#include <poll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>

void
poll_wait(int fd, int events)
{
    int n;
    struct pollfd ufds[1];
    memset((char *) &ufds, 0, sizeof(ufds));

    ufds[0].fd = fd;
    ufds[0].events = events;

    n = poll(ufds, 1, -1);
    if (n < 0) {
	perror("poll()");
	exit(1);
    }
}

int
main(int argc, char **argv)
{
    int i, s, s2, err;
    int h1,h2,h3,h4,p1,p2;
    size_t sz;
    struct sockaddr_in addr;
    struct in_addr inaddr;
    char buf[8192], junk[8192];

    /* clear out address structures */
    memset((char *) &addr, 0, sizeof(addr));

    /* Get the destination IP address */
    inet_aton("127.0.0.1", &inaddr);

    /* Set up the local address to which we will connect */
    addr.sin_family = AF_INET;
    addr.sin_addr = inaddr;
    addr.sin_port = htons(21);

    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s == -1) {
	perror("socket()");
	exit(1);
    }
    /* Connect to the destination port */
    if (connect(s, (struct sockaddr *) &addr, sizeof addr)) {
	perror("connect()");
	exit(1);
    }

    printf("Connected!\n");
    printf("Sending USER ftp, PASS nobody@\n");

    /* Log in */
    if (write(s,"USER ftp\r\n"
		"PASS nobody@\r\n", 10+14) != 10+14) {
	perror("write login:");
	exit(1);
    }

    /* Wait for the login to succeed */
    sleep(1);
    do {
	sz = read(s,buf,8192);
	if (sz < 0) {
	    perror("read login:");
	    exit(1);
	}
	printf("Got %d bytes\n", sz);
	if (sz >= 0) {
	    buf[sz]='\0';
	    printf("%s", buf);
	}
    } while (sz > 0 && !strstr(buf,"230 "));

    /* Ok. here we should have been logged in (230 reply)
     * no actual check here as I am lazy and this is not
     * production code ;-)
     */

    /* Now get the local endpoint. The data channel must be
     * bound to the same address as the control channel
     */
    sz = sizeof addr;
    if (getsockname(s, (struct sockaddr *) &addr, &sz)) {
	perror("getsockname()");
	exit(1);
    }

    printf("Creating data socket\n");

    /* Set up our data channel where the actual test occurs */
    s2 = socket(AF_INET, SOCK_STREAM, 0);
    if (s2 == -1) {
	perror("socket()");
	exit(1);
    }

    /* Bind it to the local endpoint IP address */
    addr.sin_port = 0;
    if (bind(s2, (struct sockaddr *) &addr, sizeof(addr))) {
	perror("bind()");
	exit(1);
    }

    /* Make the socket non-blocking */
    fcntl(s2, F_SETFL, fcntl(s, F_GETFL, 0) | O_NONBLOCK);

    printf("Sending PASV\n");

    /* Ask the FTP server for a passive connection */
    if (write(s, "PASV\r\n", 6) != 6) {
	perror("write pasv:");
	exit(1);
    }
    sleep(1);
    sz=read(s, buf, 8192);
    if (sz < 0) {
	perror("read pasv:");
	exit(1);
    }
    buf[sz]=0;
    printf("%s",buf);

    /* Decode the server address */
    sz = sscanf(buf, "%d%[^0123456789]%d,%d,%d,%d,%d,%d",
	    &i, junk, &h1, &h2, &h3, &h4, &p1, &p2);
    if (sz != 8 || i != 227) {
	fprintf(stderr, "Failed to parse PASV reply\n");
	exit(1);
    }
    sprintf(junk,"%d.%d.%d.%d",h1,h2,h3,h4);
    inet_aton(junk, &addr.sin_addr);
    addr.sin_port = htons((p1<<8)+p2);

    /* Connect to the destination port */
    printf("Connecting to %s:%d\n",
	inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
    if (connect(s2, (struct sockaddr *) &addr, sizeof addr) &&
	errno != EINPROGRESS) {
	perror("connect()");
	exit(1);
    }
    /* Wait for the connection to complete */
    poll_wait(s2, POLLOUT | POLLERR);

    sz = sizeof(err);
    if (getsockopt(s2, SOL_SOCKET, SO_ERROR, &err, &sz)) {
	perror("getsockopt( SOL_SOCKET SO_ERROR )");
	exit(1);
    }
    if (err) {
	errno = err;
	perror("non-blocking connect()");
	exit(1);
    }
    sz = sizeof addr;
    if (getsockname(s2, (struct sockaddr *) &addr, &sz)) {
	perror("getsockname()");
	exit(1);
    }
    printf("Connected. Local endpoint is %s:%d\n",
	inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));

    if (write(s,"LIST\r\n", 6) != 6) {
	perror("write command:");
	exit(1);
    }
    poll_wait(s, POLLERR | POLLIN);
    sz=read(s, buf, 8192);
    if (sz < 0) {
	perror("read pasv:");
	exit(1);
    }
    buf[sz]=0;
    printf("%s",buf);

    do {
	printf("Waiting for data..\n");
	poll_wait(s2, POLLERR | POLLIN);
	printf("Reading data\n");

	i = read(s2, &buf, sizeof(buf) - 1);
	if (i == 0) {
	    printf("read() returned 0 bytes.. is this really true?\n");
	    i = read(s2, &buf, sizeof(buf) - 1);
	    if (i != 0)
		printf("nope, it should have returned %d\n", i);
	    else
		printf("yep, probably so\n");
	}
	if (i < 0) {
	    perror("read()");
	    if (errno != EAGAIN)
		exit(1);
	} else {
	    buf[i] = 0;
	    printf("Got %d bytes ----------\n%s==========================\n", i, buf);
	}
    } while (i != 0);

    /* We are done */
    printf("DONE!\n");
    close(s2);
    close(s);
    return 0;
}