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 <ctype.h>
   8
   9 #include "putty.h"
  10
  11 #ifndef FALSE
  12 #define FALSE 0
  13 #endif
  14 #ifndef TRUE
  15 #define TRUE 1
  16 #endif
  17
  18 #define RLOGIN_MAX_BACKLOG 4096
  19
  20 typedef struct rlogin_tag {
  21     const struct plug_function_table *fn;
  22     /* the above field _must_ be first in the structure */
  23
  24     Socket s;
  25     int bufsize;
  26     int firstbyte;
  27     int cansize;
  28     int term_width, term_height;
  29     void *frontend;
  30
  31     Conf *conf;
  32
  33     /* In case we need to read a username from the terminal before starting */
  34     prompts_t *prompt;
  35 } *Rlogin;
  36
  37 static void rlogin_size(void *handle, int width, int height);
  38
  39 static void c_write(Rlogin rlogin, char *buf, int len)
  40 {
  41     int backlog = from_backend(rlogin->frontend, 0, buf, len);
  42     sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
  43 }
  44
  45 static void rlogin_log(Plug plug, int type, SockAddr addr, int port,
  46                        const char *error_msg, int error_code)
  47 {
  48     Rlogin rlogin = (Rlogin) plug;
  49     char addrbuf[256], *msg;
  50
  51     sk_getaddr(addr, addrbuf, lenof(addrbuf));
  52
  53     if (type == 0)
  54         msg = dupprintf("Connecting to %s port %d", addrbuf, port);
  55     else
  56         msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
  57
  58     logevent(rlogin->frontend, msg);
  59 }
  60
  61 static int rlogin_closing(Plug plug, const char *error_msg, int error_code,
  62                           int calling_back)
  63 {
  64     Rlogin rlogin = (Rlogin) plug;
  65     if (rlogin->s) {
  66         sk_close(rlogin->s);
  67         rlogin->s = NULL;
  68         notify_remote_exit(rlogin->frontend);
  69     }
  70     if (error_msg) {
  71         /* A socket error has occurred. */
  72         logevent(rlogin->frontend, error_msg);
  73         connection_fatal(rlogin->frontend, "%s", error_msg);
  74     }                                  /* Otherwise, the remote side closed the connection normally. */
  75     return 0;
  76 }
  77
  78 static int rlogin_receive(Plug plug, int urgent, char *data, int len)
  79 {
  80     Rlogin rlogin = (Rlogin) plug;
  81     if (urgent == 2) {
  82         char c;
  83
  84         c = *data++;
  85         len--;
  86         if (c == '\x80') {
  87             rlogin->cansize = 1;
  88             rlogin_size(rlogin, rlogin->term_width, rlogin->term_height);
  89         }
  90         /*
  91          * We should flush everything (aka Telnet SYNCH) if we see
  92          * 0x02, and we should turn off and on _local_ flow control
  93          * on 0x10 and 0x20 respectively. I'm not convinced it's
  94          * worth it...
  95          */
  96     } else {
  97         /*
  98          * Main rlogin protocol. This is really simple: the first
  99          * byte is expected to be NULL and is ignored, and the rest
 100          * is printed.
 101          */
 102         if (rlogin->firstbyte) {
 103             if (data[0] == '\0') {
 104                 data++;
 105                 len--;
 106             }
 107             rlogin->firstbyte = 0;
 108         }
 109         if (len > 0)
 110             c_write(rlogin, data, len);
 111     }
 112     return 1;
 113 }
 114
 115 static void rlogin_sent(Plug plug, int bufsize)
 116 {
 117     Rlogin rlogin = (Rlogin) plug;
 118     rlogin->bufsize = bufsize;
 119 }
 120
 121 static void rlogin_startup(Rlogin rlogin, const char *ruser)
 122 {
 123     char z = 0;
 124     char *p;
 125
 126     sk_write(rlogin->s, &z, 1);
 127     p = conf_get_str(rlogin->conf, CONF_localusername);
 128     sk_write(rlogin->s, p, strlen(p));
 129     sk_write(rlogin->s, &z, 1);
 130     sk_write(rlogin->s, ruser, strlen(ruser));
 131     sk_write(rlogin->s, &z, 1);
 132     p = conf_get_str(rlogin->conf, CONF_termtype);
 133     sk_write(rlogin->s, p, strlen(p));
 134     sk_write(rlogin->s, "/", 1);
 135     p = conf_get_str(rlogin->conf, CONF_termspeed);
 136     sk_write(rlogin->s, p, strspn(p, "0123456789"));
 137     rlogin->bufsize = sk_write(rlogin->s, &z, 1);
 138
 139     rlogin->prompt = NULL;
 140 }
 141
 142 /*
 143  * Called to set up the rlogin connection.
 144  *
 145  * Returns an error message, or NULL on success.
 146  *
 147  * Also places the canonical host name into `realhost'. It must be
 148  * freed by the caller.
 149  */
 150 static const char *rlogin_init(void *frontend_handle, void **backend_handle,
 151                                Conf *conf,
 152                                char *host, int port, char **realhost,
 153                                int nodelay, int keepalive)
 154 {
 155     static const struct plug_function_table fn_table = {
 156         rlogin_log,
 157         rlogin_closing,
 158         rlogin_receive,
 159         rlogin_sent
 160     };
 161     SockAddr addr;
 162     const char *err;
 163     Rlogin rlogin;
 164     char *ruser;
 165     int addressfamily;
 166     char *loghost;
 167
 168     rlogin = snew(struct rlogin_tag);
 169     rlogin->fn = &fn_table;
 170     rlogin->s = NULL;
 171     rlogin->frontend = frontend_handle;
 172     rlogin->term_width = conf_get_int(conf, CONF_width);
 173     rlogin->term_height = conf_get_int(conf, CONF_height);
 174     rlogin->firstbyte = 1;
 175     rlogin->cansize = 0;
 176     rlogin->prompt = NULL;
 177     rlogin->conf = conf_copy(conf);
 178     *backend_handle = rlogin;
 179
 180     addressfamily = conf_get_int(conf, CONF_addressfamily);
 181     /*
 182      * Try to find host.
 183      */
 184     {
 185         char *buf;
 186         buf = dupprintf("Looking up host \"%s\"%s", host,
 187                         (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
 188                          (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
 189                           "")));
 190         logevent(rlogin->frontend, buf);
 191         sfree(buf);
 192     }
 193     addr = name_lookup(host, port, realhost, conf, addressfamily);
 194     if ((err = sk_addr_error(addr)) != NULL) {
 195         sk_addr_free(addr);
 196         return err;
 197     }
 198
 199     if (port < 0)
 200         port = 513;                    /* default rlogin port */
 201
 202     /*
 203      * Open socket.
 204      */
 205     rlogin->s = new_connection(addr, *realhost, port, 1, 0,
 206                                nodelay, keepalive, (Plug) rlogin, conf);
 207     if ((err = sk_socket_error(rlogin->s)) != NULL)
 208         return err;
 209
 210     loghost = conf_get_str(conf, CONF_loghost);
 211     if (*loghost) {
 212         char *colon;
 213
 214         sfree(*realhost);
 215         *realhost = dupstr(loghost);
 216         colon = strrchr(*realhost, ':');
 217         if (colon) {
 218             /*
 219              * FIXME: if we ever update this aspect of ssh.c for
 220              * IPv6 literal management, this should change in line
 221              * with it.
 222              */
 223             *colon++ = '\0';
 224         }
 225     }
 226
 227     /*
 228      * Send local username, remote username, terminal type and
 229      * terminal speed - unless we don't have the remote username yet,
 230      * in which case we prompt for it and may end up deferring doing
 231      * anything else until the local prompt mechanism returns.
 232      */
 233     if ((ruser = get_remote_username(conf)) == NULL) {
 234         rlogin_startup(rlogin, ruser);
 235         sfree(ruser);
 236     } else {
 237         int ret;
 238
 239         rlogin->prompt = new_prompts(rlogin->frontend);
 240         rlogin->prompt->to_server = TRUE;
 241         rlogin->prompt->name = dupstr("Rlogin login name");
 242         /* 512 is an arbitrary limit :-( */
 243         add_prompt(rlogin->prompt, dupstr("rlogin username: "), TRUE, 512);
 244         ret = get_userpass_input(rlogin->prompt, NULL, 0);
 245         if (ret >= 0) {
 246             rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
 247         }
 248     }
 249
 250     return NULL;
 251 }
 252
 253 static void rlogin_free(void *handle)
 254 {
 255     Rlogin rlogin = (Rlogin) handle;
 256
 257     if (rlogin->prompt)
 258         free_prompts(rlogin->prompt);
 259     if (rlogin->s)
 260         sk_close(rlogin->s);
 261     conf_free(rlogin->conf);
 262     sfree(rlogin);
 263 }
 264
 265 /*
 266  * Stub routine (we don't have any need to reconfigure this backend).
 267  */
 268 static void rlogin_reconfig(void *handle, Conf *conf)
 269 {
 270 }
 271
 272 /*
 273  * Called to send data down the rlogin connection.
 274  */
 275 static int rlogin_send(void *handle, char *buf, int len)
 276 {
 277     Rlogin rlogin = (Rlogin) handle;
 278
 279     if (rlogin->s == NULL)
 280         return 0;
 281
 282     if (rlogin->prompt) {
 283         /*
 284          * We're still prompting for a username, and aren't talking
 285          * directly to the network connection yet.
 286          */
 287         int ret = get_userpass_input(rlogin->prompt,
 288                                      (unsigned char *)buf, len);
 289         if (ret >= 0) {
 290             rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
 291             /* that nulls out rlogin->prompt, so then we'll start sending
 292              * data down the wire in the obvious way */
 293         }
 294     } else {
 295         rlogin->bufsize = sk_write(rlogin->s, buf, len);
 296     }
 297
 298     return rlogin->bufsize;
 299 }
 300
 301 /*
 302  * Called to query the current socket sendability status.
 303  */
 304 static int rlogin_sendbuffer(void *handle)
 305 {
 306     Rlogin rlogin = (Rlogin) handle;
 307     return rlogin->bufsize;
 308 }
 309
 310 /*
 311  * Called to set the size of the window
 312  */
 313 static void rlogin_size(void *handle, int width, int height)
 314 {
 315     Rlogin rlogin = (Rlogin) handle;
 316     char b[12] = { '\xFF', '\xFF', 0x73, 0x73, 0, 0, 0, 0, 0, 0, 0, 0 };
 317
 318     rlogin->term_width = width;
 319     rlogin->term_height = height;
 320
 321     if (rlogin->s == NULL || !rlogin->cansize)
 322         return;
 323
 324     b[6] = rlogin->term_width >> 8;
 325     b[7] = rlogin->term_width & 0xFF;
 326     b[4] = rlogin->term_height >> 8;
 327     b[5] = rlogin->term_height & 0xFF;
 328     rlogin->bufsize = sk_write(rlogin->s, b, 12);
 329     return;
 330 }
 331
 332 /*
 333  * Send rlogin special codes.
 334  */
 335 static void rlogin_special(void *handle, Telnet_Special code)
 336 {
 337     /* Do nothing! */
 338     return;
 339 }
 340
 341 /*
 342  * Return a list of the special codes that make sense in this
 343  * protocol.
 344  */
 345 static const struct telnet_special *rlogin_get_specials(void *handle)
 346 {
 347     return NULL;
 348 }
 349
 350 static int rlogin_connected(void *handle)
 351 {
 352     Rlogin rlogin = (Rlogin) handle;
 353     return rlogin->s != NULL;
 354 }
 355
 356 static int rlogin_sendok(void *handle)
 357 {
 358     /* Rlogin rlogin = (Rlogin) handle; */
 359     return 1;
 360 }
 361
 362 static void rlogin_unthrottle(void *handle, int backlog)
 363 {
 364     Rlogin rlogin = (Rlogin) handle;
 365     sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
 366 }
 367
 368 static int rlogin_ldisc(void *handle, int option)
 369 {
 370     /* Rlogin rlogin = (Rlogin) handle; */
 371     return 0;
 372 }
 373
 374 static void rlogin_provide_ldisc(void *handle, void *ldisc)
 375 {
 376     /* This is a stub. */
 377 }
 378
 379 static void rlogin_provide_logctx(void *handle, void *logctx)
 380 {
 381     /* This is a stub. */
 382 }
 383
 384 static int rlogin_exitcode(void *handle)
 385 {
 386     Rlogin rlogin = (Rlogin) handle;
 387     if (rlogin->s != NULL)
 388         return -1;                     /* still connected */
 389     else
 390         /* If we ever implement RSH, we'll probably need to do this properly */
 391         return 0;
 392 }
 393
 394 /*
 395  * cfg_info for rlogin does nothing at all.
 396  */
 397 static int rlogin_cfg_info(void *handle)
 398 {
 399     return 0;
 400 }
 401
 402 Backend rlogin_backend = {
 403     rlogin_init,
 404     rlogin_free,
 405     rlogin_reconfig,
 406     rlogin_send,
 407     rlogin_sendbuffer,
 408     rlogin_size,
 409     rlogin_special,
 410     rlogin_get_specials,
 411     rlogin_connected,
 412     rlogin_exitcode,
 413     rlogin_sendok,
 414     rlogin_ldisc,
 415     rlogin_provide_ldisc,
 416     rlogin_provide_logctx,
 417     rlogin_unthrottle,
 418     rlogin_cfg_info,
 419     "rlogin",
 420     PROT_RLOGIN,
 421     513
 422 };