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 "$FreeBSD$"; 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 <arpa/inet.h> 43 #include <rpc/rpc.h> 44 #include <rpc/pmap_clnt.h> 45 #include <rpcsvc/rwall.h> 46 #include <sys/socket.h> 47 #include <sys/types.h> 48 #include <sys/wait.h> 49 #include <unistd.h> 50 51 #ifdef OSF 52 #define WALL_CMD "/usr/sbin/wall" 53 #else 54 #define WALL_CMD "/usr/bin/wall -n" 55 #endif 56 57 void wallprog_1(struct svc_req *rqstp, SVCXPRT *transp); 58 void possess(void); 59 void killkids(int sig); 60 static void usage(void); 61 62 int nodaemon = 0; 63 int from_inetd = 1; 64 65 int 66 main(int argc, char *argv[]) 67 { 68 SVCXPRT *transp; 69 int s, salen; 70 struct sockaddr_in sa; 71 int sock = 0; 72 int proto = 0; 73 74 if (argc == 2 && !strcmp(argv[1], "-n")) 75 nodaemon = 1; 76 if (argc != 1 && !nodaemon) 77 usage(); 78 79 if (geteuid() == 0) { 80 struct passwd *pep = getpwnam("nobody"); 81 if (pep) 82 setuid(pep->pw_uid); 83 else 84 setuid(getuid()); 85 } 86 87 /* 88 * See if inetd started us 89 */ 90 salen = sizeof(sa); 91 if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) { 92 from_inetd = 0; 93 sock = RPC_ANYSOCK; 94 proto = IPPROTO_UDP; 95 } 96 97 if (!from_inetd) { 98 if (!nodaemon) 99 possess(); 100 101 (void)pmap_unset(WALLPROG, WALLVERS); 102 if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) 103 err(1, "socket"); 104 bzero(&sa, sizeof sa); 105 if (bind(s, (struct sockaddr *)&sa, sizeof sa) < 0) 106 err(1, "bind"); 107 108 salen = sizeof sa; 109 if (getsockname(s, (struct sockaddr *)&sa, &salen)) 110 err(1, "getsockname"); 111 112 pmap_set(WALLPROG, WALLVERS, IPPROTO_UDP, ntohs(sa.sin_port)); 113 if (dup2(s, 0) < 0) 114 err(1, "dup2"); 115 (void)pmap_unset(WALLPROG, WALLVERS); 116 } 117 118 (void)signal(SIGCHLD, killkids); 119 120 openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON); 121 122 transp = svcudp_create(sock); 123 if (transp == NULL) { 124 syslog(LOG_ERR, "cannot create udp service"); 125 exit(1); 126 } 127 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 128 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", proto?"udp":"(inetd)"); 129 exit(1); 130 } 131 svc_run(); 132 syslog(LOG_ERR, "svc_run returned"); 133 exit(1); 134 } 135 136 static void 137 usage(void) 138 { 139 fprintf(stderr, "usage: rpc.rwalld [-n]\n"); 140 exit(1); 141 } 142 143 void 144 possess(void) 145 { 146 daemon(0, 0); 147 } 148 149 void 150 killkids(int sig) 151 { 152 while(wait4(-1, NULL, WNOHANG, NULL) > 0) 153 ; 154 } 155 156 void * 157 wallproc_wall_1_svc(wrapstring *s, 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(struct svc_req *rqstp, SVCXPRT *transp) 177 { 178 union { 179 char *wallproc_wall_1_arg; 180 } argument; 181 char *result; 182 bool_t (*xdr_argument)(), (*xdr_result)(); 183 char *(*local)(); 184 185 switch (rqstp->rq_proc) { 186 case NULLPROC: 187 (void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL); 188 goto leave; 189 190 case WALLPROC_WALL: 191 xdr_argument = xdr_wrapstring; 192 xdr_result = xdr_void; 193 local = (char *(*)()) wallproc_wall_1_svc; 194 break; 195 196 default: 197 svcerr_noproc(transp); 198 goto leave; 199 } 200 bzero(&argument, sizeof(argument)); 201 if (!svc_getargs(transp, (xdrproc_t)xdr_argument, &argument)) { 202 svcerr_decode(transp); 203 goto leave; 204 } 205 result = (*local)(&argument, rqstp); 206 if (result != NULL && 207 !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) { 208 svcerr_systemerr(transp); 209 } 210 if (!svc_freeargs(transp, (xdrproc_t)xdr_argument, &argument)) { 211 syslog(LOG_ERR, "unable to free arguments"); 212 exit(1); 213 } 214 leave: 215 if (from_inetd) 216 exit(0); 217 } 218