[apple/network_cmds.git] / rsh.tproj / rsh.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.0 (the 'License').  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License."
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1983, 1990, 1993, 1994
 *	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.
 */


/*
 * $Source: /cvs/Darwin/src/live/network_cmds/rsh.tproj/rsh.c,v $
 * $Header: /cvs/Darwin/src/live/network_cmds/rsh.tproj/rsh.c,v 1.1.1.1 1999/05/02 03:58:17 wsanchez Exp $
 */

#include <sys/types.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/file.h>

#include <netinet/in.h>
#include <netdb.h>

#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <varargs.h>

#include "pathnames.h"

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

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

/*
 * rsh - remote shell
 */
int	rfd2;

char   *copyargs __P((char **));
void	sendsig __P((int));
void	talk __P((int, long, pid_t, int));
void	usage __P((void));
void	warning __P(());

int
main(argc, argv)
	int argc;
	char **argv;
{
	struct passwd *pw;
	struct servent *sp;
	long omask;
	int argoff, asrsh, ch, dflag, nflag, one, rem;
	pid_t pid;
	uid_t uid;
	char *args, *host, *p, *user;

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

	/* if called as something other than "rsh", use it as the host name */
	if (p = strrchr(argv[0], '/'))
		++p;
	else
		p = argv[0];
	if (strcmp(p, "rsh"))
		host = p;
	else
		asrsh = 1;

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

#ifdef KERBEROS
#ifdef CRYPT
#define	OPTIONS	"8KLdek:l:nwx"
#else
#define	OPTIONS	"8KLdek:l:nw"
#endif
#else
#define	OPTIONS	"8KLdel:nw"
#endif
	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
		switch(ch) {
		case 'K':
#ifdef KERBEROS
			use_kerberos = 0;
#endif
			break;
		case 'L':	/* -8Lew are ignored to allow rlogin aliases */
		case 'e':
		case 'w':
		case '8':
			break;
		case 'd':
			dflag = 1;
			break;
		case 'l':
			user = optarg;
			break;
#ifdef KERBEROS
		case 'k':
			dest_realm = dst_realm_buf;
			strncpy(dest_realm, optarg, REALM_SZ);
			break;
#endif
		case 'n':
			nflag = 1;
			break;
#ifdef KERBEROS
#ifdef CRYPT
		case 'x':
			doencrypt = 1;
			des_set_key(cred.session, schedule);
			break;
#endif
#endif
		case '?':
		default:
			usage();
		}
	optind += argoff;

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

	/* if no further arguments, must have been called as rlogin. */
	if (!argv[optind]) {
		if (asrsh)
			*argv = "rlogin";
		execv(_PATH_RLOGIN, argv);
		err(1, "can't exec %s", _PATH_RLOGIN);
	}

	argc -= optind;
	argv += optind;

	if (!(pw = getpwuid(uid = getuid())))
		errx(1, "unknown user id");
	/* Accept user1@host format, though "-l user2" overrides user1 */
	p = strchr(host, '@');
	if (p) {
		*p = '\0';
		if (!user && p > host)
			user = host;
		host = p + 1;
		if (*host == '\0')
			usage();
	}
	if (!user)
		user = pw->pw_name;

#ifdef KERBEROS
#ifdef CRYPT
	/* -x turns off -n */
	if (doencrypt)
		nflag = 0;
#endif
#endif

	args = copyargs(argv);

	sp = NULL;
#ifdef KERBEROS
	if (use_kerberos) {
		sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
		if (sp == NULL) {
			use_kerberos = 0;
			warning("can't get entry for %s/tcp service",
			    doencrypt ? "ekshell" : "kshell");
		}
	}
#endif
	if (sp == NULL)
		sp = getservbyname("shell", "tcp");
	if (sp == NULL)
		errx(1, "shell/tcp: unknown service");

#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)))
			err(1, NULL);

		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, args,
			    &rfd2, dest_realm, &cred, schedule);
		else
#endif
			rem = krcmd(&host, sp->s_port, user, args, &rfd2,
			    dest_realm);
		if (rem < 0) {
			use_kerberos = 0;
			sp = getservbyname("shell", "tcp");
			if (sp == NULL)
				errx(1, "shell/tcp: unknown service");
			if (errno == ECONNREFUSED)
				warning("remote host doesn't support Kerberos");
			if (errno == ENOENT)
				warning("can't provide Kerberos auth data");
			goto try_connect;
		}
	} else {
		if (doencrypt)
			errx(1, "the -x flag requires Kerberos authentication");
		rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
	}
#else
	rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
#endif

	if (rem < 0)
		exit(1);

	if (rfd2 < 0)
		errx(1, "can't establish stderr");
	if (dflag) {
		if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
		    sizeof(one)) < 0)
			warn("setsockopt");
		if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
		    sizeof(one)) < 0)
			warn("setsockopt");
	}

	(void)setuid(uid);
	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
		(void)signal(SIGINT, sendsig);
	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
		(void)signal(SIGQUIT, sendsig);
	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
		(void)signal(SIGTERM, sendsig);

	if (!nflag) {
		pid = fork();
		if (pid < 0)
			err(1, "fork");
	}

#ifdef KERBEROS
#ifdef CRYPT
	if (!doencrypt)
#endif
#endif
	{
		(void)ioctl(rfd2, FIONBIO, &one);
		(void)ioctl(rem, FIONBIO, &one);
	}

	talk(nflag, omask, pid, rem);

	if (!nflag)
		(void)kill(pid, SIGKILL);
	exit(0);
}

void
talk(nflag, omask, pid, rem)
	int nflag;
	long omask;
	pid_t pid;
	int rem;
{
	int cc, wc;
	fd_set readfrom, ready, rembits;
	char *bp, buf[BUFSIZ];

	if (!nflag && pid == 0) {
		(void)close(rfd2);

reread:		errno = 0;
		if ((cc = read(0, buf, sizeof buf)) <= 0)
			goto done;
		bp = buf;

rewrite:	
		FD_ZERO(&rembits);
		FD_SET(rem, &rembits);
		if (select(16, 0, &rembits, 0, 0) < 0) {
			if (errno != EINTR)
				err(1, "select");
			goto rewrite;
		}
		if (!FD_ISSET(rem, &rembits))
			goto rewrite;
#ifdef KERBEROS
#ifdef CRYPT
		if (doencrypt)
			wc = des_write(rem, bp, cc);
		else
#endif
#endif
			wc = write(rem, bp, cc);
		if (wc < 0) {
			if (errno == EWOULDBLOCK)
				goto rewrite;
			goto done;
		}
		bp += wc;
		cc -= wc;
		if (cc == 0)
			goto reread;
		goto rewrite;
done:
		(void)shutdown(rem, 1);
		exit(0);
	}

	(void)sigsetmask(omask);
	FD_ZERO(&readfrom);
	FD_SET(rfd2, &readfrom);
	FD_SET(rem, &readfrom);
	do {
		ready = readfrom;
		if (select(16, &ready, 0, 0, 0) < 0) {
			if (errno != EINTR)
				err(1, "select");
			continue;
		}
		if (FD_ISSET(rfd2, &ready)) {
			errno = 0;
#ifdef KERBEROS
#ifdef CRYPT
			if (doencrypt)
				cc = des_read(rfd2, buf, sizeof buf);
			else
#endif
#endif
				cc = read(rfd2, buf, sizeof buf);
			if (cc <= 0) {
				if (errno != EWOULDBLOCK)
					FD_CLR(rfd2, &readfrom);
			} else
				(void)write(2, buf, cc);
		}
		if (FD_ISSET(rem, &ready)) {
			errno = 0;
#ifdef KERBEROS
#ifdef CRYPT
			if (doencrypt)
				cc = des_read(rem, buf, sizeof buf);
			else
#endif
#endif
				cc = read(rem, buf, sizeof buf);
			if (cc <= 0) {
				if (errno != EWOULDBLOCK)
					FD_CLR(rem, &readfrom);
			} else
				(void)write(1, buf, cc);
		}
	} while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
}

void
sendsig(sig)
	int sig;
{
	char signo;

	signo = sig;
#ifdef KERBEROS
#ifdef CRYPT
	if (doencrypt)
		(void)des_write(rfd2, &signo, 1);
	else
#endif
#endif
		(void)write(rfd2, &signo, 1);
}

#ifdef KERBEROS
/* VARARGS */
void
warning(va_alist)
va_dcl
{
	va_list ap;
	char *fmt;

	(void)fprintf(stderr, "rsh: warning, using standard rsh: ");
	va_start(ap);
	fmt = va_arg(ap, char *);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	(void)fprintf(stderr, ".\n");
}
#endif

char *
copyargs(argv)
	char **argv;
{
	int cc;
	char **ap, *args, *p;

	cc = 0;
	for (ap = argv; *ap; ++ap)
		cc += strlen(*ap) + 1;
	if (!(args = malloc((u_int)cc)))
		err(1, NULL);
	for (p = args, ap = argv; *ap; ++ap) {
		(void)strcpy(p, *ap);
		for (p = strcpy(p, *ap); *p; ++p);
		if (ap[1])
			*p++ = ' ';
	}
	return (args);
}

void
usage()
{

	(void)fprintf(stderr,
	    "usage: rsh [-nd%s]%s[-l login] [login@]host [command]\n",
#ifdef KERBEROS
#ifdef CRYPT
	    "x", " [-k realm] ");
#else
	    "", " [-k realm] ");
#endif
#else
	    "", " ");
#endif
	exit(1);
}
Commit	Line	Data
b7080c8e A	1	/*
	2	* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* "Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
	7	* Reserved. This file contains Original Code and/or Modifications of
	8	* Original Code as defined in and that are subject to the Apple Public
	9	* Source License Version 1.0 (the 'License'). You may not use this file
	10	* except in compliance with the License. Please obtain a copy of the
	11	* License at http://www.apple.com/publicsource and read it before using
	12	* this file.
	13	*
	14	* The Original Code and all software distributed under the License are
	15	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	16	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	17	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	18	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	19	* License for the specific language governing rights and limitations
	20	* under the License."
	21	*
	22	* @APPLE_LICENSE_HEADER_END@
	23	*/
	24	/*-
	25	* Copyright (c) 1983, 1990, 1993, 1994
	26	* The Regents of the University of California. All rights reserved.
	27	*
	28	* Redistribution and use in source and binary forms, with or without
	29	* modification, are permitted provided that the following conditions
	30	* are met:
	31	* 1. Redistributions of source code must retain the above copyright
	32	* notice, this list of conditions and the following disclaimer.
	33	* 2. Redistributions in binary form must reproduce the above copyright
	34	* notice, this list of conditions and the following disclaimer in the
	35	* documentation and/or other materials provided with the distribution.
	36	* 3. All advertising materials mentioning features or use of this software
	37	* must display the following acknowledgement:
	38	* This product includes software developed by the University of
	39	* California, Berkeley and its contributors.
	40	* 4. Neither the name of the University nor the names of its contributors
	41	* may be used to endorse or promote products derived from this software
	42	* without specific prior written permission.
	43	*
	44	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	45	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	46	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	47	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	48	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	49	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	50	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	51	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	52	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	53	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	54	* SUCH DAMAGE.
	55	*/
	56
	57
	58	/*
7ba0088d A	59	* $Source: /cvs/Darwin/src/live/network_cmds/rsh.tproj/rsh.c,v $
7ba0088d A	60	* $Header: /cvs/Darwin/src/live/network_cmds/rsh.tproj/rsh.c,v 1.1.1.1 1999/05/02 03:58:17 wsanchez Exp $
b7080c8e A	61	*/
	62
	63	#include <sys/types.h>
	64	#include <sys/signal.h>
	65	#include <sys/socket.h>
	66	#include <sys/ioctl.h>
	67	#include <sys/file.h>
	68
	69	#include <netinet/in.h>
	70	#include <netdb.h>
	71
	72	#include <err.h>
	73	#include <errno.h>
	74	#include <pwd.h>
	75	#include <signal.h>
	76	#include <stdio.h>
	77	#include <stdlib.h>
	78	#include <string.h>
	79	#include <unistd.h>
	80	#include <varargs.h>
	81
	82	#include "pathnames.h"
	83
	84	#ifdef KERBEROS
	85	#include <kerberosIV/des.h>
	86	#include <kerberosIV/krb.h>
	87
	88	CREDENTIALS cred;
	89	Key_schedule schedule;
	90	int use_kerberos = 1, doencrypt;
	91	char dst_realm_buf[REALM_SZ], *dest_realm;
	92	extern char *krb_realmofhost();
	93	#endif
	94
	95	/*
	96	* rsh - remote shell
	97	*/
	98	int rfd2;
	99
	100	char copyargs __P((char *));
	101	void sendsig __P((int));
	102	void talk __P((int, long, pid_t, int));
	103	void usage __P((void));
	104	void warning __P(());
	105
	106	int
	107	main(argc, argv)
	108	int argc;
	109	char **argv;
	110	{
	111	struct passwd *pw;
	112	struct servent *sp;
	113	long omask;
	114	int argoff, asrsh, ch, dflag, nflag, one, rem;
	115	pid_t pid;
	116	uid_t uid;
	117	char args, host, p, user;
	118
	119	argoff = asrsh = dflag = nflag = 0;
	120	one = 1;
	121	host = user = NULL;
	122
	123	/* if called as something other than "rsh", use it as the host name */
	124	if (p = strrchr(argv[0], '/'))
125	++p;
126	else
127	p = argv[0];
128	if (strcmp(p, "rsh"))
129	host = p;
130	else
131	asrsh = 1;
132
133	/* handle "rsh host flags" */
134	if (!host && argc > 2 && argv[1][0] != '-') {
135	host = argv[1];
136	argoff = 1;
137	}
138
139	#ifdef KERBEROS
140	#ifdef CRYPT
141	#define OPTIONS "8KLdek:l:nwx"
142	#else
143	#define OPTIONS "8KLdek:l:nw"
144	#endif
145	#else
146	#define OPTIONS "8KLdel:nw"
147	#endif
148	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
149	switch(ch) {
150	case 'K':
151	#ifdef KERBEROS
152	use_kerberos = 0;
153	#endif
154	break;
155	case 'L': /* -8Lew are ignored to allow rlogin aliases */
156	case 'e':
157	case 'w':
158	case '8':
159	break;
160	case 'd':
161	dflag = 1;
162	break;
163	case 'l':
164	user = optarg;
165	break;
166	#ifdef KERBEROS
167	case 'k':
168	dest_realm = dst_realm_buf;
169	strncpy(dest_realm, optarg, REALM_SZ);
170	break;
171	#endif
172	case 'n':
173	nflag = 1;
174	break;
175	#ifdef KERBEROS
176	#ifdef CRYPT
177	case 'x':
178	doencrypt = 1;
179	des_set_key(cred.session, schedule);
180	break;
181	#endif
182	#endif
183	case '?':
184	default:
185	usage();
186	}
187	optind += argoff;
188
189	/* if haven't gotten a host yet, do so */
190	if (!host && !(host = argv[optind++]))
191	usage();
192
193	/* if no further arguments, must have been called as rlogin. */
194	if (!argv[optind]) {
195	if (asrsh)
196	*argv = "rlogin";
197	execv(_PATH_RLOGIN, argv);
198	err(1, "can't exec %s", _PATH_RLOGIN);
199	}
200
201	argc -= optind;
202	argv += optind;
203
204	if (!(pw = getpwuid(uid = getuid())))
205	errx(1, "unknown user id");
206	/* Accept user1@host format, though "-l user2" overrides user1 */
207	p = strchr(host, '@');
208	if (p) {
209	*p = '\0';
210	if (!user && p > host)
211	user = host;
212	host = p + 1;
213	if (*host == '\0')
214	usage();
215	}
216	if (!user)
217	user = pw->pw_name;
218
219	#ifdef KERBEROS
220	#ifdef CRYPT
221	/* -x turns off -n */
222	if (doencrypt)
223	nflag = 0;
224	#endif
225	#endif
226
227	args = copyargs(argv);
228
229	sp = NULL;
230	#ifdef KERBEROS
231	if (use_kerberos) {
232	sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
233	if (sp == NULL) {
234	use_kerberos = 0;
235	warning("can't get entry for %s/tcp service",
236	doencrypt ? "ekshell" : "kshell");
237	}
238	}
239	#endif
240	if (sp == NULL)
241	sp = getservbyname("shell", "tcp");
242	if (sp == NULL)
243	errx(1, "shell/tcp: unknown service");
244
245	#ifdef KERBEROS
246	try_connect:
247	if (use_kerberos) {
248	struct hostent *hp;
249
250	/* fully qualify hostname (needed for krb_realmofhost) */
251	hp = gethostbyname(host);
252	if (hp != NULL && !(host = strdup(hp->h_name)))
253	err(1, NULL);
254
255	rem = KSUCCESS;
256	errno = 0;
257	if (dest_realm == NULL)
258	dest_realm = krb_realmofhost(host);
259
260	#ifdef CRYPT
261	if (doencrypt)
262	rem = krcmd_mutual(&host, sp->s_port, user, args,
263	&rfd2, dest_realm, &cred, schedule);
264	else
265	#endif
266	rem = krcmd(&host, sp->s_port, user, args, &rfd2,
267	dest_realm);
268	if (rem < 0) {
269	use_kerberos = 0;
270	sp = getservbyname("shell", "tcp");
271	if (sp == NULL)
272	errx(1, "shell/tcp: unknown service");
273	if (errno == ECONNREFUSED)
274	warning("remote host doesn't support Kerberos");
275	if (errno == ENOENT)
276	warning("can't provide Kerberos auth data");
277	goto try_connect;
278	}
279	} else {
280	if (doencrypt)
281	errx(1, "the -x flag requires Kerberos authentication");
282	rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
283	}
284	#else
285	rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
286	#endif
287
288	if (rem < 0)
289	exit(1);
290
291	if (rfd2 < 0)
292	errx(1, "can't establish stderr");
293	if (dflag) {
294	if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
295	sizeof(one)) < 0)
296	warn("setsockopt");
297	if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
298	sizeof(one)) < 0)
299	warn("setsockopt");
300	}
301
302	(void)setuid(uid);
303	omask = sigblock(sigmask(SIGINT)\|sigmask(SIGQUIT)\|sigmask(SIGTERM));
304	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
305	(void)signal(SIGINT, sendsig);
306	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
307	(void)signal(SIGQUIT, sendsig);
308	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
309	(void)signal(SIGTERM, sendsig);
310
311	if (!nflag) {
312	pid = fork();
313	if (pid < 0)
314	err(1, "fork");
315	}
316
317	#ifdef KERBEROS
318	#ifdef CRYPT
319	if (!doencrypt)
320	#endif
321	#endif
322	{
323	(void)ioctl(rfd2, FIONBIO, &one);
324	(void)ioctl(rem, FIONBIO, &one);
325	}
326
327	talk(nflag, omask, pid, rem);
328
329	if (!nflag)
330	(void)kill(pid, SIGKILL);
331	exit(0);
332	}
333
334	void
335	talk(nflag, omask, pid, rem)
336	int nflag;
337	long omask;
338	pid_t pid;
339	int rem;
340	{
341	int cc, wc;
342	fd_set readfrom, ready, rembits;
343	char *bp, buf[BUFSIZ];
344
345	if (!nflag && pid == 0) {
346	(void)close(rfd2);
347
348	reread: errno = 0;
349	if ((cc = read(0, buf, sizeof buf)) <= 0)
350	goto done;
351	bp = buf;
352
353	rewrite:
354	FD_ZERO(&rembits);
355	FD_SET(rem, &rembits);
356	if (select(16, 0, &rembits, 0, 0) < 0) {
357	if (errno != EINTR)
358	err(1, "select");
359	goto rewrite;
360	}
361	if (!FD_ISSET(rem, &rembits))
362	goto rewrite;
363	#ifdef KERBEROS
364	#ifdef CRYPT
365	if (doencrypt)
366	wc = des_write(rem, bp, cc);
367	else
368	#endif
369	#endif
370	wc = write(rem, bp, cc);
371	if (wc < 0) {
372	if (errno == EWOULDBLOCK)
373	goto rewrite;
374	goto done;
375	}
376	bp += wc;
377	cc -= wc;
378	if (cc == 0)
379	goto reread;
380	goto rewrite;
381	done:
382	(void)shutdown(rem, 1);
383	exit(0);
384	}
385
386	(void)sigsetmask(omask);
387	FD_ZERO(&readfrom);
388	FD_SET(rfd2, &readfrom);
389	FD_SET(rem, &readfrom);
390	do {
391	ready = readfrom;
392	if (select(16, &ready, 0, 0, 0) < 0) {
393	if (errno != EINTR)
394	err(1, "select");
395	continue;
396	}
397	if (FD_ISSET(rfd2, &ready)) {
398	errno = 0;
399	#ifdef KERBEROS
400	#ifdef CRYPT
401	if (doencrypt)
402	cc = des_read(rfd2, buf, sizeof buf);
403	else
404	#endif
405	#endif
406	cc = read(rfd2, buf, sizeof buf);
407	if (cc <= 0) {
408	if (errno != EWOULDBLOCK)
409	FD_CLR(rfd2, &readfrom);
410	} else
411	(void)write(2, buf, cc);
412	}
413	if (FD_ISSET(rem, &ready)) {
414	errno = 0;
415	#ifdef KERBEROS
416	#ifdef CRYPT
417	if (doencrypt)
418	cc = des_read(rem, buf, sizeof buf);
419	else
420	#endif
421	#endif
422	cc = read(rem, buf, sizeof buf);
423	if (cc <= 0) {
424	if (errno != EWOULDBLOCK)
425	FD_CLR(rem, &readfrom);
426	} else
427	(void)write(1, buf, cc);
428	}
429	} while (FD_ISSET(rfd2, &readfrom) \|\| FD_ISSET(rem, &readfrom));
430	}
431
432	void
433	sendsig(sig)
434	int sig;
435	{
436	char signo;
437
438	signo = sig;
439	#ifdef KERBEROS
440	#ifdef CRYPT
441	if (doencrypt)
442	(void)des_write(rfd2, &signo, 1);
443	else
444	#endif
445	#endif
446	(void)write(rfd2, &signo, 1);
447	}
448
449	#ifdef KERBEROS
450	/* VARARGS */
451	void
452	warning(va_alist)
453	va_dcl
454	{
455	va_list ap;
456	char *fmt;
457
458	(void)fprintf(stderr, "rsh: warning, using standard rsh: ");
459	va_start(ap);
460	fmt = va_arg(ap, char *);
461	vfprintf(stderr, fmt, ap);
462	va_end(ap);
463	(void)fprintf(stderr, ".\n");
464	}
465	#endif
466
467	char *
468	copyargs(argv)
469	char **argv;
470	{
471	int cc;
472	char *ap, args, *p;
473
474	cc = 0;
475	for (ap = argv; *ap; ++ap)
476	cc += strlen(*ap) + 1;
477	if (!(args = malloc((u_int)cc)))
478	err(1, NULL);
479	for (p = args, ap = argv; *ap; ++ap) {
480	(void)strcpy(p, *ap);
481	for (p = strcpy(p, ap); p; ++p);
482	if (ap[1])
483	*p++ = ' ';
484	}
485	return (args);
486	}
487
488	void
489	usage()
490	{
491
492	(void)fprintf(stderr,
493	"usage: rsh [-nd%s]%s[-l login] [login@]host [command]\n",
494	#ifdef KERBEROS
495	#ifdef CRYPT
496	"x", " [-k realm] ");
497	#else
498	"", " [-k realm] ");
499	#endif
500	#else
501	"", " ");
502	#endif
503	exit(1);
504	}