#include <u.h>#include <libc.h> /* *  prompt for a string with a possible default response */char*readcons(char *prompt, char *def, int raw){	int fdin, fdout, ctl, n;	char *s, *p; 	s = p = nil;	fdout = ctl = -1; 	if((fdin = open("/dev/cons", OREAD)) < 0)		goto Out;	if((fdout = open("/dev/cons", OWRITE)) < 0)		goto Out; 	if(raw){		if((ctl = open("/dev/consctl", OWRITE)) < 0)			goto Out;		write(ctl, "rawon", 5);	} 	if(def != nil)		fprint(fdout, "%s[%s]: ", prompt, def);	else		fprint(fdout, "%s: ", prompt); 	for(;;){		n = p - s;		if((n % 32) == 0){			if((p = realloc(s, n+32)) == nil)				break;			s = p, p += n;		} 		if(read(fdin, p, 1) <= 0 || *p == 0x7f)			break; 		if(*p == '\n' || *p == '\r'){			if(p == s && def != nil){				free(s);				s = strdup(def);			} else				*p = 0;			if(raw)				write(fdout, "\n", 1);			goto Out;		} else if(*p == '\b') {			while(p > s && (p[-1] & 0xc0) == 0x80)				*p-- = 0;			if(p > s)				*p-- = 0;		} else if(*p == 0x15) {	/* ^U: line kill */			if(def != nil)				fprint(fdout, "\n%s[%s]: ", prompt, def);			else				fprint(fdout, "\n%s: ", prompt);			while(p > s)				*p-- = 0;		} else if(*p >= ' ')			p++;	}	free(s);	s = nil;	if(raw)		write(fdout, "\n", 1);Out:	if(ctl >= 0){		write(ctl, "rawoff", 6);		close(ctl);	}	if(fdin >= 0)		close(fdin);	if(fdout >= 0)		close(fdout); 	return s;}