mdw@git.distorted.org.uk Git - sgt/putty/blob - windows/winser.c

   1 /*
   2  * Serial back end (Windows-specific).
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <limits.h>
   8
   9 #include "putty.h"
  10
  11 #define SERIAL_MAX_BACKLOG 4096
  12
  13 typedef struct serial_backend_data {
  14     HANDLE port;
  15     struct handle *out, *in;
  16     void *frontend;
  17     int bufsize;
  18     long clearbreak_time;
  19     int break_in_progress;
  20 } *Serial;
  21
  22 static void serial_terminate(Serial serial)
  23 {
  24     if (serial->out) {
  25         handle_free(serial->out);
  26         serial->out = NULL;
  27     }
  28     if (serial->in) {
  29         handle_free(serial->in);
  30         serial->in = NULL;
  31     }
  32     if (serial->port) {
  33         if (serial->break_in_progress)
  34             ClearCommBreak(serial->port);
  35         CloseHandle(serial->port);
  36         serial->port = NULL;
  37     }
  38 }
  39
  40 static int serial_gotdata(struct handle *h, void *data, int len)
  41 {
  42     Serial serial = (Serial)handle_get_privdata(h);
  43     if (len <= 0) {
  44         const char *error_msg;
  45
  46         /*
  47          * Currently, len==0 should never happen because we're
  48          * ignoring EOFs. However, it seems not totally impossible
  49          * that this same back end might be usable to talk to named
  50          * pipes or some other non-serial device, in which case EOF
  51          * may become meaningful here.
  52          */
  53         if (len == 0)
  54             error_msg = "End of file reading from serial device";
  55         else
  56             error_msg = "Error reading from serial device";
  57
  58         serial_terminate(serial);
  59
  60         notify_remote_exit(serial->frontend);
  61
  62         logevent(serial->frontend, error_msg);
  63
  64         connection_fatal(serial->frontend, "%s", error_msg);
  65
  66         return 0;                      /* placate optimiser */
  67     } else {
  68         return from_backend(serial->frontend, 0, data, len);
  69     }
  70 }
  71
  72 static void serial_sentdata(struct handle *h, int new_backlog)
  73 {
  74     Serial serial = (Serial)handle_get_privdata(h);
  75     if (new_backlog < 0) {
  76         const char *error_msg = "Error writing to serial device";
  77
  78         serial_terminate(serial);
  79
  80         notify_remote_exit(serial->frontend);
  81
  82         logevent(serial->frontend, error_msg);
  83
  84         connection_fatal(serial->frontend, "%s", error_msg);
  85     } else {
  86         serial->bufsize = new_backlog;
  87     }
  88 }
  89
  90 static const char *serial_configure(Serial serial, HANDLE serport, Config *cfg)
  91 {
  92     DCB dcb;
  93     COMMTIMEOUTS timeouts;
  94
  95     /*
  96      * Set up the serial port parameters. If we can't even
  97      * GetCommState, we ignore the problem on the grounds that the
  98      * user might have pointed us at some other type of two-way
  99      * device instead of a serial port.
 100      */
 101     if (GetCommState(serport, &dcb)) {
 102         char *msg;
 103         const char *str;
 104
 105         /*
 106          * Boilerplate.
 107          */
 108         dcb.fBinary = TRUE;
 109         dcb.fDtrControl = DTR_CONTROL_ENABLE;
 110         dcb.fDsrSensitivity = FALSE;
 111         dcb.fTXContinueOnXoff = FALSE;
 112         dcb.fOutX = FALSE;
 113         dcb.fInX = FALSE;
 114         dcb.fErrorChar = FALSE;
 115         dcb.fNull = FALSE;
 116         dcb.fRtsControl = RTS_CONTROL_ENABLE;
 117         dcb.fAbortOnError = FALSE;
 118         dcb.fOutxCtsFlow = FALSE;
 119         dcb.fOutxDsrFlow = FALSE;
 120
 121         /*
 122          * Configurable parameters.
 123          */
 124         dcb.BaudRate = cfg->serspeed;
 125         msg = dupprintf("Configuring baud rate %d", cfg->serspeed);
 126         logevent(serial->frontend, msg);
 127         sfree(msg);
 128
 129         dcb.ByteSize = cfg->serdatabits;
 130         msg = dupprintf("Configuring %d data bits", cfg->serdatabits);
 131         logevent(serial->frontend, msg);
 132         sfree(msg);
 133
 134         switch (cfg->serstopbits) {
 135           case 2: dcb.StopBits = ONESTOPBIT; str = "1"; break;
 136           case 3: dcb.StopBits = ONE5STOPBITS; str = "1.5"; break;
 137           case 4: dcb.StopBits = TWOSTOPBITS; str = "2"; break;
 138           default: return "Invalid number of stop bits (need 1, 1.5 or 2)";
 139         }
 140         msg = dupprintf("Configuring %s data bits", str);
 141         logevent(serial->frontend, msg);
 142         sfree(msg);
 143
 144         switch (cfg->serparity) {
 145           case SER_PAR_NONE: dcb.Parity = NOPARITY; str = "no"; break;
 146           case SER_PAR_ODD: dcb.Parity = ODDPARITY; str = "odd"; break;
 147           case SER_PAR_EVEN: dcb.Parity = EVENPARITY; str = "even"; break;
 148           case SER_PAR_MARK: dcb.Parity = MARKPARITY; str = "mark"; break;
 149           case SER_PAR_SPACE: dcb.Parity = SPACEPARITY; str = "space"; break;
 150         }
 151         msg = dupprintf("Configuring %s parity", str);
 152         logevent(serial->frontend, msg);
 153         sfree(msg);
 154
 155         switch (cfg->serflow) {
 156           case SER_FLOW_NONE:
 157             str = "no";
 158             break;
 159           case SER_FLOW_XONXOFF:
 160             dcb.fOutX = dcb.fInX = TRUE;
 161             str = "XON/XOFF";
 162             break;
 163           case SER_FLOW_RTSCTS:
 164             dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
 165             dcb.fOutxCtsFlow = TRUE;
 166             str = "RTS/CTS";
 167             break;
 168           case SER_FLOW_DSRDTR:
 169             dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
 170             dcb.fOutxDsrFlow = TRUE;
 171             str = "DSR/DTR";
 172             break;
 173         }
 174         msg = dupprintf("Configuring %s flow control", str);
 175         logevent(serial->frontend, msg);
 176         sfree(msg);
 177
 178         if (!SetCommState(serport, &dcb))
 179             return "Unable to configure serial port";
 180
 181         timeouts.ReadIntervalTimeout = 1;
 182         timeouts.ReadTotalTimeoutMultiplier = 0;
 183         timeouts.ReadTotalTimeoutConstant = 0;
 184         timeouts.WriteTotalTimeoutMultiplier = 0;
 185         timeouts.WriteTotalTimeoutConstant = 0;
 186         if (!SetCommTimeouts(serport, &timeouts))
 187             return "Unable to configure serial timeouts";
 188     }
 189
 190     return NULL;
 191 }
 192
 193 /*
 194  * Called to set up the serial connection.
 195  *
 196  * Returns an error message, or NULL on success.
 197  *
 198  * Also places the canonical host name into `realhost'. It must be
 199  * freed by the caller.
 200  */
 201 static const char *serial_init(void *frontend_handle, void **backend_handle,
 202                                Config *cfg,
 203                                char *host, int port, char **realhost, int nodelay,
 204                                int keepalive)
 205 {
 206     Serial serial;
 207     HANDLE serport;
 208     const char *err;
 209
 210     serial = snew(struct serial_backend_data);
 211     serial->port = NULL;
 212     serial->out = serial->in = NULL;
 213     serial->bufsize = 0;
 214     serial->break_in_progress = FALSE;
 215     *backend_handle = serial;
 216
 217     serial->frontend = frontend_handle;
 218
 219     {
 220         char *msg = dupprintf("Opening serial device %s", cfg->serline);
 221         logevent(serial->frontend, msg);
 222     }
 223
 224     serport = CreateFile(cfg->serline, GENERIC_READ | GENERIC_WRITE, 0, NULL,
 225                          OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
 226     if (serport == INVALID_HANDLE_VALUE)
 227         return "Unable to open serial port";
 228
 229     err = serial_configure(serial, serport, cfg);
 230     if (err)
 231         return err;
 232
 233     serial->port = serport;
 234     serial->out = handle_output_new(serport, serial_sentdata, serial,
 235                                     HANDLE_FLAG_OVERLAPPED);
 236     serial->in = handle_input_new(serport, serial_gotdata, serial,
 237                                   HANDLE_FLAG_OVERLAPPED |
 238                                   HANDLE_FLAG_IGNOREEOF |
 239                                   HANDLE_FLAG_UNITBUFFER);
 240
 241     *realhost = dupstr(cfg->serline);
 242
 243     /*
 244      * Specials are always available.
 245      */
 246     update_specials_menu(serial->frontend);
 247
 248     return NULL;
 249 }
 250
 251 static void serial_free(void *handle)
 252 {
 253     Serial serial = (Serial) handle;
 254
 255     serial_terminate(serial);
 256     expire_timer_context(serial);
 257     sfree(serial);
 258 }
 259
 260 static void serial_reconfig(void *handle, Config *cfg)
 261 {
 262     Serial serial = (Serial) handle;
 263     const char *err;
 264
 265     err = serial_configure(serial, serial->port, cfg);
 266
 267     /*
 268      * FIXME: what should we do if err returns something?
 269      */
 270 }
 271
 272 /*
 273  * Called to send data down the serial connection.
 274  */
 275 static int serial_send(void *handle, char *buf, int len)
 276 {
 277     Serial serial = (Serial) handle;
 278
 279     if (serial->out == NULL)
 280         return 0;
 281
 282     serial->bufsize = handle_write(serial->out, buf, len);
 283     return serial->bufsize;
 284 }
 285
 286 /*
 287  * Called to query the current sendability status.
 288  */
 289 static int serial_sendbuffer(void *handle)
 290 {
 291     Serial serial = (Serial) handle;
 292     return serial->bufsize;
 293 }
 294
 295 /*
 296  * Called to set the size of the window
 297  */
 298 static void serial_size(void *handle, int width, int height)
 299 {
 300     /* Do nothing! */
 301     return;
 302 }
 303
 304 static void serbreak_timer(void *ctx, long now)
 305 {
 306     Serial serial = (Serial)ctx;
 307
 308     if (now >= serial->clearbreak_time && serial->port) {
 309         ClearCommBreak(serial->port);
 310         serial->break_in_progress = FALSE;
 311         logevent(serial->frontend, "Finished serial break");
 312     }
 313 }
 314
 315 /*
 316  * Send serial special codes.
 317  */
 318 static void serial_special(void *handle, Telnet_Special code)
 319 {
 320     Serial serial = (Serial) handle;
 321
 322     if (serial->port && code == TS_BRK) {
 323         logevent(serial->frontend, "Starting serial break at user request");
 324         SetCommBreak(serial->port);
 325         /*
 326          * To send a serial break on Windows, we call SetCommBreak
 327          * to begin the break, then wait a bit, and then call
 328          * ClearCommBreak to finish it. Hence, I must use timing.c
 329          * to arrange a callback when it's time to do the latter.
 330          *
 331          * SUS says that a default break length must be between 1/4
 332          * and 1/2 second. FreeBSD apparently goes with 2/5 second,
 333          * and so will I.
 334          */
 335         serial->clearbreak_time =
 336             schedule_timer(TICKSPERSEC * 2 / 5, serbreak_timer, serial);
 337         serial->break_in_progress = TRUE;
 338     }
 339
 340     return;
 341 }
 342
 343 /*
 344  * Return a list of the special codes that make sense in this
 345  * protocol.
 346  */
 347 static const struct telnet_special *serial_get_specials(void *handle)
 348 {
 349     static const struct telnet_special specials[] = {
 350         {"Break", TS_BRK},
 351         {NULL, TS_EXITMENU}
 352     };
 353     return specials;
 354 }
 355
 356 static int serial_connected(void *handle)
 357 {
 358     return 1;                          /* always connected */
 359 }
 360
 361 static int serial_sendok(void *handle)
 362 {
 363     return 1;
 364 }
 365
 366 static void serial_unthrottle(void *handle, int backlog)
 367 {
 368     Serial serial = (Serial) handle;
 369     if (serial->in)
 370         handle_unthrottle(serial->in, backlog);
 371 }
 372
 373 static int serial_ldisc(void *handle, int option)
 374 {
 375     /*
 376      * Local editing and local echo are off by default.
 377      */
 378     return 0;
 379 }
 380
 381 static void serial_provide_ldisc(void *handle, void *ldisc)
 382 {
 383     /* This is a stub. */
 384 }
 385
 386 static void serial_provide_logctx(void *handle, void *logctx)
 387 {
 388     /* This is a stub. */
 389 }
 390
 391 static int serial_exitcode(void *handle)
 392 {
 393     Serial serial = (Serial) handle;
 394     if (serial->port != NULL)
 395         return -1;                     /* still connected */
 396     else
 397         /* Exit codes are a meaningless concept with serial ports */
 398         return INT_MAX;
 399 }
 400
 401 /*
 402  * cfg_info for Serial does nothing at all.
 403  */
 404 static int serial_cfg_info(void *handle)
 405 {
 406     return 0;
 407 }
 408
 409 Backend serial_backend = {
 410     serial_init,
 411     serial_free,
 412     serial_reconfig,
 413     serial_send,
 414     serial_sendbuffer,
 415     serial_size,
 416     serial_special,
 417     serial_get_specials,
 418     serial_connected,
 419     serial_exitcode,
 420     serial_sendok,
 421     serial_ldisc,
 422     serial_provide_ldisc,
 423     serial_provide_logctx,
 424     serial_unthrottle,
 425     serial_cfg_info,
 426     1
 427 };