server receives data from multiple client and store in seperate file at same time in linux using c by threading
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I have a server and two client.I want to store data in different file coming from clients at a same time.
Presently I'm storing data in a same file coming from two client.And after one client send the data, second starts to send.

I want that two client send the data at same time.
Anyone can help me...

server.c
 

    void *function1(void *ptr);
    typedef struct{
    int port_id;
    int thread_id;}conn_id;

    int main(int argc, char *argv[])
    {
    conn_id conn_id1[2];
    conn_id1[0].port_id=7350;
    conn_id1[0].thread_id=1;
    conn_id1[1].port_id=7351;
    conn_id1[1].thread_id=2;
    conn_id* conn_ptr;


    pthread_t thread[2];
    int index=0;
    for(index=0;index<2;index++){
    conn_ptr=&conn_id1[index];
    pthread_create(&thread[index],NULL,&function1,(void*)conn_ptr);}

    pthread_join(thread[0],NULL);
    pthread_join(thread[1],NULL);

    return 0;
    }
    void *function1( void *ptr)
    {
    //Declaring process variables.
    int server_sockfd, client_sockfd;
    int server_len ; 
    int rc ; 
    conn_id* conn_ptr;
    conn_ptr = (conn_id*)ptr;
    unsigned client_len;
    char revbuf[LENGTH];

    struct sockaddr_in server_address;
    struct sockaddr_in client_address;


    //Remove any old socket and create an unnamed socket for the server.
    server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htons(INADDR_ANY);
    server_address.sin_port = htons(conn_ptr->port_id);
    server_len = sizeof(server_address);
    bzero(&(server_address.sin_zero), 8);
    rc = bind(server_sockfd, (struct sockaddr *) &server_address, server_len);
    printf("RC from bind = %d\n", rc ) ; 

    //Create a connection queue and wait for clients
    rc = listen(server_sockfd, 5);
    printf("RC from listen = %d\n", rc ) ; 

    client_len = sizeof(client_address);
    client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_address,                &client_len);
    printf("after accept()... client = %s\n", inet_ntoa(client_address.sin_addr)) ; 

    while(1)
    {
    /*Receive File from Client */
		char* fr_name = "/home/server/Desktop/fr_client.dat";
		FILE *fr = fopen(fr_name, "a"); 

		if(fr == NULL)
			printf("File %s Cannot be opened file on server.\n", fr_name);
		else
		{
			bzero(revbuf, LENGTH); 
			int fr_block_sz = 0;
			while((fr_block_sz = recv(client_sockfd, revbuf, LENGTH, 0)) > 0) 
			{
			    int write_sz = fwrite(revbuf, sizeof(char), fr_block_sz, fr);
				if(write_sz < fr_block_sz)
			    {
			        error("File write failed on server.\n");
			    }
				bzero(revbuf, LENGTH);
				if (fr_block_sz == 0 || fr_block_sz != 512) 
				{
					break;
				}
			}
			if(fr_block_sz < 0)
		    {
		        if (errno == EAGAIN)
	        	{
	                printf("recv() timed out.\n");
	            }
	            else
	            {
	                fprintf(stderr, "recv() failed due to errno = %d\n", errno);
					exit(1);
	            }
        	}
			printf("Ok received from client!\n");
			fclose(fr); 
		}
 
    /* Call the Script */
		system("cd ; chmod +x script.sh ; ./script.sh");

		/* Send File to Client */
		
		    char* fs_name = "/home/server/Desktop/output.txt";
		    char sdbuf[LENGTH]; // Send buffer
		    printf("[Server] Sending %s to the Client...", fs_name);
		    FILE *fs = fopen(fs_name, "r");
		    if(fs == NULL)
		    {
		        fprintf(stderr, "ERROR: File %s not found on server. (errno =   %d)\n", fs_name, errno);
				exit(1);
		    }

		    bzero(sdbuf, LENGTH); 
		    int fs_block_sz; 
		    while((fs_block_sz = fread(sdbuf, sizeof(char), LENGTH, fs))>0)
		    {
		        if(send(client_sockfd, sdbuf, fs_block_sz, 0) < 0)
		        {
		            fprintf(stderr, "ERROR: Failed to send file %s. (errno =  %d)\n", fs_name, errno);
		            exit(1);
		        }
		        bzero(sdbuf, LENGTH);
		    }
		    printf("Ok sent to client!\n");
		 
		    close(client_sockfd);
		    printf("[Server] Connection with Client closed. Server will wait  now...\n");
		    while(waitpid(-1, NULL, WNOHANG) > 0);break;
		
	}
  
    }



   


