xref: /dragonfly/libexec/fingerd/fingerd.c (revision ed5d5720)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
34  * @(#)fingerd.c	8.1 (Berkeley) 6/4/93
35  * $FreeBSD: src/libexec/fingerd/fingerd.c,v 1.16.2.3 2002/04/03 09:05:23 mike Exp $
36  * $DragonFly: src/libexec/fingerd/fingerd.c,v 1.3 2003/11/14 03:54:29 dillon Exp $
37  */
38 
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #include <sys/socket.h>
42 #include <netinet/in.h>
43 #include <netinet/tcp.h>
44 #include <arpa/inet.h>
45 #include <errno.h>
46 
47 #include <unistd.h>
48 #include <syslog.h>
49 #include <libutil.h>
50 #include <netdb.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <strings.h>
54 #include "pathnames.h"
55 
56 void logerr (const char *, ...);
57 
58 int
59 main(argc, argv)
60 	int argc;
61 	char *argv[];
62 {
63 	register FILE *fp;
64 	register int ch;
65 	register char *lp;
66 	struct sockaddr_storage ss;
67 	int p[2], logging, secure, sval;
68 #define	ENTRIES	50
69 	char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
70 	char rhost[MAXHOSTNAMELEN];
71 
72 	prog = _PATH_FINGER;
73 	logging = secure = 0;
74 	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
75 	opterr = 0;
76 	while ((ch = getopt(argc, argv, "slp:")) != -1)
77 		switch (ch) {
78 		case 'l':
79 			logging = 1;
80 			break;
81 		case 'p':
82 			prog = optarg;
83 			break;
84 		case 's':
85 			secure = 1;
86 			break;
87 		case '?':
88 		default:
89 			logerr("illegal option -- %c", optopt);
90 		}
91 
92 	/*
93 	 * Enable server-side Transaction TCP.
94 	 */
95 	{
96 		int one = 1;
97 		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
98 			       sizeof one) < 0) {
99 			logerr("setsockopt(TCP_NOPUSH) failed: %m");
100 		}
101 	}
102 
103 	if (!fgets(line, sizeof(line), stdin))
104 		exit(1);
105 
106 	if (logging) {
107 		char *t;
108 		char *end;
109 
110 		end = memchr(line, 0, sizeof(line));
111 		if (end == NULL) {
112 			if ((t = malloc(sizeof(line) + 1)) == NULL)
113 				logerr("malloc: %s", strerror(errno));
114 			memcpy(t, line, sizeof(line));
115 			t[sizeof(line)] = 0;
116 		} else {
117 			if ((t = strdup(line)) == NULL)
118 				logerr("strdup: %s", strerror(errno));
119 		}
120 		for (end = t; *end; end++)
121 			if (*end == '\n' || *end == '\r')
122 				*end = ' ';
123 		sval = sizeof(ss);
124 		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
125 			logerr("getpeername: %s", strerror(errno));
126 		realhostname_sa(rhost, sizeof rhost - 1,
127 				(struct sockaddr *)&ss, sval);
128 		rhost[sizeof(rhost) - 1] = '\0';
129 		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
130 	}
131 
132 	comp = &av[1];
133 	av[2] = "--";
134 	for (lp = line, ap = &av[3];;) {
135 		*ap = strtok(lp, " \t\r\n");
136 		if (!*ap) {
137 			if (secure && ap == &av[3]) {
138 				puts("must provide username\r\n");
139 				exit(1);
140 			}
141 			break;
142 		}
143 		if (secure && strchr(*ap, '@')) {
144 			puts("forwarding service denied\r\n");
145 			exit(1);
146 		}
147 
148 		/* RFC742: "/[Ww]" == "-l" */
149 		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
150 			av[1] = "-l";
151 			comp = &av[0];
152 		}
153 		else if (++ap == av + ENTRIES) {
154 			*ap = NULL;
155 			break;
156 		}
157 		lp = NULL;
158 	}
159 
160 	if (lp = strrchr(prog, '/'))
161 		*comp = ++lp;
162 	else
163 		*comp = prog;
164 	if (pipe(p) < 0)
165 		logerr("pipe: %s", strerror(errno));
166 
167 	switch(vfork()) {
168 	case 0:
169 		(void)close(p[0]);
170 		if (p[1] != 1) {
171 			(void)dup2(p[1], 1);
172 			(void)close(p[1]);
173 		}
174 		execv(prog, comp);
175 		logerr("execv: %s: %s", prog, strerror(errno));
176 		_exit(1);
177 	case -1:
178 		logerr("fork: %s", strerror(errno));
179 	}
180 	(void)close(p[1]);
181 	if (!(fp = fdopen(p[0], "r")))
182 		logerr("fdopen: %s", strerror(errno));
183 	while ((ch = getc(fp)) != EOF) {
184 		if (ch == '\n')
185 			putchar('\r');
186 		putchar(ch);
187 	}
188 	exit(0);
189 }
190 
191 #if __STDC__
192 #include <stdarg.h>
193 #else
194 #include <varargs.h>
195 #endif
196 
197 void
198 #if __STDC__
199 logerr(const char *fmt, ...)
200 #else
201 logerr(fmt, va_alist)
202 	char *fmt;
203         va_dcl
204 #endif
205 {
206 	va_list ap;
207 #if __STDC__
208 	va_start(ap, fmt);
209 #else
210 	va_start(ap);
211 #endif
212 	(void)vsyslog(LOG_ERR, fmt, ap);
213 	va_end(ap);
214 	exit(1);
215 	/* NOTREACHED */
216 }
217