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      1 /*	$NetBSD: rexec.c,v 1.16 2003/08/07 16:44:16 agc Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)rexec.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: rexec.c,v 1.16 2003/08/07 16:44:16 agc Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <sys/types.h>
     42 #include <sys/socket.h>
     43 
     44 #include <netinet/in.h>
     45 
     46 #include <assert.h>
     47 #include <err.h>
     48 #include <errno.h>
     49 #include <netdb.h>
     50 #include <stdio.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 
     54 int	rexecoptions;
     55 
     56 int	ruserpass __P((const char *, char **, char **));
     57 int	rexec __P((char **, int, char *, char *, char *, int *));
     58 
     59 int
     60 rexec(ahost, rport, name, pass, cmd, fd2p)
     61 	char **ahost;
     62 	int rport;
     63 	char *name, *pass, *cmd;
     64 	int *fd2p;
     65 {
     66 	struct sockaddr_in rsin, from;
     67 	socklen_t fromlen;
     68 	struct hostent *hp;
     69 	u_short port;
     70 	size_t len;
     71 	unsigned int timo = 1;
     72 	int s, s3;
     73 	char c;
     74 
     75 	_DIAGASSERT(ahost != NULL);
     76 	_DIAGASSERT(name != NULL);
     77 	_DIAGASSERT(pass != NULL);
     78 	_DIAGASSERT(cmd != NULL);
     79 	/* fd2p may be NULL */
     80 
     81 	hp = gethostbyname(*ahost);
     82 	if (hp == 0) {
     83 		warnx("Error resolving %s (%s)", *ahost, hstrerror(h_errno));
     84 		return -1;
     85 	}
     86 	*ahost = hp->h_name;
     87 	(void)ruserpass(hp->h_name, &name, &pass);
     88 retry:
     89 	if ((s = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
     90 		warn("Cannot create socket");
     91 		return (-1);
     92 	}
     93 	rsin.sin_family = hp->h_addrtype;
     94 	rsin.sin_len = sizeof(rsin);
     95 	rsin.sin_port = rport;
     96 	/* Avoid data corruption from bogus DNS results */
     97 	if (hp->h_length > (int) sizeof(rsin.sin_addr))
     98 		len = sizeof(rsin.sin_addr);
     99 	else
    100 		len = hp->h_length;
    101 	memcpy(&rsin.sin_addr, hp->h_addr, len);
    102 	if (connect(s, (struct sockaddr *)(void *)&rsin, sizeof(rsin)) == -1) {
    103 		if (errno == ECONNREFUSED && timo <= 16) {
    104 			(void)close(s);
    105 			sleep(timo);
    106 			timo *= 2;
    107 			goto retry;
    108 		}
    109 		warn("Cannot connect to %s", hp->h_name);
    110 		return -1;
    111 	}
    112 	port = 0;
    113 	if (fd2p == 0) {
    114 		(void)write(s, "", 1);
    115 	} else {
    116 		char num[8];
    117 		int s2;
    118 		struct sockaddr_in sin2;
    119 		socklen_t sin2len;
    120 
    121 		s2 = socket(AF_INET, SOCK_STREAM, 0);
    122 		if (s2 == -1) {
    123 			warn("Error creating socket");
    124 			(void)close(s);
    125 			return -1;
    126 		}
    127 		listen(s2, 1);
    128 		sin2len = sizeof(sin2);
    129 		if (getsockname(s2, (struct sockaddr *)(void *)&sin2,
    130 		    &sin2len) == -1 || sin2len != sizeof(sin2)) {
    131 			warn("Failed to get socket name");
    132 			(void)close(s2);
    133 			goto bad;
    134 		}
    135 		port = ntohs((u_short)sin2.sin_port);
    136 		(void)snprintf(num, sizeof(num), "%u", port);
    137 		(void)write(s, num, strlen(num)+1);
    138 
    139 		fromlen = sizeof(from);
    140 		s3 = accept(s2, (struct sockaddr *)(void *)&from, &fromlen);
    141 		(void)close(s2);
    142 		if (s3 == -1) {
    143 			warn("Error accepting connection");
    144 			port = 0;
    145 			goto bad;
    146 		}
    147 		*fd2p = s3;
    148 	}
    149 	(void)write(s, name, strlen(name) + 1);
    150 	/* should public key encypt the password here */
    151 	(void)write(s, pass, strlen(pass) + 1);
    152 	(void)write(s, cmd, strlen(cmd) + 1);
    153 	if (read(s, &c, 1) != 1) {
    154 		warn("Error reading from %s", *ahost);
    155 		goto bad;
    156 	}
    157 	if (c != 0) {
    158 		while (read(s, &c, 1) == 1) {
    159 			(void) write(2, &c, 1);
    160 			if (c == '\n')
    161 				break;
    162 		}
    163 		goto bad;
    164 	}
    165 	return s;
    166 bad:
    167 	if (port)
    168 		(void)close(*fd2p);
    169 	(void)close(s);
    170 	return -1;
    171 }
    172