Write a client program that writes a struct with a privateFIFO name (call it FIFO_, where 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

client code:

#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:

#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);

}

Explanation: