/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <auth.h>#include <libsec.h> #include "../ip/telnet.h" /*  console state (for consctl) */typedef struct Consstate	Consstate;struct Consstate{	int raw;	int hold;};Consstate *cons; int notefd;		/* for sending notes to the child */int noproto;		/* true if we shouldn't be using the telnet protocol */int trusted;		/* true if we need not authenticate - current user				is ok */int nonone = 1;		/* don't allow none logins */int noworldonly;	/* only noworld accounts */ enum{	Maxpath=	256,	Maxuser=	64,	Maxvar=		32,}; /* input and output buffers for network connection */Biobuf	netib;Biobuf	childib;char	remotesys[Maxpath];	/* name of remote system */ int	alnum(int);int	conssim(void);int	fromchild(char*, int);int	fromnet(char*, int);int	termchange(Biobuf*, int);int	termsub(Biobuf*, uchar*, int);int	xlocchange(Biobuf*, int);int	xlocsub(Biobuf*, uchar*, int);int	challuser(char*);int	noworldlogin(char*);void*	share(ulong);int	doauth(char*); #define TELNETLOG "telnet" voidlogit(char *fmt, ...){	va_list arg;	char buf[8192]; 	va_start(arg, fmt);	vseprint(buf, buf + sizeof(buf) / sizeof(*buf), fmt, arg);	va_end(arg);	syslog(0, TELNETLOG, "(%s) %s", remotesys, buf);} voidgetremote(char *dir){	int fd, n;	char remfile[Maxpath]; 	sprint(remfile, "%s/remote", dir);	fd = open(remfile, OREAD);	if(fd < 0)		strcpy(remotesys, "unknown2");	n = read(fd, remotesys, sizeof(remotesys)-1);	if(n>0)		remotesys[n-1] = 0;	else		strcpy(remotesys, remfile);	close(fd);} voidmain(int argc, char *argv[]){	char buf[1024];	int fd;	char user[Maxuser];	int tries = 0;	int childpid;	int n, eofs; 	memset(user, 0, sizeof(user));	ARGBEGIN {	case 'n':		opt[Echo].local = 1;		noproto = 1;		break;	case 'p':		noproto = 1;		break;	case 'a':		nonone = 0;		break;	case 't':		trusted = 1;		strncpy(user, getuser(), sizeof(user)-1);		break;	case 'u':		strncpy(user, ARGF(), sizeof(user)-1);		break;	case 'd':		debug = 1;		break;	case 'N':		noworldonly = 1;		break;	} ARGEND 	if(argc)		getremote(argv[argc-1]);	else		strcpy(remotesys, "unknown"); 	/* options we need routines for */	opt[Term].change = termchange;	opt[Term].sub = termsub;	opt[Xloc].sub = xlocsub; 	/* setup default telnet options */	if(!noproto){		send3(1, Iac, Will, opt[Echo].code);		send3(1, Iac, Do, opt[Term].code);		send3(1, Iac, Do, opt[Xloc].code);	} 	/* shared data for console state */	cons = share(sizeof(Consstate));	if(cons == 0)		fatal("shared memory", 0, 0); 	/* authenticate and create new name space */	Binit(&netib, 0, OREAD);	if (!trusted){		while(doauth(user) < 0)			if(++tries == 5){				logit("failed as %s: %r", user);				print("authentication failure:%r\r\n");				exits("authentication");			}	}	logit("logged in as %s", user);	putenv("service", "con"); 	/* simulate /dev/consctl and /dev/cons using pipes */	fd = conssim();	if(fd < 0)		fatal("simulating", 0, 0);	Binit(&childib, fd, OREAD); 	/* start a shell in a different process group */	switch(childpid = rfork(RFPROC|RFNAMEG|RFFDG|RFNOTEG)){	case -1:		fatal("fork", 0, 0);	case 0:		close(fd);		fd = open("/dev/cons", OREAD);		dup(fd, 0);		close(fd);		fd = open("/dev/cons", OWRITE);		dup(fd, 1);		dup(fd, 2);		close(fd);		segdetach(cons);		execl("/bin/rc", "rc", "-il", nil);		fatal("/bin/rc", 0, 0);	default:		sprint(buf, "/proc/%d/notepg", childpid);		notefd = open(buf, OWRITE);		break;	} 	/* two processes to shuttle bytes twixt children and network */	switch(fork()){	case -1:		fatal("fork", 0, 0);	case 0:		eofs = 0;		for(;;){			n = fromchild(buf, sizeof(buf));			if(n <= 0){				if(eofs++ > 2)					break;				continue;			}			eofs = 0;			if(write(1, buf, n) != n)				break;		}		break;	default:		while((n = fromnet(buf, sizeof(buf))) >= 0)			if(write(fd, buf, n) != n)				break;		break;	} 	/* kill off all server processes */	sprint(buf, "/proc/%d/notepg", getpid());	fd = open(buf, OWRITE);	write(fd, "die", 3);	exits(0);} voidprompt(char *p, char *b, int n, int raw){	char *e;	int i;	int echo; 	echo = opt[Echo].local;	if(raw)		opt[Echo].local = 0;	print("%s: ", p);	for(e = b+n; b < e;){		i = fromnet(b, e-b);		if(i <= 0)			exits("fromnet: hungup");		b += i;		if(*(b-1) == '\n' || *(b-1) == '\r'){			*(b-1) = 0;			break;		}	}	if(raw)		opt[Echo].local = echo;} /* *  challenge user */intchalluser(char *user){	char nchall[64];	char response[64];	Chalstate *ch;	AuthInfo *ai; 	if(strcmp(user, "none") == 0){		if(nonone)			return -1;		newns("none", nil);		return 0;	}	if((ch = auth_challenge("proto=p9cr role=server user=%q", user)) == nil)		return -1;	snprint(nchall, sizeof nchall, "challenge: %s\r\nresponse", ch->chal);	prompt(nchall, response, sizeof response, 0);	ch->resp = response;	ch->nresp = strlen(response);	ai = auth_response(ch);	auth_freechal(ch);	if(ai == nil){		rerrstr(response, sizeof response);		print("!%s\n", response);		return -1;	}	if(auth_chuid(ai, nil) < 0)		return -1;	return 0;}/* *  use the in the clear apop password to change user id */intnoworldlogin(char *user){	char password[256]; 	prompt("password", password, sizeof(password), 1);	if(login(user, password, "/lib/namespace.noworld") < 0)		return -1;	rfork(RFNOMNT);	/* sandbox */	return 0;} intdoauth(char *user){	if(*user == 0)		prompt("user", user, Maxuser, 0);	if(noworld(user))		return noworldlogin(user);	if(noworldonly)		return -1;	return challuser(user);		} /* *  Process some input from the child, add protocol if needed.  If *  the input buffer goes empty, return. */intfromchild(char *bp, int len){	int c;	char *start; 	for(start = bp; bp-start < len-1; ){		c = Bgetc(&childib);		if(c < 0){			if(bp == start)				return -1;			else				break;		}		if(cons->raw == 0 && c == '\n')			*bp++ = '\r';		*bp++ = c;		if(Bbuffered(&childib) == 0)			break;	}	return bp-start;} /* *  Read from the network up to a '\n' or some other break. * *  If in binary mode, buffer characters but don't  * *  The following characters are special: *	'\r\n's and '\r's get turned into '\n's. *	^H erases the last character buffered. *	^U kills the whole line buffered. *	^W erases the last word *	^D causes a 0-length line to be returned. *	Intr causes an "interrupt" note to be sent to the children. */#define ECHO(c) { *ebp++ = (c); }intfromnet(char *bp, int len){	int c;	char echobuf[1024];	char *ebp;	char *start;	static int crnl;	static int doeof;  	/* simulate an EOF as a 0 length input */	if(doeof){		doeof = 0;		return 0;	} 	for(ebp = echobuf,start = bp; bp-start < len && ebp-echobuf < sizeof(echobuf); ){		c = Bgetc(&netib);		if(c < 0){			if(bp == start)				return -1;			else				break;		} 		/* telnet protocol only */		if(!noproto){			/* protocol messages */			switch(c){			case Iac:				crnl = 0;				c = Bgetc(&netib);				if(c == Iac)					break;				control(&netib, c);				continue;			} 		} 		/* \r\n or \n\r become \n  */		if(c == '\r' || c == '\n'){			if(crnl && crnl != c){				crnl = 0;				continue;			}			if(cons->raw == 0 && opt[Echo].local){				ECHO('\r');				ECHO('\n');			}			crnl = c;			if(cons->raw == 0)				*bp++ = '\n';			else				*bp++ = c;			break;		} else			crnl = 0; 		/* raw processing (each character terminates */		if(cons->raw){			*bp++ = c;			break;		} 		/* in binary mode, there are no control characters */		if(opt[Binary].local){			if(opt[Echo].local)				ECHO(c);			*bp++ = c;			continue;		} 		/* cooked processing */		switch(c){		case 0x00:			if(noproto)		/* telnet ignores nulls */				*bp++ = c;			continue;		case 0x04:			if(bp != start)				doeof = 1;			goto out; 		case 0x08:	/* ^H */			if(start < bp)				bp--;			if(opt[Echo].local)				ECHO(c);			break; 		case 0x15:	/* ^U */			bp = start;			if(opt[Echo].local){				ECHO('^');				ECHO('U');				ECHO('\r');				ECHO('\n');			}			break; 		case 0x17:	/* ^W */			if (opt[Echo].local) {				while (--bp >= start && !alnum(*bp))					ECHO('\b');				while (bp >= start && alnum(*bp)) {					ECHO('\b');					bp--;				}				bp++;			}			break; 		case 0x7f:	/* Del */			write(notefd, "interrupt", 9);			bp = start;			break; 		default:			if(opt[Echo].local)				ECHO(c);			*bp++ = c;		}		if(ebp != echobuf)			write(1, echobuf, ebp-echobuf);		ebp = echobuf;	}out:	if(ebp != echobuf)		write(1, echobuf, ebp-echobuf);	return bp - start;} inttermchange(Biobuf *bp, int cmd){	char buf[8];	char *p = buf; 	if(cmd != Will)		return 0; 	/* ask other side to send term type info */	*p++ = Iac;	*p++ = Sb;	*p++ = opt[Term].code;	*p++ = 1;	*p++ = Iac;	*p++ = Se;	return iwrite(Bfildes(bp), buf, p-buf);

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