Sending large files over socket in c - c

Question

So this code works ok for small files of up to 20KB but when i try to send or receive larger files it stops reading at some point. Two functions for client and server, to send and receive files. I know it might have some leaks and stuff but I will fix that later. At first I want it to work properly. BUF_SIZE=512
// SENDING BYTES
void send_bytes(int connfd, int client_number, char **command_parts)
{
FILE *fp;
fp = fopen(command_parts[1], "r");
int i = 0;
// FINDING BYTE SIZE OF THE FILE
fseek(fp, 0, SEEK_END); /* PUTTING FILE POINTER TO THE END OF THE FILE */
int num_of_bytes = ftell(fp);
fseek(fp, 0, SEEK_SET); /* RESETTING FILE POINTER TO THE BEGINNING OF THE FILE */
char *sendbuff = malloc(num_of_bytes * sizeof(char));
memset(sendbuff, '\0', num_of_bytes);
// SENDING TOTAL BYTES TO SEND
while (write(connfd, itoa(num_of_bytes), 10) < 0)
{
}
printf("\nClient #%d --> Size of file sent: %d\n", client_number, num_of_bytes);
// IF BYTES MORE THAN 512 SENDING IT IN PARTS
if(num_of_bytes > BUF_SIZE)
{
int bytes_left_to_send = num_of_bytes;
char *tempbuff = calloc(BUF_SIZE, sizeof(char));
while(bytes_left_to_send > 0)
{
if(bytes_left_to_send >= BUF_SIZE)
{
// READING 512 BYTES AND PASSING IT TO TEMPBUFF
for (i = 0; i < BUF_SIZE; i++)
{
fread(&tempbuff[i], 1, 1, fp);
}
// SENDING BYTES
while (write(connfd, tempbuff, BUF_SIZE) < 0)
{
}
bytes_left_to_send = bytes_left_to_send - BUF_SIZE;
memset(tempbuff, '\0', BUF_SIZE);
}
else
{
// READING 512 BYTES AND PASSING IT TO TEMPBUFF
for (i = 0; i < bytes_left_to_send; i++)
{
fread(&tempbuff[i], 1, 1, fp);
}
// SENDING BYTES
while (write(connfd, tempbuff, bytes_left_to_send) < 0)
{
}
bytes_left_to_send = bytes_left_to_send - bytes_left_to_send;
memset(tempbuff, '\0', BUF_SIZE);
}
}
}
else
{
// READING EACH BYTE AND PASSING IT TO SENDBUFF
for (i = 0; i < num_of_bytes; i++)
{
fread(&sendbuff[i], 1, 1, fp);
}
// SENDING BYTES
while (write(connfd, sendbuff, num_of_bytes) < 0)
{
}
}
// FREEING MEMORY
fclose(fp);
free(sendbuff);
printf("\nClient #%d --> File sent\n", client_number);
}
// RECEIVING BYTES
void recv_bytes(int connfd, int client_number, char **command_parts)
{
int bytes_read = 0, bytes_read_in_total = 0, i = 0;
char *num_of_bytes = malloc(10 * sizeof(char));
char *recvbuff = NULL;
FILE *fp;
fp = fopen(command_parts[2], "w");
// RECEIVING BYTES TO RECEIVE
while (read(connfd, num_of_bytes, 10) < 0)
{
}
printf("\nClient #%d --> Size of file received: %d\n", client_number, atoi(num_of_bytes));
recvbuff = malloc(atoi(num_of_bytes) * sizeof(char)); /* ALLOCATING recvbuff WITH RECEIVED SIZE */
memset(recvbuff, '\0', atoi(num_of_bytes));
// IF BYTES MORE THAN 512 RECEIVING IT IN PARTS
if(atoi(num_of_bytes) > BUF_SIZE)
{
int bytes_left_to_read = atoi(num_of_bytes);
char *tempbuff = calloc(BUF_SIZE, sizeof(char));
while(bytes_left_to_read > 0)
{
if(bytes_left_to_read >= BUF_SIZE)
{
// READING BYTES
while (bytes_read = read(connfd, tempbuff, BUF_SIZE) < 0)
{
}
bytes_read = strlen(tempbuff);
// WRITING BYTES READ SO FAR TO THE FILE
for (i = 0; i < bytes_read; i++)
{
fwrite(&tempbuff[i], 1, 1, fp);
}
bytes_left_to_read = bytes_left_to_read - bytes_read;
memset(tempbuff, '\0', BUF_SIZE);
}
else
{
// READING BYTES
while (bytes_read = read(connfd, tempbuff, bytes_left_to_read) < 0)
{
}
bytes_read = strlen(tempbuff);
// WRITING BYTES READ SO FAR TO THE FILE
for (i = 0; i < bytes_read; i++)
{
fwrite(&tempbuff[i], 1, 1, fp);
}
bytes_left_to_read = bytes_left_to_read - bytes_read;
memset(tempbuff, '\0', BUF_SIZE);
}
}
}
else
{
// RECEIVING BYTES
while (bytes_read_in_total < atoi(num_of_bytes))
{
while (bytes_read = read(connfd, recvbuff, atoi(num_of_bytes)) < 0)
{
}
bytes_read = strlen(recvbuff);
bytes_read_in_total = bytes_read_in_total + bytes_read;
// WRITING BYTES READ SO FAR TO THE FILE
for (i = 0; i < bytes_read; i++)
{
fwrite(&recvbuff[i], 1, 1, fp);
}
memset(recvbuff, '\0', atoi(num_of_bytes));
}
}
free(recvbuff);
fclose(fp);
printf("\nClient #%d --> File received\n", client_number);
}