xref: /freebsd/libexec/fingerd/fingerd.c (revision e4bc453cc2658df97063d1539941a70980e48058)
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 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1983, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)fingerd.c	8.1 (Berkeley) 6/4/93";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <sys/types.h>
49 #include <sys/param.h>
50 #include <sys/socket.h>
51 #include <netinet/in.h>
52 #include <netinet/tcp.h>
53 #include <arpa/inet.h>
54 #include <errno.h>
55 
56 #include <unistd.h>
57 #include <syslog.h>
58 #include <libutil.h>
59 #include <netdb.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <strings.h>
63 #include "pathnames.h"
64 
65 void logerr(const char *, ...);
66 
67 int
68 main(int argc, char *argv[])
69 {
70 	FILE *fp;
71 	int ch;
72 	char *lp;
73 	struct sockaddr_storage ss;
74 	int p[2], logging, secure, sval;
75 #define	ENTRIES	50
76 	char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
77 	char rhost[MAXHOSTNAMELEN];
78 
79 	prog = _PATH_FINGER;
80 	logging = secure = 0;
81 	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
82 	opterr = 0;
83 	while ((ch = getopt(argc, argv, "slp:")) != -1)
84 		switch (ch) {
85 		case 'l':
86 			logging = 1;
87 			break;
88 		case 'p':
89 			prog = optarg;
90 			break;
91 		case 's':
92 			secure = 1;
93 			break;
94 		case '?':
95 		default:
96 			logerr("illegal option -- %c", optopt);
97 		}
98 
99 	/*
100 	 * Enable server-side Transaction TCP.
101 	 */
102 	{
103 #if	!defined(__alpha__) /* XXX FIXME */
104 		int one = 1;
105 		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
106 			       sizeof one) < 0) {
107 			logerr("setsockopt(TCP_NOPUSH) failed: %m");
108 		}
109 #endif
110 	}
111 
112 	if (!fgets(line, sizeof(line), stdin))
113 		exit(1);
114 
115 	if (logging) {
116 		char *t;
117 		char *end;
118 
119 		end = memchr(line, 0, sizeof(line));
120 		if (end == NULL) {
121 			if ((t = malloc(sizeof(line) + 1)) == NULL)
122 				logerr("malloc: %s", strerror(errno));
123 			memcpy(t, line, sizeof(line));
124 			t[sizeof(line)] = 0;
125 		} else {
126 			if ((t = strdup(line)) == NULL)
127 				logerr("strdup: %s", strerror(errno));
128 		}
129 		for (end = t; *end; end++)
130 			if (*end == '\n' || *end == '\r')
131 				*end = ' ';
132 		sval = sizeof(ss);
133 		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
134 			logerr("getpeername: %s", strerror(errno));
135 		realhostname_sa(rhost, sizeof rhost - 1,
136 				(struct sockaddr *)&ss, sval);
137 		rhost[sizeof(rhost) - 1] = '\0';
138 		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
139 	}
140 
141 	comp = &av[1];
142 	av[2] = "--";
143 	for (lp = line, ap = &av[3];;) {
144 		*ap = strtok(lp, " \t\r\n");
145 		if (!*ap) {
146 			if (secure && ap == &av[3]) {
147 				puts("must provide username\r\n");
148 				exit(1);
149 			}
150 			break;
151 		}
152 		if (secure && strchr(*ap, '@')) {
153 			puts("forwarding service denied\r\n");
154 			exit(1);
155 		}
156 
157 		/* RFC742: "/[Ww]" == "-l" */
158 		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
159 			av[1] = "-l";
160 			comp = &av[0];
161 		}
162 		else if (++ap == av + ENTRIES) {
163 			*ap = NULL;
164 			break;
165 		}
166 		lp = NULL;
167 	}
168 
169 	if (lp = strrchr(prog, '/'))
170 		*comp = ++lp;
171 	else
172 		*comp = prog;
173 	if (pipe(p) < 0)
174 		logerr("pipe: %s", strerror(errno));
175 
176 	switch(vfork()) {
177 	case 0:
178 		(void)close(p[0]);
179 		if (p[1] != 1) {
180 			(void)dup2(p[1], 1);
181 			(void)close(p[1]);
182 		}
183 		execv(prog, comp);
184 		logerr("execv: %s: %s", prog, strerror(errno));
185 		_exit(1);
186 	case -1:
187 		logerr("fork: %s", strerror(errno));
188 	}
189 	(void)close(p[1]);
190 	if (!(fp = fdopen(p[0], "r")))
191 		logerr("fdopen: %s", strerror(errno));
192 	while ((ch = getc(fp)) != EOF) {
193 		if (ch == '\n')
194 			putchar('\r');
195 		putchar(ch);
196 	}
197 	exit(0);
198 }
199 
200 #include <stdarg.h>
201 
202 void
203 logerr(const char *fmt, ...)
204 {
205 	va_list ap;
206 	va_start(ap, fmt);
207 	(void)vsyslog(LOG_ERR, fmt, ap);
208 	va_end(ap);
209 	exit(1);
210 	/* NOTREACHED */
211 }
212