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rwalld.c revision 1.6 
      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 char rcsid[] = "$Id: rwalld.c,v 1.6 1995/01/13 19:18:08 mycroft Exp $";
     32 #endif /* not lint */
     33 
     34 #include <unistd.h>
     35 #include <sys/types.h>
     36 #include <pwd.h>
     37 #include <stdio.h>
     38 #include <string.h>
     39 #include <syslog.h>
     40 #include <errno.h>
     41 #include <sys/socket.h>
     42 #include <signal.h>
     43 #include <sys/wait.h>
     44 #include <rpc/rpc.h>
     45 #include <rpcsvc/rwall.h>
     46 
     47 #ifdef OSF
     48 #define WALL_CMD "/usr/sbin/wall"
     49 #else
     50 #define WALL_CMD "/usr/bin/wall -n"
     51 #endif
     52 
     53 void wallprog_1();
     54 
     55 int from_inetd = 1;
     56 
     57 void
     58 cleanup()
     59 {
     60 	(void) pmap_unset(WALLPROG, WALLVERS);
     61 	exit(0);
     62 }
     63 
     64 main(argc, argv)
     65 	int argc;
     66 	char *argv[];
     67 {
     68 	SVCXPRT *transp;
     69 	int sock = 0;
     70 	int proto = 0;
     71 	struct sockaddr_in from;
     72 	int fromlen;
     73 
     74 	if (geteuid() == 0) {
     75 		struct passwd *pep = getpwnam("nobody");
     76 		if (pep)
     77 			setuid(pep->pw_uid);
     78 		else
     79 			setuid(getuid());
     80 	}
     81 
     82 	/*
     83 	 * See if inetd started us
     84 	 */
     85 	fromlen = sizeof(from);
     86 	if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) {
     87 		from_inetd = 0;
     88 		sock = RPC_ANYSOCK;
     89 		proto = IPPROTO_UDP;
     90 	}
     91 
     92 	if (!from_inetd) {
     93 		daemon(0, 0);
     94 
     95 		(void) pmap_unset(WALLPROG, WALLVERS);
     96 
     97 		(void) signal(SIGINT, cleanup);
     98 		(void) signal(SIGTERM, cleanup);
     99 		(void) signal(SIGHUP, cleanup);
    100 	}
    101 
    102 	openlog("rpc.rwalld", LOG_CONS|LOG_PID, LOG_DAEMON);
    103 
    104 	transp = svcudp_create(sock);
    105 	if (transp == NULL) {
    106 		syslog(LOG_ERR, "cannot create udp service.");
    107 		exit(1);
    108 	}
    109 	if (!svc_register(transp, WALLPROG, WALLVERS, wallprog_1, proto)) {
    110 		syslog(LOG_ERR, "unable to register (WALLPROG, WALLVERS, %s).", 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(s)
    122 	char **s;
    123 {
    124 	FILE *pfp;
    125 
    126 	pfp = popen(WALL_CMD, "w");
    127 	if (pfp != NULL) {
    128 		fprintf(pfp, "\007\007%s", *s);
    129 		pclose(pfp);
    130 	}
    131 
    132 	return (NULL);
    133 }
    134 
    135 void
    136 wallprog_1(rqstp, transp)
    137 	struct svc_req *rqstp;
    138 	SVCXPRT *transp;
    139 {
    140 	union {
    141 		char *wallproc_wall_1_arg;
    142 	} argument;
    143 	char *result;
    144 	bool_t (*xdr_argument)(), (*xdr_result)();
    145 	char *(*local)();
    146 
    147 	switch (rqstp->rq_proc) {
    148 	case NULLPROC:
    149 		(void)svc_sendreply(transp, xdr_void, (char *)NULL);
    150 		goto leave;
    151 
    152 	case WALLPROC_WALL:
    153 		xdr_argument = xdr_wrapstring;
    154 		xdr_result = xdr_void;
    155 		local = (char *(*)()) wallproc_wall_1;
    156 		break;
    157 
    158 	default:
    159 		svcerr_noproc(transp);
    160 		goto leave;
    161 	}
    162 	bzero((char *)&argument, sizeof(argument));
    163 	if (!svc_getargs(transp, xdr_argument, (caddr_t)&argument)) {
    164 		svcerr_decode(transp);
    165 		goto leave;
    166 	}
    167 	result = (*local)(&argument, rqstp);
    168 	if (result != NULL && !svc_sendreply(transp, xdr_result, result)) {
    169 		svcerr_systemerr(transp);
    170 	}
    171 	if (!svc_freeargs(transp, xdr_argument, (caddr_t)&argument)) {
    172 		syslog(LOG_ERR, "unable to free arguments");
    173 		exit(1);
    174 	}
    175 leave:
    176 	if (from_inetd)
    177 		exit(0);
    178 }
    179