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_iflag &= ~(IXON|IXOFF);
 166 #ifdef CRTSCTS
 167     options.c_cflag &= ~CRTSCTS;
 168 #endif
 169 #ifdef CNEW_RTSCTS
 170     options.c_cflag &= ~CNEW_RTSCTS;
 171 #endif
 172     if (cfg->serflow == SER_FLOW_XONXOFF) {
 173         options.c_iflag |= IXON | IXOFF;
 174         str = "XON/XOFF";
 175     } else if (cfg->serflow == SER_FLOW_RTSCTS) {
 176 #ifdef CRTSCTS
 177         options.c_cflag |= CRTSCTS;
 178 #endif
 179 #ifdef CNEW_RTSCTS
 180         options.c_cflag |= CNEW_RTSCTS;
 181 #endif
 182         str = "RTS/CTS";
 183     } else
 184         str = "no";
 185     msg = dupprintf("Configuring %s flow control", str);
 186     logevent(serial->frontend, msg);
 187     sfree(msg);
 188
 189     /* Parity */
 190     if (cfg->serparity == SER_PAR_ODD) {
 191         options.c_cflag |= PARENB;
 192         options.c_cflag |= PARODD;
 193         str = "odd";
 194     } else if (cfg->serparity == SER_PAR_EVEN) {
 195         options.c_cflag |= PARENB;
 196         options.c_cflag &= ~PARODD;
 197         str = "even";
 198     } else {
 199         options.c_cflag &= ~PARENB;
 200         str = "no";
 201     }
 202     msg = dupprintf("Configuring %s parity", str);
 203     logevent(serial->frontend, msg);
 204     sfree(msg);
 205
 206     options.c_cflag |= CLOCAL | CREAD;
 207     options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
 208     options.c_oflag &= ~OPOST;
 209     options.c_cc[VMIN] = 1;
 210     options.c_cc[VTIME] = 0;
 211
 212     if (tcsetattr(serial->fd, TCSANOW, &options) < 0)
 213         return "Unable to configure serial port";
 214
 215     return NULL;
 216 }
 217
 218 /*
 219  * Called to set up the serial connection.
 220  *
 221  * Returns an error message, or NULL on success.
 222  *
 223  * Also places the canonical host name into `realhost'. It must be
 224  * freed by the caller.
 225  */
 226 static const char *serial_init(void *frontend_handle, void **backend_handle,
 227                                Config *cfg,
 228                                char *host, int port, char **realhost, int nodelay,
 229                                int keepalive)
 230 {
 231     Serial serial;
 232     const char *err;
 233
 234     serial = snew(struct serial_backend_data);
 235     *backend_handle = serial;
 236
 237     serial->frontend = frontend_handle;
 238     serial->finished = FALSE;
 239     serial->inbufsize = 0;
 240     bufchain_init(&serial->output_data);
 241
 242     {
 243         char *msg = dupprintf("Opening serial device %s", cfg->serline);
 244         logevent(serial->frontend, msg);
 245     }
 246
 247     serial->fd = open(cfg->serline, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
 248     if (serial->fd < 0)
 249         return "Unable to open serial port";
 250
 251     err = serial_configure(serial, cfg);
 252     if (err)
 253         return err;
 254
 255     *realhost = dupstr(cfg->serline);
 256
 257     if (!serial_by_fd)
 258         serial_by_fd = newtree234(serial_compare_by_fd);
 259     add234(serial_by_fd, serial);
 260
 261     serial_uxsel_setup(serial);
 262
 263     /*
 264      * Specials are always available.
 265      */
 266     update_specials_menu(serial->frontend);
 267
 268     return NULL;
 269 }
 270
 271 static void serial_close(Serial serial)
 272 {
 273     if (serial->fd >= 0) {
 274         close(serial->fd);
 275         serial->fd = -1;
 276     }
 277 }
 278
 279 static void serial_free(void *handle)
 280 {
 281     Serial serial = (Serial) handle;
 282
 283     serial_close(serial);
 284
 285     bufchain_clear(&serial->output_data);
 286
 287     sfree(serial);
 288 }
 289
 290 static void serial_reconfig(void *handle, Config *cfg)
 291 {
 292     Serial serial = (Serial) handle;
 293     const char *err;
 294
 295     err = serial_configure(serial, cfg);
 296
 297     /*
 298      * FIXME: what should we do if err returns something?
 299      */
 300 }
 301
 302 static int serial_select_result(int fd, int event)
 303 {
 304     Serial serial;
 305     char buf[4096];
 306     int ret;
 307     int finished = FALSE;
 308
 309     serial = find234(serial_by_fd, &fd, serial_find_by_fd);
 310
 311     if (!serial)
 312         return 1;                      /* spurious event; keep going */
 313
 314     if (event == 1) {
 315         ret = read(serial->fd, buf, sizeof(buf));
 316
 317         if (ret == 0) {
 318             /*
 319              * Shouldn't happen on a real serial port, but I'm open
 320              * to the idea that there might be two-way devices we
 321              * can treat _like_ serial ports which can return EOF.
 322              */
 323             finished = TRUE;
 324         } else if (ret < 0) {
 325             perror("read serial port");
 326             exit(1);
 327         } else if (ret > 0) {
 328             serial->inbufsize = from_backend(serial->frontend, 0, buf, ret);
 329             serial_uxsel_setup(serial); /* might acquire backlog and freeze */
 330         }
 331     } else if (event == 2) {
 332         /*
 333          * Attempt to send data down the pty.
 334          */
 335         serial_try_write(serial);
 336     }
 337
 338     if (finished) {
 339         serial_close(serial);
 340
 341         serial->finished = TRUE;
 342
 343         notify_remote_exit(serial->frontend);
 344     }
 345
 346     return !finished;
 347 }
 348
 349 static void serial_uxsel_setup(Serial serial)
 350 {
 351     int rwx = 0;
 352
 353     if (serial->inbufsize <= SERIAL_MAX_BACKLOG)
 354         rwx |= 1;
 355     if (bufchain_size(&serial->output_data))
 356         rwx |= 2;                      /* might also want to write to it */
 357     uxsel_set(serial->fd, rwx, serial_select_result);
 358 }
 359
 360 static void serial_try_write(Serial serial)
 361 {
 362     void *data;
 363     int len, ret;
 364
 365     assert(serial->fd >= 0);
 366
 367     while (bufchain_size(&serial->output_data) > 0) {
 368         bufchain_prefix(&serial->output_data, &data, &len);
 369         ret = write(serial->fd, data, len);
 370
 371         if (ret < 0 && (errno == EWOULDBLOCK)) {
 372             /*
 373              * We've sent all we can for the moment.
 374              */
 375             break;
 376         }
 377         if (ret < 0) {
 378             perror("write serial port");
 379             exit(1);
 380         }
 381         bufchain_consume(&serial->output_data, ret);
 382     }
 383
 384     serial_uxsel_setup(serial);
 385 }
 386
 387 /*
 388  * Called to send data down the serial connection.
 389  */
 390 static int serial_send(void *handle, char *buf, int len)
 391 {
 392     Serial serial = (Serial) handle;
 393
 394     if (serial->fd < 0)
 395         return 0;
 396
 397     bufchain_add(&serial->output_data, buf, len);
 398     serial_try_write(serial);
 399
 400     return bufchain_size(&serial->output_data);
 401 }
 402
 403 /*
 404  * Called to query the current sendability status.
 405  */
 406 static int serial_sendbuffer(void *handle)
 407 {
 408     Serial serial = (Serial) handle;
 409     return bufchain_size(&serial->output_data);
 410 }
 411
 412 /*
 413  * Called to set the size of the window
 414  */
 415 static void serial_size(void *handle, int width, int height)
 416 {
 417     /* Do nothing! */
 418     return;
 419 }
 420
 421 /*
 422  * Send serial special codes.
 423  */
 424 static void serial_special(void *handle, Telnet_Special code)
 425 {
 426     Serial serial = (Serial) handle;
 427
 428     if (serial->fd >= 0 && code == TS_BRK) {
 429         tcsendbreak(serial->fd, 0);
 430         logevent(serial->frontend, "Sending serial break at user request");
 431     }
 432
 433     return;
 434 }
 435
 436 /*
 437  * Return a list of the special codes that make sense in this
 438  * protocol.
 439  */
 440 static const struct telnet_special *serial_get_specials(void *handle)
 441 {
 442     static const struct telnet_special specials[] = {
 443         {"Break", TS_BRK},
 444         {NULL, TS_EXITMENU}
 445     };
 446     return specials;
 447 }
 448
 449 static int serial_connected(void *handle)
 450 {
 451     return 1;                          /* always connected */
 452 }
 453
 454 static int serial_sendok(void *handle)
 455 {
 456     return 1;
 457 }
 458
 459 static void serial_unthrottle(void *handle, int backlog)
 460 {
 461     Serial serial = (Serial) handle;
 462     serial->inbufsize = backlog;
 463     serial_uxsel_setup(serial);
 464 }
 465
 466 static int serial_ldisc(void *handle, int option)
 467 {
 468     /*
 469      * Local editing and local echo are off by default.
 470      */
 471     return 0;
 472 }
 473
 474 static void serial_provide_ldisc(void *handle, void *ldisc)
 475 {
 476     /* This is a stub. */
 477 }
 478
 479 static void serial_provide_logctx(void *handle, void *logctx)
 480 {
 481     /* This is a stub. */
 482 }
 483
 484 static int serial_exitcode(void *handle)
 485 {
 486     Serial serial = (Serial) handle;
 487     if (serial->fd >= 0)
 488         return -1;                     /* still connected */
 489     else
 490         /* Exit codes are a meaningless concept with serial ports */
 491         return INT_MAX;
 492 }
 493
 494 /*
 495  * cfg_info for Serial does nothing at all.
 496  */
 497 static int serial_cfg_info(void *handle)
 498 {
 499     return 0;
 500 }
 501
 502 Backend serial_backend = {
 503     serial_init,
 504     serial_free,
 505     serial_reconfig,
 506     serial_send,
 507     serial_sendbuffer,
 508     serial_size,
 509     serial_special,
 510     serial_get_specials,
 511     serial_connected,
 512     serial_exitcode,
 513     serial_sendok,
 514     serial_ldisc,
 515     serial_provide_ldisc,
 516     serial_provide_logctx,
 517     serial_unthrottle,
 518     serial_cfg_info,
 519     1
 520 };