Question

Write a client program that writes a struct with a privateFIFO name (call it FIFO_XXXX, where XXXX is the pid that you got from the getpid( ) function) to the server. Have the server read the privateFIFO name and write a message back to the client. Read the message and print it on the client side. Take screenshots of the output from your client and server programs. Send the output to Blackboard. What I'm checking for on this homework is that the name got created in the client and passed correctly to the server and the server can respond to the client. Turn the background of your window white and increase the font size.

Write in C, Will be used on Putty.

Thank you.

Answer 1

client code can be written as:

#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

int main (void)
{

struct values
{
    char privateFIFO[14];
    int intbuff;
}input;

int fda; // common FIFO to read to write to server
int fdb;      // Private FIFO to read from server
int clientID;
int retbuff;
char temp[14];

clientID = getpid();
strcpy(input.privateFIFO, "FIFO_");
sprintf(temp, "%d", clientID);
strcat(input.privateFIFO, temp);
printf("\nFIFO name is %s", input.privateFIFO);

// Open common FIFO to write to server
if((fda=open("FIFO_to_server", O_WRONLY))<0)
     printf("cant open fifo to write");

write(fda, &input, sizeof(input));    // write the struct to the server
close(fda);

// Open private FIFO to read
if((fdb=open(input.privateFIFO, O_RDONLY))<0)
     read(fdb, &retbuff, sizeof(retbuff));

printf("\nAll done\n");

close(fdb);

}

server code can be written as:

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

struct values
{
    char privateFIFO[14];
    int intbuff;
}input;

int main (void)
{

int fda; //common FIFO to read from client
int fdb; //private FIFO to write to client
int retbuff;
int output;
// create the common FIFO
if ((mkfifo("FIFO_to_server",0666)<0 && errno != EEXIST))
        {
        perror("cant create FIFO_to_server");
        exit(-1);
}

// open the common FIFO
if((fda=open("FIFO_to_server", O_RDONLY))<0)
     printf("cant open fifo to write");
output = read(fda, &input, sizeof(input));

// create the private FIFO
if ((mkfifo(input.privateFIFO, 0666)<0 && errno != EEXIST))
{
    perror("cant create privateFIFO_to_server");
    exit(-1);
}

printf("Private FIFO received from the client and sent back from server is: %d", output);

//open private FIFO to write to client
if((fdb=open(input.privateFIFO, O_WRONLY))<0)
    printf("cant open fifo to read");
write(fdb, &retbuff, sizeof(retbuff));

close(fda);
unlink("FIFO_to_server");
close(fdb);
unlink(input.privateFIFO);

}