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
54 void wallprog_1(struct svc_req *rqstp, SVCXPRT *transp);
55 void possess(void);
56 void killkids(int sig);
57 static void usage(void) __dead2;
58
59 int nodaemon = 0;
60 int from_inetd = 1;
61
62 int
main(int argc,char * argv[])63 main(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
123 static void
usage(void)124 usage(void)
125 {
126 fprintf(stderr, "usage: rpc.rwalld [-n]\n");
127 exit(1);
128 }
129
130 void
possess(void)131 possess(void)
132 {
133 daemon(0, 0);
134 }
135
136 void
killkids(int sig __unused)137 killkids(int sig __unused)
138 {
139 while(wait4(-1, NULL, WNOHANG, NULL) > 0)
140 ;
141 }
142
143 void *
wallproc_wall_1_svc(wrapstring * s,struct svc_req * rqstp __unused)144 wallproc_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
162 void
wallprog_1(struct svc_req * rqstp,SVCXPRT * transp)163 wallprog_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 }
202 leave:
203 if (from_inetd)
204 exit(0);
205 }
206