xref: /freebsd/usr.bin/finger/net.c (revision 63a938566d524836885917d95bd491aa4400b181)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Tony Nardo of the Johns Hopkins University/Applied Physics Lab.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #if 0
36 #ifndef lint
37 static char sccsid[] = "@(#)net.c	8.4 (Berkeley) 4/28/95";
38 #endif
39 #endif
40 
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <sys/param.h>
45 #include <sys/socket.h>
46 #include <sys/uio.h>
47 #include <wctype.h>
48 #include <db.h>
49 #include <err.h>
50 #include <netdb.h>
51 #include <pwd.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <utmpx.h>
57 #include <wchar.h>
58 #include "finger.h"
59 
60 static void cleanup(int sig);
61 static int do_protocol(const char *name, const struct addrinfo *ai);
62 static void trying(const struct addrinfo *ai);
63 
64 void
65 netfinger(char *name)
66 {
67 	int error, multi;
68 	char *host;
69 	struct addrinfo *ai, *ai0;
70 	static struct addrinfo hint;
71 
72 	host = strrchr(name, '@');
73 	if (host == NULL)
74 		return;
75 	*host++ = '\0';
76 	signal(SIGALRM, cleanup);
77 	alarm(TIME_LIMIT);
78 
79 	hint.ai_flags = AI_CANONNAME;
80 	hint.ai_family = family;
81 	hint.ai_socktype = SOCK_STREAM;
82 
83 	error = getaddrinfo(host, "finger", &hint, &ai0);
84 	if (error) {
85 		warnx("%s: %s", host, gai_strerror(error));
86 		return;
87 	}
88 
89 	multi = (ai0->ai_next) != 0;
90 
91 	/* ai_canonname may not be filled in if the user specified an IP. */
92 	if (ai0->ai_canonname == 0)
93 		printf("[%s]\n", host);
94 	else
95 		printf("[%s]\n", ai0->ai_canonname);
96 
97 	for (ai = ai0; ai != NULL; ai = ai->ai_next) {
98 		if (multi)
99 			trying(ai);
100 
101 		error = do_protocol(name, ai);
102 		if (!error)
103 			break;
104 	}
105 	alarm(0);
106 	freeaddrinfo(ai0);
107 }
108 
109 static int
110 do_protocol(const char *name, const struct addrinfo *ai)
111 {
112 	int cnt, line_len, s;
113 	FILE *fp;
114 	wint_t c, lastc;
115 	struct iovec iov[3];
116 	struct msghdr msg;
117 	static char slash_w[] = "/W ";
118 	static char neteol[] = "\r\n";
119 
120 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
121 	if (s < 0) {
122 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
123 		     ai->ai_protocol);
124 		return -1;
125 	}
126 
127 	msg.msg_name = (void *)ai->ai_addr;
128 	msg.msg_namelen = ai->ai_addrlen;
129 	msg.msg_iov = iov;
130 	msg.msg_iovlen = 0;
131 	msg.msg_control = 0;
132 	msg.msg_controllen = 0;
133 	msg.msg_flags = 0;
134 
135 	/* -l flag for remote fingerd  */
136 	if (lflag) {
137 		iov[msg.msg_iovlen].iov_base = slash_w;
138 		iov[msg.msg_iovlen++].iov_len = 3;
139 	}
140 	/* send the name followed by <CR><LF> */
141 	iov[msg.msg_iovlen].iov_base = strdup(name);
142 	iov[msg.msg_iovlen++].iov_len = strlen(name);
143 	iov[msg.msg_iovlen].iov_base = neteol;
144 	iov[msg.msg_iovlen++].iov_len = 2;
145 
146 	if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
147 		warn("connect");
148 		close(s);
149 		return -1;
150 	}
151 
152 	if (sendmsg(s, &msg, 0) < 0) {
153 		warn("sendmsg");
154 		close(s);
155 		return -1;
156 	}
157 
158 	/*
159 	 * Read from the remote system; once we're connected, we assume some
160 	 * data.  If none arrives, we hang until the user interrupts.
161 	 *
162 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
163 	 * a newline; if followed by a newline character, only output one
164 	 * newline.
165 	 *
166 	 * Otherwise, all high bits are stripped; if it isn't printable and
167 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
168 	 * character with bit 7 set is printable.
169 	 */
170 	lastc = 0;
171 	if ((fp = fdopen(s, "r")) != NULL) {
172 		cnt = 0;
173 		line_len = 0;
174 		while ((c = getwc(fp)) != EOF) {
175 			if (++cnt > OUTPUT_MAX) {
176 				printf("\n\n Output truncated at %d bytes...\n",
177 					cnt - 1);
178 				break;
179 			}
180 			if (c == 0x0d) {
181 				if (lastc == '\r')	/* ^M^M - skip dupes */
182 					continue;
183 				c = '\n';
184 				lastc = '\r';
185 			} else {
186 				if (!iswprint(c) && !iswspace(c)) {
187 					c &= 0x7f;
188 					c |= 0x40;
189 				}
190 				if (lastc != '\r' || c != '\n')
191 					lastc = c;
192 				else {
193 					lastc = '\n';
194 					continue;
195 				}
196 			}
197 			putwchar(c);
198 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
199 				putchar('\\');
200 				putchar('\n');
201 				lastc = '\r';
202 			}
203 			if (lastc == '\n' || lastc == '\r')
204 				line_len = 0;
205 		}
206 		if (ferror(fp)) {
207 			/*
208 			 * Assume that whatever it was set errno...
209 			 */
210 			warn("reading from network");
211 		}
212 		if (lastc != L'\n')
213 			putchar('\n');
214 
215 		fclose(fp);
216 	}
217 	return 0;
218 }
219 
220 static void
221 trying(const struct addrinfo *ai)
222 {
223 	char buf[NI_MAXHOST];
224 
225 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
226 			(char *)0, 0, NI_NUMERICHOST) != 0)
227 		return;		/* XXX can't happen */
228 
229 	printf("Trying %s...\n", buf);
230 }
231 
232 static void
233 cleanup(int sig __unused)
234 {
235 #define	ERRSTR	"Timed out.\n"
236 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
237 	exit(1);
238 }
239 
240