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

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