rlogin.c

早期freebsd实现

/*
 * Copyright (c) 1983, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1983, 1990, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)rlogin.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

/*
 * rlogin - remote login
 */
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>

#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <setjmp.h>
#include <sgtty.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

#ifdef KERBEROS
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>

#include "krb.h"

CREDENTIALS cred;
Key_schedule schedule;
int use_kerberos = 1, doencrypt;
char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
#endif

#ifndef TIOCPKT_WINDOW
#define	TIOCPKT_WINDOW	0x80
#endif

/* concession to Sun */
#ifndef SIGUSR1
#define	SIGUSR1	30
#endif

int eight, litout, rem;

int noescape;
u_char escapechar = '~';

char *speeds[] = {
	"0", "50", "75", "110", "134", "150", "200", "300", "600", "1200",
	"1800", "2400", "4800", "9600", "19200", "38400"
};

#ifdef OLDSUN
struct winsize {
	unsigned short ws_row, ws_col;
	unsigned short ws_xpixel, ws_ypixel;
};
#else
#define	get_window_size(fd, wp)	ioctl(fd, TIOCGWINSZ, wp)
#endif
struct	winsize winsize;

void		catch_child __P((int));
void		copytochild __P((int));
__dead void	doit __P((long));
__dead void	done __P((int));
void		echo __P((char));
u_int		getescape __P((char *));
void		lostpeer __P((int));
void		mode __P((int));
void		msg __P((char *));
void		oob __P((int));
int		reader __P((int));
void		sendwindow __P((void));
void		setsignal __P((int));
void		sigwinch __P((int));
void		stop __P((char));
__dead void	usage __P((void));
void		writer __P((void));
void		writeroob __P((int));

#ifdef	KERBEROS
void		warning __P((const char *, ...));
#endif
#ifdef OLDSUN
int		get_window_size __P((int, struct winsize *));
#endif

int
main(argc, argv)
	int argc;
	char *argv[];
{
	extern char *optarg;
	extern int optind;
	struct passwd *pw;
	struct servent *sp;
	struct sgttyb ttyb;
	long omask;
	int argoff, ch, dflag, one, uid;
	char *host, *p, *user, term[1024];

	argoff = dflag = 0;
	one = 1;
	host = user = NULL;

	if (p = rindex(argv[0], '/'))
		++p;
	else
		p = argv[0];

	if (strcmp(p, "rlogin"))
		host = p;

	/* handle "rlogin host flags" */
	if (!host && argc > 2 && argv[1][0] != '-') {
		host = argv[1];
		argoff = 1;
	}

#ifdef KERBEROS
#define	OPTIONS	"8EKLde:k:l:x"
#else
#define	OPTIONS	"8EKLde:l:"
#endif
	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
		switch(ch) {
		case '8':
			eight = 1;
			break;
		case 'E':
			noescape = 1;
			break;
		case 'K':
#ifdef KERBEROS
			use_kerberos = 0;
#endif
			break;
		case 'L':
			litout = 1;
			break;
		case 'd':
			dflag = 1;
			break;
		case 'e':
			noescape = 0;
			escapechar = getescape(optarg);
			break;
#ifdef KERBEROS
		case 'k':
			dest_realm = dst_realm_buf;
			(void)strncpy(dest_realm, optarg, REALM_SZ);
			break;
#endif
		case 'l':
			user = optarg;
			break;
#ifdef CRYPT
#ifdef KERBEROS
		case 'x':
			doencrypt = 1;
			des_set_key(cred.session, schedule);
			break;
#endif
#endif
		case '?':
		default:
			usage();
		}
	optind += argoff;
	argc -= optind;
	argv += optind;

	/* if haven't gotten a host yet, do so */
	if (!host && !(host = *argv++))
		usage();

	if (*argv)
		usage();

	if (!(pw = getpwuid(uid = getuid()))) {
		(void)fprintf(stderr, "rlogin: unknown user id.\n");
		exit(1);
	}
	if (!user)
		user = pw->pw_name;

	sp = NULL;
#ifdef KERBEROS
	if (use_kerberos) {
		sp = getservbyname((doencrypt ? "eklogin" : "klogin"), "tcp");
		if (sp == NULL) {
			use_kerberos = 0;
			warning("can't get entry for %s/tcp service",
			    doencrypt ? "eklogin" : "klogin");
		}
	}
#endif
	if (sp == NULL)
		sp = getservbyname("login", "tcp");
	if (sp == NULL) {
		(void)fprintf(stderr, "rlogin: login/tcp: unknown service.\n");
		exit(1);
	}

	(void)strcpy(term, (p = getenv("TERM")) ? p : "network");
	if (ioctl(0, TIOCGETP, &ttyb) == 0) {
		(void)strcat(term, "/");
		(void)strcat(term, speeds[(int)ttyb.sg_ospeed]);
	}

	(void)get_window_size(0, &winsize);

	(void)signal(SIGPIPE, lostpeer);
	/* will use SIGUSR1 for window size hack, so hold it off */
	omask = sigblock(sigmask(SIGURG) | sigmask(SIGUSR1));
	/*
	 * We set SIGURG and SIGUSR1 below so that an
	 * incoming signal will be held pending rather than being
	 * discarded. Note that these routines will be ready to get
	 * a signal by the time that they are unblocked below.
	 */
	(void)signal(SIGURG, copytochild);
	(void)signal(SIGUSR1, writeroob);

#ifdef KERBEROS
try_connect:
	if (use_kerberos) {
		struct hostent *hp;

		/* Fully qualify hostname (needed for krb_realmofhost). */
		hp = gethostbyname(host);
		if (hp != NULL && !(host = strdup(hp->h_name))) {
			(void)fprintf(stderr, "rlogin: %s\n",
			    strerror(ENOMEM));
			exit(1);
		}

		rem = KSUCCESS;
		errno = 0;
		if (dest_realm == NULL)
			dest_realm = krb_realmofhost(host);

#ifdef CRYPT
		if (doencrypt)
			rem = krcmd_mutual(&host, sp->s_port, user, term, 0,
			    dest_realm, &cred, schedule);
		else
#endif /* CRYPT */
			rem = krcmd(&host, sp->s_port, user, term, 0,
			    dest_realm);
		if (rem < 0) {
			use_kerberos = 0;
			sp = getservbyname("login", "tcp");
			if (sp == NULL) {
				(void)fprintf(stderr,
				    "rlogin: unknown service login/tcp.\n");
				exit(1);
			}
			if (errno == ECONNREFUSED)
				warning("remote host doesn't support Kerberos");
			if (errno == ENOENT)
				warning("can't provide Kerberos auth data");
			goto try_connect;
		}
	} else {
#ifdef CRYPT
		if (doencrypt) {
			(void)fprintf(stderr,
			    "rlogin: the -x flag requires Kerberos authentication.\n");
			exit(1);
		}
#endif /* CRYPT */
		rem = rcmd(&host, sp->s_port, pw->pw_name, user, term, 0);
	}
#else
	rem = rcmd(&host, sp->s_port, pw->pw_name, user, term, 0);
#endif /* KERBEROS */

	if (rem < 0)
		exit(1);

	if (dflag &&
	    setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0)
		(void)fprintf(stderr, "rlogin: setsockopt: %s.\n",
		    strerror(errno));
	one = IPTOS_LOWDELAY;
	if (setsockopt(rem, IPPROTO_IP, IP_TOS, (char *)&one, sizeof(int)) < 0)
		perror("rlogin: setsockopt TOS (ignored)");

	(void)setuid(uid);
	doit(omask);
	/*NOTREACHED*/
}

int child, defflags, deflflags, tabflag;
char deferase, defkill;
struct tchars deftc;
struct ltchars defltc;
struct tchars notc = { -1, -1, -1, -1, -1, -1 };
struct ltchars noltc = { -1, -1, -1, -1, -1, -1 };

void
doit(omask)
	long omask;
{
	struct sgttyb sb;

	(void)ioctl(0, TIOCGETP, (char *)&sb);
	defflags = sb.sg_flags;
	tabflag = defflags & TBDELAY;
	defflags &= ECHO | CRMOD;
	deferase = sb.sg_erase;
	defkill = sb.sg_kill;
	(void)ioctl(0, TIOCLGET, &deflflags);
	(void)ioctl(0, TIOCGETC, &deftc);
	notc.t_startc = deftc.t_startc;
	notc.t_stopc = deftc.t_stopc;
	(void)ioctl(0, TIOCGLTC, &defltc);
	(void)signal(SIGINT, SIG_IGN);
	setsignal(SIGHUP);
	setsignal(SIGQUIT);
	child = fork();
	if (child == -1) {
		(void)fprintf(stderr, "rlogin: fork: %s.\n", strerror(errno));
		done(1);
	}
	if (child == 0) {
		mode(1);
		if (reader(omask) == 0) {
			msg("connection closed.");
			exit(0);
		}
		sleep(1);
		msg("\007connection closed.");
		exit(1);
	}

	/*
	 * We may still own the socket, and may have a pending SIGURG (or might
	 * receive one soon) that we really want to send to the reader.  When
	 * one of these comes in, the trap copytochild simply copies such
	 * signals to the child. We can now unblock SIGURG and SIGUSR1
	 * that were set above.
	 */
	(void)sigsetmask(omask);
	(void)signal(SIGCHLD, catch_child);
	writer();
	msg("closed connection.");
	done(0);
}

/* trap a signal, unless it is being ignored. */
void
setsignal(sig)
	int sig;
{
	int omask = sigblock(sigmask(sig));

	if (signal(sig, exit) == SIG_IGN)
		(void)signal(sig, SIG_IGN);
	(void)sigsetmask(omask);
}

__dead void
done(status)
	int status;
{
	int w, wstatus;

	mode(0);
	if (child > 0) {
		/* make sure catch_child does not snap it up */
		(void)signal(SIGCHLD, SIG_DFL);
		if (kill(child, SIGKILL) >= 0)
			while ((w = wait(&wstatus)) > 0 && w != child);
	}
	exit(status);
}

int dosigwinch;

/*
 * This is called when the reader process gets the out-of-band (urgent)
 * request to turn on the window-changing protocol.
 */
void
writeroob(signo)
	int signo;
{
	if (dosigwinch == 0) {
		sendwindow();
		(void)signal(SIGWINCH, sigwinch);
	}
	dosigwinch = 1;
}

void
catch_child(signo)
	int signo;
{
	union wait status;
	int pid;

	for (;;) {
		pid = wait3((int *)&status, WNOHANG|WUNTRACED, NULL);
		if (pid == 0)
			return;
		/* if the child (reader) dies, just quit */
		if (pid < 0 || (pid == child && !WIFSTOPPED(status)))
			done((int)(status.w_termsig | status.w_retcode));
	}
	/* NOTREACHED */
}

/*
 * writer: write to remote: 0 -> line.
 * ~.				terminate