client.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>

#define LENGTH 2048

// Global variables

//sig_atomic_t = this type guarantees that read and write use one command
volatile sig_atomic_t flag = 0;
int sockfd = 0;
char name[32];

void str_overwrite_stdout()
{
  printf("%s", "> ");
  fflush(stdout);
}

void str_trim_lf (char* arr, int length)
{
  int i;
  for (i = 0; i < length; i++)
  {
      if (arr[i] == '\n')
      {
          arr[i] = '\0';
          break;
      }
  }
}

void catch_ctrl_c_and_exit(int sig)
{
    flag = 1;
}

void send_msg_handler()
{
    char message[LENGTH] = {};
    char buffer[LENGTH + 32] = {};

    while(1)
    {
        str_overwrite_stdout();
        fgets(message, LENGTH, stdin);
        str_trim_lf(message, LENGTH);

        //exiting from program
        if (strcmp(message, "exit") == 0)
        {
			break;
        }
        
        else
        {
            sprintf(buffer, "\033[37;1;4m%s\033[0m: %s\n", name, message);
            send(sockfd, buffer, strlen(buffer), 0);
        }

		bzero(message, LENGTH);
        bzero(buffer, LENGTH + 32);
    }
  catch_ctrl_c_and_exit(2);
}

void recv_msg_handler()
{
	char message[LENGTH] = {};
    
    while (1)
    {
        int receive = recv(sockfd, message, LENGTH, 0);
      
        if (receive > 0)
        {
            printf("%s", message);
            str_overwrite_stdout();
        }
        
    else if (receive == 0)
    {
			break;
    }
        
    else
    {
			// -1
    }
		memset(message, 0, sizeof(message));
   }
}

int main(int argc, char **argv)
{
	if(argc != 2)
    {
		printf(" %s <port> in use \n", argv[0]);
		return EXIT_FAILURE;
	}

	char *ip = "127.0.0.1";
	int port = atoi(argv[1]);

	signal(SIGINT, catch_ctrl_c_and_exit);

	printf("Please enter your name which will show on program: ");
    fgets(name, 32, stdin);
    str_trim_lf(name, strlen(name));


	if (strlen(name) > 32 || strlen(name) < 2)
    {
      printf("Name variable must be more than 2 characters and less than 30. \n");
		  return EXIT_FAILURE;
	  }

	struct sockaddr_in server_addr;

	// Socket settings
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr(ip);
    server_addr.sin_port = htons(port);


  // Connecting into server
  int err = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    
  if (err == -1)
  {
		printf("ERROR: connection error \n");
		return EXIT_FAILURE;
	}

	// Sending the name of user
	send(sockfd, name, 32, 0);

  printf("=== SAY HELLO TO THE CHAT APP IN BASH === \n");

	pthread_t send_msg_thread;
    
  if(pthread_create(&send_msg_thread, NULL, (void *) send_msg_handler, NULL) != 0)
  {
      printf("ERROR: pthread\n");
      
      return EXIT_FAILURE;
  }

	pthread_t recv_msg_thread;
    
  if(pthread_create(&recv_msg_thread, NULL, (void *) recv_msg_handler, NULL) != 0)
  {
		printf("ERROR: pthread\n");
		return EXIT_FAILURE;
  }

	while (1)
    {
		if(flag)
        {
			printf("\n BYE. STAY METAL \n");
			break;
        }
	}

	close(sockfd);

	return EXIT_SUCCESS;
}