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#include <err.h>
34#include <pwd.h>
35#include <signal.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <syslog.h>
40#include <arpa/inet.h>
41#include <rpc/rpc.h>
42#include <rpcsvc/rwall.h>
43#include <sys/socket.h>
44#include <sys/types.h>
45#include <sys/wait.h>
46#include <unistd.h>
47
48#ifdef OSF
49#define WALL_CMD "/usr/sbin/wall"
50#else
51#define WALL_CMD "/usr/bin/wall -n"
52#endif
53
54void wallprog_1(struct svc_req *rqstp, SVCXPRT *transp);
55void possess(void);
56void killkids(int sig);
57static void usage(void) __dead2;
58
59int nodaemon = 0;
60int from_inetd = 1;
61
62int
63main(int argc, char *argv[])
64{
65	SVCXPRT *transp;
66	socklen_t salen;
67	int ok;
68	struct sockaddr_storage sa;
69
70	if (argc == 2 && !strcmp(argv[1], "-n"))
71		nodaemon = 1;
72	if (argc != 1 && !nodaemon)
73		usage();
74
75	if (geteuid() == 0) {
76		struct passwd *pep = getpwnam("nobody");
77		if (pep)
78			setuid(pep->pw_uid);
79		else
80			setuid(getuid());
81	}
82
83        /*
84         * See if inetd started us
85         */
86	salen = sizeof(sa);
87        if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) {
88                from_inetd = 0;
89        }
90
91        if (!from_inetd) {
92                if (!nodaemon)
93                        possess();
94
95		(void)rpcb_unset(WALLPROG, WALLVERS, NULL);
96        }
97
98	(void)signal(SIGCHLD, killkids);
99
100	openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON);
101
102	/* create and register the service */
103	if (from_inetd) {
104		transp = svc_tli_create(0, NULL, NULL, 0, 0);
105		if (transp == NULL) {
106			syslog(LOG_ERR, "couldn't create udp service.");
107			exit(1);
108		}
109		ok = svc_reg(transp, WALLPROG, WALLVERS,
110			     wallprog_1, NULL);
111	} else
112		ok = svc_create(wallprog_1,
113				WALLPROG, WALLVERS, "udp");
114	if (!ok) {
115		syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", (!from_inetd)?"udp":"(inetd)");
116		exit(1);
117	}
118	svc_run();
119	syslog(LOG_ERR, "svc_run returned");
120	exit(1);
121}
122
123static void
124usage(void)
125{
126	fprintf(stderr, "usage: rpc.rwalld [-n]\n");
127	exit(1);
128}
129
130void
131possess(void)
132{
133	daemon(0, 0);
134}
135
136void
137killkids(int sig __unused)
138{
139	while(wait4(-1, NULL, WNOHANG, NULL) > 0)
140		;
141}
142
143void *
144wallproc_wall_1_svc(wrapstring *s, struct svc_req *rqstp __unused)
145{
146	static void		*dummy = NULL;
147
148	/* fork, popen wall with special option, and send the message */
149	if (fork() == 0) {
150		FILE *pfp;
151
152		pfp = popen(WALL_CMD, "w");
153		if (pfp != NULL) {
154			fprintf(pfp, "\007\007%s", *s);
155			pclose(pfp);
156			exit(0);
157		}
158	}
159	return(&dummy);
160}
161
162void
163wallprog_1(struct svc_req *rqstp, SVCXPRT *transp)
164{
165	union {
166		char *wallproc_wall_1_arg;
167	} argument;
168	void *result;
169	xdrproc_t xdr_argument, xdr_result;
170	typedef void *(svc_cb)(void *arg, struct svc_req *rqstp);
171	svc_cb *local;
172
173	switch (rqstp->rq_proc) {
174	case NULLPROC:
175		(void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL);
176		goto leave;
177
178	case WALLPROC_WALL:
179		xdr_argument = (xdrproc_t)xdr_wrapstring;
180		xdr_result = (xdrproc_t)xdr_void;
181		local = (svc_cb *)wallproc_wall_1_svc;
182		break;
183
184	default:
185		svcerr_noproc(transp);
186		goto leave;
187	}
188	bzero(&argument, sizeof(argument));
189	if (!svc_getargs(transp, xdr_argument, &argument)) {
190		svcerr_decode(transp);
191		goto leave;
192	}
193	result = (*local)(&argument, rqstp);
194	if (result != NULL &&
195	    !svc_sendreply(transp, xdr_result, result)) {
196		svcerr_systemerr(transp);
197	}
198	if (!svc_freeargs(transp, xdr_argument, &argument)) {
199		syslog(LOG_ERR, "unable to free arguments");
200		exit(1);
201	}
202leave:
203        if (from_inetd)
204                exit(0);
205}
206