xref: /freebsd/crypto/heimdal/appl/rcp/rcp.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*
2  * Copyright (c) 1983, 1990, 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include "rcp_locl.h"
31 #include <getarg.h>
32 
33 #define RSH_PROGRAM "rsh"
34 
35 struct  passwd *pwd;
36 uid_t	userid;
37 int     errs, remin, remout;
38 int     pflag, iamremote, iamrecursive, targetshouldbedirectory;
39 int     doencrypt, noencrypt;
40 int     usebroken, usekrb4, usekrb5, forwardtkt;
41 char    *port;
42 int     eflag = 0;
43 
44 #define	CMDNEEDS	64
45 char cmd[CMDNEEDS];		/* must hold "rcp -r -p -d\0" */
46 
47 int	 response (void);
48 void	 rsource (char *, struct stat *);
49 void	 sink (int, char *[]);
50 void	 source (int, char *[]);
51 void	 tolocal (int, char *[]);
52 void	 toremote (char *, int, char *[]);
53 
54 int      do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout);
55 
56 static int fflag, tflag;
57 
58 static int version_flag, help_flag;
59 
60 struct getargs args[] = {
61     { NULL,	'4', arg_flag,		&usekrb4,	"use Kerberos 4 authentication" },
62     { NULL,	'5', arg_flag,		&usekrb5,	"use Kerberos 5 authentication" },
63     { NULL,	'F', arg_flag,		&forwardtkt,	"forward credentials" },
64     { NULL,	'K', arg_flag,		&usebroken,	"use BSD authentication" },
65     { NULL,	'P', arg_string,	&port,		"non-default port", "port" },
66     { NULL,	'p', arg_flag,		&pflag,	"preserve file permissions" },
67     { NULL,	'r', arg_flag,		&iamrecursive,	"recursive mode" },
68     { NULL,	'x', arg_flag,		&doencrypt,	"use encryption" },
69     { NULL,	'z', arg_flag,		&noencrypt,	"don't encrypt" },
70     { NULL,	'd', arg_flag,		&targetshouldbedirectory },
71     { NULL,	'e', arg_flag,		&eflag, 	"passed to rsh" },
72     { NULL,	'f', arg_flag,		&fflag },
73     { NULL,	't', arg_flag,		&tflag },
74     { "version", 0,  arg_flag,		&version_flag },
75     { "help",	 0,  arg_flag,		&help_flag }
76 };
77 
78 static void
79 usage (int ret)
80 {
81     arg_printusage (args,
82 		    sizeof(args) / sizeof(args[0]),
83 		    NULL,
84 		    "file1 file2|file... directory");
85     exit (ret);
86 }
87 
88 int
89 main(int argc, char **argv)
90 {
91 	char *targ;
92 	int optind = 0;
93 
94 	setprogname(argv[0]);
95 	if (getarg (args, sizeof(args) / sizeof(args[0]), argc, argv,
96 		    &optind))
97 	    usage (1);
98 	if(help_flag)
99 	    usage(0);
100 	if (version_flag) {
101 	    print_version (NULL);
102 	    return 0;
103 	}
104 
105 	iamremote = (fflag || tflag);
106 
107 	argc -= optind;
108 	argv += optind;
109 
110 	if ((pwd = getpwuid(userid = getuid())) == NULL)
111 		errx(1, "unknown user %d", (int)userid);
112 
113 	remin = STDIN_FILENO;		/* XXX */
114 	remout = STDOUT_FILENO;
115 
116 	if (fflag) {			/* Follow "protocol", send data. */
117 		(void)response();
118 		source(argc, argv);
119 		exit(errs);
120 	}
121 
122 	if (tflag) {			/* Receive data. */
123 		sink(argc, argv);
124 		exit(errs);
125 	}
126 
127 	if (argc < 2)
128 	    usage(1);
129 	if (argc > 2)
130 		targetshouldbedirectory = 1;
131 
132 	remin = remout = -1;
133 	/* Command to be executed on remote system using "rsh". */
134 	snprintf(cmd, sizeof(cmd),
135 		 "rcp%s%s%s", iamrecursive ? " -r" : "",
136 		 pflag ? " -p" : "", targetshouldbedirectory ? " -d" : "");
137 
138 	signal(SIGPIPE, lostconn);
139 
140 	if ((targ = colon(argv[argc - 1])))	/* Dest is remote host. */
141 		toremote(targ, argc, argv);
142 	else {
143 		tolocal(argc, argv);		/* Dest is local host. */
144 		if (targetshouldbedirectory)
145 			verifydir(argv[argc - 1]);
146 	}
147 	exit(errs);
148 }
149 
150 void
151 toremote(char *targ, int argc, char **argv)
152 {
153 	int i;
154 	char *bp, *host, *src, *suser, *thost, *tuser;
155 
156 	*targ++ = 0;
157 	if (*targ == 0)
158 		targ = ".";
159 
160 	if ((thost = strchr(argv[argc - 1], '@')) != NULL) {
161 		/* user@host */
162 		*thost++ = 0;
163 		tuser = argv[argc - 1];
164 		if (*tuser == '\0')
165 			tuser = NULL;
166 		else if (!okname(tuser))
167 			exit(1);
168 	} else {
169 		thost = argv[argc - 1];
170 		tuser = NULL;
171 	}
172 	thost = unbracket(thost);
173 
174 	for (i = 0; i < argc - 1; i++) {
175 		src = colon(argv[i]);
176 		if (src) {			/* remote to remote */
177 			int ret;
178 			*src++ = 0;
179 			if (*src == 0)
180 				src = ".";
181 			host = strchr(argv[i], '@');
182 			if (host) {
183 				*host++ = '\0';
184 				host = unbracket(host);
185 				suser = argv[i];
186 				if (*suser == '\0')
187 					suser = pwd->pw_name;
188 				else if (!okname(suser))
189 					continue;
190 				ret = asprintf(&bp,
191 				    "%s%s %s -l %s -n %s %s '%s%s%s:%s'",
192 					 _PATH_RSH, eflag ? " -e" : "",
193 					 host, suser, cmd, src,
194 				    tuser ? tuser : "", tuser ? "@" : "",
195 				    thost, targ);
196 			} else {
197 				host = unbracket(argv[i]);
198 				ret = asprintf(&bp,
199 					 "exec %s%s %s -n %s %s '%s%s%s:%s'",
200 					 _PATH_RSH, eflag ? " -e" : "",
201 					 host, cmd, src,
202 					 tuser ? tuser : "", tuser ? "@" : "",
203 					 thost, targ);
204 			}
205 			if (ret == -1)
206 				err (1, "malloc");
207 			susystem(bp);
208 			free(bp);
209 		} else {			/* local to remote */
210 			if (remin == -1) {
211 				if (asprintf(&bp, "%s -t %s", cmd, targ) == -1)
212 					err (1, "malloc");
213 				host = thost;
214 
215 				if (do_cmd(host, tuser, bp, &remin, &remout) < 0)
216 					exit(1);
217 
218 				if (response() < 0)
219 					exit(1);
220 				free(bp);
221 			}
222 			source(1, argv+i);
223 		}
224 	}
225 }
226 
227 void
228 tolocal(int argc, char **argv)
229 {
230 	int i;
231 	char *bp, *host, *src, *suser;
232 
233 	for (i = 0; i < argc - 1; i++) {
234 		int ret;
235 
236 		if (!(src = colon(argv[i]))) {		/* Local to local. */
237 			ret = asprintf(&bp, "exec %s%s%s %s %s", _PATH_CP,
238 			    iamrecursive ? " -PR" : "", pflag ? " -p" : "",
239 			    argv[i], argv[argc - 1]);
240 			if (ret == -1)
241 				err (1, "malloc");
242 			if (susystem(bp))
243 				++errs;
244 			free(bp);
245 			continue;
246 		}
247 		*src++ = 0;
248 		if (*src == 0)
249 			src = ".";
250 		if ((host = strchr(argv[i], '@')) == NULL) {
251 			host = argv[i];
252 			suser = pwd->pw_name;
253 		} else {
254 			*host++ = 0;
255 			suser = argv[i];
256 			if (*suser == '\0')
257 				suser = pwd->pw_name;
258 			else if (!okname(suser))
259 				continue;
260 		}
261 		ret = asprintf(&bp, "%s -f %s", cmd, src);
262 		if (ret == -1)
263 			err (1, "malloc");
264 		if (do_cmd(host, suser, bp, &remin, &remout) < 0) {
265 			free(bp);
266 			++errs;
267 			continue;
268 		}
269 		free(bp);
270 		sink(1, argv + argc - 1);
271 		close(remin);
272 		remin = remout = -1;
273 	}
274 }
275 
276 void
277 source(int argc, char **argv)
278 {
279 	struct stat stb;
280 	static BUF buffer;
281 	BUF *bp;
282 	off_t i;
283 	off_t amt;
284 	int fd, haderr, indx, result;
285 	char *last, *name, buf[BUFSIZ];
286 
287 	for (indx = 0; indx < argc; ++indx) {
288                 name = argv[indx];
289 		if ((fd = open(name, O_RDONLY, 0)) < 0)
290 			goto syserr;
291 		if (fstat(fd, &stb)) {
292 syserr:			run_err("%s: %s", name, strerror(errno));
293 			goto next;
294 		}
295 		if (S_ISDIR(stb.st_mode) && iamrecursive) {
296 			rsource(name, &stb);
297 			goto next;
298 		} else if (!S_ISREG(stb.st_mode)) {
299 			run_err("%s: not a regular file", name);
300 			goto next;
301 		}
302 		if ((last = strrchr(name, '/')) == NULL)
303 			last = name;
304 		else
305 			++last;
306 		if (pflag) {
307 			/*
308 			 * Make it compatible with possible future
309 			 * versions expecting microseconds.
310 			 */
311 			snprintf(buf, sizeof(buf), "T%ld 0 %ld 0\n",
312 			    (long)stb.st_mtime,
313 			    (long)stb.st_atime);
314 			write(remout, buf, strlen(buf));
315 			if (response() < 0)
316 				goto next;
317 		}
318 #undef MODEMASK
319 #define	MODEMASK	(S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO)
320 		snprintf(buf, sizeof(buf), "C%04o %lu %s\n",
321 			 (unsigned int)(stb.st_mode & MODEMASK),
322 			 (unsigned long)stb.st_size,
323 			 last);
324 		write(remout, buf, strlen(buf));
325 		if (response() < 0)
326 			goto next;
327 		if ((bp = allocbuf(&buffer, fd, BUFSIZ)) == NULL) {
328 next:			close(fd);
329 			continue;
330 		}
331 
332 		/* Keep writing after an error so that we stay sync'd up. */
333 		for (haderr = i = 0; i < stb.st_size; i += bp->cnt) {
334 			amt = bp->cnt;
335 			if (i + amt > stb.st_size)
336 				amt = stb.st_size - i;
337 			if (!haderr) {
338 			        result = read(fd, bp->buf, (size_t)amt);
339 				if (result != amt)
340 					haderr = result >= 0 ? EIO : errno;
341 			}
342 			if (haderr)
343 				write(remout, bp->buf, amt);
344 			else {
345 			        result = write(remout, bp->buf, (size_t)amt);
346 				if (result != amt)
347 					haderr = result >= 0 ? EIO : errno;
348 			}
349 		}
350 		if (close(fd) && !haderr)
351 			haderr = errno;
352 		if (!haderr)
353 			write(remout, "", 1);
354 		else
355 			run_err("%s: %s", name, strerror(haderr));
356 		response();
357 	}
358 }
359 
360 void
361 rsource(char *name, struct stat *statp)
362 {
363 	DIR *dirp;
364 	struct dirent *dp;
365 	char *last, *vect[1], path[MAXPATHLEN];
366 
367 	if (!(dirp = opendir(name))) {
368 		run_err("%s: %s", name, strerror(errno));
369 		return;
370 	}
371 	last = strrchr(name, '/');
372 	if (last == 0)
373 		last = name;
374 	else
375 		last++;
376 	if (pflag) {
377 		snprintf(path, sizeof(path), "T%ld 0 %ld 0\n",
378 		    (long)statp->st_mtime,
379 		    (long)statp->st_atime);
380 		write(remout, path, strlen(path));
381 		if (response() < 0) {
382 			closedir(dirp);
383 			return;
384 		}
385 	}
386 	snprintf(path, sizeof(path),
387 		 "D%04o %d %s\n",
388 		 (unsigned int)(statp->st_mode & MODEMASK), 0, last);
389 	write(remout, path, strlen(path));
390 	if (response() < 0) {
391 		closedir(dirp);
392 		return;
393 	}
394 	while ((dp = readdir(dirp)) != NULL) {
395 		if (dp->d_ino == 0)
396 			continue;
397 		if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, ".."))
398 			continue;
399 		if (strlen(name) + 1 + strlen(dp->d_name) >= MAXPATHLEN - 1) {
400 			run_err("%s/%s: name too long", name, dp->d_name);
401 			continue;
402 		}
403 		snprintf(path, sizeof(path), "%s/%s", name, dp->d_name);
404 		vect[0] = path;
405 		source(1, vect);
406 	}
407 	closedir(dirp);
408 	write(remout, "E\n", 2);
409 	response();
410 }
411 
412 void
413 sink(int argc, char **argv)
414 {
415 	static BUF buffer;
416 	struct stat stb;
417 	struct timeval tv[2];
418 	enum { YES, NO, DISPLAYED } wrerr;
419 	BUF *bp;
420 	off_t i, j, size;
421 	int amt, count, exists, first, mask, mode, ofd, omode;
422 	int setimes, targisdir, wrerrno = 0;
423 	char ch, *cp, *np, *targ, *why, *vect[1], buf[BUFSIZ];
424 
425 #define	atime	tv[0]
426 #define	mtime	tv[1]
427 #define	SCREWUP(str)	{ why = str; goto screwup; }
428 
429 	setimes = targisdir = 0;
430 	mask = umask(0);
431 	if (!pflag)
432 		umask(mask);
433 	if (argc != 1) {
434 		run_err("ambiguous target");
435 		exit(1);
436 	}
437 	targ = *argv;
438 	if (targetshouldbedirectory)
439 		verifydir(targ);
440 	write(remout, "", 1);
441 	if (stat(targ, &stb) == 0 && S_ISDIR(stb.st_mode))
442 		targisdir = 1;
443 	for (first = 1;; first = 0) {
444 		cp = buf;
445 		if (read(remin, cp, 1) <= 0)
446 			return;
447 		if (*cp++ == '\n')
448 			SCREWUP("unexpected <newline>");
449 		do {
450 			if (read(remin, &ch, sizeof(ch)) != sizeof(ch))
451 				SCREWUP("lost connection");
452 			*cp++ = ch;
453 		} while (cp < &buf[BUFSIZ - 1] && ch != '\n');
454 		*cp = 0;
455 
456 		if (buf[0] == '\01' || buf[0] == '\02') {
457 			if (iamremote == 0)
458 				write(STDERR_FILENO,
459 				    buf + 1, strlen(buf + 1));
460 			if (buf[0] == '\02')
461 				exit(1);
462 			++errs;
463 			continue;
464 		}
465 		if (buf[0] == 'E') {
466 			write(remout, "", 1);
467 			return;
468 		}
469 
470 		if (ch == '\n')
471 			*--cp = 0;
472 
473 		cp = buf;
474 		if (*cp == 'T') {
475 			setimes++;
476 			cp++;
477 			mtime.tv_sec = strtol(cp, &cp, 10);
478 			if (!cp || *cp++ != ' ')
479 				SCREWUP("mtime.sec not delimited");
480 			mtime.tv_usec = strtol(cp, &cp, 10);
481 			if (!cp || *cp++ != ' ')
482 				SCREWUP("mtime.usec not delimited");
483 			atime.tv_sec = strtol(cp, &cp, 10);
484 			if (!cp || *cp++ != ' ')
485 				SCREWUP("atime.sec not delimited");
486 			atime.tv_usec = strtol(cp, &cp, 10);
487 			if (!cp || *cp++ != '\0')
488 				SCREWUP("atime.usec not delimited");
489 			write(remout, "", 1);
490 			continue;
491 		}
492 		if (*cp != 'C' && *cp != 'D') {
493 			/*
494 			 * Check for the case "rcp remote:foo\* local:bar".
495 			 * In this case, the line "No match." can be returned
496 			 * by the shell before the rcp command on the remote is
497 			 * executed so the ^Aerror_message convention isn't
498 			 * followed.
499 			 */
500 			if (first) {
501 				run_err("%s", cp);
502 				exit(1);
503 			}
504 			SCREWUP("expected control record");
505 		}
506 		mode = 0;
507 		for (++cp; cp < buf + 5; cp++) {
508 			if (*cp < '0' || *cp > '7')
509 				SCREWUP("bad mode");
510 			mode = (mode << 3) | (*cp - '0');
511 		}
512 		if (*cp++ != ' ')
513 			SCREWUP("mode not delimited");
514 
515 		for (size = 0; isdigit((unsigned char)*cp);)
516 			size = size * 10 + (*cp++ - '0');
517 		if (*cp++ != ' ')
518 			SCREWUP("size not delimited");
519 		if (targisdir) {
520 			static char *namebuf;
521 			static int cursize;
522 			size_t need;
523 
524 			need = strlen(targ) + strlen(cp) + 250;
525 			if (need > cursize) {
526 				if (!(namebuf = malloc(need)))
527 					run_err("%s", strerror(errno));
528 			}
529 			snprintf(namebuf, need, "%s%s%s", targ,
530 			    *targ ? "/" : "", cp);
531 			np = namebuf;
532 		} else
533 			np = targ;
534 		exists = stat(np, &stb) == 0;
535 		if (buf[0] == 'D') {
536 			int mod_flag = pflag;
537 			if (exists) {
538 				if (!S_ISDIR(stb.st_mode)) {
539 					errno = ENOTDIR;
540 					goto bad;
541 				}
542 				if (pflag)
543 					chmod(np, mode);
544 			} else {
545 				/* Handle copying from a read-only directory */
546 				mod_flag = 1;
547 				if (mkdir(np, mode | S_IRWXU) < 0)
548 					goto bad;
549 			}
550 			vect[0] = np;
551 			sink(1, vect);
552 			if (setimes) {
553 				setimes = 0;
554 				if (utimes(np, tv) < 0)
555 				    run_err("%s: set times: %s",
556 					np, strerror(errno));
557 			}
558 			if (mod_flag)
559 				chmod(np, mode);
560 			continue;
561 		}
562 		omode = mode;
563 		mode |= S_IWRITE;
564 		if ((ofd = open(np, O_WRONLY|O_CREAT, mode)) < 0) {
565 bad:			run_err("%s: %s", np, strerror(errno));
566 			continue;
567 		}
568 		write(remout, "", 1);
569 		if ((bp = allocbuf(&buffer, ofd, BUFSIZ)) == NULL) {
570 			close(ofd);
571 			continue;
572 		}
573 		cp = bp->buf;
574 		wrerr = NO;
575 		for (count = i = 0; i < size; i += BUFSIZ) {
576 			amt = BUFSIZ;
577 			if (i + amt > size)
578 				amt = size - i;
579 			count += amt;
580 			if((j = net_read(remin, cp, amt)) != amt) {
581 			    run_err("%s", j ? strerror(errno) :
582 				    "dropped connection");
583 			    exit(1);
584 			}
585 			amt -= j;
586 			cp += j;
587 			if (count == bp->cnt) {
588 				/* Keep reading so we stay sync'd up. */
589 				if (wrerr == NO) {
590 					j = write(ofd, bp->buf, (size_t)count);
591 					if (j != count) {
592 						wrerr = YES;
593 						wrerrno = j >= 0 ? EIO : errno;
594 					}
595 				}
596 				count = 0;
597 				cp = bp->buf;
598 			}
599 		}
600 		if (count != 0 && wrerr == NO &&
601 		    (j = write(ofd, bp->buf, (size_t)count)) != count) {
602 			wrerr = YES;
603 			wrerrno = j >= 0 ? EIO : errno;
604 		}
605 		if (ftruncate(ofd, size)) {
606 			run_err("%s: truncate: %s", np, strerror(errno));
607 			wrerr = DISPLAYED;
608 		}
609 		if (pflag) {
610 			if (exists || omode != mode)
611 				if (fchmod(ofd, omode))
612 					run_err("%s: set mode: %s",
613 					    np, strerror(errno));
614 		} else {
615 			if (!exists && omode != mode)
616 				if (fchmod(ofd, omode & ~mask))
617 					run_err("%s: set mode: %s",
618 					    np, strerror(errno));
619 		}
620 		close(ofd);
621 		response();
622 		if (setimes && wrerr == NO) {
623 			setimes = 0;
624 			if (utimes(np, tv) < 0) {
625 				run_err("%s: set times: %s",
626 				    np, strerror(errno));
627 				wrerr = DISPLAYED;
628 			}
629 		}
630 		switch(wrerr) {
631 		case YES:
632 			run_err("%s: %s", np, strerror(wrerrno));
633 			break;
634 		case NO:
635 			write(remout, "", 1);
636 			break;
637 		case DISPLAYED:
638 			break;
639 		}
640 	}
641 screwup:
642 	run_err("protocol error: %s", why);
643 	exit(1);
644 }
645 
646 int
647 response(void)
648 {
649 	char ch, *cp, resp, rbuf[BUFSIZ];
650 
651 	if (read(remin, &resp, sizeof(resp)) != sizeof(resp))
652 		lostconn(0);
653 
654 	cp = rbuf;
655 	switch(resp) {
656 	case 0:				/* ok */
657 		return (0);
658 	default:
659 		*cp++ = resp;
660 		/* FALLTHROUGH */
661 	case 1:				/* error, followed by error msg */
662 	case 2:				/* fatal error, "" */
663 		do {
664 			if (read(remin, &ch, sizeof(ch)) != sizeof(ch))
665 				lostconn(0);
666 			*cp++ = ch;
667 		} while (cp < &rbuf[BUFSIZ] && ch != '\n');
668 
669 		if (!iamremote)
670 			write(STDERR_FILENO, rbuf, cp - rbuf);
671 		++errs;
672 		if (resp == 1)
673 			return (-1);
674 		exit(1);
675 	}
676 	/* NOTREACHED */
677 }
678 
679 #include <stdarg.h>
680 
681 void
682 run_err(const char *fmt, ...)
683 {
684 	static FILE *fp;
685 	va_list ap;
686 
687 	++errs;
688 	if (fp == NULL && !(fp = fdopen(remout, "w")))
689 		return;
690 	va_start(ap, fmt);
691 	fprintf(fp, "%c", 0x01);
692 	fprintf(fp, "rcp: ");
693 	vfprintf(fp, fmt, ap);
694 	fprintf(fp, "\n");
695 	fflush(fp);
696 	va_end(ap);
697 
698 	if (!iamremote) {
699 	    va_start(ap, fmt);
700 	    vwarnx(fmt, ap);
701 	    va_end(ap);
702 	}
703 }
704 
705 /*
706  * This function executes the given command as the specified user on the
707  * given host.  This returns < 0 if execution fails, and >= 0 otherwise. This
708  * assigns the input and output file descriptors on success.
709  *
710  * If it cannot create necessary pipes it exits with error message.
711  */
712 
713 int
714 do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout)
715 {
716 	int pin[2], pout[2], reserved[2];
717 
718 	/*
719 	 * Reserve two descriptors so that the real pipes won't get
720 	 * descriptors 0 and 1 because that will screw up dup2 below.
721 	 */
722 	pipe(reserved);
723 
724 	/* Create a socket pair for communicating with rsh. */
725 	if (pipe(pin) < 0) {
726 		perror("pipe");
727 		exit(255);
728 	}
729 	if (pipe(pout) < 0) {
730 		perror("pipe");
731 		exit(255);
732 	}
733 
734 	/* Free the reserved descriptors. */
735 	close(reserved[0]);
736 	close(reserved[1]);
737 
738 	/* For a child to execute the command on the remote host using rsh. */
739 	if (fork() == 0) {
740 		char *args[100];
741 		unsigned int i;
742 
743 		/* Child. */
744 		close(pin[1]);
745 		close(pout[0]);
746 		dup2(pin[0], 0);
747 		dup2(pout[1], 1);
748 		close(pin[0]);
749 		close(pout[1]);
750 
751 		i = 0;
752 		args[i++] = RSH_PROGRAM;
753 		if (usekrb4)
754 			args[i++] = "-4";
755 		if (usekrb5)
756 			args[i++] = "-5";
757 		if (usebroken)
758 			args[i++] = "-K";
759 		if (doencrypt)
760 			args[i++] = "-x";
761 		if (forwardtkt)
762 			args[i++] = "-F";
763 		if (noencrypt)
764 			args[i++] = "-z";
765 		if (port != NULL) {
766 			args[i++] = "-p";
767 			args[i++] = port;
768 		}
769 		if (eflag)
770 		    args[i++] = "-e";
771 		if (remuser != NULL) {
772 			args[i++] = "-l";
773 			args[i++] = remuser;
774 		}
775 		args[i++] = host;
776 		args[i++] = cmd;
777 		args[i++] = NULL;
778 
779 		execvp(RSH_PROGRAM, args);
780 		perror(RSH_PROGRAM);
781 		exit(1);
782 	}
783 	/* Parent.  Close the other side, and return the local side. */
784 	close(pin[0]);
785 	*fdout = pin[1];
786 	close(pout[1]);
787 	*fdin = pout[0];
788 	return 0;
789 }
790