1 /* $OpenBSD: rwalld.c,v 1.15 2016/04/25 15:43:34 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1993 Christopher G. Demetriou 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote 16 * products derived from this software without specific prior written 17 * permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 20 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/socket.h> 34 #include <sys/wait.h> 35 #include <pwd.h> 36 #include <stdlib.h> 37 #include <stdio.h> 38 #include <string.h> 39 #include <syslog.h> 40 #include <errno.h> 41 #include <unistd.h> 42 #include <signal.h> 43 #include <rpc/rpc.h> 44 #include <rpcsvc/rwall.h> 45 46 #ifdef OSF 47 #define WALL_CMD "/usr/sbin/wall" 48 #else 49 #define WALL_CMD "/usr/bin/wall -n" 50 #endif 51 52 void wallprog_1(struct svc_req *, SVCXPRT *); 53 54 int from_inetd = 1; 55 56 static void 57 cleanup(int signo) 58 { 59 (void) pmap_unset(WALLPROG, WALLVERS); /* XXX signal race */ 60 _exit(0); 61 } 62 63 int 64 main(int argc, char *argv[]) 65 { 66 int sock = 0, proto = 0; 67 socklen_t fromlen; 68 struct sockaddr_storage from; 69 SVCXPRT *transp; 70 71 struct passwd *pw = getpwnam("_rwalld"); 72 if (pw == NULL) { 73 syslog(LOG_ERR, "no such user _rwalld"); 74 exit(1); 75 } 76 77 setgroups(1, &pw->pw_gid); 78 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid); 79 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid); 80 81 /* 82 * See if inetd started us 83 */ 84 fromlen = sizeof(from); 85 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 86 from_inetd = 0; 87 sock = RPC_ANYSOCK; 88 proto = IPPROTO_UDP; 89 } 90 91 if (!from_inetd) { 92 daemon(0, 0); 93 94 (void) pmap_unset(WALLPROG, WALLVERS); 95 96 (void) signal(SIGINT, cleanup); 97 (void) signal(SIGTERM, cleanup); 98 (void) signal(SIGHUP, cleanup); 99 } 100 101 openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON); 102 103 transp = svcudp_create(sock); 104 if (transp == NULL) { 105 syslog(LOG_ERR, "cannot create udp service."); 106 exit(1); 107 } 108 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 109 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s).", 110 proto ? "udp" : "(inetd)"); 111 exit(1); 112 } 113 114 svc_run(); 115 syslog(LOG_ERR, "svc_run returned"); 116 exit(1); 117 118 } 119 120 void * 121 wallproc_wall_1_svc(char **s, struct svc_req *rqstp) 122 { 123 FILE *pfp; 124 125 pfp = popen(WALL_CMD, "w"); 126 if (pfp != NULL) { 127 fprintf(pfp, "\007\007%s", *s); 128 pclose(pfp); 129 } 130 131 return (*s); 132 } 133 134 void 135 wallprog_1(struct svc_req *rqstp, SVCXPRT *transp) 136 { 137 char *(*local)(char **, struct svc_req *); 138 xdrproc_t xdr_argument, xdr_result; 139 union { 140 char *wallproc_wall_1_arg; 141 } argument; 142 char *result; 143 144 switch (rqstp->rq_proc) { 145 case NULLPROC: 146 (void)svc_sendreply(transp, xdr_void, (char *)NULL); 147 goto leave; 148 149 case WALLPROC_WALL: 150 xdr_argument = (xdrproc_t)xdr_wrapstring; 151 xdr_result = (xdrproc_t)xdr_void; 152 local = (char *(*)(char **, struct svc_req *)) 153 wallproc_wall_1_svc; 154 break; 155 156 default: 157 svcerr_noproc(transp); 158 goto leave; 159 } 160 bzero((char *)&argument, sizeof(argument)); 161 if (!svc_getargs(transp, xdr_argument, (caddr_t)&argument)) { 162 svcerr_decode(transp); 163 goto leave; 164 } 165 result = (*local)((char **)&argument, rqstp); 166 if (result != NULL && !svc_sendreply(transp, xdr_result, result)) { 167 svcerr_systemerr(transp); 168 } 169 if (!svc_freeargs(transp, xdr_argument, (caddr_t)&argument)) { 170 syslog(LOG_ERR, "unable to free arguments"); 171 exit(1); 172 } 173 leave: 174 if (from_inetd) 175 exit(0); 176 } 177