xref: /freebsd/usr.bin/finger/net.c (revision 38f0b757fd84d17d0fc24739a7cda160c4516d81)
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  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #if 0
34 #ifndef lint
35 static char sccsid[] = "@(#)net.c	8.4 (Berkeley) 4/28/95";
36 #endif
37 #endif
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include <sys/param.h>
43 #include <sys/socket.h>
44 #include <sys/uio.h>
45 #include <ctype.h>
46 #include <db.h>
47 #include <err.h>
48 #include <netdb.h>
49 #include <pwd.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <utmpx.h>
55 #include "finger.h"
56 
57 static void cleanup(int sig);
58 static int do_protocol(const char *name, const struct addrinfo *ai);
59 static void trying(const struct addrinfo *ai);
60 
61 void
62 netfinger(char *name)
63 {
64 	int error, multi;
65 	char *host;
66 	struct addrinfo *ai, *ai0;
67 	static struct addrinfo hint;
68 
69 	host = strrchr(name, '@');
70 	if (host == 0)
71 		return;
72 	*host++ = '\0';
73 	signal(SIGALRM, cleanup);
74 	alarm(TIME_LIMIT);
75 
76 	hint.ai_flags = AI_CANONNAME;
77 	hint.ai_family = family;
78 	hint.ai_socktype = SOCK_STREAM;
79 
80 	error = getaddrinfo(host, "finger", &hint, &ai0);
81 	if (error) {
82 		warnx("%s: %s", host, gai_strerror(error));
83 		return;
84 	}
85 
86 	multi = (ai0->ai_next) != 0;
87 
88 	/* ai_canonname may not be filled in if the user specified an IP. */
89 	if (ai0->ai_canonname == 0)
90 		printf("[%s]\n", host);
91 	else
92 		printf("[%s]\n", ai0->ai_canonname);
93 
94 	for (ai = ai0; ai != 0; ai = ai->ai_next) {
95 		if (multi)
96 			trying(ai);
97 
98 		error = do_protocol(name, ai);
99 		if (!error)
100 			break;
101 	}
102 	alarm(0);
103 	freeaddrinfo(ai0);
104 }
105 
106 static int
107 do_protocol(const char *name, const struct addrinfo *ai)
108 {
109 	int cnt, line_len, s;
110 	FILE *fp;
111 	int c, lastc;
112 	struct iovec iov[3];
113 	struct msghdr msg;
114 	static char slash_w[] = "/W ";
115 	static char neteol[] = "\r\n";
116 
117 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
118 	if (s < 0) {
119 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
120 		     ai->ai_protocol);
121 		return -1;
122 	}
123 
124 	msg.msg_name = (void *)ai->ai_addr;
125 	msg.msg_namelen = ai->ai_addrlen;
126 	msg.msg_iov = iov;
127 	msg.msg_iovlen = 0;
128 	msg.msg_control = 0;
129 	msg.msg_controllen = 0;
130 	msg.msg_flags = 0;
131 
132 	/* -l flag for remote fingerd  */
133 	if (lflag) {
134 		iov[msg.msg_iovlen].iov_base = slash_w;
135 		iov[msg.msg_iovlen++].iov_len = 3;
136 	}
137 	/* send the name followed by <CR><LF> */
138 	iov[msg.msg_iovlen].iov_base = strdup(name);
139 	iov[msg.msg_iovlen++].iov_len = strlen(name);
140 	iov[msg.msg_iovlen].iov_base = neteol;
141 	iov[msg.msg_iovlen++].iov_len = 2;
142 
143 	if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
144 		warn("connect");
145 		close(s);
146 		return -1;
147 	}
148 
149 	if (sendmsg(s, &msg, 0) < 0) {
150 		warn("sendmsg");
151 		close(s);
152 		return -1;
153 	}
154 
155 	/*
156 	 * Read from the remote system; once we're connected, we assume some
157 	 * data.  If none arrives, we hang until the user interrupts.
158 	 *
159 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
160 	 * a newline; if followed by a newline character, only output one
161 	 * newline.
162 	 *
163 	 * Otherwise, all high bits are stripped; if it isn't printable and
164 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
165 	 * character with bit 7 set is printable.
166 	 */
167 	lastc = 0;
168 	if ((fp = fdopen(s, "r")) != NULL) {
169 		cnt = 0;
170 		line_len = 0;
171 		while ((c = getc(fp)) != EOF) {
172 			if (++cnt > OUTPUT_MAX) {
173 				printf("\n\n Output truncated at %d bytes...\n",
174 					cnt - 1);
175 				break;
176 			}
177 			if (c == 0x0d) {
178 				if (lastc == '\r')	/* ^M^M - skip dupes */
179 					continue;
180 				c = '\n';
181 				lastc = '\r';
182 			} else {
183 				if (!isprint(c) && !isspace(c)) {
184 					c &= 0x7f;
185 					c |= 0x40;
186 				}
187 				if (lastc != '\r' || c != '\n')
188 					lastc = c;
189 				else {
190 					lastc = '\n';
191 					continue;
192 				}
193 			}
194 			putchar(c);
195 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
196 				putchar('\\');
197 				putchar('\n');
198 				lastc = '\r';
199 			}
200 			if (lastc == '\n' || lastc == '\r')
201 				line_len = 0;
202 		}
203 		if (ferror(fp)) {
204 			/*
205 			 * Assume that whatever it was set errno...
206 			 */
207 			warn("reading from network");
208 		}
209 		if (lastc != '\n')
210 			putchar('\n');
211 
212 		fclose(fp);
213 	}
214 	return 0;
215 }
216 
217 static void
218 trying(const struct addrinfo *ai)
219 {
220 	char buf[NI_MAXHOST];
221 
222 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
223 			(char *)0, 0, NI_NUMERICHOST) != 0)
224 		return;		/* XXX can't happen */
225 
226 	printf("Trying %s...\n", buf);
227 }
228 
229 static void
230 cleanup(int sig __unused)
231 {
232 #define	ERRSTR	"Timed out.\n"
233 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
234 	exit(1);
235 }
236 
237