rwalld.c revision 31488
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 31static const char rcsid[] = 32 "$Id$"; 33#endif /* not lint */ 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 <rpc/rpc.h> 43#include <rpc/pmap_clnt.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 56void wallprog_1(); 57void possess(); 58void killkids(); 59static void usage __P((void)); 60 61int nodaemon = 0; 62int from_inetd = 1; 63 64int 65main(argc, argv) 66 int argc; 67 char *argv[]; 68{ 69 SVCXPRT *transp; 70 int s, salen; 71 struct sockaddr_in sa; 72 int sock = 0; 73 int proto = 0; 74 75 if (argc == 2 && !strcmp(argv[1], "-n")) 76 nodaemon = 1; 77 if (argc != 1 && !nodaemon) 78 usage(); 79 80 if (geteuid() == 0) { 81 struct passwd *pep = getpwnam("nobody"); 82 if (pep) 83 setuid(pep->pw_uid); 84 else 85 setuid(getuid()); 86 } 87 88 /* 89 * See if inetd started us 90 */ 91 salen = sizeof(sa); 92 if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) { 93 from_inetd = 0; 94 sock = RPC_ANYSOCK; 95 proto = IPPROTO_UDP; 96 } 97 98 if (!from_inetd) { 99 if (!nodaemon) 100 possess(); 101 102 (void)pmap_unset(WALLPROG, WALLVERS); 103 if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) 104 err(1, "socket"); 105 bzero((char *)&sa, sizeof sa); 106 if (bind(s, (struct sockaddr *)&sa, sizeof sa) < 0) 107 err(1, "bind"); 108 109 salen = sizeof sa; 110 if (getsockname(s, (struct sockaddr *)&sa, &salen)) 111 err(1, "getsockname"); 112 113 pmap_set(WALLPROG, WALLVERS, IPPROTO_UDP, ntohs(sa.sin_port)); 114 if (dup2(s, 0) < 0) 115 err(1, "dup2"); 116 (void)pmap_unset(WALLPROG, WALLVERS); 117 } 118 119 (void)signal(SIGCHLD, killkids); 120 121 openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON); 122 123 transp = svcudp_create(sock); 124 if (transp == NULL) { 125 syslog(LOG_ERR, "cannot create udp service"); 126 exit(1); 127 } 128 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 129 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", proto?"udp":"(inetd)"); 130 exit(1); 131 } 132 svc_run(); 133 syslog(LOG_ERR, "svc_run returned"); 134 exit(1); 135} 136 137static void 138usage() 139{ 140 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 141 exit(1); 142} 143 144void possess() 145{ 146 daemon(0, 0); 147} 148 149void killkids() 150{ 151 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 152 ; 153} 154 155void *wallproc_wall_1(s) 156 char **s; 157{ 158 /* fork, popen wall with special option, and send the message */ 159 if (fork() == 0) { 160 FILE *pfp; 161 162 pfp = popen(WALL_CMD, "w"); 163 if (pfp != NULL) { 164 fprintf(pfp, "\007\007%s", *s); 165 pclose(pfp); 166 exit(0); 167 } 168 } 169 return(NULL); 170} 171 172void 173wallprog_1(rqstp, transp) 174 struct svc_req *rqstp; 175 SVCXPRT *transp; 176{ 177 union { 178 char *wallproc_wall_1_arg; 179 } argument; 180 char *result; 181 bool_t (*xdr_argument)(), (*xdr_result)(); 182 char *(*local)(); 183 184 switch (rqstp->rq_proc) { 185 case NULLPROC: 186 (void)svc_sendreply(transp, xdr_void, (char *)NULL); 187 goto leave; 188 189 case WALLPROC_WALL: 190 xdr_argument = xdr_wrapstring; 191 xdr_result = xdr_void; 192 local = (char *(*)()) wallproc_wall_1; 193 break; 194 195 default: 196 svcerr_noproc(transp); 197 goto leave; 198 } 199 bzero((char *)&argument, sizeof(argument)); 200 if (!svc_getargs(transp, xdr_argument, &argument)) { 201 svcerr_decode(transp); 202 goto leave; 203 } 204 result = (*local)(&argument, rqstp); 205 if (result != NULL && !svc_sendreply(transp, xdr_result, result)) { 206 svcerr_systemerr(transp); 207 } 208 if (!svc_freeargs(transp, xdr_argument, &argument)) { 209 syslog(LOG_ERR, "unable to free arguments"); 210 exit(1); 211 } 212leave: 213 if (from_inetd) 214 exit(0); 215} 216