1 /* $OpenBSD: rwalld.c,v 1.16 2017/05/27 07:39:27 tedu 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 #define WALL_CMD "/usr/bin/wall -n" 47 48 void wallprog_1(struct svc_req *, SVCXPRT *); 49 50 int from_inetd = 1; 51 52 static void 53 cleanup(int signo) 54 { 55 (void) pmap_unset(WALLPROG, WALLVERS); /* XXX signal race */ 56 _exit(0); 57 } 58 59 int 60 main(int argc, char *argv[]) 61 { 62 int sock = 0, proto = 0; 63 socklen_t fromlen; 64 struct sockaddr_storage from; 65 SVCXPRT *transp; 66 67 struct passwd *pw = getpwnam("_rwalld"); 68 if (pw == NULL) { 69 syslog(LOG_ERR, "no such user _rwalld"); 70 exit(1); 71 } 72 73 setgroups(1, &pw->pw_gid); 74 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid); 75 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid); 76 77 /* 78 * See if inetd started us 79 */ 80 fromlen = sizeof(from); 81 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 82 from_inetd = 0; 83 sock = RPC_ANYSOCK; 84 proto = IPPROTO_UDP; 85 } 86 87 if (!from_inetd) { 88 daemon(0, 0); 89 90 (void) pmap_unset(WALLPROG, WALLVERS); 91 92 (void) signal(SIGINT, cleanup); 93 (void) signal(SIGTERM, cleanup); 94 (void) signal(SIGHUP, cleanup); 95 } 96 97 openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON); 98 99 transp = svcudp_create(sock); 100 if (transp == NULL) { 101 syslog(LOG_ERR, "cannot create udp service."); 102 exit(1); 103 } 104 if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) { 105 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s).", 106 proto ? "udp" : "(inetd)"); 107 exit(1); 108 } 109 110 svc_run(); 111 syslog(LOG_ERR, "svc_run returned"); 112 exit(1); 113 114 } 115 116 void * 117 wallproc_wall_1_svc(char **s, struct svc_req *rqstp) 118 { 119 FILE *pfp; 120 121 pfp = popen(WALL_CMD, "w"); 122 if (pfp != NULL) { 123 fprintf(pfp, "\007\007%s", *s); 124 pclose(pfp); 125 } 126 127 return (*s); 128 } 129 130 void 131 wallprog_1(struct svc_req *rqstp, SVCXPRT *transp) 132 { 133 char *(*local)(char **, struct svc_req *); 134 xdrproc_t xdr_argument, xdr_result; 135 union { 136 char *wallproc_wall_1_arg; 137 } argument; 138 char *result; 139 140 switch (rqstp->rq_proc) { 141 case NULLPROC: 142 (void)svc_sendreply(transp, xdr_void, (char *)NULL); 143 goto leave; 144 145 case WALLPROC_WALL: 146 xdr_argument = (xdrproc_t)xdr_wrapstring; 147 xdr_result = (xdrproc_t)xdr_void; 148 local = (char *(*)(char **, struct svc_req *)) 149 wallproc_wall_1_svc; 150 break; 151 152 default: 153 svcerr_noproc(transp); 154 goto leave; 155 } 156 bzero((char *)&argument, sizeof(argument)); 157 if (!svc_getargs(transp, xdr_argument, (caddr_t)&argument)) { 158 svcerr_decode(transp); 159 goto leave; 160 } 161 result = (*local)((char **)&argument, rqstp); 162 if (result != NULL && !svc_sendreply(transp, xdr_result, result)) { 163 svcerr_systemerr(transp); 164 } 165 if (!svc_freeargs(transp, xdr_argument, (caddr_t)&argument)) { 166 syslog(LOG_ERR, "unable to free arguments"); 167 exit(1); 168 } 169 leave: 170 if (from_inetd) 171 exit(0); 172 } 173