void

consoleintr(int c)

{

acquire(&cons.lock);

switch(c){

caseC('P'): // Print process list.

procdump();

break;

caseC('U'): // Kill line.

while(cons.e!=cons.w&&

cons.buf[(cons.e-1) %INPUT_BUF_SIZE] !='\n'){

cons.e--;

consputc(BACKSPACE);

}

break;

caseC('H'): // Backspace

case'\x7f': // Delete key

if(cons.e!=cons.w){

cons.e--;

consputc(BACKSPACE);

}

break;

default:

if(c!=0&&cons.e-cons.r<INPUT_BUF_SIZE){

c= (c=='\r') ?'\n':c;

// echo back to the user.

consputc(c);

// store for consumption by consoleread().

cons.buf[cons.e++%INPUT_BUF_SIZE] =c;

if(c=='\n'||c==C('D') ||cons.e-cons.r==INPUT_BUF_SIZE){

// wake up consoleread() if a whole line (or end-of-file)

// has arrived.

cons.w=cons.e;

wakeup(&cons.r);

}

break;

}

release(&cons.lock);

}

int

consoleioctl(int user_dst, uint64 dst, int request)

{

intres=-1;

returnres;

}

void

consoleinit(void)

{

initlock(&cons.lock, "cons");

uartinit();

// connect read and write system calls

// to consoleread and consolewrite.

devsw[CONSOLE].read=consoleread;

devsw[CONSOLE].write=consolewrite;

devsw[CONSOLE].ioctl=consoleioctl;

}

------------------------------------------------

console.h

/* Console flags, settable with ioctl */

#define CONSOLE_FL_NONBLOCK (1)

#define CONSOLE_FL_NOECHO (2)

/* ioctl request types */

#define CONSOLE_SETFL (1)

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