xref: /openbsd/usr.bin/finger/net.c (revision 09467b48)
1 /*	$OpenBSD: net.c,v 1.14 2019/06/28 13:35:01 deraadt Exp $	*/
2 
3 /*
4  * Copyright (c) 1989 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Tony Nardo of the Johns Hopkins University/Applied Physics Lab.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/socket.h>
36 #include <netinet/in.h>
37 #include <arpa/inet.h>
38 #include <netdb.h>
39 #include <stdio.h>
40 #include <string.h>
41 #include <ctype.h>
42 #include <unistd.h>
43 #include <err.h>
44 #include "finger.h"
45 #include "extern.h"
46 
47 void
48 netfinger(name)
49 	char *name;
50 {
51 	FILE *fp;
52 	int c, lastc;
53 	int s;
54 	char *host;
55 	struct addrinfo hints, *res0, *res;
56 	int error;
57 	char hbuf[NI_MAXHOST];
58 
59 	lastc = 0;
60 	if (!(host = strrchr(name, '@')))
61 		return;
62 	*host++ = '\0';
63 	memset(&hints, 0, sizeof(hints));
64 	hints.ai_family = PF_UNSPEC;
65 	hints.ai_socktype = SOCK_STREAM;
66 	error = getaddrinfo(host, "finger", &hints, &res0);
67 	if (error) {
68 		warnx("%s", gai_strerror(error));
69 		return;
70 	}
71 
72 	s = -1;
73 	for (res = res0; res; res = res->ai_next) {
74 		if ((s = socket(res->ai_family, res->ai_socktype,
75 				res->ai_protocol)) == -1) {
76 			continue;
77 		}
78 		if (connect(s, res->ai_addr, res->ai_addrlen) == -1) {
79 			(void)close(s);
80 			s = -1;
81 			continue;
82 		}
83 
84 		break;
85 	}
86 
87 	if (s == -1) {
88 		perror("finger");
89 		freeaddrinfo(res0);
90 		return;
91 	}
92 
93 	/* have network connection; identify the host connected with */
94 	if (getnameinfo(res->ai_addr, res->ai_addrlen, hbuf, sizeof(hbuf),
95 	    NULL, 0, NI_NUMERICHOST) != 0) {
96 		strlcpy(hbuf, "(invalid)", sizeof hbuf);
97 	}
98 	(void)printf("[%s/%s]\n", host, hbuf);
99 
100 	freeaddrinfo(res0);
101 
102 	/* -l flag for remote fingerd  */
103 	if (lflag)
104 		write(s, "/W ", 3);
105 	/* send the name followed by <CR><LF> */
106 	(void)write(s, name, strlen(name));
107 	(void)write(s, "\r\n", 2);
108 
109 	/*
110 	 * Read from the remote system; once we're connected, we assume some
111 	 * data.  If none arrives, we hang until the user interrupts.
112 	 *
113 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
114 	 * a newline; if followed by a newline character, only output one
115 	 * newline.
116 	 *
117 	 * Otherwise, all high bits are stripped; if it isn't printable and
118 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
119 	 * character with bit 7 set is printable.
120 	 */
121 	if ((fp = fdopen(s, "r")) != NULL)
122 		while ((c = getc(fp)) != EOF) {
123 			c &= 0x7f;
124 			if (c == '\r') {
125 				if (lastc == '\r')
126 					continue;
127 				c = '\n';
128 				lastc = '\r';
129 			} else {
130 				if (!isprint(c) && !isspace(c))
131 					c |= 0x40;
132 				if (lastc != '\r' || c != '\n')
133 					lastc = c;
134 				else {
135 					lastc = '\n';
136 					continue;
137 				}
138 			}
139 			putchar(c);
140 		}
141 	if (lastc != '\n')
142 		putchar('\n');
143 	(void)fclose(fp);
144 }
145