git.distorted.org.uk Git - u/mdw/putty/blob - rlogin.c

   1 /*
   2  * Rlogin backend.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <limits.h>
   8 #include <ctype.h>
   9
  10 #include "putty.h"
  11
  12 #ifndef FALSE
  13 #define FALSE 0
  14 #endif
  15 #ifndef TRUE
  16 #define TRUE 1
  17 #endif
  18
  19 #define RLOGIN_MAX_BACKLOG 4096
  20
  21 typedef struct rlogin_tag {
  22     const struct plug_function_table *fn;
  23     /* the above field _must_ be first in the structure */
  24
  25     Socket s;
  26     int closed_on_socket_error;
  27     int bufsize;
  28     int firstbyte;
  29     int cansize;
  30     int term_width, term_height;
  31     void *frontend;
  32
  33     Conf *conf;
  34
  35     /* In case we need to read a username from the terminal before starting */
  36     prompts_t *prompt;
  37 } *Rlogin;
  38
  39 static void rlogin_size(void *handle, int width, int height);
  40
  41 static void c_write(Rlogin rlogin, char *buf, int len)
  42 {
  43     int backlog = from_backend(rlogin->frontend, 0, buf, len);
  44     sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
  45 }
  46
  47 static void rlogin_log(Plug plug, int type, SockAddr addr, int port,
  48                        const char *error_msg, int error_code)
  49 {
  50     Rlogin rlogin = (Rlogin) plug;
  51     char addrbuf[256], *msg;
  52
  53     sk_getaddr(addr, addrbuf, lenof(addrbuf));
  54
  55     if (type == 0)
  56         msg = dupprintf("Connecting to %s port %d", addrbuf, port);
  57     else
  58         msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
  59
  60     logevent(rlogin->frontend, msg);
  61     sfree(msg);
  62 }
  63
  64 static int rlogin_closing(Plug plug, const char *error_msg, int error_code,
  65                           int calling_back)
  66 {
  67     Rlogin rlogin = (Rlogin) plug;
  68
  69     /*
  70      * We don't implement independent EOF in each direction for Telnet
  71      * connections; as soon as we get word that the remote side has
  72      * sent us EOF, we wind up the whole connection.
  73      */
  74
  75     if (rlogin->s) {
  76         sk_close(rlogin->s);
  77         rlogin->s = NULL;
  78         if (error_msg)
  79             rlogin->closed_on_socket_error = TRUE;
  80         notify_remote_exit(rlogin->frontend);
  81     }
  82     if (error_msg) {
  83         /* A socket error has occurred. */
  84         logevent(rlogin->frontend, error_msg);
  85         connection_fatal(rlogin->frontend, "%s", error_msg);
  86     }                                  /* Otherwise, the remote side closed the connection normally. */
  87     return 0;
  88 }
  89
  90 static int rlogin_receive(Plug plug, int urgent, char *data, int len)
  91 {
  92     Rlogin rlogin = (Rlogin) plug;
  93     if (urgent == 2) {
  94         char c;
  95
  96         c = *data++;
  97         len--;
  98         if (c == '\x80') {
  99             rlogin->cansize = 1;
 100             rlogin_size(rlogin, rlogin->term_width, rlogin->term_height);
 101         }
 102         /*
 103          * We should flush everything (aka Telnet SYNCH) if we see
 104          * 0x02, and we should turn off and on _local_ flow control
 105          * on 0x10 and 0x20 respectively. I'm not convinced it's
 106          * worth it...
 107          */
 108     } else {
 109         /*
 110          * Main rlogin protocol. This is really simple: the first
 111          * byte is expected to be NULL and is ignored, and the rest
 112          * is printed.
 113          */
 114         if (rlogin->firstbyte) {
 115             if (data[0] == '\0') {
 116                 data++;
 117                 len--;
 118             }
 119             rlogin->firstbyte = 0;
 120         }
 121         if (len > 0)
 122             c_write(rlogin, data, len);
 123     }
 124     return 1;
 125 }
 126
 127 static void rlogin_sent(Plug plug, int bufsize)
 128 {
 129     Rlogin rlogin = (Rlogin) plug;
 130     rlogin->bufsize = bufsize;
 131 }
 132
 133 static void rlogin_startup(Rlogin rlogin, const char *ruser)
 134 {
 135     char z = 0;
 136     char *p;
 137
 138     sk_write(rlogin->s, &z, 1);
 139     p = conf_get_str(rlogin->conf, CONF_localusername);
 140     sk_write(rlogin->s, p, strlen(p));
 141     sk_write(rlogin->s, &z, 1);
 142     sk_write(rlogin->s, ruser, strlen(ruser));
 143     sk_write(rlogin->s, &z, 1);
 144     p = conf_get_str(rlogin->conf, CONF_termtype);
 145     sk_write(rlogin->s, p, strlen(p));
 146     sk_write(rlogin->s, "/", 1);
 147     p = conf_get_str(rlogin->conf, CONF_termspeed);
 148     sk_write(rlogin->s, p, strspn(p, "0123456789"));
 149     rlogin->bufsize = sk_write(rlogin->s, &z, 1);
 150
 151     rlogin->prompt = NULL;
 152 }
 153
 154 /*
 155  * Called to set up the rlogin connection.
 156  *
 157  * Returns an error message, or NULL on success.
 158  *
 159  * Also places the canonical host name into `realhost'. It must be
 160  * freed by the caller.
 161  */
 162 static const char *rlogin_init(void *frontend_handle, void **backend_handle,
 163                                Conf *conf,
 164                                char *host, int port, char **realhost,
 165                                int nodelay, int keepalive)
 166 {
 167     static const struct plug_function_table fn_table = {
 168         rlogin_log,
 169         rlogin_closing,
 170         rlogin_receive,
 171         rlogin_sent
 172     };
 173     SockAddr addr;
 174     const char *err;
 175     Rlogin rlogin;
 176     char *ruser;
 177     int addressfamily;
 178     char *loghost;
 179
 180     rlogin = snew(struct rlogin_tag);
 181     rlogin->fn = &fn_table;
 182     rlogin->s = NULL;
 183     rlogin->closed_on_socket_error = FALSE;
 184     rlogin->frontend = frontend_handle;
 185     rlogin->term_width = conf_get_int(conf, CONF_width);
 186     rlogin->term_height = conf_get_int(conf, CONF_height);
 187     rlogin->firstbyte = 1;
 188     rlogin->cansize = 0;
 189     rlogin->prompt = NULL;
 190     rlogin->conf = conf_copy(conf);
 191     *backend_handle = rlogin;
 192
 193     addressfamily = conf_get_int(conf, CONF_addressfamily);
 194     /*
 195      * Try to find host.
 196      */
 197     {
 198         char *buf;
 199         buf = dupprintf("Looking up host \"%s\"%s", host,
 200                         (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
 201                          (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
 202                           "")));
 203         logevent(rlogin->frontend, buf);
 204         sfree(buf);
 205     }
 206     addr = name_lookup(host, port, realhost, conf, addressfamily);
 207     if ((err = sk_addr_error(addr)) != NULL) {
 208         sk_addr_free(addr);
 209         return err;
 210     }
 211
 212     if (port < 0)
 213         port = 513;                    /* default rlogin port */
 214
 215     /*
 216      * Open socket.
 217      */
 218     rlogin->s = new_connection(addr, *realhost, port, 1, 0,
 219                                nodelay, keepalive, (Plug) rlogin, conf);
 220     if ((err = sk_socket_error(rlogin->s)) != NULL)
 221         return err;
 222
 223     loghost = conf_get_str(conf, CONF_loghost);
 224     if (*loghost) {
 225         char *colon;
 226
 227         sfree(*realhost);
 228         *realhost = dupstr(loghost);
 229         colon = strrchr(*realhost, ':');
 230         if (colon) {
 231             /*
 232              * FIXME: if we ever update this aspect of ssh.c for
 233              * IPv6 literal management, this should change in line
 234              * with it.
 235              */
 236             *colon++ = '\0';
 237         }
 238     }
 239
 240     /*
 241      * Send local username, remote username, terminal type and
 242      * terminal speed - unless we don't have the remote username yet,
 243      * in which case we prompt for it and may end up deferring doing
 244      * anything else until the local prompt mechanism returns.
 245      */
 246     if ((ruser = get_remote_username(conf)) != NULL) {
 247         rlogin_startup(rlogin, ruser);
 248         sfree(ruser);
 249     } else {
 250         int ret;
 251
 252         rlogin->prompt = new_prompts(rlogin->frontend);
 253         rlogin->prompt->to_server = TRUE;
 254         rlogin->prompt->name = dupstr("Rlogin login name");
 255         add_prompt(rlogin->prompt, dupstr("rlogin username: "), TRUE);
 256         ret = get_userpass_input(rlogin->prompt, NULL, 0);
 257         if (ret >= 0) {
 258             rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
 259         }
 260     }
 261
 262     return NULL;
 263 }
 264
 265 static void rlogin_free(void *handle)
 266 {
 267     Rlogin rlogin = (Rlogin) handle;
 268
 269     if (rlogin->prompt)
 270         free_prompts(rlogin->prompt);
 271     if (rlogin->s)
 272         sk_close(rlogin->s);
 273     conf_free(rlogin->conf);
 274     sfree(rlogin);
 275 }
 276
 277 /*
 278  * Stub routine (we don't have any need to reconfigure this backend).
 279  */
 280 static void rlogin_reconfig(void *handle, Conf *conf)
 281 {
 282 }
 283
 284 /*
 285  * Called to send data down the rlogin connection.
 286  */
 287 static int rlogin_send(void *handle, char *buf, int len)
 288 {
 289     Rlogin rlogin = (Rlogin) handle;
 290
 291     if (rlogin->s == NULL)
 292         return 0;
 293
 294     if (rlogin->prompt) {
 295         /*
 296          * We're still prompting for a username, and aren't talking
 297          * directly to the network connection yet.
 298          */
 299         int ret = get_userpass_input(rlogin->prompt,
 300                                      (unsigned char *)buf, len);
 301         if (ret >= 0) {
 302             rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
 303             /* that nulls out rlogin->prompt, so then we'll start sending
 304              * data down the wire in the obvious way */
 305         }
 306     } else {
 307         rlogin->bufsize = sk_write(rlogin->s, buf, len);
 308     }
 309
 310     return rlogin->bufsize;
 311 }
 312
 313 /*
 314  * Called to query the current socket sendability status.
 315  */
 316 static int rlogin_sendbuffer(void *handle)
 317 {
 318     Rlogin rlogin = (Rlogin) handle;
 319     return rlogin->bufsize;
 320 }
 321
 322 /*
 323  * Called to set the size of the window
 324  */
 325 static void rlogin_size(void *handle, int width, int height)
 326 {
 327     Rlogin rlogin = (Rlogin) handle;
 328     char b[12] = { '\xFF', '\xFF', 0x73, 0x73, 0, 0, 0, 0, 0, 0, 0, 0 };
 329
 330     rlogin->term_width = width;
 331     rlogin->term_height = height;
 332
 333     if (rlogin->s == NULL || !rlogin->cansize)
 334         return;
 335
 336     b[6] = rlogin->term_width >> 8;
 337     b[7] = rlogin->term_width & 0xFF;
 338     b[4] = rlogin->term_height >> 8;
 339     b[5] = rlogin->term_height & 0xFF;
 340     rlogin->bufsize = sk_write(rlogin->s, b, 12);
 341     return;
 342 }
 343
 344 /*
 345  * Send rlogin special codes.
 346  */
 347 static void rlogin_special(void *handle, Telnet_Special code)
 348 {
 349     /* Do nothing! */
 350     return;
 351 }
 352
 353 /*
 354  * Return a list of the special codes that make sense in this
 355  * protocol.
 356  */
 357 static const struct telnet_special *rlogin_get_specials(void *handle)
 358 {
 359     return NULL;
 360 }
 361
 362 static int rlogin_connected(void *handle)
 363 {
 364     Rlogin rlogin = (Rlogin) handle;
 365     return rlogin->s != NULL;
 366 }
 367
 368 static int rlogin_sendok(void *handle)
 369 {
 370     /* Rlogin rlogin = (Rlogin) handle; */
 371     return 1;
 372 }
 373
 374 static void rlogin_unthrottle(void *handle, int backlog)
 375 {
 376     Rlogin rlogin = (Rlogin) handle;
 377     sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
 378 }
 379
 380 static int rlogin_ldisc(void *handle, int option)
 381 {
 382     /* Rlogin rlogin = (Rlogin) handle; */
 383     return 0;
 384 }
 385
 386 static void rlogin_provide_ldisc(void *handle, void *ldisc)
 387 {
 388     /* This is a stub. */
 389 }
 390
 391 static void rlogin_provide_logctx(void *handle, void *logctx)
 392 {
 393     /* This is a stub. */
 394 }
 395
 396 static int rlogin_exitcode(void *handle)
 397 {
 398     Rlogin rlogin = (Rlogin) handle;
 399     if (rlogin->s != NULL)
 400         return -1;                     /* still connected */
 401     else if (rlogin->closed_on_socket_error)
 402         return INT_MAX;     /* a socket error counts as an unclean exit */
 403     else
 404         /* If we ever implement RSH, we'll probably need to do this properly */
 405         return 0;
 406 }
 407
 408 /*
 409  * cfg_info for rlogin does nothing at all.
 410  */
 411 static int rlogin_cfg_info(void *handle)
 412 {
 413     return 0;
 414 }
 415
 416 Backend rlogin_backend = {
 417     rlogin_init,
 418     rlogin_free,
 419     rlogin_reconfig,
 420     rlogin_send,
 421     rlogin_sendbuffer,
 422     rlogin_size,
 423     rlogin_special,
 424     rlogin_get_specials,
 425     rlogin_connected,
 426     rlogin_exitcode,
 427     rlogin_sendok,
 428     rlogin_ldisc,
 429     rlogin_provide_ldisc,
 430     rlogin_provide_logctx,
 431     rlogin_unthrottle,
 432     rlogin_cfg_info,
 433     "rlogin",
 434     PROT_RLOGIN,
 435     513
 436 };