Print Message Program With Remote Version

Example D-7 printmesg.c

/* printmsg.c: print a message on the console */
#include <stdio.h>

main(argc, argv)
     int argc;
     char *argv[];
{
    char *message;

    if (argc != 2) {
        fprintf(stderr, "usage: %s <message>\n", argv[0]);
        exit(1);
    }
    message = argv[1];
    if( !printmessage(message) ) {
        fprintf(stderr, "%s: couldn't print your message\n",
                argv[0]);
        exit(1);
    }
    printf("Message Delivered!\n");
    exit(0);
}

/* Print a message to the console. */

/*
 * Return a boolean indicating whether the message was actually
 * printed.
 */
printmessage(msg)
    char *msg;
{
    FILE *f;

    if = fopen("/dev/console","w");
        if (f == (FILE *)NULL)
            return (0);
    fprintf(f,"%sen”, msg);
    fclose(f);
    return (1);
}

Example D-8 Remote Version of printmesg.c

/*
 * rprintmsg.c: remote version of "printmsg.c”
 */ 
#include <stdio.h> 
#include <rpc/rpc.h>    /* always needed */ 
#include "msg.h”     /* msg.h generated by rpcgen */ 

main(argc, argv) 
    int argc;
    char *argv[];
{
    CLIENT *cl; 
    int *result;      
    char *server;
    char *message;
    extern int sys_nerr;
    extern char *sys_errlist[]; 

    if (argc != 3) { 
        fprintf(stderr,"usage: %s host messagen", argv[0]);
        exit(1);
    }
    /* 
     * Save values of command line arguments
     */
    server = argv[1];
    message = argv[2]; 
/*
 * Create client"handle” used for calling
 * MESSAGEPROG on the server
 * designated on the command line.
 */ 
    cl = clnt_create(server, MESSAGEPROG, PRINTMESSAGEVERS,
                     "visible");
    if (cl == (CLIENT *)NULL) {
        /* 
         * Couldn't establish connection with server.
         * Print error message and die.
         */
        clnt_pcreateerror(server);
        exit(1);
    }
    /* Call the remote procedure "printmessage" on the server */
    result = printmessage_1(&message, cl);
    if (result == (int *)NULL) {      
    /*
     * An error occurred while calling the server.
     * Print error message and die.
     */ 
        clnt_perror(cl, server);
        exit(1);
    }
    /* Okay, we successfully called the remote procedure. */
    if (*result == 0) { 
        /*
         * Server was unable to print our message.
         * Print error message and die.
         */
        fprintf(stderr,"%s"
    }
/* The message got printed on the server's console */
    printf("Message delivered to %s!\n", server);
    exit(0);
}

Example D-9 rpcgen Program: msg.x

/* msg.x: Remote message printing protocol */
program MESSAGEPROG {
     version MESSAGEVERS {
         int PRINTMESSAGE(string) = 1;
     } = 1;
} = 0x20000001;

Example D-10 mesg_proc.c

/*
 * msg_proc.c: implementation of the remote
 * procedure "printmessage"
 */

#include <stdio.h>
#include <rpc/rpc.h>     /* always needed */
#include "msg.h”     /* msg.h generated by rpcgen */

/*
 * Remote version of "printmessage"
 */
/*ARGSUSED1*/
int printmessage_1(msg, req)
    char **msg;
    struct svc_req *req;
{
    static int result; /* must be static! */
    FILE *f;

    f = fopen("/dev/console", "w");
    if (f == (FILE *)NULL) {
        result = 0;
        return (&result);
    }
    fprintf(f, "%sen", *msg);
     fclose(f);
     result = 1;
     return (&result);
}