1 /* 2 * Copyright (c) 1993 Christopher G. Demetriou 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote 14 * products derived from this software without specific prior written 15 * permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #ifndef lint 31 static char rcsid[] = "$Id: rwalld.c,v 1.2 1994/11/18 22:50:22 ats Exp $"; 32 #endif /* not lint */ 33 34 #include <unistd.h> 35 #include <sys/types.h> 36 #include <pwd.h> 37 #include <stdio.h> 38 #include <string.h> 39 #include <errno.h> 40 #include <sys/socket.h> 41 #include <signal.h> 42 #include <sys/wait.h> 43 #include <rpc/rpc.h> 44 #include <rpcsvc/rwall.h> 45 46 #ifdef OSF 47 #define WALL_CMD "/usr/sbin/wall" 48 #else 49 #define WALL_CMD "/usr/bin/wall -n" 50 #endif 51 52 void wallprog_1(); 53 void possess(); 54 void killkids(); 55 56 int nodaemon = 0; 57 int from_inetd = 1; 58 59 main(argc, argv) 60 int argc; 61 char *argv[]; 62 { 63 SVCXPRT *transp; 64 int s, salen; 65 struct sockaddr_in sa; 66 int sock = 0; 67 int proto = 0; 68 69 if (argc == 2 && !strcmp(argv[1], "-n")) 70 nodaemon = 1; 71 if (argc != 1 && !nodaemon) { 72 printf("usage: %s [-n]\n", argv[0]); 73 exit(1); 74 } 75 76 if (geteuid() == 0) { 77 struct passwd *pep = getpwnam("nobody"); 78 if (pep) 79 setuid(pep->pw_uid); 80 else 81 setuid(getuid()); 82 } 83 84 /* 85 * See if inetd started us 86 */ 87 salen = sizeof(sa); 88 if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) { 89 from_inetd = 0; 90 sock = RPC_ANYSOCK; 91 proto = IPPROTO_UDP; 92 } 93 94 if (!from_inetd) { 95 if (!nodaemon) 96 possess(); 97 98 (void)pmap_unset(WALLPROG, WALLVERS); 99 if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) { 100 perror("socket"); 101 exit(1); 102 } 103 bzero((char *)&sa, sizeof sa); 104 if (bind(s, (struct sockaddr *)&sa, sizeof sa) < 0) { 105 perror("bind"); 106 exit(1); 107 } 108 109 salen = sizeof sa; 110 if (getsockname(s, (struct sockaddr *)&sa, &salen)) { 111 perror("getsockname"); 112 exit(1); 113 } 114 115 pmap_set(WALLPROG, WALLVERS, IPPROTO_UDP, ntohs(sa.sin_port)); 116 if (dup2(s, 0) < 0) { 117 perror("dup2"); 118 exit(1); 119 } 120 (void)pmap_unset(WALLPROG, WALLVERS); 121 } 122 123 (void)signal(SIGCHLD, killkids); 124 125 transp = svcudp_create(sock); 126 if (transp == NULL) { 127 (void)fprintf(stderr, "cannot create udp service.\n"); 128 exit(1); 129 } 130 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 131 (void)fprintf(stderr, "unable to register (WALLPROG, WALLVERS, udp).\n"); 132 exit(1); 133 } 134 svc_run(); 135 (void)fprintf(stderr, "svc_run returned\n"); 136 exit(1); 137 138 } 139 140 void possess() 141 { 142 daemon(0, 0); 143 } 144 145 void killkids() 146 { 147 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 148 ; 149 } 150 151 void *wallproc_wall_1(s) 152 char **s; 153 { 154 /* fork, popen wall with special option, and send the message */ 155 if (fork() == 0) { 156 FILE *pfp; 157 158 pfp = popen(WALL_CMD, "w"); 159 if (pfp != NULL) { 160 fprintf(pfp, "\007\007%s", *s); 161 pclose(pfp); 162 exit(0); 163 } 164 } 165 } 166 167 void 168 wallprog_1(rqstp, transp) 169 struct svc_req *rqstp; 170 SVCXPRT *transp; 171 { 172 union { 173 char *wallproc_wall_1_arg; 174 } argument; 175 char *result; 176 bool_t (*xdr_argument)(), (*xdr_result)(); 177 char *(*local)(); 178 179 switch (rqstp->rq_proc) { 180 case NULLPROC: 181 (void)svc_sendreply(transp, xdr_void, (char *)NULL); 182 goto leave; 183 184 case WALLPROC_WALL: 185 xdr_argument = xdr_wrapstring; 186 xdr_result = xdr_void; 187 local = (char *(*)()) wallproc_wall_1; 188 break; 189 190 default: 191 svcerr_noproc(transp); 192 goto leave; 193 } 194 bzero((char *)&argument, sizeof(argument)); 195 if (!svc_getargs(transp, xdr_argument, &argument)) { 196 svcerr_decode(transp); 197 goto leave; 198 } 199 result = (*local)(&argument, rqstp); 200 if (result != NULL && !svc_sendreply(transp, xdr_result, result)) { 201 svcerr_systemerr(transp); 202 } 203 if (!svc_freeargs(transp, xdr_argument, &argument)) { 204 (void)fprintf(stderr, "unable to free arguments\n"); 205 exit(1); 206 } 207 leave: 208 if (from_inetd) 209 exit(0); 210 } 211