xref: /freebsd/usr.bin/finger/net.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
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   "$FreeBSD$";
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 <signal.h>
62 #include <limits.h>
63 #include "finger.h"
64 
65 void
66 cleanup(sig)
67 	int sig;
68 {
69 	exit(0);
70 }
71 
72 void
73 netfinger(name)
74 	char *name;
75 {
76 	int cnt;
77 	int line_len;
78 	extern int lflag;
79 	extern int Tflag;
80 	register FILE *fp;
81 	register int c, lastc;
82 	struct in_addr defaddr;
83 	struct hostent *hp, def;
84 	struct servent *sp;
85 	struct sockaddr_in sin;
86 	int s;
87 	char *alist[1], *host;
88 	struct iovec iov[3];
89 	struct msghdr msg;
90 
91 	if (!(host = rindex(name, '@')))
92 		return;
93 	*host++ = '\0';
94 	signal(SIGALRM, cleanup);
95 	(void) alarm(TIME_LIMIT);
96 	if (isdigit(*host) && (defaddr.s_addr = inet_addr(host)) != -1) {
97 		def.h_name = host;
98 		def.h_addr_list = alist;
99 		def.h_addr = (char *)&defaddr;
100 		def.h_length = sizeof(struct in_addr);
101 		def.h_addrtype = AF_INET;
102 		def.h_aliases = 0;
103 		hp = &def;
104 	} else if (!(hp = gethostbyname(host))) {
105 		warnx("unknown host: %s", host);
106 		return;
107 	}
108 	if (!(sp = getservbyname("finger", "tcp"))) {
109 		warnx("tcp/finger: unknown service");
110 		return;
111 	}
112 	sin.sin_family = hp->h_addrtype;
113 	bcopy(hp->h_addr, (char *)&sin.sin_addr, MIN(hp->h_length,sizeof(sin.sin_addr)));
114 	sin.sin_port = sp->s_port;
115 	if ((s = socket(hp->h_addrtype, SOCK_STREAM, 0)) < 0) {
116 		perror("finger: socket");
117 		return;
118 	}
119 
120 	/* have network connection; identify the host connected with */
121 	(void)printf("[%s]\n", hp->h_name);
122 
123 	msg.msg_name = (void *)&sin;
124 	msg.msg_namelen = sizeof sin;
125 	msg.msg_iov = iov;
126 	msg.msg_iovlen = 0;
127 	msg.msg_control = 0;
128 	msg.msg_controllen = 0;
129 	msg.msg_flags = 0;
130 
131 	/* -l flag for remote fingerd  */
132 	if (lflag) {
133 		iov[msg.msg_iovlen].iov_base = "/W ";
134 		iov[msg.msg_iovlen++].iov_len = 3;
135 	}
136 	/* send the name followed by <CR><LF> */
137 	iov[msg.msg_iovlen].iov_base = name;
138 	iov[msg.msg_iovlen++].iov_len = strlen(name);
139 	iov[msg.msg_iovlen].iov_base = "\r\n";
140 	iov[msg.msg_iovlen++].iov_len = 2;
141 
142 	/* -T disables T/TCP: compatibility option to finger broken hosts */
143 	if (Tflag && connect(s, (struct sockaddr *)&sin, sizeof (sin))) {
144 		perror("finger: connect");
145 		return;
146 	}
147 
148 	if (sendmsg(s, &msg, 0) < 0) {
149 		perror("finger: sendmsg");
150 		close(s);
151 		return;
152 	}
153 
154 	/*
155 	 * Read from the remote system; once we're connected, we assume some
156 	 * data.  If none arrives, we hang until the user interrupts.
157 	 *
158 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
159 	 * a newline; if followed by a newline character, only output one
160 	 * newline.
161 	 *
162 	 * Otherwise, all high bits are stripped; if it isn't printable and
163 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
164 	 * character with bit 7 set is printable.
165 	 */
166 	lastc = 0;
167 	if ((fp = fdopen(s, "r")) != NULL) {
168 		cnt = 0;
169 		line_len = 0;
170 		while ((c = getc(fp)) != EOF) {
171 			if (++cnt > OUTPUT_MAX) {
172 				printf("\n\n Output truncated at %d bytes...\n",
173 					cnt - 1);
174 				break;
175 			}
176 			if (c == 0x0d) {
177 				if (lastc == '\r')	/* ^M^M - skip dupes */
178 					continue;
179 				c = '\n';
180 				lastc = '\r';
181 			} else {
182 				if (!isprint(c) && !isspace(c)) {
183 					c &= 0x7f;
184 					c |= 0x40;
185 				}
186 				if (lastc != '\r' || c != '\n')
187 					lastc = c;
188 				else {
189 					lastc = '\n';
190 					continue;
191 				}
192 			}
193 			putchar(c);
194 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
195 				putchar('\\');
196 				putchar('\n');
197 				lastc = '\r';
198 			}
199 			if (lastc == '\n' || lastc == '\r')
200 				line_len = 0;
201 		}
202 		if (lastc != '\n')
203 			putchar('\n');
204 
205 		if (ferror(fp)) {
206 			/*
207 			 * Assume that whatever it was set errno...
208 			 */
209 			perror("finger: read");
210 		}
211 		(void)fclose(fp);
212 	}
213 }
214