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