Question

Need help with this code in C

Write your own simple client/server set of processes. The client should use a shared memory segment to send a command message to the server. The server process should monitor the shared memory segment, and respond as follows: "HI" - - The server prints "Greetings" to the screen. "PID" - - The server prints it's process id to the screen. "QUIT" - - The server terminates gracefully, detaching and releasing the shared memory segment. Terminal 1: [stalica@trig ~]$ cc cl.c -ocl [stalica@trig ~]$ ./cl > HI > PID > QUIT [stalica@trig ~]$ [stalica@trig ~]$ cc server.c - oserver [stalica@trig ~]$ ./server Greetings! Server pid: 24700 GOODBYE! [stalica@trig ~]$

Answer 1

Executable Code:

#include <signal.h>

#include <stdio.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/shm.h>

#include <sys/sem.h>

#include <errno.h>

void hand_contr(int);

int shm_id,pid=0;

char * pshmatt=NULL;

int main()

{

     signal(SIGINT,hand_contr);

     // Create the segment

     shm_id=shmget(100,200,IPC_CREAT|IPC_EXCL|0777);

     // Attach the shared memory

     pshmatt=shmat(shm_id,NULL,0);

     while(1)

     {

          // Compare if it is "HI"

          if(strcmp(pshmatt,"HI")==0)

          {

              printf("Greetings!\n");

              fflush(stdout);

              pshmatt[0]='\0';

          }

          // Compare if it is "PID"

          else if(strcmp(pshmatt,"PID")==0)

          {

              // Get the id of process

              pid=(int)getpid();

              printf("Server pid: %i\n",pid);

              fflush(stdout);

              pshmatt[0]='\0';

          }

          // Compare if it is "QUIT"

          else if(strcmp(pshmatt,"QUIT")==0)

          {

              shmctl(shm_id,IPC_RMID,NULL);

              shmdt(pshmatt);

              printf("GOODBYE!\n");

              exit(0);

          }

     }

}

void hand_contr(int XYZ)

{

     shmctl(shm_id,IPC_RMID,NULL);

     shmdt(pshmatt);

     printf("GOODBYE!\n");

     exit(0);

}