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 * $FreeBSD: src/libexec/rpc.rwalld/rwalld.c,v 1.8 1999/08/28 00:09:57 peter Exp $ 30 */ 31 32 #include <err.h> 33 #include <pwd.h> 34 #include <signal.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <syslog.h> 39 #include <rpc/rpc.h> 40 #include <rpc/pmap_clnt.h> 41 #include <rpcsvc/rwall.h> 42 #include <sys/socket.h> 43 #include <sys/types.h> 44 #include <sys/wait.h> 45 #include <unistd.h> 46 47 #ifdef OSF 48 #define WALL_CMD "/usr/sbin/wall" 49 #else 50 #define WALL_CMD "/usr/bin/wall -n" 51 #endif 52 53 void wallprog_1(); 54 void possess(); 55 void killkids(); 56 static void usage (void); 57 58 int nodaemon = 0; 59 int from_inetd = 1; 60 61 int 62 main(int argc, char *argv[]) 63 { 64 SVCXPRT *transp; 65 int s, salen; 66 struct sockaddr_in sa; 67 int sock = 0; 68 int proto = 0; 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 sock = RPC_ANYSOCK; 90 proto = IPPROTO_UDP; 91 } 92 93 if (!from_inetd) { 94 if (!nodaemon) 95 possess(); 96 97 (void)pmap_unset(WALLPROG, WALLVERS); 98 if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) 99 err(1, "socket"); 100 bzero((char *)&sa, sizeof sa); 101 if (bind(s, (struct sockaddr *)&sa, sizeof sa) < 0) 102 err(1, "bind"); 103 104 salen = sizeof sa; 105 if (getsockname(s, (struct sockaddr *)&sa, &salen)) 106 err(1, "getsockname"); 107 108 pmap_set(WALLPROG, WALLVERS, IPPROTO_UDP, ntohs(sa.sin_port)); 109 if (dup2(s, 0) < 0) 110 err(1, "dup2"); 111 (void)pmap_unset(WALLPROG, WALLVERS); 112 } 113 114 (void)signal(SIGCHLD, killkids); 115 116 openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON); 117 118 transp = svcudp_create(sock); 119 if (transp == NULL) { 120 syslog(LOG_ERR, "cannot create udp service"); 121 exit(1); 122 } 123 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 124 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", proto?"udp":"(inetd)"); 125 exit(1); 126 } 127 svc_run(); 128 syslog(LOG_ERR, "svc_run returned"); 129 exit(1); 130 } 131 132 static void 133 usage(void) 134 { 135 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 136 exit(1); 137 } 138 139 void 140 possess(void) 141 { 142 daemon(0, 0); 143 } 144 145 void 146 killkids(void) 147 { 148 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 149 ; 150 } 151 152 void * 153 wallproc_wall_1_svc(wrapstring *s, struct svc_req *rqstp) 154 { 155 static void *dummy = NULL; 156 157 /* fork, popen wall with special option, and send the message */ 158 if (fork() == 0) { 159 FILE *pfp; 160 161 pfp = popen(WALL_CMD, "w"); 162 if (pfp != NULL) { 163 fprintf(pfp, "\007\007%s", *s); 164 pclose(pfp); 165 exit(0); 166 } 167 } 168 return(&dummy); 169 } 170 171 void 172 wallprog_1(struct svc_req *rqstp, SVCXPRT *transp) 173 { 174 union { 175 char *wallproc_wall_1_arg; 176 } argument; 177 char *result; 178 bool_t (*xdr_argument)(), (*xdr_result)(); 179 char *(*local)(); 180 181 switch (rqstp->rq_proc) { 182 case NULLPROC: 183 (void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL); 184 goto leave; 185 186 case WALLPROC_WALL: 187 xdr_argument = xdr_wrapstring; 188 xdr_result = xdr_void; 189 local = (char *(*)()) wallproc_wall_1_svc; 190 break; 191 192 default: 193 svcerr_noproc(transp); 194 goto leave; 195 } 196 bzero((char *)&argument, sizeof(argument)); 197 if (!svc_getargs(transp, (xdrproc_t)xdr_argument, (caddr_t)&argument)) { 198 svcerr_decode(transp); 199 goto leave; 200 } 201 result = (*local)(&argument, rqstp); 202 if (result != NULL && 203 !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) { 204 svcerr_systemerr(transp); 205 } 206 if (!svc_freeargs(transp, (xdrproc_t)xdr_argument, (caddr_t)&argument)) { 207 syslog(LOG_ERR, "unable to free arguments"); 208 exit(1); 209 } 210 leave: 211 if (from_inetd) 212 exit(0); 213 } 214