xref: /freebsd/usr.bin/finger/net.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
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 #include <sys/param.h>
43 #include <sys/socket.h>
44 #include <sys/uio.h>
45 #include <wctype.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 <wchar.h>
56 #include "finger.h"
57 
58 static void cleanup(int sig);
59 static int do_protocol(const char *name, const struct addrinfo *ai);
60 static void trying(const struct addrinfo *ai);
61 
62 void
63 netfinger(char *name)
64 {
65 	int error, multi;
66 	char *host;
67 	struct addrinfo *ai, *ai0;
68 	static struct addrinfo hint;
69 
70 	host = strrchr(name, '@');
71 	if (host == NULL)
72 		return;
73 	*host++ = '\0';
74 	signal(SIGALRM, cleanup);
75 	alarm(TIME_LIMIT);
76 
77 	hint.ai_flags = AI_CANONNAME;
78 	hint.ai_family = family;
79 	hint.ai_socktype = SOCK_STREAM;
80 
81 	error = getaddrinfo(host, "finger", &hint, &ai0);
82 	if (error) {
83 		warnx("%s: %s", host, gai_strerror(error));
84 		return;
85 	}
86 
87 	multi = (ai0->ai_next) != 0;
88 
89 	/* ai_canonname may not be filled in if the user specified an IP. */
90 	if (ai0->ai_canonname == 0)
91 		printf("[%s]\n", host);
92 	else
93 		printf("[%s]\n", ai0->ai_canonname);
94 
95 	for (ai = ai0; ai != NULL; ai = ai->ai_next) {
96 		if (multi)
97 			trying(ai);
98 
99 		error = do_protocol(name, ai);
100 		if (!error)
101 			break;
102 	}
103 	alarm(0);
104 	freeaddrinfo(ai0);
105 }
106 
107 static int
108 do_protocol(const char *name, const struct addrinfo *ai)
109 {
110 	int cnt, line_len, s;
111 	FILE *fp;
112 	wint_t c, lastc;
113 	struct iovec iov[3];
114 	struct msghdr msg;
115 	static char slash_w[] = "/W ";
116 	static char neteol[] = "\r\n";
117 
118 	s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
119 	if (s < 0) {
120 		warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
121 		     ai->ai_protocol);
122 		return -1;
123 	}
124 
125 	msg.msg_name = (void *)ai->ai_addr;
126 	msg.msg_namelen = ai->ai_addrlen;
127 	msg.msg_iov = iov;
128 	msg.msg_iovlen = 0;
129 	msg.msg_control = 0;
130 	msg.msg_controllen = 0;
131 	msg.msg_flags = 0;
132 
133 	/* -l flag for remote fingerd  */
134 	if (lflag) {
135 		iov[msg.msg_iovlen].iov_base = slash_w;
136 		iov[msg.msg_iovlen++].iov_len = 3;
137 	}
138 	/* send the name followed by <CR><LF> */
139 	iov[msg.msg_iovlen].iov_base = strdup(name);
140 	iov[msg.msg_iovlen++].iov_len = strlen(name);
141 	iov[msg.msg_iovlen].iov_base = neteol;
142 	iov[msg.msg_iovlen++].iov_len = 2;
143 
144 	if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
145 		warn("connect");
146 		close(s);
147 		return -1;
148 	}
149 
150 	if (sendmsg(s, &msg, 0) < 0) {
151 		warn("sendmsg");
152 		close(s);
153 		return -1;
154 	}
155 
156 	/*
157 	 * Read from the remote system; once we're connected, we assume some
158 	 * data.  If none arrives, we hang until the user interrupts.
159 	 *
160 	 * If we see a <CR> or a <CR> with the high bit set, treat it as
161 	 * a newline; if followed by a newline character, only output one
162 	 * newline.
163 	 *
164 	 * Otherwise, all high bits are stripped; if it isn't printable and
165 	 * it isn't a space, we can simply set the 7th bit.  Every ASCII
166 	 * character with bit 7 set is printable.
167 	 */
168 	lastc = 0;
169 	if ((fp = fdopen(s, "r")) != NULL) {
170 		cnt = 0;
171 		line_len = 0;
172 		while ((c = getwc(fp)) != EOF) {
173 			if (++cnt > OUTPUT_MAX) {
174 				printf("\n\n Output truncated at %d bytes...\n",
175 					cnt - 1);
176 				break;
177 			}
178 			if (c == 0x0d) {
179 				if (lastc == '\r')	/* ^M^M - skip dupes */
180 					continue;
181 				c = '\n';
182 				lastc = '\r';
183 			} else {
184 				if (!iswprint(c) && !iswspace(c)) {
185 					c &= 0x7f;
186 					c |= 0x40;
187 				}
188 				if (lastc != '\r' || c != '\n')
189 					lastc = c;
190 				else {
191 					lastc = '\n';
192 					continue;
193 				}
194 			}
195 			putwchar(c);
196 			if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
197 				putchar('\\');
198 				putchar('\n');
199 				lastc = '\r';
200 			}
201 			if (lastc == '\n' || lastc == '\r')
202 				line_len = 0;
203 		}
204 		if (ferror(fp)) {
205 			/*
206 			 * Assume that whatever it was set errno...
207 			 */
208 			warn("reading from network");
209 		}
210 		if (lastc != L'\n')
211 			putchar('\n');
212 
213 		fclose(fp);
214 	}
215 	return 0;
216 }
217 
218 static void
219 trying(const struct addrinfo *ai)
220 {
221 	char buf[NI_MAXHOST];
222 
223 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
224 			(char *)0, 0, NI_NUMERICHOST) != 0)
225 		return;		/* XXX can't happen */
226 
227 	printf("Trying %s...\n", buf);
228 }
229 
230 static void
231 cleanup(int sig __unused)
232 {
233 #define	ERRSTR	"Timed out.\n"
234 	write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
235 	exit(1);
236 }
237 
238