readwrite Server

#include <stdio.h>
#include <string.h>    //strlen
#include <sys/socket.h>
#include <arpa/inet.h> //inet_addr
#include <unistd.h>    //write
#include <fcntl.h>     //for open
#include <unistd.h>    //for close
#include <stdbool.h>
#include <stdlib.h>

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT   27015

char* List(FILE *fp) {
    char data[DEFAULT_BUFLEN];
    char *lista = NULL;
    long filesize = ftell(fp);
    lista = malloc(filesize);
    while(fscanf(fp, "%s", data) == 1) {
        strcat(lista, data);
        strcat(lista, "\n");
    }

    return lista;
}

int WriteList(FILE *fp, char *data) {
    int flag = 0;
    char ime[DEFAULT_BUFLEN];
    while(fscanf(fp, "%s", ime) != EOF) {
        if(strcmp(ime, data) == 0) {
            flag = 1;
            printf("Datoteka sa istim imenom vec postoji\n");
            break;
        }
    }
    if(flag == 0) {
        fprintf(fp, "%s\n", data);
        printf("Uspesno upisana datoteka u listu\n");
    }
    return flag;
}

int ReadList(FILE *fp, char *data) {
    int flag = 0;
    char ime[DEFAULT_BUFLEN];
    while(fscanf(fp, "%s", ime) != EOF) {
        if(strcmp(ime, data) == 0) {
            printf("Datoteka postoji, OK\n");
            break;
        }
        flag = 1;
    }
    return flag;
}

//////////////////////////////////////// READ
bool readdata(int sock, void *buf, int buflen)
{
    unsigned char *pbuf = (unsigned char *) buf;

    while (buflen > 0)
    {
        int num = recv(sock, pbuf, buflen, 0);

        pbuf += num;
        buflen -= num;
    }

    return true;
}

bool readlong(int sock, long *value)
{
    if (!readdata(sock, value, sizeof(value)))
        return false;
    *value = ntohl(*value);
    return true;
}

bool readfile(int sock, FILE *f)
{
    long filesize;
    if (!readlong(sock, &filesize))
        return false;
    if (filesize > 0)
    {
        char buffer[1024];
        do
        {
            int num;
            if(filesize > sizeof(buffer))
                num = sizeof(buffer);
            else
                num = filesize;

            if (!readdata(sock, buffer, num))
                return false;
            int offset = 0;
            do
            {
                size_t written = fwrite(&buffer[offset], 1, num-offset, f);
                if (written < 1)
                    return false;
                offset += written;
            }
            while (offset < num);
            filesize -= num;
        }
        while (filesize > 0);
    }
    return true;
}
//////////////////////////////////////// SEND
bool senddata(int sock, void *buf, int buflen)
{
    unsigned char *pbuf = (unsigned char *) buf;

    while (buflen > 0)
    {
        int num = send(sock, pbuf, buflen, 0);

        pbuf += num;
        buflen -= num;
    }

    return true;
}

bool sendlong(int sock, long value)
{
    value = htonl(value);
    return senddata(sock, &value, sizeof(value));
}

bool sendfile(int sock, FILE *f)
{
    fseek(f, 0, SEEK_END);
    long filesize = ftell(f);
    rewind(f);
    if (filesize == EOF)
        return false;
    if(!sendlong(sock, filesize))
        return false;
    if (filesize > 0)
    {
        char buffer[1024];
        do
        {
            size_t num;
            if(filesize > sizeof(buffer))
                num = sizeof(buffer);
            else
                num = filesize;
            num = fread(buffer, 1, num, f);
            if (num < 1)
                return false;
            if (!senddata(sock, buffer, num))
                return false;
            filesize -= num;
        }
        while (filesize > 0);
    }
    return true;
}


int main(int argc , char *argv[])
{
    int socket_desc , client_sock, c , read_size;
    struct sockaddr_in server , client;
    char client_message[DEFAULT_BUFLEN];

    //Create socket
    socket_desc = socket(AF_INET , SOCK_STREAM , 0);
    if (socket_desc == -1)
    {
        printf("Server: Could not create socket");
    }
    puts("Server: Socket created");

    //Prepare the sockaddr_in structure
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_family = AF_INET;
    server.sin_port = htons(DEFAULT_PORT);

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

    //Listen
    listen(socket_desc , 3);

    //Accept and incoming connection
    puts("Server: Waiting for incoming connections...");
    c = sizeof(struct sockaddr_in);

    //accept connection from an incoming client
    client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c);

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

    puts("Server: Connection accepted");



    char ime[DEFAULT_BUFLEN];
    char ime2[DEFAULT_BUFLEN] = "../";
    char *lista;
    int opcija;

    recv(client_sock, &opcija, sizeof(opcija), 0);

    int flagwrite = -1;
    int flagread = -1;
    FILE *fplist, *fp;

    if(opcija == 1) {
        printf("Opcija: %d\n", opcija);
        read_size = recv(client_sock, ime, DEFAULT_BUFLEN, 0);
        ime[read_size] = '\0';
        printf("Ime: %s\n", ime);
        strcat(ime2, ime);

        fplist = fopen("lista.txt", "r+");
        flagwrite = WriteList(fplist, ime);
        fclose(fplist);
        send(client_sock, &flagwrite, sizeof(flagwrite), 0);
        if(flagwrite == 0) {

            fp = fopen(ime2, "wb");
            if(fp != NULL) {
                readfile(client_sock, fp);
                fclose(fp);
            }
        }
    }
    else if(opcija == 2) {
        printf("Opcija: %d\n", opcija);
        read_size = recv(client_sock, ime, DEFAULT_BUFLEN, 0);
        ime[read_size] = '\0';
        printf("Ime: %s\n", ime);
        strcat(ime2, ime);

        fplist = fopen("lista.txt", "r");
        flagread = ReadList(fplist, ime);
        fclose(fplist);
        send(client_sock, &flagread, sizeof(flagread), 0);
        if(flagread == 0) {

            fp = fopen(ime2, "rb");
            sendfile(client_sock, fp);
            fclose(fp);
        }
    }
    else if(opcija == 3) {
        fplist = fopen("lista.txt", "r");
        lista = List(fplist);
        send(client_sock, lista, strlen(lista), 0);
        fclose(fplist);
    }

    close(socket_desc);
    close(client_sock);

    return 0;
}