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

   1 /*
   2  * Serial back end (Unix-specific).
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <assert.h>
   8 #include <limits.h>
   9
  10 #include <errno.h>
  11 #include <unistd.h>
  12 #include <fcntl.h>
  13 #include <termios.h>
  14
  15 #include "putty.h"
  16 #include "tree234.h"
  17
  18 #define SERIAL_MAX_BACKLOG 4096
  19
  20 typedef struct serial_backend_data {
  21     void *frontend;
  22     int fd;
  23     int finished;
  24     int inbufsize;
  25     bufchain output_data;
  26 } *Serial;
  27
  28 /*
  29  * We store our serial backends in a tree sorted by fd, so that
  30  * when we get an uxsel notification we know which backend instance
  31  * is the owner of the serial port that caused it.
  32  */
  33 static int serial_compare_by_fd(void *av, void *bv)
  34 {
  35     Serial a = (Serial)av;
  36     Serial b = (Serial)bv;
  37
  38     if (a->fd < b->fd)
  39         return -1;
  40     else if (a->fd > b->fd)
  41         return +1;
  42     return 0;
  43 }
  44
  45 static int serial_find_by_fd(void *av, void *bv)
  46 {
  47     int a = *(int *)av;
  48     Serial b = (Serial)bv;
  49
  50     if (a < b->fd)
  51         return -1;
  52     else if (a > b->fd)
  53         return +1;
  54     return 0;
  55 }
  56
  57 static tree234 *serial_by_fd = NULL;
  58
  59 static int serial_select_result(int fd, int event);
  60 static void serial_uxsel_setup(Serial serial);
  61 static void serial_try_write(Serial serial);
  62
  63 static const char *serial_configure(Serial serial, Config *cfg)
  64 {
  65     struct termios options;
  66     int bflag, bval;
  67     const char *str;
  68     char *msg;
  69
  70     if (serial->fd < 0)
  71         return "Unable to reconfigure already-closed serial connection";
  72
  73     tcgetattr(serial->fd, &options);
  74
  75     /*
  76      * Find the appropriate baud rate flag.
  77      */
  78 #define SETBAUD(x) (bflag = B ## x, bval = x)
  79 #define CHECKBAUD(x) do { if (cfg->serspeed >= x) SETBAUD(x); } while (0)
  80     SETBAUD(50);
  81 #ifdef B75
  82     CHECKBAUD(75);
  83 #endif
  84 #ifdef B110
  85     CHECKBAUD(110);
  86 #endif
  87 #ifdef B134
  88     CHECKBAUD(134);
  89 #endif
  90 #ifdef B150
  91     CHECKBAUD(150);
  92 #endif
  93 #ifdef B200
  94     CHECKBAUD(200);
  95 #endif
  96 #ifdef B300
  97     CHECKBAUD(300);
  98 #endif
  99 #ifdef B600
 100     CHECKBAUD(600);
 101 #endif
 102 #ifdef B1200
 103     CHECKBAUD(1200);
 104 #endif
 105 #ifdef B1800
 106     CHECKBAUD(1800);
 107 #endif
 108 #ifdef B2400
 109     CHECKBAUD(2400);
 110 #endif
 111 #ifdef B4800
 112     CHECKBAUD(4800);
 113 #endif
 114 #ifdef B9600
 115     CHECKBAUD(9600);
 116 #endif
 117 #ifdef B19200
 118     CHECKBAUD(19200);
 119 #endif
 120 #ifdef B38400
 121     CHECKBAUD(38400);
 122 #endif
 123 #ifdef B57600
 124     CHECKBAUD(57600);
 125 #endif
 126 #ifdef B76800
 127     CHECKBAUD(76800);
 128 #endif
 129 #ifdef B115200
 130     CHECKBAUD(115200);
 131 #endif
 132 #ifdef B230400
 133     CHECKBAUD(230400);
 134 #endif
 135 #undef CHECKBAUD
 136 #undef SETBAUD
 137     cfsetispeed(&options, bflag);
 138     cfsetospeed(&options, bflag);
 139     msg = dupprintf("Configuring baud rate %d", bval);
 140     logevent(serial->frontend, msg);
 141     sfree(msg);
 142
 143     options.c_cflag &= ~CSIZE;
 144     switch (cfg->serdatabits) {
 145       case 5: options.c_cflag |= CS5; break;
 146       case 6: options.c_cflag |= CS6; break;
 147       case 7: options.c_cflag |= CS7; break;
 148       case 8: options.c_cflag |= CS8; break;
 149       default: return "Invalid number of data bits (need 5, 6, 7 or 8)";
 150     }
 151     msg = dupprintf("Configuring %d data bits", cfg->serdatabits);
 152     logevent(serial->frontend, msg);
 153     sfree(msg);
 154
 155     if (cfg->serstopbits >= 4) {
 156         options.c_cflag |= CSTOPB;
 157     } else {
 158         options.c_cflag &= ~CSTOPB;
 159     }
 160     msg = dupprintf("Configuring %d stop bits",
 161                     (options.c_cflag & CSTOPB ? 2 : 1));
 162     logevent(serial->frontend, msg);
 163     sfree(msg);
 164
 165     options.c_cflag &= ~(IXON|IXOFF);
 166     if (cfg->serflow == SER_FLOW_XONXOFF) {
 167         options.c_cflag |= IXON | IXOFF;
 168         str = "XON/XOFF";
 169     } else if (cfg->serflow == SER_FLOW_RTSCTS) {
 170 #ifdef CRTSCTS
 171         options.c_cflag |= CRTSCTS;
 172 #endif
 173 #ifdef CNEW_RTSCTS
 174         options.c_cflag |= CNEW_RTSCTS;
 175 #endif
 176         str = "RTS/CTS";
 177     } else
 178         str = "no";
 179     msg = dupprintf("Configuring %s flow control", str);
 180     logevent(serial->frontend, msg);
 181     sfree(msg);
 182
 183     /* Parity */
 184     if (cfg->serparity == SER_PAR_ODD) {
 185         options.c_cflag |= PARENB;
 186         options.c_cflag |= PARODD;
 187         str = "odd";
 188     } else if (cfg->serparity == SER_PAR_EVEN) {
 189         options.c_cflag |= PARENB;
 190         options.c_cflag &= ~PARODD;
 191         str = "even";
 192     } else {
 193         options.c_cflag &= ~PARENB;
 194         str = "no";
 195     }
 196     msg = dupprintf("Configuring %s parity", str);
 197     logevent(serial->frontend, msg);
 198     sfree(msg);
 199
 200     options.c_cflag |= CLOCAL | CREAD;
 201     options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
 202     options.c_oflag &= ~OPOST;
 203     options.c_cc[VMIN] = 1;
 204     options.c_cc[VTIME] = 0;
 205
 206     if (tcsetattr(serial->fd, TCSANOW, &options) < 0)
 207         return "Unable to configure serial port";
 208
 209     return NULL;
 210 }
 211
 212 /*
 213  * Called to set up the serial connection.
 214  *
 215  * Returns an error message, or NULL on success.
 216  *
 217  * Also places the canonical host name into `realhost'. It must be
 218  * freed by the caller.
 219  */
 220 static const char *serial_init(void *frontend_handle, void **backend_handle,
 221                                Config *cfg,
 222                                char *host, int port, char **realhost, int nodelay,
 223                                int keepalive)
 224 {
 225     Serial serial;
 226     const char *err;
 227
 228     serial = snew(struct serial_backend_data);
 229     *backend_handle = serial;
 230
 231     serial->frontend = frontend_handle;
 232     serial->finished = FALSE;
 233     serial->inbufsize = 0;
 234     bufchain_init(&serial->output_data);
 235
 236     {
 237         char *msg = dupprintf("Opening serial device %s", cfg->serline);
 238         logevent(serial->frontend, msg);
 239     }
 240
 241     serial->fd = open(cfg->serline, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
 242     if (serial->fd < 0)
 243         return "Unable to open serial port";
 244
 245     err = serial_configure(serial, cfg);
 246     if (err)
 247         return err;
 248
 249     *realhost = dupstr(cfg->serline);
 250
 251     if (!serial_by_fd)
 252         serial_by_fd = newtree234(serial_compare_by_fd);
 253     add234(serial_by_fd, serial);
 254
 255     serial_uxsel_setup(serial);
 256
 257     /*
 258      * Specials are always available.
 259      */
 260     update_specials_menu(serial->frontend);
 261
 262     return NULL;
 263 }
 264
 265 static void serial_close(Serial serial)
 266 {
 267     if (serial->fd >= 0) {
 268         close(serial->fd);
 269         serial->fd = -1;
 270     }
 271 }
 272
 273 static void serial_free(void *handle)
 274 {
 275     Serial serial = (Serial) handle;
 276
 277     serial_close(serial);
 278
 279     bufchain_clear(&serial->output_data);
 280
 281     sfree(serial);
 282 }
 283
 284 static void serial_reconfig(void *handle, Config *cfg)
 285 {
 286     Serial serial = (Serial) handle;
 287     const char *err;
 288
 289     err = serial_configure(serial, cfg);
 290
 291     /*
 292      * FIXME: what should we do if err returns something?
 293      */
 294 }
 295
 296 static int serial_select_result(int fd, int event)
 297 {
 298     Serial serial;
 299     char buf[4096];
 300     int ret;
 301     int finished = FALSE;
 302
 303     serial = find234(serial_by_fd, &fd, serial_find_by_fd);
 304
 305     if (!serial)
 306         return 1;                      /* spurious event; keep going */
 307
 308     if (event == 1) {
 309         ret = read(serial->fd, buf, sizeof(buf));
 310
 311         if (ret == 0) {
 312             /*
 313              * Shouldn't happen on a real serial port, but I'm open
 314              * to the idea that there might be two-way devices we
 315              * can treat _like_ serial ports which can return EOF.
 316              */
 317             finished = TRUE;
 318         } else if (ret < 0) {
 319             perror("read serial port");
 320             exit(1);
 321         } else if (ret > 0) {
 322             serial->inbufsize = from_backend(serial->frontend, 0, buf, ret);
 323             serial_uxsel_setup(serial); /* might acquire backlog and freeze */
 324         }
 325     } else if (event == 2) {
 326         /*
 327          * Attempt to send data down the pty.
 328          */
 329         serial_try_write(serial);
 330     }
 331
 332     if (finished) {
 333         serial_close(serial);
 334
 335         serial->finished = TRUE;
 336
 337         notify_remote_exit(serial->frontend);
 338     }
 339
 340     return !finished;
 341 }
 342
 343 static void serial_uxsel_setup(Serial serial)
 344 {
 345     int rwx = 0;
 346
 347     if (serial->inbufsize <= SERIAL_MAX_BACKLOG)
 348         rwx |= 1;
 349     if (bufchain_size(&serial->output_data))
 350         rwx |= 2;                      /* might also want to write to it */
 351     uxsel_set(serial->fd, rwx, serial_select_result);
 352 }
 353
 354 static void serial_try_write(Serial serial)
 355 {
 356     void *data;
 357     int len, ret;
 358
 359     assert(serial->fd >= 0);
 360
 361     while (bufchain_size(&serial->output_data) > 0) {
 362         bufchain_prefix(&serial->output_data, &data, &len);
 363         ret = write(serial->fd, data, len);
 364
 365         if (ret < 0 && (errno == EWOULDBLOCK)) {
 366             /*
 367              * We've sent all we can for the moment.
 368              */
 369             break;
 370         }
 371         if (ret < 0) {
 372             perror("write serial port");
 373             exit(1);
 374         }
 375         bufchain_consume(&serial->output_data, ret);
 376     }
 377
 378     serial_uxsel_setup(serial);
 379 }
 380
 381 /*
 382  * Called to send data down the serial connection.
 383  */
 384 static int serial_send(void *handle, char *buf, int len)
 385 {
 386     Serial serial = (Serial) handle;
 387
 388     if (serial->fd < 0)
 389         return 0;
 390
 391     bufchain_add(&serial->output_data, buf, len);
 392     serial_try_write(serial);
 393
 394     return bufchain_size(&serial->output_data);
 395 }
 396
 397 /*
 398  * Called to query the current sendability status.
 399  */
 400 static int serial_sendbuffer(void *handle)
 401 {
 402     Serial serial = (Serial) handle;
 403     return bufchain_size(&serial->output_data);
 404 }
 405
 406 /*
 407  * Called to set the size of the window
 408  */
 409 static void serial_size(void *handle, int width, int height)
 410 {
 411     /* Do nothing! */
 412     return;
 413 }
 414
 415 /*
 416  * Send serial special codes.
 417  */
 418 static void serial_special(void *handle, Telnet_Special code)
 419 {
 420     Serial serial = (Serial) handle;
 421
 422     if (serial->fd >= 0 && code == TS_BRK) {
 423         tcsendbreak(serial->fd, 0);
 424         logevent(serial->frontend, "Sending serial break at user request");
 425     }
 426
 427     return;
 428 }
 429
 430 /*
 431  * Return a list of the special codes that make sense in this
 432  * protocol.
 433  */
 434 static const struct telnet_special *serial_get_specials(void *handle)
 435 {
 436     static const struct telnet_special specials[] = {
 437         {"Break", TS_BRK},
 438         {NULL, TS_EXITMENU}
 439     };
 440     return specials;
 441 }
 442
 443 static int serial_connected(void *handle)
 444 {
 445     return 1;                          /* always connected */
 446 }
 447
 448 static int serial_sendok(void *handle)
 449 {
 450     return 1;
 451 }
 452
 453 static void serial_unthrottle(void *handle, int backlog)
 454 {
 455     Serial serial = (Serial) handle;
 456     serial->inbufsize = backlog;
 457     serial_uxsel_setup(serial);
 458 }
 459
 460 static int serial_ldisc(void *handle, int option)
 461 {
 462     /*
 463      * Local editing and local echo are off by default.
 464      */
 465     return 0;
 466 }
 467
 468 static void serial_provide_ldisc(void *handle, void *ldisc)
 469 {
 470     /* This is a stub. */
 471 }
 472
 473 static void serial_provide_logctx(void *handle, void *logctx)
 474 {
 475     /* This is a stub. */
 476 }
 477
 478 static int serial_exitcode(void *handle)
 479 {
 480     Serial serial = (Serial) handle;
 481     if (serial->fd >= 0)
 482         return -1;                     /* still connected */
 483     else
 484         /* Exit codes are a meaningless concept with serial ports */
 485         return INT_MAX;
 486 }
 487
 488 /*
 489  * cfg_info for Serial does nothing at all.
 490  */
 491 static int serial_cfg_info(void *handle)
 492 {
 493     return 0;
 494 }
 495
 496 Backend serial_backend = {
 497     serial_init,
 498     serial_free,
 499     serial_reconfig,
 500     serial_send,
 501     serial_sendbuffer,
 502     serial_size,
 503     serial_special,
 504     serial_get_specials,
 505     serial_connected,
 506     serial_exitcode,
 507     serial_sendok,
 508     serial_ldisc,
 509     serial_provide_ldisc,
 510     serial_provide_logctx,
 511     serial_unthrottle,
 512     serial_cfg_info,
 513     1
 514 };