putty-source/rlogin.c

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include "putty.h"

#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif

static Socket s = NULL;

static void rlogin_size(void);

static int sb_opt, sb_len;
static char *sb_buf = NULL;
static int sb_size = 0;
#define SB_DELTA 1024

static void c_write (char *buf, int len) {
    from_backend(0, buf, len);
}

static int rlogin_receive (Socket skt, int urgent, char *data, int len) {
    if (urgent==3) {
        /* A socket error has occurred. */
        sk_close(s);
        s = NULL;
        connection_fatal(data);
        return 0;
    } else if (!len) {
	/* Connection has closed. */
	sk_close(s);
	s = NULL;
	return 0;
    }
    if (urgent == 2) {
        char c;
        
        c = *data++; len--;
        if (c == '\x80')
            rlogin_size();
        /*
         * We should flush everything (aka Telnet SYNCH) if we see
         * 0x02, and we should turn off and on _local_ flow control
         * on 0x10 and 0x20 respectively. I'm not convinced it's
         * worth it...
         */
    } else {
        /*
         * Main rlogin protocol. This is really simple: the first
         * byte is expected to be NULL and is ignored, and the rest
         * is printed.
         */
        static int firstbyte = 1;
        if (firstbyte) {
            if (data[0] == '\0') {
                data++;
                len--;
            }
            firstbyte = 0;
        }
        c_write(data, len);
    }
    return 1;
}

/*
 * Called to set up the rlogin connection.
 * 
 * Returns an error message, or NULL on success.
 *
 * Also places the canonical host name into `realhost'.
 */
static char *rlogin_init (char *host, int port, char **realhost) {
    SockAddr addr;
    char *err;

    /*
     * Try to find host.
     */
    addr = sk_namelookup(host, realhost);
    if ( (err = sk_addr_error(addr)) )
	return err;

    if (port < 0)
	port = 513;		       /* default rlogin port */

    /*
     * Open socket.
     */
    s = sk_new(addr, port, 1, 0, rlogin_receive);
    if ( (err = sk_socket_error(s)) )
	return err;

    sk_addr_free(addr);

    /*
     * Send local username, remote username, terminal/speed
     */

    {
        char z = 0;
        char *p;
        sk_write(s, &z, 1);
        sk_write(s, cfg.localusername, strlen(cfg.localusername));
        sk_write(s, &z, 1);
        sk_write(s, cfg.username, strlen(cfg.username));
        sk_write(s, &z, 1);
        sk_write(s, cfg.termtype, strlen(cfg.termtype));
        sk_write(s, "/", 1);
        for(p = cfg.termspeed; isdigit(*p); p++);
        sk_write(s, cfg.termspeed, p - cfg.termspeed);
        sk_write(s, &z, 1);
    }

    return NULL;
}

/*
 * Called to send data down the rlogin connection.
 */
static void rlogin_send (char *buf, int len) {

    if (s == NULL)
	return;

    sk_write(s, buf, len);
}

/*
 * Called to set the size of the window
 */
static void rlogin_size(void) {
    char b[12] = { '\xFF', '\xFF', 0x73, 0x73, 0, 0, 0, 0, 0, 0, 0, 0 };

    b[6] = cols >> 8; b[7] = cols & 0xFF;
    b[4] = rows >> 8; b[5] = rows & 0xFF;
    sk_write(s, b, 12);
    return;
}

/*
 * Send rlogin special codes.
 */
static void rlogin_special (Telnet_Special code) {
    /* Do nothing! */
    return;
}

static Socket rlogin_socket(void) { return s; }

static int rlogin_sendok(void) { return 1; }

static int rlogin_ldisc(int option) {
    return 0;
}

Backend rlogin_backend = {
    rlogin_init,
    rlogin_send,
    rlogin_size,
    rlogin_special,
    rlogin_socket,
    rlogin_sendok,
    rlogin_ldisc,
    1
};