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