1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1993 Christopher G. Demetriou
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
20 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD$");
34
35#include <err.h>
36#include <pwd.h>
37#include <signal.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <syslog.h>
42#include <arpa/inet.h>
43#include <rpc/rpc.h>
44#include <rpcsvc/rwall.h>
45#include <sys/socket.h>
46#include <sys/types.h>
47#include <sys/wait.h>
48#include <unistd.h>
49
50#ifdef OSF
51#define WALL_CMD "/usr/sbin/wall"
52#else
53#define WALL_CMD "/usr/bin/wall -n"
54#endif
55
56void wallprog_1(struct svc_req *rqstp, SVCXPRT *transp);
57void possess(void);
58void killkids(int sig);
59static void usage(void);
60
61int nodaemon = 0;
62int from_inetd = 1;
63
64int
65main(int argc, char *argv[])
66{
67	SVCXPRT *transp;
68	socklen_t salen;
69	int ok;
70	struct sockaddr_storage sa;
71
72	if (argc == 2 && !strcmp(argv[1], "-n"))
73		nodaemon = 1;
74	if (argc != 1 && !nodaemon)
75		usage();
76
77	if (geteuid() == 0) {
78		struct passwd *pep = getpwnam("nobody");
79		if (pep)
80			setuid(pep->pw_uid);
81		else
82			setuid(getuid());
83	}
84
85        /*
86         * See if inetd started us
87         */
88	salen = sizeof(sa);
89        if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) {
90                from_inetd = 0;
91        }
92
93        if (!from_inetd) {
94                if (!nodaemon)
95                        possess();
96
97		(void)rpcb_unset(WALLPROG, WALLVERS, NULL);
98        }
99
100	(void)signal(SIGCHLD, killkids);
101
102	openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON);
103
104	/* create and register the service */
105	if (from_inetd) {
106		transp = svc_tli_create(0, NULL, NULL, 0, 0);
107		if (transp == NULL) {
108			syslog(LOG_ERR, "couldn't create udp service.");
109			exit(1);
110		}
111		ok = svc_reg(transp, WALLPROG, WALLVERS,
112			     wallprog_1, NULL);
113	} else
114		ok = svc_create(wallprog_1,
115				WALLPROG, WALLVERS, "udp");
116	if (!ok) {
117		syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", (!from_inetd)?"udp":"(inetd)");
118		exit(1);
119	}
120	svc_run();
121	syslog(LOG_ERR, "svc_run returned");
122	exit(1);
123}
124
125static void
126usage(void)
127{
128	fprintf(stderr, "usage: rpc.rwalld [-n]\n");
129	exit(1);
130}
131
132void
133possess(void)
134{
135	daemon(0, 0);
136}
137
138void
139killkids(int sig __unused)
140{
141	while(wait4(-1, NULL, WNOHANG, NULL) > 0)
142		;
143}
144
145void *
146wallproc_wall_1_svc(wrapstring *s, struct svc_req *rqstp __unused)
147{
148	static void		*dummy = NULL;
149
150	/* fork, popen wall with special option, and send the message */
151	if (fork() == 0) {
152		FILE *pfp;
153
154		pfp = popen(WALL_CMD, "w");
155		if (pfp != NULL) {
156			fprintf(pfp, "\007\007%s", *s);
157			pclose(pfp);
158			exit(0);
159		}
160	}
161	return(&dummy);
162}
163
164void
165wallprog_1(struct svc_req *rqstp, SVCXPRT *transp)
166{
167	union {
168		char *wallproc_wall_1_arg;
169	} argument;
170	char *result;
171	bool_t (*xdr_argument)(), (*xdr_result)();
172	char *(*local)();
173
174	switch (rqstp->rq_proc) {
175	case NULLPROC:
176		(void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL);
177		goto leave;
178
179	case WALLPROC_WALL:
180		xdr_argument = xdr_wrapstring;
181		xdr_result = xdr_void;
182		local = (char *(*)()) wallproc_wall_1_svc;
183		break;
184
185	default:
186		svcerr_noproc(transp);
187		goto leave;
188	}
189	bzero(&argument, sizeof(argument));
190	if (!svc_getargs(transp, (xdrproc_t)xdr_argument, &argument)) {
191		svcerr_decode(transp);
192		goto leave;
193	}
194	result = (*local)(&argument, rqstp);
195	if (result != NULL &&
196	    !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) {
197		svcerr_systemerr(transp);
198	}
199	if (!svc_freeargs(transp, (xdrproc_t)xdr_argument, &argument)) {
200		syslog(LOG_ERR, "unable to free arguments");
201		exit(1);
202	}
203leave:
204        if (from_inetd)
205                exit(0);
206}
207