xref: /freebsd/usr.bin/finger/net.c (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Tony Nardo of the Johns Hopkins University/Applied Physics Lab.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)net.c	8.4 (Berkeley) 4/28/95";
40 #else
41 static const char rcsid[] =
42 	"$Id: net.c,v 1.9 1997/08/01 20:10:44 wollman Exp $";
43 #endif
44 #endif /* not lint */
45 
46 #include <sys/types.h>
47 #include <sys/param.h>
48 #include <sys/socket.h>
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
51 #include <netdb.h>
52 #include <db.h>
53 #include <err.h>
54 #include <unistd.h>
55 #include <pwd.h>
56 #include <utmp.h>
57 #include <stdio.h>
58 #include <ctype.h>
59 #include <string.h>
60 #include <sys/uio.h>
61 #include "finger.h"
62 
63 void
64 netfinger(name)
65 	char *name;
66 {
67 	extern int lflag;
68 	extern int Tflag;
69 	register FILE *fp;
70 	register int c, lastc;
71 	struct in_addr defaddr;
72 	struct hostent *hp, def;
73 	struct servent *sp;
74 	struct sockaddr_in sin;
75 	int s;
76 	char *alist[1], *host;
77 	struct iovec iov[3];
78 	struct msghdr msg;
79 
80 	if (!(host = rindex(name, '@')))
81 		return;
82 	*host++ = '\0';
83 	if (isdigit(*host) && (defaddr.s_addr = inet_addr(host)) != -1) {
84 		def.h_name = host;
85 		def.h_addr_list = alist;
86 		def.h_addr = (char *)&defaddr;
87 		def.h_length = sizeof(struct in_addr);
88 		def.h_addrtype = AF_INET;
89 		def.h_aliases = 0;
90 		hp = &def;
91 	} else if (!(hp = gethostbyname(host))) {
92 		warnx("unknown host: %s", host);
93 		return;
94 	}
95 	if (!(sp = getservbyname("finger", "tcp"))) {
96 		warnx("tcp/finger: unknown service");
97 		return;
98 	}
99 	sin.sin_family = hp->h_addrtype;
100 	bcopy(hp->h_addr, (char *)&sin.sin_addr, MIN(hp->h_length,sizeof(sin.sin_addr)));
101 	sin.sin_port = sp->s_port;
102 	if ((s = socket(hp->h_addrtype, SOCK_STREAM, 0)) < 0) {
103 		perror("finger: socket");
104 		return;
105 	}
106 
107 	/* have network connection; identify the host connected with */
108 	(void)printf("[%s]\n", hp->h_name);
109 
110 	msg.msg_name = (void *)&sin;
111 	msg.msg_namelen = sizeof sin;
112 	msg.msg_iov = iov;
113 	msg.msg_iovlen = 0;
114 	msg.msg_control = 0;
115 	msg.msg_controllen = 0;
116 	msg.msg_flags = 0;
117 
118 	/* -l flag for remote fingerd  */
119 	if (lflag) {
120 		iov[msg.msg_iovlen].iov_base = "/W ";
121 		iov[msg.msg_iovlen++].iov_len = 3;
122 	}
123 	/* send the name followed by <CR><LF> */
124 	iov[msg.msg_iovlen].iov_base = name;
125 	iov[msg.msg_iovlen++].iov_len = strlen(name);
126 	iov[msg.msg_iovlen].iov_base = "\r\n";
127 	iov[msg.msg_iovlen++].iov_len = 2;
128 
129 	/* -T disables T/TCP: compatibility option to finger broken hosts */
130 	if (Tflag && connect(s, (struct sockaddr *)&sin, sizeof (sin))) {
131 		perror("finger: connect");
132 		return;
133 	}
134 
135 	if (sendmsg(s, &msg, 0) < 0) {
136 		perror("finger: sendmsg");
137 		close(s);
138 		return;
139 	}
140 
141 	/*
142 	 * Read from the remote system; once we're connected, we assume some
143 	 * data.  If none arrives, we hang until the user interrupts.
144 	 *
145 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
146 	 * a newline; if followed by a newline character, only output one
147 	 * newline.
148 	 *
149 	 * Otherwise, all high bits are stripped; if it isn't printable and
150 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
151 	 * character with bit 7 set is printable.
152 	 */
153 	lastc = 0;
154 	if ((fp = fdopen(s, "r")) != NULL) {
155 		while ((c = getc(fp)) != EOF) {
156 			if (c == 0x0d) {
157 				if (lastc == '\r')	/* ^M^M - skip dupes */
158 					continue;
159 				c = '\n';
160 				lastc = '\r';
161 			} else {
162 				if (!isprint(c) && !isspace(c)) {
163 					c &= 0x7f;
164 					c |= 0x40;
165 				}
166 				if (lastc != '\r' || c != '\n')
167 					lastc = c;
168 				else {
169 					lastc = '\n';
170 					continue;
171 				}
172 			}
173 			putchar(c);
174 		}
175 		if (lastc != '\n')
176 			putchar('\n');
177 
178 		if (ferror(fp)) {
179 			/*
180 			 * Assume that whatever it was set errno...
181 			 */
182 			perror("finger: read");
183 		}
184 		(void)fclose(fp);
185 	}
186 }
187