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, Conf *conf)
  64 {
  65     struct termios options;
  66     int bflag, bval, speed, flow, parity;
  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     speed = conf_get_int(conf, CONF_serspeed);
  79 #define SETBAUD(x) (bflag = B ## x, bval = x)
  80 #define CHECKBAUD(x) do { if (speed >= x) SETBAUD(x); } while (0)
  81     SETBAUD(50);
  82 #ifdef B75
  83     CHECKBAUD(75);
  84 #endif
  85 #ifdef B110
  86     CHECKBAUD(110);
  87 #endif
  88 #ifdef B134
  89     CHECKBAUD(134);
  90 #endif
  91 #ifdef B150
  92     CHECKBAUD(150);
  93 #endif
  94 #ifdef B200
  95     CHECKBAUD(200);
  96 #endif
  97 #ifdef B300
  98     CHECKBAUD(300);
  99 #endif
 100 #ifdef B600
 101     CHECKBAUD(600);
 102 #endif
 103 #ifdef B1200
 104     CHECKBAUD(1200);
 105 #endif
 106 #ifdef B1800
 107     CHECKBAUD(1800);
 108 #endif
 109 #ifdef B2400
 110     CHECKBAUD(2400);
 111 #endif
 112 #ifdef B4800
 113     CHECKBAUD(4800);
 114 #endif
 115 #ifdef B9600
 116     CHECKBAUD(9600);
 117 #endif
 118 #ifdef B19200
 119     CHECKBAUD(19200);
 120 #endif
 121 #ifdef B38400
 122     CHECKBAUD(38400);
 123 #endif
 124 #ifdef B57600
 125     CHECKBAUD(57600);
 126 #endif
 127 #ifdef B76800
 128     CHECKBAUD(76800);
 129 #endif
 130 #ifdef B115200
 131     CHECKBAUD(115200);
 132 #endif
 133 #ifdef B153600
 134     CHECKBAUD(153600);
 135 #endif
 136 #ifdef B230400
 137     CHECKBAUD(230400);
 138 #endif
 139 #ifdef B307200
 140     CHECKBAUD(307200);
 141 #endif
 142 #ifdef B460800
 143     CHECKBAUD(460800);
 144 #endif
 145 #ifdef B500000
 146     CHECKBAUD(500000);
 147 #endif
 148 #ifdef B576000
 149     CHECKBAUD(576000);
 150 #endif
 151 #ifdef B921600
 152     CHECKBAUD(921600);
 153 #endif
 154 #ifdef B1000000
 155     CHECKBAUD(1000000);
 156 #endif
 157 #ifdef B1152000
 158     CHECKBAUD(1152000);
 159 #endif
 160 #ifdef B1500000
 161     CHECKBAUD(1500000);
 162 #endif
 163 #ifdef B2000000
 164     CHECKBAUD(2000000);
 165 #endif
 166 #ifdef B2500000
 167     CHECKBAUD(2500000);
 168 #endif
 169 #ifdef B3000000
 170     CHECKBAUD(3000000);
 171 #endif
 172 #ifdef B3500000
 173     CHECKBAUD(3500000);
 174 #endif
 175 #ifdef B4000000
 176     CHECKBAUD(4000000);
 177 #endif
 178 #undef CHECKBAUD
 179 #undef SETBAUD
 180     cfsetispeed(&options, bflag);
 181     cfsetospeed(&options, bflag);
 182     msg = dupprintf("Configuring baud rate %d", bval);
 183     logevent(serial->frontend, msg);
 184     sfree(msg);
 185
 186     options.c_cflag &= ~CSIZE;
 187     switch (conf_get_int(conf, CONF_serdatabits)) {
 188       case 5: options.c_cflag |= CS5; break;
 189       case 6: options.c_cflag |= CS6; break;
 190       case 7: options.c_cflag |= CS7; break;
 191       case 8: options.c_cflag |= CS8; break;
 192       default: return "Invalid number of data bits (need 5, 6, 7 or 8)";
 193     }
 194     msg = dupprintf("Configuring %d data bits",
 195                     conf_get_int(conf, CONF_serdatabits));
 196     logevent(serial->frontend, msg);
 197     sfree(msg);
 198
 199     if (conf_get_int(conf, CONF_serstopbits) >= 4) {
 200         options.c_cflag |= CSTOPB;
 201     } else {
 202         options.c_cflag &= ~CSTOPB;
 203     }
 204     msg = dupprintf("Configuring %d stop bits",
 205                     (options.c_cflag & CSTOPB ? 2 : 1));
 206     logevent(serial->frontend, msg);
 207     sfree(msg);
 208
 209     options.c_iflag &= ~(IXON|IXOFF);
 210 #ifdef CRTSCTS
 211     options.c_cflag &= ~CRTSCTS;
 212 #endif
 213 #ifdef CNEW_RTSCTS
 214     options.c_cflag &= ~CNEW_RTSCTS;
 215 #endif
 216     flow = conf_get_int(conf, CONF_serflow);
 217     if (flow == SER_FLOW_XONXOFF) {
 218         options.c_iflag |= IXON | IXOFF;
 219         str = "XON/XOFF";
 220     } else if (flow == SER_FLOW_RTSCTS) {
 221 #ifdef CRTSCTS
 222         options.c_cflag |= CRTSCTS;
 223 #endif
 224 #ifdef CNEW_RTSCTS
 225         options.c_cflag |= CNEW_RTSCTS;
 226 #endif
 227         str = "RTS/CTS";
 228     } else
 229         str = "no";
 230     msg = dupprintf("Configuring %s flow control", str);
 231     logevent(serial->frontend, msg);
 232     sfree(msg);
 233
 234     /* Parity */
 235     parity = conf_get_int(conf, CONF_serparity);
 236     if (parity == SER_PAR_ODD) {
 237         options.c_cflag |= PARENB;
 238         options.c_cflag |= PARODD;
 239         str = "odd";
 240     } else if (parity == SER_PAR_EVEN) {
 241         options.c_cflag |= PARENB;
 242         options.c_cflag &= ~PARODD;
 243         str = "even";
 244     } else {
 245         options.c_cflag &= ~PARENB;
 246         str = "no";
 247     }
 248     msg = dupprintf("Configuring %s parity", str);
 249     logevent(serial->frontend, msg);
 250     sfree(msg);
 251
 252     options.c_cflag |= CLOCAL | CREAD;
 253     options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
 254     options.c_iflag &= ~(ISTRIP | IGNCR | INLCR | ICRNL
 255 #ifdef IUCLC
 256                          | IUCLC
 257 #endif
 258                          );
 259     options.c_oflag &= ~(OPOST
 260 #ifdef ONLCR
 261                          | ONLCR
 262 #endif
 263 #ifdef OCRNL
 264                          | OCRNL
 265 #endif
 266 #ifdef ONOCR
 267                          | ONOCR
 268 #endif
 269 #ifdef ONLRET
 270                          | ONLRET
 271 #endif
 272                          );
 273     options.c_cc[VMIN] = 1;
 274     options.c_cc[VTIME] = 0;
 275
 276     if (tcsetattr(serial->fd, TCSANOW, &options) < 0)
 277         return "Unable to configure serial port";
 278
 279     return NULL;
 280 }
 281
 282 /*
 283  * Called to set up the serial connection.
 284  *
 285  * Returns an error message, or NULL on success.
 286  *
 287  * Also places the canonical host name into `realhost'. It must be
 288  * freed by the caller.
 289  */
 290 static const char *serial_init(void *frontend_handle, void **backend_handle,
 291                                Conf *conf,
 292                                char *host, int port, char **realhost, int nodelay,
 293                                int keepalive)
 294 {
 295     Serial serial;
 296     const char *err;
 297     char *line;
 298
 299     serial = snew(struct serial_backend_data);
 300     *backend_handle = serial;
 301
 302     serial->frontend = frontend_handle;
 303     serial->finished = FALSE;
 304     serial->inbufsize = 0;
 305     bufchain_init(&serial->output_data);
 306
 307     line = conf_get_str(conf, CONF_serline);
 308     {
 309         char *msg = dupprintf("Opening serial device %s", line);
 310         logevent(serial->frontend, msg);
 311     }
 312
 313     serial->fd = open(line, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
 314     if (serial->fd < 0)
 315         return "Unable to open serial port";
 316
 317     cloexec(serial->fd);
 318
 319     err = serial_configure(serial, conf);
 320     if (err)
 321         return err;
 322
 323     *realhost = dupstr(line);
 324
 325     if (!serial_by_fd)
 326         serial_by_fd = newtree234(serial_compare_by_fd);
 327     add234(serial_by_fd, serial);
 328
 329     serial_uxsel_setup(serial);
 330
 331     /*
 332      * Specials are always available.
 333      */
 334     update_specials_menu(serial->frontend);
 335
 336     return NULL;
 337 }
 338
 339 static void serial_close(Serial serial)
 340 {
 341     if (serial->fd >= 0) {
 342         close(serial->fd);
 343         serial->fd = -1;
 344     }
 345 }
 346
 347 static void serial_free(void *handle)
 348 {
 349     Serial serial = (Serial) handle;
 350
 351     serial_close(serial);
 352
 353     bufchain_clear(&serial->output_data);
 354
 355     sfree(serial);
 356 }
 357
 358 static void serial_reconfig(void *handle, Conf *conf)
 359 {
 360     Serial serial = (Serial) handle;
 361
 362     /*
 363      * FIXME: what should we do if this returns an error?
 364      */
 365     serial_configure(serial, conf);
 366 }
 367
 368 static int serial_select_result(int fd, int event)
 369 {
 370     Serial serial;
 371     char buf[4096];
 372     int ret;
 373     int finished = FALSE;
 374
 375     serial = find234(serial_by_fd, &fd, serial_find_by_fd);
 376
 377     if (!serial)
 378         return 1;                      /* spurious event; keep going */
 379
 380     if (event == 1) {
 381         ret = read(serial->fd, buf, sizeof(buf));
 382
 383         if (ret == 0) {
 384             /*
 385              * Shouldn't happen on a real serial port, but I'm open
 386              * to the idea that there might be two-way devices we
 387              * can treat _like_ serial ports which can return EOF.
 388              */
 389             finished = TRUE;
 390         } else if (ret < 0) {
 391 #ifdef EAGAIN
 392             if (errno == EAGAIN)
 393                 return 1;              /* spurious */
 394 #endif
 395 #ifdef EWOULDBLOCK
 396             if (errno == EWOULDBLOCK)
 397                 return 1;              /* spurious */
 398 #endif
 399             perror("read serial port");
 400             exit(1);
 401         } else if (ret > 0) {
 402             serial->inbufsize = from_backend(serial->frontend, 0, buf, ret);
 403             serial_uxsel_setup(serial); /* might acquire backlog and freeze */
 404         }
 405     } else if (event == 2) {
 406         /*
 407          * Attempt to send data down the pty.
 408          */
 409         serial_try_write(serial);
 410     }
 411
 412     if (finished) {
 413         serial_close(serial);
 414
 415         serial->finished = TRUE;
 416
 417         notify_remote_exit(serial->frontend);
 418     }
 419
 420     return !finished;
 421 }
 422
 423 static void serial_uxsel_setup(Serial serial)
 424 {
 425     int rwx = 0;
 426
 427     if (serial->inbufsize <= SERIAL_MAX_BACKLOG)
 428         rwx |= 1;
 429     if (bufchain_size(&serial->output_data))
 430         rwx |= 2;                      /* might also want to write to it */
 431     uxsel_set(serial->fd, rwx, serial_select_result);
 432 }
 433
 434 static void serial_try_write(Serial serial)
 435 {
 436     void *data;
 437     int len, ret;
 438
 439     assert(serial->fd >= 0);
 440
 441     while (bufchain_size(&serial->output_data) > 0) {
 442         bufchain_prefix(&serial->output_data, &data, &len);
 443         ret = write(serial->fd, data, len);
 444
 445         if (ret < 0 && (errno == EWOULDBLOCK)) {
 446             /*
 447              * We've sent all we can for the moment.
 448              */
 449             break;
 450         }
 451         if (ret < 0) {
 452             perror("write serial port");
 453             exit(1);
 454         }
 455         bufchain_consume(&serial->output_data, ret);
 456     }
 457
 458     serial_uxsel_setup(serial);
 459 }
 460
 461 /*
 462  * Called to send data down the serial connection.
 463  */
 464 static int serial_send(void *handle, char *buf, int len)
 465 {
 466     Serial serial = (Serial) handle;
 467
 468     if (serial->fd < 0)
 469         return 0;
 470
 471     bufchain_add(&serial->output_data, buf, len);
 472     serial_try_write(serial);
 473
 474     return bufchain_size(&serial->output_data);
 475 }
 476
 477 /*
 478  * Called to query the current sendability status.
 479  */
 480 static int serial_sendbuffer(void *handle)
 481 {
 482     Serial serial = (Serial) handle;
 483     return bufchain_size(&serial->output_data);
 484 }
 485
 486 /*
 487  * Called to set the size of the window
 488  */
 489 static void serial_size(void *handle, int width, int height)
 490 {
 491     /* Do nothing! */
 492     return;
 493 }
 494
 495 /*
 496  * Send serial special codes.
 497  */
 498 static void serial_special(void *handle, Telnet_Special code)
 499 {
 500     Serial serial = (Serial) handle;
 501
 502     if (serial->fd >= 0 && code == TS_BRK) {
 503         tcsendbreak(serial->fd, 0);
 504         logevent(serial->frontend, "Sending serial break at user request");
 505     }
 506
 507     return;
 508 }
 509
 510 /*
 511  * Return a list of the special codes that make sense in this
 512  * protocol.
 513  */
 514 static const struct telnet_special *serial_get_specials(void *handle)
 515 {
 516     static const struct telnet_special specials[] = {
 517         {"Break", TS_BRK},
 518         {NULL, TS_EXITMENU}
 519     };
 520     return specials;
 521 }
 522
 523 static int serial_connected(void *handle)
 524 {
 525     return 1;                          /* always connected */
 526 }
 527
 528 static int serial_sendok(void *handle)
 529 {
 530     return 1;
 531 }
 532
 533 static void serial_unthrottle(void *handle, int backlog)
 534 {
 535     Serial serial = (Serial) handle;
 536     serial->inbufsize = backlog;
 537     serial_uxsel_setup(serial);
 538 }
 539
 540 static int serial_ldisc(void *handle, int option)
 541 {
 542     /*
 543      * Local editing and local echo are off by default.
 544      */
 545     return 0;
 546 }
 547
 548 static void serial_provide_ldisc(void *handle, void *ldisc)
 549 {
 550     /* This is a stub. */
 551 }
 552
 553 static void serial_provide_logctx(void *handle, void *logctx)
 554 {
 555     /* This is a stub. */
 556 }
 557
 558 static int serial_exitcode(void *handle)
 559 {
 560     Serial serial = (Serial) handle;
 561     if (serial->fd >= 0)
 562         return -1;                     /* still connected */
 563     else
 564         /* Exit codes are a meaningless concept with serial ports */
 565         return INT_MAX;
 566 }
 567
 568 /*
 569  * cfg_info for Serial does nothing at all.
 570  */
 571 static int serial_cfg_info(void *handle)
 572 {
 573     return 0;
 574 }
 575
 576 Backend serial_backend = {
 577     serial_init,
 578     serial_free,
 579     serial_reconfig,
 580     serial_send,
 581     serial_sendbuffer,
 582     serial_size,
 583     serial_special,
 584     serial_get_specials,
 585     serial_connected,
 586     serial_exitcode,
 587     serial_sendok,
 588     serial_ldisc,
 589     serial_provide_ldisc,
 590     serial_provide_logctx,
 591     serial_unthrottle,
 592     serial_cfg_info,
 593     "serial",
 594     PROT_SERIAL,
 595     0
 596 };