/*
 * $Id; stfufs-server.c $
 *
 * Author: Tomi Ollila -- too ät iki piste fi
 *
 *	Copyright (c) 2007 tomi Ollila
 *	    All rights reserved
 *
 * Created: Sun 26 Aug 2007 08:18:39 AM EEST too
 * Last modified: Wed Jan 30 21:43:02 EET 2008 too
 */

#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "util.h"
#include "pretocol.h"
#include "random.h"

#define STFUFS_SERVER 1
#include "stfufs.h"


static int srv_doaccept(unsigned char * buf, int port)
{
    int ssd;
    unsigned char msg[10];
    memcpy(msg, buf, 4);

    if (port == 0) {
	int i;
	for (i = -500; i < 500; i += 10) {
	    port = 14168 + i;
	    ssd = dobindandlisten(port, false);
	    if (ssd >= 0)
		break;
	}
	if (ssd < 0)
	    die("Can not find suitable port where to bind");
	/* else */
    }
    else
	ssd = dobindandlisten(port, true);

    /* currently a big hacky, let's see if ever changed. */
    memcpy(msg, buf, 4);
    msg[4] = port >> 8; msg[5] = port;
    msg[6] = 0; msg[7] = 0; msg[8] = 128; msg[9] = 0; /* 32768 */

    writehsmsg(1, msg, 10);

    return doaccept(buf, ssd);
}

static int srv_doconnect(unsigned char * buf, int port, char * host)
{
    char hostbuf[256];
    char c;

    if (host[0] == '\0')
    {
	char * ssh_client, *p;
	ssh_client = getenv("SSH_CLIENT");

	if (ssh_client == null)
	    die("SSH_CLIENT environment variable undefined");
	p = strchr(ssh_client, ' ');
	if (p == null)
	    die("Unexpected SSH_CLIENT environment variable value");
	if ((size_t)(p - ssh_client) >= sizeof hostbuf)
	    die("Remote host part of SSH_CLIENT environment variable too long");
	memcpy(hostbuf, ssh_client, p - ssh_client);
	hostbuf[p - ssh_client] = '\0';
	host = hostbuf;
    }
    writehsmsg(1, buf, 6);
    readwt(1, &c, 1, 10 * 1000);

    return doconnect(buf, host, port);
}


static int create_connection(void)
{
    unsigned char buf[260];
    int i;
    char c;

    sendident(1);
    randombytes(buf, 4);
    i = recvident(1, 10 * 1000);
    if (i < 0)
	readwt(1, &c, 1, 10 * 1000); /* consume ack */
    else c = i;

    d0(("%d %d", c, i));

    if (c != 0)
	die("Client did not accept our ident");

    write(1, "", 1); /* our ack, '\0'-byte */

    /* read directory to be mounted */
    i = readhsmsg(1, buf + 4);
    if (i > 1 && chdir(U2S(buf, char, [], *) + 4) < 0)
	die("Can not chdir to '%s': %s", buf, strerror(errno));
    write(1, "", 1); /* ack again */

    i = readhsmsg(1, buf + 4);
    if (i < 6)
	die("Too short message from client");

    if (i == 6)
	return srv_doaccept(buf, (buf[8] << 8) + buf[9]);
    else
	return srv_doconnect(buf, (buf[8] << 8) + buf[9],
			     U2S(buf, char, [], *) + 10);
}


int main(void)
{
    int fd, fd2;

    util_init("Server");
    fd2 = fd = create_connection();

    switch (fork())
    {
    case -1: die("fork failed");
    case 0:  break;
    default: return 0; /* parent */
    }

#if DEBUG
    fd2 = 2;
#endif

    /* child */
    dup2(fd, 0); dup2(fd, 1); dup2(fd2, 2); setsid();
    if (fd > 2) close(fd);
    stfufs_server();
    return 0;
}


/*
 * Local variables:
 * mode: c
 * c-file-style: "stroustrup"
 * tab-width: 8
 * End:
 */