c send and receive file
Try this code:
Client side:
/* Client code */
/* TODO : Modify to meet your need */
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netinet/in.h>
#define PORT_NUMBER 5000
#define SERVER_ADDRESS "192.168.1.7"
#define FILENAME "/home/toc/foo.c"
int main(int argc, char **argv)
{
int client_socket;
ssize_t len;
struct sockaddr_in remote_addr;
char buffer[BUFSIZ];
int file_size;
FILE *received_file;
int remain_data = 0;
/* Zeroing remote_addr struct */
memset(&remote_addr, 0, sizeof(remote_addr));
/* Construct remote_addr struct */
remote_addr.sin_family = AF_INET;
inet_pton(AF_INET, SERVER_ADDRESS, &(remote_addr.sin_addr));
remote_addr.sin_port = htons(PORT_NUMBER);
/* Create client socket */
client_socket = socket(AF_INET, SOCK_STREAM, 0);
if (client_socket == -1)
{
fprintf(stderr, "Error creating socket --> %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
/* Connect to the server */
if (connect(client_socket, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
{
fprintf(stderr, "Error on connect --> %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
/* Receiving file size */
recv(client_socket, buffer, BUFSIZ, 0);
file_size = atoi(buffer);
//fprintf(stdout, "\nFile size : %d\n", file_size);
received_file = fopen(FILENAME, "w");
if (received_file == NULL)
{
fprintf(stderr, "Failed to open file foo --> %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
remain_data = file_size;
while ((remain_data > 0) && ((len = recv(client_socket, buffer, BUFSIZ, 0)) > 0))
{
fwrite(buffer, sizeof(char), len, received_file);
remain_data -= len;
fprintf(stdout, "Receive %d bytes and we hope :- %d bytes\n", len, remain_data);
}
fclose(received_file);
close(client_socket);
return 0;
}
Server side:
/* Server code */
/* TODO : Modify to meet your need */
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/sendfile.h>
#define PORT_NUMBER 5000
#define SERVER_ADDRESS "192.168.1.7"
#define FILE_TO_SEND "hello.c"
int main(int argc, char **argv)
{
int server_socket;
int peer_socket;
socklen_t sock_len;
ssize_t len;
struct sockaddr_in server_addr;
struct sockaddr_in peer_addr;
int fd;
int sent_bytes = 0;
char file_size[256];
struct stat file_stat;
int offset;
int remain_data;
/* Create server socket */
server_socket = socket(AF_INET, SOCK_STREAM, 0);
if (server_socket == -1)
{
fprintf(stderr, "Error creating socket --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
/* Zeroing server_addr struct */
memset(&server_addr, 0, sizeof(server_addr));
/* Construct server_addr struct */
server_addr.sin_family = AF_INET;
inet_pton(AF_INET, SERVER_ADDRESS, &(server_addr.sin_addr));
server_addr.sin_port = htons(PORT_NUMBER);
/* Bind */
if ((bind(server_socket, (struct sockaddr *)&server_addr, sizeof(struct sockaddr))) == -1)
{
fprintf(stderr, "Error on bind --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
/* Listening to incoming connections */
if ((listen(server_socket, 5)) == -1)
{
fprintf(stderr, "Error on listen --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
fd = open(FILE_TO_SEND, O_RDONLY);
if (fd == -1)
{
fprintf(stderr, "Error opening file --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
/* Get file stats */
if (fstat(fd, &file_stat) < 0)
{
fprintf(stderr, "Error fstat --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
fprintf(stdout, "File Size: \n%d bytes\n", file_stat.st_size);
sock_len = sizeof(struct sockaddr_in);
/* Accepting incoming peers */
peer_socket = accept(server_socket, (struct sockaddr *)&peer_addr, &sock_len);
if (peer_socket == -1)
{
fprintf(stderr, "Error on accept --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
fprintf(stdout, "Accept peer --> %s\n", inet_ntoa(peer_addr.sin_addr));
sprintf(file_size, "%d", file_stat.st_size);
/* Sending file size */
len = send(peer_socket, file_size, sizeof(file_size), 0);
if (len < 0)
{
fprintf(stderr, "Error on sending greetings --> %s", strerror(errno));
exit(EXIT_FAILURE);
}
fprintf(stdout, "Server sent %d bytes for the size\n", len);
offset = 0;
remain_data = file_stat.st_size;
/* Sending file data */
while (((sent_bytes = sendfile(peer_socket, fd, &offset, BUFSIZ)) > 0) && (remain_data > 0))
{
fprintf(stdout, "1. Server sent %d bytes from file's data, offset is now : %d and remaining data = %d\n", sent_bytes, offset, remain_data);
remain_data -= sent_bytes;
fprintf(stdout, "2. Server sent %d bytes from file's data, offset is now : %d and remaining data = %d\n", sent_bytes, offset, remain_data);
}
close(peer_socket);
close(server_socket);
return 0;
}
EDIT : Adding explanation from the man about the offset
The man page of send file said:
If offset is not NULL, then it points to a variable holding the file offset from which sendfile() will start reading data from in_fd.
When sendfile() returns, this variable will be set to the offset of the byte following the last byte that was read.