xref: /freebsd/usr.bin/finger/net.c (revision 87569f75a91f298c52a71823c04d41cf53c88889)
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 #if 0
38 #ifndef lint
39 static char sccsid[] = "@(#)net.c	8.4 (Berkeley) 4/28/95";
40 #endif
41 #endif
42 
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include <sys/param.h>
47 #include <sys/socket.h>
48 #include <sys/uio.h>
49 #include <ctype.h>
50 #include <db.h>
51 #include <err.h>
52 #include <netdb.h>
53 #include <pwd.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <utmp.h>
59 #include "finger.h"
60 
61 static void cleanup(int sig);
62 static int do_protocol(const char *name, const struct addrinfo *ai);
63 static void trying(const struct addrinfo *ai);
64 
65 void
66 netfinger(char *name)
67 {
68 	int error, multi;
69 	char *host;
70 	struct addrinfo *ai, *ai0;
71 	static struct addrinfo hint;
72 
73 	host = strrchr(name, '@');
74 	if (host == 0)
75 		return;
76 	*host++ = '\0';
77 	signal(SIGALRM, cleanup);
78 	alarm(TIME_LIMIT);
79 
80 	hint.ai_flags = AI_CANONNAME;
81 	hint.ai_family = family;
82 	hint.ai_socktype = SOCK_STREAM;
83 
84 	error = getaddrinfo(host, "finger", &hint, &ai0);
85 	if (error) {
86 		warnx("%s: %s", host, gai_strerror(error));
87 		return;
88 	}
89 
90 	multi = (ai0->ai_next) != 0;
91 
92 	/* ai_canonname may not be filled in if the user specified an IP. */
93 	if (ai0->ai_canonname == 0)
94 		printf("[%s]\n", host);
95 	else
96 		printf("[%s]\n", ai0->ai_canonname);
97 
98 	for (ai = ai0; ai != 0; ai = ai->ai_next) {
99 		if (multi)
100 			trying(ai);
101 
102 		error = do_protocol(name, ai);
103 		if (!error)
104 			break;
105 	}
106 	alarm(0);
107 	freeaddrinfo(ai0);
108 }
109 
110 static int
111 do_protocol(const char *name, const struct addrinfo *ai)
112 {
113 	int cnt, line_len, s;
114 	FILE *fp;
115 	int c, lastc;
116 	struct iovec iov[3];
117 	struct msghdr msg;
118 	static char slash_w[] = "/W ";
119 	static char neteol[] = "\r\n";
120 
121 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
122 	if (s < 0) {
123 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
124 		     ai->ai_protocol);
125 		return -1;
126 	}
127 
128 	msg.msg_name = (void *)ai->ai_addr;
129 	msg.msg_namelen = ai->ai_addrlen;
130 	msg.msg_iov = iov;
131 	msg.msg_iovlen = 0;
132 	msg.msg_control = 0;
133 	msg.msg_controllen = 0;
134 	msg.msg_flags = 0;
135 
136 	/* -l flag for remote fingerd  */
137 	if (lflag) {
138 		iov[msg.msg_iovlen].iov_base = slash_w;
139 		iov[msg.msg_iovlen++].iov_len = 3;
140 	}
141 	/* send the name followed by <CR><LF> */
142 	iov[msg.msg_iovlen].iov_base = strdup(name);
143 	iov[msg.msg_iovlen++].iov_len = strlen(name);
144 	iov[msg.msg_iovlen].iov_base = neteol;
145 	iov[msg.msg_iovlen++].iov_len = 2;
146 
147 	/*
148 	 * -T disables data-on-SYN: compatibility option to finger broken
149 	 * hosts.  Also, the implicit-open API is broken on IPv6, so do
150 	 * the explicit connect there, too.
151 	 */
152 	if ((Tflag || ai->ai_addr->sa_family == AF_INET6)
153 	    && connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
154 		warn("connect");
155 		close(s);
156 		return -1;
157 	}
158 
159 	if (sendmsg(s, &msg, 0) < 0) {
160 		warn("sendmsg");
161 		close(s);
162 		return -1;
163 	}
164 
165 	/*
166 	 * Read from the remote system; once we're connected, we assume some
167 	 * data.  If none arrives, we hang until the user interrupts.
168 	 *
169 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
170 	 * a newline; if followed by a newline character, only output one
171 	 * newline.
172 	 *
173 	 * Otherwise, all high bits are stripped; if it isn't printable and
174 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
175 	 * character with bit 7 set is printable.
176 	 */
177 	lastc = 0;
178 	if ((fp = fdopen(s, "r")) != NULL) {
179 		cnt = 0;
180 		line_len = 0;
181 		while ((c = getc(fp)) != EOF) {
182 			if (++cnt > OUTPUT_MAX) {
183 				printf("\n\n Output truncated at %d bytes...\n",
184 					cnt - 1);
185 				break;
186 			}
187 			if (c == 0x0d) {
188 				if (lastc == '\r')	/* ^M^M - skip dupes */
189 					continue;
190 				c = '\n';
191 				lastc = '\r';
192 			} else {
193 				if (!isprint(c) && !isspace(c)) {
194 					c &= 0x7f;
195 					c |= 0x40;
196 				}
197 				if (lastc != '\r' || c != '\n')
198 					lastc = c;
199 				else {
200 					lastc = '\n';
201 					continue;
202 				}
203 			}
204 			putchar(c);
205 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
206 				putchar('\\');
207 				putchar('\n');
208 				lastc = '\r';
209 			}
210 			if (lastc == '\n' || lastc == '\r')
211 				line_len = 0;
212 		}
213 		if (ferror(fp)) {
214 			/*
215 			 * Assume that whatever it was set errno...
216 			 */
217 			warn("reading from network");
218 		}
219 		if (lastc != '\n')
220 			putchar('\n');
221 
222 		fclose(fp);
223 	}
224 	return 0;
225 }
226 
227 static void
228 trying(const struct addrinfo *ai)
229 {
230 	char buf[NI_MAXHOST];
231 
232 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
233 			(char *)0, 0, NI_NUMERICHOST) != 0)
234 		return;		/* XXX can't happen */
235 
236 	printf("Trying %s...\n", buf);
237 }
238 
239 void
240 cleanup(int sig __unused)
241 {
242 #define	ERRSTR	"Timed out.\n"
243 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
244 	exit(1);
245 }
246 
247