Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
/* This page contains the client program. The following one contains the
* server program. Once the server has been compiled and started, clients
* anywhere on the Internet can send commands (file names) to the server.
* The server responds by opening and returning the entire file requested.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#define SERVER_PORT 12345 /* arbitrary, but client and server must agree */
#define BUF_SIZE 4096 /* block transfer size */
int main(int argc, char **argv)
{
int c, s, bytes;
char buf[BUF_SIZE]; /* buffer for incoming file */
char obuf[BUF_SIZE]; /* buffer for outgoing file */
struct hostent *h; /* info about server */
struct sockaddr_in channel; /* holds IP address */
if (argc != 3) fatal("Usage: client server-name file-name");
h = gethostbyname(argv[1]); /* look up host's IP address */
if (!h) fatal("gethostbyname failed");
s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s < 0) fatal("socket");
memset(&channel, 0, sizeof(channel));
channel.sin_family= AF_INET;
memcpy(&channel.sin_addr.s_addr, h->h_addr, h->h_length);
channel.sin_port= htons(SERVER_PORT);
c = connect(s, (struct sockaddr *) &channel, sizeof(channel));
if (c < 0) fatal("connect failed");
/* Connection is now established. Send file name including 0 byte at end. */
write(s, argv[2], strlen(argv[2])+1);
/* Go get the file and write it to a local file
(new or existing, overwritten) of the same name. */
FILE *dst;
sprintf(obuf, "out/%s", argv[2]);
dst = fopen(obuf, "w+");
while (1) {
bytes = read(s, buf, BUF_SIZE); /* read from socket */
if (bytes <= 0) exit(0); /* check for end of file */
fwrite(buf, sizeof(char), bytes, dst);
// write(1, buf, bytes); /* write to standard output */
}
fclose(dst);
}
fatal(char *string)
{
printf("%s\n", string);
exit(1);
}
#include <sys/types.h>
#include <sys/fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define SERVER_PORT 12345 /* arbitrary, but client and server must agree */
#define BUF_SIZE 4096 /* block transfer size */
#define QUEUE_SIZE 10
int main(int argc, char *argv[])
{
int s, b, l, fd, sa, bytes, on = 1;
char buf[BUF_SIZE]; /* buffer for outgoing file */
struct sockaddr_in channel; /* hold's IP address */
/* Build address structure to bind to socket. */
memset(&channel, 0, sizeof(channel)); /* zero channel */
channel.sin_family = AF_INET;
channel.sin_addr.s_addr = htonl(INADDR_ANY);
channel.sin_port = htons(SERVER_PORT);
/* Passive open. Wait for connection. */
s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); /* create socket */
if (s < 0) fatal("socket failed");
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof(on));
b = bind(s, (struct sockaddr *) &channel, sizeof(channel));
if (b < 0) fatal("bind failed");
l = listen(s, QUEUE_SIZE); /* specify queue size */
if (l < 0) fatal("listen failed");
/* Socket is now set up and bound. Wait for connection and process it. */
while (1) {
sa = accept(s, 0, 0); /* block for connection request */
if (sa < 0) fatal("accept failed");
read(sa, buf, BUF_SIZE); /* read file name from socket */
/* Get and return the file. */
fd = open(buf, O_RDONLY); /* open the file to be sent back */
if (fd < 0) fatal("open failed");
while (1) {
bytes = read(fd, buf, BUF_SIZE); /* read from file */
if (bytes <= 0) break; /* check for end of file */
write(sa, buf, bytes); /* write bytes to socket */
}
close(fd); /* close file */
close(sa); /* close connection */
}
}
fatal(char *string)
{
printf("%s", string);
exit(1);
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment