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 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 124 usage(void) 125 { 126 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 127 exit(1); 128 } 129 130 void 131 possess(void) 132 { 133 daemon(0, 0); 134 } 135 136 void 137 killkids(int sig __unused) 138 { 139 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 140 ; 141 } 142 143 void * 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 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