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 56 void wallprog_1(struct svc_req *rqstp, SVCXPRT *transp); 57 void possess(void); 58 void killkids(int sig); 59 static void usage(void); 60 61 int nodaemon = 0; 62 int from_inetd = 1; 63 64 int 65 main(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 } 124 125 static void 126 usage(void) 127 { 128 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 129 exit(1); 130 } 131 132 void 133 possess(void) 134 { 135 daemon(0, 0); 136 } 137 138 void 139 killkids(int sig __unused) 140 { 141 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 142 ; 143 } 144 145 void * 146 wallproc_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 } 163 164 void 165 wallprog_1(struct svc_req *rqstp, SVCXPRT *transp) 166 { 167 union { 168 char *wallproc_wall_1_arg; 169 } argument; 170 void *result; 171 xdrproc_t xdr_argument, xdr_result; 172 typedef void *(svc_cb)(void *arg, struct svc_req *rqstp); 173 svc_cb *local; 174 175 switch (rqstp->rq_proc) { 176 case NULLPROC: 177 (void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL); 178 goto leave; 179 180 case WALLPROC_WALL: 181 xdr_argument = (xdrproc_t)xdr_wrapstring; 182 xdr_result = (xdrproc_t)xdr_void; 183 local = (svc_cb *)wallproc_wall_1_svc; 184 break; 185 186 default: 187 svcerr_noproc(transp); 188 goto leave; 189 } 190 bzero(&argument, sizeof(argument)); 191 if (!svc_getargs(transp, xdr_argument, &argument)) { 192 svcerr_decode(transp); 193 goto leave; 194 } 195 result = (*local)(&argument, rqstp); 196 if (result != NULL && 197 !svc_sendreply(transp, xdr_result, result)) { 198 svcerr_systemerr(transp); 199 } 200 if (!svc_freeargs(transp, xdr_argument, &argument)) { 201 syslog(LOG_ERR, "unable to free arguments"); 202 exit(1); 203 } 204 leave: 205 if (from_inetd) 206 exit(0); 207 } 208