xref: /freebsd/usr.bin/finger/net.c (revision 77a0943ded95b9e6438f7db70c4a28e4d93946d4)
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 extern int lflag;		/* XXX finger.h? */
66 extern int Tflag;		/* XXX finger.h? */
67 
68 static void cleanup(int sig);;
69 static int do_protocol(const char *name, const struct addrinfo *ai);
70 static void trying(const struct addrinfo *ai);
71 
72 void
73 netfinger(name)
74 	char *name;
75 {
76 	int error, multi;
77 	char *host;
78 	struct addrinfo *ai, *ai0;
79 	static struct addrinfo hint;
80 
81 	host = strrchr(name, '@');
82 	if (host == 0)
83 		return;
84 	*host++ = '\0';
85 	signal(SIGALRM, cleanup);
86 	alarm(TIME_LIMIT);
87 
88 	hint.ai_flags = AI_CANONNAME;
89 	hint.ai_family = PF_UNSPEC;
90 	hint.ai_socktype = SOCK_STREAM;
91 
92 	error = getaddrinfo(host, "finger", &hint, &ai0);
93 	if (error) {
94 		warnx("%s: %s", host, gai_strerror(error));
95 		return;
96 	}
97 
98 	multi = (ai0->ai_next) != 0;
99 
100 	/* ai_canonname may not be filled in if the user specified an IP. */
101 	if (ai0->ai_canonname == 0)
102 		printf("[%s]\n", host);
103 	else
104 		printf("[%s]\n", ai0->ai_canonname);
105 
106 	for (ai = ai0; ai != 0; ai = ai->ai_next) {
107 		if (multi)
108 			trying(ai);
109 
110 		error = do_protocol(name, ai);
111 		if (!error)
112 			break;
113 	}
114 	alarm(0);
115 	freeaddrinfo(ai0);
116 }
117 
118 static int
119 do_protocol(const char *name, const struct addrinfo *ai)
120 {
121 	int cnt, line_len, s;
122 	register FILE *fp;
123 	register int c, lastc;
124 	struct iovec iov[3];
125 	struct msghdr msg;
126 
127 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
128 	if (s < 0) {
129 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
130 		     ai->ai_protocol);
131 		return -1;
132 	}
133 
134 	msg.msg_name = (void *)ai->ai_addr;
135 	msg.msg_namelen = ai->ai_addrlen;
136 	msg.msg_iov = iov;
137 	msg.msg_iovlen = 0;
138 	msg.msg_control = 0;
139 	msg.msg_controllen = 0;
140 	msg.msg_flags = 0;
141 
142 	/* -l flag for remote fingerd  */
143 	if (lflag) {
144 		iov[msg.msg_iovlen].iov_base = "/W ";
145 		iov[msg.msg_iovlen++].iov_len = 3;
146 	}
147 	/* send the name followed by <CR><LF> */
148 	iov[msg.msg_iovlen].iov_base = (char *)name;
149 	iov[msg.msg_iovlen++].iov_len = strlen(name);
150 	iov[msg.msg_iovlen].iov_base = "\r\n";
151 	iov[msg.msg_iovlen++].iov_len = 2;
152 
153 	/*
154 	 * -T disables data-on-SYN: compatibility option to finger broken
155 	 * hosts.  Also, the implicit-open API is broken on IPv6, so do
156 	 * the explicit connect there, too.
157 	 */
158 	if ((Tflag || ai->ai_addr->sa_family == AF_INET6)
159 	    && connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
160 		warn("connect");
161 		close(s);
162 		return -1;
163 	}
164 
165 	if (sendmsg(s, &msg, 0) < 0) {
166 		warn("sendmsg");
167 		close(s);
168 		return -1;
169 	}
170 
171 	/*
172 	 * Read from the remote system; once we're connected, we assume some
173 	 * data.  If none arrives, we hang until the user interrupts.
174 	 *
175 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
176 	 * a newline; if followed by a newline character, only output one
177 	 * newline.
178 	 *
179 	 * Otherwise, all high bits are stripped; if it isn't printable and
180 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
181 	 * character with bit 7 set is printable.
182 	 */
183 	lastc = 0;
184 	if ((fp = fdopen(s, "r")) != NULL) {
185 		cnt = 0;
186 		line_len = 0;
187 		while ((c = getc(fp)) != EOF) {
188 			if (++cnt > OUTPUT_MAX) {
189 				printf("\n\n Output truncated at %d bytes...\n",
190 					cnt - 1);
191 				break;
192 			}
193 			if (c == 0x0d) {
194 				if (lastc == '\r')	/* ^M^M - skip dupes */
195 					continue;
196 				c = '\n';
197 				lastc = '\r';
198 			} else {
199 				if (!isprint(c) && !isspace(c)) {
200 					c &= 0x7f;
201 					c |= 0x40;
202 				}
203 				if (lastc != '\r' || c != '\n')
204 					lastc = c;
205 				else {
206 					lastc = '\n';
207 					continue;
208 				}
209 			}
210 			putchar(c);
211 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
212 				putchar('\\');
213 				putchar('\n');
214 				lastc = '\r';
215 			}
216 			if (lastc == '\n' || lastc == '\r')
217 				line_len = 0;
218 		}
219 		if (ferror(fp)) {
220 			/*
221 			 * Assume that whatever it was set errno...
222 			 */
223 			warn("reading from network");
224 		}
225 		if (lastc != '\n')
226 			putchar('\n');
227 
228 		fclose(fp);
229 	}
230 	return 0;
231 }
232 
233 static void
234 trying(const struct addrinfo *ai)
235 {
236 	char buf[NI_MAXHOST];
237 
238 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
239 			(char *)0, 0, NI_NUMERICHOST) != 0)
240 		return;		/* XXX can't happen */
241 
242 	printf("Trying %s...\n", buf);
243 }
244 
245 void
246 cleanup(int sig)
247 {
248 #define	ERRSTR	"Timed out.\n"
249 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
250 	exit(1);
251 }
252 
253