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 const char rcsid[] = 32 "$FreeBSD: src/libexec/rpc.rwalld/rwalld.c,v 1.8 1999/08/28 00:09:57 peter Exp $"; 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 56 void wallprog_1(); 57 void possess(); 58 void killkids(); 59 static void usage __P((void)); 60 61 int nodaemon = 0; 62 int from_inetd = 1; 63 64 int 65 main(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 } 136 137 static void 138 usage() 139 { 140 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 141 exit(1); 142 } 143 144 void possess() 145 { 146 daemon(0, 0); 147 } 148 149 void killkids() 150 { 151 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 152 ; 153 } 154 155 void *wallproc_wall_1_svc(s, rqstp) 156 wrapstring *s; 157 struct svc_req *rqstp; 158 { 159 static void *dummy = NULL; 160 161 /* fork, popen wall with special option, and send the message */ 162 if (fork() == 0) { 163 FILE *pfp; 164 165 pfp = popen(WALL_CMD, "w"); 166 if (pfp != NULL) { 167 fprintf(pfp, "\007\007%s", *s); 168 pclose(pfp); 169 exit(0); 170 } 171 } 172 return(&dummy); 173 } 174 175 void 176 wallprog_1(rqstp, transp) 177 struct svc_req *rqstp; 178 SVCXPRT *transp; 179 { 180 union { 181 char *wallproc_wall_1_arg; 182 } argument; 183 char *result; 184 bool_t (*xdr_argument)(), (*xdr_result)(); 185 char *(*local)(); 186 187 switch (rqstp->rq_proc) { 188 case NULLPROC: 189 (void)svc_sendreply(transp, xdr_void, (char *)NULL); 190 goto leave; 191 192 case WALLPROC_WALL: 193 xdr_argument = xdr_wrapstring; 194 xdr_result = xdr_void; 195 local = (char *(*)()) wallproc_wall_1_svc; 196 break; 197 198 default: 199 svcerr_noproc(transp); 200 goto leave; 201 } 202 bzero((char *)&argument, sizeof(argument)); 203 if (!svc_getargs(transp, xdr_argument, (caddr_t)&argument)) { 204 svcerr_decode(transp); 205 goto leave; 206 } 207 result = (*local)(&argument, rqstp); 208 if (result != NULL && !svc_sendreply(transp, xdr_result, result)) { 209 svcerr_systemerr(transp); 210 } 211 if (!svc_freeargs(transp, xdr_argument, (caddr_t)&argument)) { 212 syslog(LOG_ERR, "unable to free arguments"); 213 exit(1); 214 } 215 leave: 216 if (from_inetd) 217 exit(0); 218 } 219