client/server application fifo c program

Lab 9 – FIFO
Use FIFO to write a client side of program to work with the server side program server.c. This
client/server application performs a simple instant messaging between two users on the same
machine.
The server program is started first, waiting for client to connect. The user on the client side can
decide to quit the conversation by typing CTRL-C. When the client stops the conversation, only
the client program is terminated. The server program will wait for the next connection from
client. The server will terminate if CTRL-C is received from the user. When the server is
terminated, the client is also terminated.
The communication should be done using two FIFOs. They are created by the server in the
current directory.
Part of the server.c code is provided. Note that the dotted lines represent some missing code.
Sample run:

server.c
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/stat.h>
int main(int argc, char *argv[]) {
int fd1, fd2;
pid_t pid;
char ch;
char blanks[55]=” | “;
int writeblanks = 1;
unlink(“./fifo1”);
unlink(“./fifo2”);
if ( mkfifo(“./fifo1”, 0777) || mkfifo(“./fifo2”, 0777)) {
perror(“fifo”);
exit(1);
}
while (1) {
printf(“\nWaiting for connection…\n”);
fd1 = open(“./fifo1”, O_RDONLY);
fd2 = open(“./fifo2”, O_WRONLY);
printf(“\n my messages (server) received messages (client) \n”);
printf(“——————————————————————————-\n”);
if ( (pid = fork()) == -1 ) {
perror(“fork”);
exit(1);
}
if ( pid == 0 )
while (1) {

……..
}
while ( read(fd1, &ch, 1) == 1 ) {
if ( writeblanks == 1 )
write(1, blanks, sizeof(blanks));
write(1, &ch, 1);
……..
}
close(fd1);
close(fd2);
printf(“\nClient left.\n\n\n”);
kill(pid, SIGTERM);
}
}

Answer:

server.c

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/stat.h>
void stdinread(int fd);
int main(int argc, char *argv[]) {
    int fd1, fd2;
    pid_t pid;
    char ch;
    char blanks[55]="                         | ";
    int writeblanks = 1;
    unlink("./fifo1");
    unlink("./fifo2");
    if ( mkfifo("./fifo1", 0777) || mkfifo("./fifo2", 0777)) {
        perror("fifo");
        exit(1);
    }
    while (1) {
        printf("\nWaiting for connection...\n");
        fd1 = open("./fifo1", O_RDONLY);
        fd2 = open("./fifo2", O_WRONLY);
        printf("\n my messages (server) received messages (client) \n");
        printf("-------------------------------------------------------------------------------\n");
        if ( (pid = fork()) == -1 ) {
            perror("fork");
            exit(1);
        }
        if ( pid == 0 )
            while (1) {
                read(STDIN_FILENO, &ch, 1);
                if ( write(fd2, &ch, 1) == -1 )
                    exit(0);
			}
        while ( read(fd1, &ch, 1) == 1 ) {
            if ( writeblanks == 1 )
                write(1, blanks, sizeof(blanks));
            write(1, &ch, 1);
            if ( ch == '\n' )
                writeblanks = 1;

            else
                writeblanks = 0;
        }
        close(fd1);
        close(fd2);
        printf("\nClient left.\n\n\n");
        kill(pid, SIGTERM);
    }
}

client.c

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/stat.h>
void stdinread(int fd);
int main(int argc, char *argv[]) {
    int fd1, fd2;
    pid_t pid;
    char ch;
    char blanks[55]="                                       | ";
    int writeblanks = 1;


    printf("\nClient has connected\n");
    fd1 = open("./fifo1", O_WRONLY);
    fd2 = open("./fifo2", O_RDONLY);
    printf("\n my messages (client) received messages (server) \n");
    printf("-------------------------------------------------------------------------------\n");
        if ( (pid = fork()) == -1 ) {
            perror("fork");
            exit(1);
        }
        if ( pid == 0 )
        while (1) {
                read(STDIN_FILENO, &ch, 1);
                if ( write(fd1, &ch, 1) == -1 )
                    exit(0);
        }

        while ( read(fd2, &ch, 1) == 1 ) {
            if ( writeblanks == 1 )
                write(1, blanks, sizeof(blanks));
            write(1, &ch, 1);
            if (ch == '\n')
                writeblanks = 1;
            else
                writeblanks = 0;
        }

        close(fd1);
        close(fd2);
        printf("\nDisconnected.\n\n\n");
        kill(pid, SIGTERM);
}