使用C在服务器端读取从客户端发送的文本文件

我想从客户端发送一个文本文件,想在服务器端读取文本文件,并想在服务器终端屏幕上显示文本。我已经成功地为服务器和多个客户端编写了代码。我还从客户端向服务器端发送了一个文本文件。但现在我想知道如何修改文本文件并发送它,并在服务器端读取从客户端发送的文本文件。我的服务器和客户端代码如下:

服务器和客户端代码:

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <pthread.h>
#define filename "//home//myname//Documents//folder1//folder2//input.txt"

#define MAX_CLIENTS 5


//the thread function
void *new_connection_handler(void *);

int main(int argc , char *argv[])
{

    //client variables
    int sock;
    struct sockaddr_in server;
    char buffer[256], server_reply[2000];
    int len;

    //server variables
    int socket_desc , client_sock;
    struct sockaddr_in client;
    socklen_t c = sizeof(client);


    //check if the the command contain less than two arguments
    if(argc != 2)
    {
        printf("use either: %s <server/client>\n", argv[0]);
    }

    // If the command contains minumum 2 arguments
    else{


        // If argv is client then execute the client code
        if(strcmp("client",argv[1]) == 0)
        {
            /****************/// Client code here **********************************************************************
            //Create socket
            sock = socket(AF_INET , SOCK_STREAM , 0);
            if (sock == -1)
            {
                printf("Could not create socket");
            }
            puts("Socket created");

            server.sin_addr.s_addr = inet_addr("127.0.0.1");
            server.sin_family = AF_INET;
            server.sin_port = htons( 8888 );


            //Connect to remote server
            if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
            {
                perror("connect failed. Error");
                return 1;
            }

            puts("Connected\n");


            //keep communicating with server
            /* Time to send the file */

            /******************************************************/
            FILE *pf;
            int fsize;

            pf = fopen(filename, "rb");
            if (pf == NULL)
            {
                printf("File not found!\n");
                return 1;
            }
            else
            {
                printf("Found file %s\n", filename);

                fseek(pf, 0, SEEK_END);
                fsize = ftell(pf);
                rewind(pf);

                printf("File contains %ld bytes!\n", fsize);
                printf("Sending the file now\n");
            }

            while (1)
            {
                // Read data into buffer.  We may not have enough to fill up buffer, so we
                // store how many bytes were actually read in bytes_read.
                int bytes_read = fread(buffer, sizeof(buffer), 1, pf);
                if (bytes_read == 0) // We're done reading from the file
                    break;

                if (bytes_read < 0)
                {
                    error("ERROR reading from file\n");
                }

                while (bytes_read > 0)
                {
                    int bytes_written = write(sock, buffer, bytes_read);
                    if (bytes_written <= 0)
                    {
                        error("ERROR writing to socket\n");
                    }

                }
            }

            printf("Done Sending the File!\n");
            printf("Now Closing Connection.\n");

            /*********************************************************************************/

            close(sock);

        }

        /****************/// Server code here **********************************************************************
        // If argv is server then execute the server code
        if(strcmp("server", argv[1]) == 0 )
        {
            //Create socket
            socket_desc = socket(AF_INET , SOCK_STREAM , 0);
            if (socket_desc == -1)
            {
                printf("Could not create socket");
            }

            //Prepare the sockaddr_in structure
            server.sin_family = AF_INET;
            server.sin_addr.s_addr = INADDR_ANY;
            server.sin_port = htons( 8888 );
            bzero (&server.sin_zero, 8);

            //Bind
            if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
            {
                //print the error message
                perror("bind failed. Error");
                return 1;
            }

            //Listen
            listen(socket_desc , MAX_CLIENTS);

            //Accept and incoming connection
            printf("Waiting for incoming connections\n");

            c = sizeof(client);
            while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, &c)) )
            {
                printf("Connection accepted\n");
                pthread_t thread_id;

                if( pthread_create( &thread_id , NULL ,  new_connection_handler , (void*) (intptr_t)client_sock) < 0)
                {
                    perror("could not create thread");
                    return 1;
                }

                printf("Handler assigned\n");
            }


            if (client_sock < 0)
            {
                perror("accept failed");
                return 1;
            }
        } 
    }
    return 0;
}


void *new_connection_handler(void *socket_desc)
{
    //Get the socket descriptor
    int sock = (intptr_t)socket_desc;
    int read_size = 0;
    char client_message[2000];

    //PROBLEM **read the text file sent from client side and display the text on screen**
    while( (read_size = recv(sock , client_message , sizeof(client_message) , 0)) > 0 )
    printf("Read Text: %.*s", read_size, client_message);

if(read_size == 0)
{
    printf("Client disconnected\n");
    fflush(stdout);
}
else if(read_size == -1)
{
    perror("recv failed");
}


    return 0;
}