libexec/rpc.rwalld/rwalld.c

   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  * $FreeBSD: src/libexec/rpc.rwalld/rwalld.c,v 1.8 1999/08/28 00:09:57 peter Exp $
  30  */
  31
  32 #include <err.h>
  33 #include <pwd.h>
  34 #include <signal.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <syslog.h>
  39 #include <rpc/rpc.h>
  40 #include <rpcsvc/rwall.h>
  41 #include <sys/socket.h>
  42 #include <sys/types.h>
  43 #include <sys/wait.h>
  44 #include <unistd.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();
  53 void possess();
  54 void killkids();
  55 static void usage (void);
  56
  57 int nodaemon = 0;
  58 int from_inetd = 1;
  59
  60 int
  61 main(int argc, char *argv[])
  62 {
  63         SVCXPRT *transp;
  64         int ok, salen;
  65         struct sockaddr_storage sa;
  66
  67         if (argc == 2 && !strcmp(argv[1], "-n"))
  68                 nodaemon = 1;
  69         if (argc != 1 && !nodaemon)
  70                 usage();
  71
  72         if (geteuid() == 0) {
  73                 struct passwd *pep = getpwnam("nobody");
  74                 if (pep)
  75                         setuid(pep->pw_uid);
  76                 else
  77                         setuid(getuid());
  78         }
  79
  80         /*
  81          * See if inetd started us
  82          */
  83         salen = sizeof(sa);
  84         if (getsockname(0, (struct sockaddr *)&sa, &salen) < 0) {
  85                 from_inetd = 0;
  86         }
  87
  88         if (!from_inetd) {
  89                 if (!nodaemon)
  90                         possess();
  91
  92                 (void)rpcb_unset(WALLPROG, WALLVERS, NULL);
  93         }
  94
  95         (void)signal(SIGCHLD, killkids);
  96
  97         openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON);
  98
  99         /* create and register the service */
 100         if (from_inetd) {
 101                 transp = svc_tli_create(0, NULL, NULL, 0, 0);
 102                 if (transp == NULL) {
 103                         syslog(LOG_ERR, "couldn't create udp service.");
 104                         exit(1);
 105                 }
 106                 ok = svc_reg(transp, WALLPROG, WALLVERS,
 107                     wallprog_1, NULL);
 108         } else
 109                 ok = svc_create(wallprog_1,
 110                     WALLPROG, WALLVERS, "udp");
 111         if (!ok) {
 112                 syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s)", (!from_inetd)?"udp":"(inetd)");
 113                 exit(1);
 114         }
 115         svc_run();
 116         syslog(LOG_ERR, "svc_run returned");
 117         exit(1);
 118 }
 119
 120 static void
 121 usage(void)
 122 {
 123         fprintf(stderr, "usage: rpc.rwalld [-n]\n");
 124         exit(1);
 125 }
 126
 127 void
 128 possess(void)
 129 {
 130         daemon(0, 0);
 131 }
 132
 133 void
 134 killkids(void)
 135 {
 136         while(wait4(-1, NULL, WNOHANG, NULL) > 0)
 137                 ;
 138 }
 139
 140 void *
 141 wallproc_wall_1_svc(wrapstring *s, struct svc_req *rqstp)
 142 {
 143         static void             *dummy = NULL;
 144
 145         /* fork, popen wall with special option, and send the message */
 146         if (fork() == 0) {
 147                 FILE *pfp;
 148
 149                 pfp = popen(WALL_CMD, "w");
 150                 if (pfp != NULL) {
 151                         fprintf(pfp, "\007\007%s", *s);
 152                         pclose(pfp);
 153                         exit(0);
 154                 }
 155         }
 156         return(&dummy);
 157 }
 158
 159 void
 160 wallprog_1(struct svc_req *rqstp, SVCXPRT *transp)
 161 {
 162         union {
 163                 char *wallproc_wall_1_arg;
 164         } argument;
 165         char *result;
 166         bool_t (*xdr_argument)(), (*xdr_result)();
 167         char *(*local)();
 168
 169         switch (rqstp->rq_proc) {
 170         case NULLPROC:
 171                 (void)svc_sendreply(transp, (xdrproc_t)xdr_void, NULL);
 172                 goto leave;
 173
 174         case WALLPROC_WALL:
 175                 xdr_argument = xdr_wrapstring;
 176                 xdr_result = xdr_void;
 177                 local = (char *(*)()) wallproc_wall_1_svc;
 178                 break;
 179
 180         default:
 181                 svcerr_noproc(transp);
 182                 goto leave;
 183         }
 184         bzero((char *)&argument, sizeof(argument));
 185         if (!svc_getargs(transp, (xdrproc_t)xdr_argument, (caddr_t)&argument)) {
 186                 svcerr_decode(transp);
 187                 goto leave;
 188         }
 189         result = (*local)(&argument, rqstp);
 190         if (result != NULL &&
 191             !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) {
 192                 svcerr_systemerr(transp);
 193         }
 194         if (!svc_freeargs(transp, (xdrproc_t)xdr_argument, (caddr_t)&argument)) {
 195                 syslog(LOG_ERR, "unable to free arguments");
 196                 exit(1);
 197         }
 198 leave:
 199         if (from_inetd)
 200                 exit(0);
 201 }