Lab 4 Develop a C program which demonstrates interprocess communication between a reader process and a writer process. Use mkfifo, open, read, write and close APIs in your program.

Objective:

The objective is to demonstrate interprocess communication between a writer process and a reader process using named pipes (FIFO) in a C program. The program should utilize mkfifo, open, read, write, and close APIs to establish communication between these two processes through a shared named pipe.

Overview:

1. Writer Process (writerProcess()):

   • Create a named pipe (FIFO) using mkfifo with a specified name (FIFO_NAME).
   • Open the FIFO in write-only mode (O_WRONLY) using open.
   • Write a message or data into the FIFO using write.
   • Close the FIFO using close after writing the data.

2. Reader Process (readerProcess()):

   • Open the same named pipe created by the writer in read-only mode (O_RDONLY) using open.
   • Read data from the FIFO using read.
   • Print the received data or message.
   • Close the FIFO using close after reading the data.

3. Main Function (main()):

   • Fork a child process using fork().
   • In the parent process (writer), call the writerProcess() function to write data to the named pipe.
   • In the child process (reader), call the readerProcess() function to read data from the named pipe.
   • Ensure proper handling of errors such as failed forks, pipe creation, and data reading/writing failures.

4. Execution:

   • Compile the C program using a C compiler (e.g., gcc).
   • Run the compiled program, which will create two processes – a writer and a reader – that communicate through the named pipe.

5. Cleanup:

• Ensure the named pipe is properly closed and unlinked after both processes finish communicating.
• Handle resource release to avoid memory leaks or unwanted resources.

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <string.h>

#define FIFO_NAME "myfifo"

void writerProcess() {

    int fd;

    char *message = "Hello, reader!";

    mkfifo(FIFO_NAME, 0666);

    fd = open(FIFO_NAME, O_WRONLY);

    write(fd, message, strlen(message) + 1);

    close(fd);

    printf("Data sent to reader successfully!\n");

}

void readerProcess() {

    int fd;

    char readMessage[100];

    fd = open(FIFO_NAME, O_RDONLY);

    read(fd, readMessage, sizeof(readMessage));

    printf("Received message: %s\n", readMessage);

    close(fd);

}

int main() {

    pid_t pid;

    // Create a child process

    pid = fork();

    if (pid < 0) {

        fprintf(stderr, "Fork failed!\n");

        return 1;

    } else if (pid > 0) {

        // Parent process (Writer)

        writerProcess();

    } else {

        // Child process (Reader)

        readerProcess();

    }

    return 0;

}

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OUTPUT

opera@opera-virtual-machine:~/Desktop$ gcc -o 1 1.c opera@opera-virtual-machine:~/Desktop$ ./1 Data sent to reader successfully! Received message: Hello, reader! opera@opera-virtual-machine:~/Desktop$