send file from client to server using socket in c on linux - c

Question

I'm very new in C language and linux and English is not my mother language. Sorry for those in advance.
What I need to is to send .avi or .mp4 files from a client to a server using socket on Linux. I can send the file from client to server but the video on the server is not working.
When I try to play the video, I keep getting an error like "could not determine the type of stream". When I checked the original video on client, the size was 5,787,969 bytes but the size of the video transferred on server is 5,786,954 bytes. I think this is because of data loss when I transfer the file.
How do I fix this?
This is my code below:
Server
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> // read, write
#include <arpa/inet.h>
#include <sys/types.h> // socket, bind, accept, open
#include <sys/socket.h> // socket, bind, listen, accept
#include <sys/stat.h> // open
#include <fcntl.h> // open
#include <errno.h>
#define PORT 5500
#define MAXBUF 1024
int main() {
int server_sockfd;
int client_sockfd;
int des_fd; // file num
struct sockaddr_in serveraddr, clientaddr;
int client_len, read_len, file_read_len; // length
char buf[MAXBUF];
int check_bind;
client_len = sizeof(clientaddr);
/* socket() */
server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(server_sockfd == -1) {
perror("socket error : ");
exit(0);
}
/* bind() */
bzero(&serveraddr, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
serveraddr.sin_port = htons(PORT);
if(bind(server_sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) > 0) {
perror("bind error : ");
exit(0);
}
/* listen */
if(listen(server_sockfd, 5) != 0) {
perror("listen error : ");
}
while(1) {
char file_name[MAXBUF]; // local val
memset(buf, 0x00, MAXBUF);
/* accept() */
client_sockfd = accept(server_sockfd, (struct sockaddr *)&clientaddr, &client_len);
printf("New Client Connect : %s\n", inet_ntoa(clientaddr.sin_addr));
/* file name */
read_len = read(client_sockfd, buf, MAXBUF);
if(read_len > 0) {
strcpy(file_name, buf);
printf("%s > %s\n", inet_ntoa(clientaddr.sin_addr), file_name);
} else {
close(client_sockfd);
break;
}
/* create file */
des_fd = open(file_name, O_WRONLY | O_CREAT | O_EXCL, 0700);
if(!des_fd) {
perror("file open error : ");
break;
}
/* file save */
while(1) {
memset(buf, 0x00, MAXBUF);
file_read_len = read(client_sockfd, buf, MAXBUF);
write(des_fd, buf, file_read_len);
if(file_read_len == EOF | file_read_len == 0) {
printf("finish file\n");
break;
}
}
close(client_sockfd);
close(des_fd);
}
close(server_sockfd);
return 0;
}
Client
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#define PORT 5500
#define IP "127.0.0.1"
#define MAXBUF 1024
int main() {
struct sockaddr_in serv_addr;
int s;
int sourse_fd;
char buf[MAXBUF];
int file_name_len, read_len;
/* socket() */
s = socket(AF_INET, SOCK_STREAM, 0);
if(s == -1) {
return 1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = inet_addr(IP);
serv_addr.sin_port = htons(PORT);
if(connect(s, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1) {
perror("connect : ");
printf("fail to connect.\n");
close(s);
return 1;
}
memset(buf, 0x00, MAXBUF);
printf("write file name to send to the server: ");
scanf("%s", buf);
printf(" > %s\n", buf);
file_name_len = strlen(buf);
send(s, buf, file_name_len, 0);
sourse_fd = open(buf, O_RDONLY);
if(!sourse_fd) {
perror("Error : ");
return 1;
}
while(1) {
memset(buf, 0x00, MAXBUF);
read_len = read(sourse_fd, buf, MAXBUF);
send(s, buf, read_len, 0);
if(read_len == 0) {
break;
}
}
return 0;
}

Answer 1

In Server
Look at your "file save" while loop in Server:
/* file save */
while(1) {
memset(buf, 0x00, MAXBUF);
file_read_len = read(client_sockfd, buf, MAXBUF);
write(des_fd, buf, file_read_len);
if(file_read_len == EOF | file_read_len == 0) {
printf("finish file\n");
break;
}
}
Instead of file_read_len == EOF | file_read_len == 0 you should use only file_read_len == 0.
Still in Server, inside open() function that creates the file, I also recommend to change 0700 to S_IRWXU & (~S_IXUSR) __but_it_is_not_mandatory__. See user#host:~$ man 2 open for more details.
In Client
In Client you only need to add "+ 1" in strlen(buf):
file_name_len = strlen(buf) + 1;
That is because a string needs to end with a null byte. And strlen() returns the length of string minus the null byte at the end :-)
I also recommend you to use argc and argv to get arguments, look:
#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
int
main (int argc, char **argv) {
int how_many_files = argc - 1; /* '- 1' cause first arg is program name
*/
int fd; /* file descriptor */
int i; /* a counter */
char buffer[10]; /* a buffer */
for (i = 0; i < how_many_files; i++) {
fd = open(argv[i + 1], O_RDONLY);
if (fd == -1)
continue;
read(fd, buffer, 10);
buffer[9] = '\0'; /* last byte of buffer needs to be null char*/
printf("First 10 Bytes of the file is: %s\n",
buffer);
close(fd);
}
return 0;
}