xref: /freebsd/usr.bin/finger/net.c (revision 409a390c3341fb4f162cd7de1fd595a323ebbfd8)
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 #define	_ULOG_POSIX_NAMES
58 #include <ulog.h>
59 #include <unistd.h>
60 #include "finger.h"
61 
62 static void cleanup(int sig);
63 static int do_protocol(const char *name, const struct addrinfo *ai);
64 static void trying(const struct addrinfo *ai);
65 
66 void
67 netfinger(char *name)
68 {
69 	int error, multi;
70 	char *host;
71 	struct addrinfo *ai, *ai0;
72 	static struct addrinfo hint;
73 
74 	host = strrchr(name, '@');
75 	if (host == 0)
76 		return;
77 	*host++ = '\0';
78 	signal(SIGALRM, cleanup);
79 	alarm(TIME_LIMIT);
80 
81 	hint.ai_flags = AI_CANONNAME;
82 	hint.ai_family = family;
83 	hint.ai_socktype = SOCK_STREAM;
84 
85 	error = getaddrinfo(host, "finger", &hint, &ai0);
86 	if (error) {
87 		warnx("%s: %s", host, gai_strerror(error));
88 		return;
89 	}
90 
91 	multi = (ai0->ai_next) != 0;
92 
93 	/* ai_canonname may not be filled in if the user specified an IP. */
94 	if (ai0->ai_canonname == 0)
95 		printf("[%s]\n", host);
96 	else
97 		printf("[%s]\n", ai0->ai_canonname);
98 
99 	for (ai = ai0; ai != 0; ai = ai->ai_next) {
100 		if (multi)
101 			trying(ai);
102 
103 		error = do_protocol(name, ai);
104 		if (!error)
105 			break;
106 	}
107 	alarm(0);
108 	freeaddrinfo(ai0);
109 }
110 
111 static int
112 do_protocol(const char *name, const struct addrinfo *ai)
113 {
114 	int cnt, line_len, s;
115 	FILE *fp;
116 	int c, lastc;
117 	struct iovec iov[3];
118 	struct msghdr msg;
119 	static char slash_w[] = "/W ";
120 	static char neteol[] = "\r\n";
121 
122 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
123 	if (s < 0) {
124 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
125 		     ai->ai_protocol);
126 		return -1;
127 	}
128 
129 	msg.msg_name = (void *)ai->ai_addr;
130 	msg.msg_namelen = ai->ai_addrlen;
131 	msg.msg_iov = iov;
132 	msg.msg_iovlen = 0;
133 	msg.msg_control = 0;
134 	msg.msg_controllen = 0;
135 	msg.msg_flags = 0;
136 
137 	/* -l flag for remote fingerd  */
138 	if (lflag) {
139 		iov[msg.msg_iovlen].iov_base = slash_w;
140 		iov[msg.msg_iovlen++].iov_len = 3;
141 	}
142 	/* send the name followed by <CR><LF> */
143 	iov[msg.msg_iovlen].iov_base = strdup(name);
144 	iov[msg.msg_iovlen++].iov_len = strlen(name);
145 	iov[msg.msg_iovlen].iov_base = neteol;
146 	iov[msg.msg_iovlen++].iov_len = 2;
147 
148 	if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
149 		warn("connect");
150 		close(s);
151 		return -1;
152 	}
153 
154 	if (sendmsg(s, &msg, 0) < 0) {
155 		warn("sendmsg");
156 		close(s);
157 		return -1;
158 	}
159 
160 	/*
161 	 * Read from the remote system; once we're connected, we assume some
162 	 * data.  If none arrives, we hang until the user interrupts.
163 	 *
164 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
165 	 * a newline; if followed by a newline character, only output one
166 	 * newline.
167 	 *
168 	 * Otherwise, all high bits are stripped; if it isn't printable and
169 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
170 	 * character with bit 7 set is printable.
171 	 */
172 	lastc = 0;
173 	if ((fp = fdopen(s, "r")) != NULL) {
174 		cnt = 0;
175 		line_len = 0;
176 		while ((c = getc(fp)) != EOF) {
177 			if (++cnt > OUTPUT_MAX) {
178 				printf("\n\n Output truncated at %d bytes...\n",
179 					cnt - 1);
180 				break;
181 			}
182 			if (c == 0x0d) {
183 				if (lastc == '\r')	/* ^M^M - skip dupes */
184 					continue;
185 				c = '\n';
186 				lastc = '\r';
187 			} else {
188 				if (!isprint(c) && !isspace(c)) {
189 					c &= 0x7f;
190 					c |= 0x40;
191 				}
192 				if (lastc != '\r' || c != '\n')
193 					lastc = c;
194 				else {
195 					lastc = '\n';
196 					continue;
197 				}
198 			}
199 			putchar(c);
200 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
201 				putchar('\\');
202 				putchar('\n');
203 				lastc = '\r';
204 			}
205 			if (lastc == '\n' || lastc == '\r')
206 				line_len = 0;
207 		}
208 		if (ferror(fp)) {
209 			/*
210 			 * Assume that whatever it was set errno...
211 			 */
212 			warn("reading from network");
213 		}
214 		if (lastc != '\n')
215 			putchar('\n');
216 
217 		fclose(fp);
218 	}
219 	return 0;
220 }
221 
222 static void
223 trying(const struct addrinfo *ai)
224 {
225 	char buf[NI_MAXHOST];
226 
227 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
228 			(char *)0, 0, NI_NUMERICHOST) != 0)
229 		return;		/* XXX can't happen */
230 
231 	printf("Trying %s...\n", buf);
232 }
233 
234 void
235 cleanup(int sig __unused)
236 {
237 #define	ERRSTR	"Timed out.\n"
238 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
239 	exit(1);
240 }
241 
242