/* * Terminal support (standard input/output). */ #include	"u.h"#include	<termios.h>#include	<sys/termios.h>#include	"lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"error.h" static int ttyprint = 0;static int ttyecho = 0;static struct termios ttprevmode; /* * Normal prints and console output go to standard output. */voiduartputs(char *buf, int n){	if(!ttyprint)		return;	write(1, buf, n);} voidrestoretty(void){	if(ttyecho && tcsetattr(0, TCSANOW, &ttprevmode) < 0){		ttyecho = 0;		panic("could not restore previous tty mode");	}} voidbye(int sig){	restoretty();	exit(0);} voiduartreader(void *v){	char buf[256];	int n;	static struct termios ttmode;		/*	 * Try to disable host echo, save	 * current state to restore it at exit. 	 * If successful, remember to echo	 * what gets typed ourselves.	 */	if(tcgetattr(0, &ttprevmode) < 0)		/*		 * We do not panic here so that		 * 9vx can be run without a tty		 */		goto Read;	if(tcgetattr(0, &ttmode) >= 0){		ttmode.c_lflag &= ~(ECHO|ICANON);		if(tcsetattr(0, TCSANOW, &ttmode) >= 0)			ttyecho = 1;	}	signal(SIGINT, bye);	signal(SIGTERM, bye);Read:	while((n = read(0, buf, sizeof buf)) > 0)		echo(buf, n);} voiduartinit(int usetty){	ttyprint = usetty;	kbdq = qopen(4*1024, 0, 0, 0);	if(usetty)		kproc("*tty*", uartreader, nil);} voiduartecho(char *buf, int n){	if(ttyecho)		write(1, buf, n);}