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