gdb/ser-unix.c

   1 /* Serial interface for local (hardwired) serial ports on Un*x like systems
   2
   3    Copyright (C) 1992-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "serial.h"
  22 #include "ser-base.h"
  23 #include "ser-unix.h"
  24
  25 #include <fcntl.h>
  26 #include <sys/types.h>
  27 #include "terminal.h"
  28 #include <sys/socket.h>
  29 #include "gdbsupport/gdb_sys_time.h"
  30
  31 #include "gdbsupport/gdb_select.h"
  32 #include "gdbcmd.h"
  33 #include "gdbsupport/filestuff.h"
  34 #include <termios.h>
  35 #include "gdbsupport/scoped_ignore_sigttou.h"
  36
  37 struct hardwire_ttystate
  38   {
  39     struct termios termios;
  40   };
  41
  42 #ifdef CRTSCTS
  43 /* Boolean to explicitly enable or disable h/w flow control.  */
  44 static bool serial_hwflow;
  45 static void
  46 show_serial_hwflow (struct ui_file *file, int from_tty,
  47                     struct cmd_list_element *c, const char *value)
  48 {
  49   fprintf_filtered (file, _("Hardware flow control is %s.\n"), value);
  50 }
  51 #endif
  52
  53 static int hardwire_open (struct serial *scb, const char *name);
  54 static void hardwire_raw (struct serial *scb);
  55 static int rate_to_code (int rate);
  56 static int hardwire_setbaudrate (struct serial *scb, int rate);
  57 static int hardwire_setparity (struct serial *scb, int parity);
  58 static void hardwire_close (struct serial *scb);
  59 static int get_tty_state (struct serial *scb,
  60                           struct hardwire_ttystate * state);
  61 static int set_tty_state (struct serial *scb,
  62                           struct hardwire_ttystate * state);
  63 static serial_ttystate hardwire_get_tty_state (struct serial *scb);
  64 static int hardwire_set_tty_state (struct serial *scb, serial_ttystate state);
  65 static void hardwire_print_tty_state (struct serial *, serial_ttystate,
  66                                       struct ui_file *);
  67 static int hardwire_drain_output (struct serial *);
  68 static int hardwire_flush_output (struct serial *);
  69 static int hardwire_flush_input (struct serial *);
  70 static int hardwire_send_break (struct serial *);
  71 static int hardwire_setstopbits (struct serial *, int);
  72
  73 /* Open up a real live device for serial I/O.  */
  74
  75 static int
  76 hardwire_open (struct serial *scb, const char *name)
  77 {
  78   scb->fd = gdb_open_cloexec (name, O_RDWR, 0);
  79   if (scb->fd < 0)
  80     return -1;
  81
  82   return 0;
  83 }
  84
  85 static int
  86 get_tty_state (struct serial *scb, struct hardwire_ttystate *state)
  87 {
  88   if (tcgetattr (scb->fd, &state->termios) < 0)
  89     return -1;
  90
  91   return 0;
  92 }
  93
  94 static int
  95 set_tty_state (struct serial *scb, struct hardwire_ttystate *state)
  96 {
  97   if (tcsetattr (scb->fd, TCSANOW, &state->termios) < 0)
  98     return -1;
  99
 100   return 0;
 101 }
 102
 103 static serial_ttystate
 104 hardwire_get_tty_state (struct serial *scb)
 105 {
 106   struct hardwire_ttystate *state = XNEW (struct hardwire_ttystate);
 107
 108   if (get_tty_state (scb, state))
 109     {
 110       xfree (state);
 111       return NULL;
 112     }
 113
 114   return (serial_ttystate) state;
 115 }
 116
 117 static serial_ttystate
 118 hardwire_copy_tty_state (struct serial *scb, serial_ttystate ttystate)
 119 {
 120   struct hardwire_ttystate *state = XNEW (struct hardwire_ttystate);
 121
 122   *state = *(struct hardwire_ttystate *) ttystate;
 123
 124   return (serial_ttystate) state;
 125 }
 126
 127 static int
 128 hardwire_set_tty_state (struct serial *scb, serial_ttystate ttystate)
 129 {
 130   struct hardwire_ttystate *state;
 131
 132   state = (struct hardwire_ttystate *) ttystate;
 133
 134   return set_tty_state (scb, state);
 135 }
 136
 137 static void
 138 hardwire_print_tty_state (struct serial *scb,
 139                           serial_ttystate ttystate,
 140                           struct ui_file *stream)
 141 {
 142   struct hardwire_ttystate *state = (struct hardwire_ttystate *) ttystate;
 143   int i;
 144
 145   fprintf_filtered (stream, "c_iflag = 0x%x, c_oflag = 0x%x,\n",
 146                     (int) state->termios.c_iflag,
 147                     (int) state->termios.c_oflag);
 148   fprintf_filtered (stream, "c_cflag = 0x%x, c_lflag = 0x%x\n",
 149                     (int) state->termios.c_cflag,
 150                     (int) state->termios.c_lflag);
 151 #if 0
 152   /* This not in POSIX, and is not really documented by those systems
 153      which have it (at least not Sun).  */
 154   fprintf_filtered (stream, "c_line = 0x%x.\n", state->termios.c_line);
 155 #endif
 156   fprintf_filtered (stream, "c_cc: ");
 157   for (i = 0; i < NCCS; i += 1)
 158     fprintf_filtered (stream, "0x%x ", state->termios.c_cc[i]);
 159   fprintf_filtered (stream, "\n");
 160 }
 161
 162 /* Wait for the output to drain away, as opposed to flushing
 163    (discarding) it.  */
 164
 165 static int
 166 hardwire_drain_output (struct serial *scb)
 167 {
 168   /* Ignore SIGTTOU which may occur during the drain.  */
 169   scoped_ignore_sigttou ignore_sigttou;
 170
 171   return tcdrain (scb->fd);
 172 }
 173
 174 static int
 175 hardwire_flush_output (struct serial *scb)
 176 {
 177   return tcflush (scb->fd, TCOFLUSH);
 178 }
 179
 180 static int
 181 hardwire_flush_input (struct serial *scb)
 182 {
 183   ser_base_flush_input (scb);
 184
 185   return tcflush (scb->fd, TCIFLUSH);
 186 }
 187
 188 static int
 189 hardwire_send_break (struct serial *scb)
 190 {
 191   return tcsendbreak (scb->fd, 0);
 192 }
 193
 194 static void
 195 hardwire_raw (struct serial *scb)
 196 {
 197   struct hardwire_ttystate state;
 198
 199   if (get_tty_state (scb, &state))
 200     fprintf_unfiltered (gdb_stderr, "get_tty_state failed: %s\n",
 201                         safe_strerror (errno));
 202
 203   state.termios.c_iflag = 0;
 204   state.termios.c_oflag = 0;
 205   state.termios.c_lflag = 0;
 206   state.termios.c_cflag &= ~CSIZE;
 207   state.termios.c_cflag |= CLOCAL | CS8;
 208 #ifdef CRTSCTS
 209   /* h/w flow control.  */
 210   if (serial_hwflow)
 211     state.termios.c_cflag |= CRTSCTS;
 212   else
 213     state.termios.c_cflag &= ~CRTSCTS;
 214 #ifdef CRTS_IFLOW
 215   if (serial_hwflow)
 216     state.termios.c_cflag |= CRTS_IFLOW;
 217   else
 218     state.termios.c_cflag &= ~CRTS_IFLOW;
 219 #endif
 220 #endif
 221   state.termios.c_cc[VMIN] = 0;
 222   state.termios.c_cc[VTIME] = 0;
 223
 224   if (set_tty_state (scb, &state))
 225     fprintf_unfiltered (gdb_stderr, "set_tty_state failed: %s\n",
 226                         safe_strerror (errno));
 227 }
 228
 229 #ifndef B19200
 230 #define B19200 EXTA
 231 #endif
 232
 233 #ifndef B38400
 234 #define B38400 EXTB
 235 #endif
 236
 237 /* Translate baud rates from integers to damn B_codes.  Unix should
 238    have outgrown this crap years ago, but even POSIX wouldn't buck it.  */
 239
 240 static struct
 241 {
 242   int rate;
 243   int code;
 244 }
 245 baudtab[] =
 246 {
 247   {
 248     50, B50
 249   }
 250   ,
 251   {
 252     75, B75
 253   }
 254   ,
 255   {
 256     110, B110
 257   }
 258   ,
 259   {
 260     134, B134
 261   }
 262   ,
 263   {
 264     150, B150
 265   }
 266   ,
 267   {
 268     200, B200
 269   }
 270   ,
 271   {
 272     300, B300
 273   }
 274   ,
 275   {
 276     600, B600
 277   }
 278   ,
 279   {
 280     1200, B1200
 281   }
 282   ,
 283   {
 284     1800, B1800
 285   }
 286   ,
 287   {
 288     2400, B2400
 289   }
 290   ,
 291   {
 292     4800, B4800
 293   }
 294   ,
 295   {
 296     9600, B9600
 297   }
 298   ,
 299   {
 300     19200, B19200
 301   }
 302   ,
 303   {
 304     38400, B38400
 305   }
 306   ,
 307 #ifdef B57600
 308   {
 309     57600, B57600
 310   }
 311   ,
 312 #endif
 313 #ifdef B115200
 314   {
 315     115200, B115200
 316   }
 317   ,
 318 #endif
 319 #ifdef B230400
 320   {
 321     230400, B230400
 322   }
 323   ,
 324 #endif
 325 #ifdef B460800
 326   {
 327     460800, B460800
 328   }
 329   ,
 330 #endif
 331   {
 332     -1, -1
 333   }
 334   ,
 335 };
 336
 337 static int
 338 rate_to_code (int rate)
 339 {
 340   int i;
 341
 342   for (i = 0; baudtab[i].rate != -1; i++)
 343     {
 344       /* test for perfect macth.  */
 345       if (rate == baudtab[i].rate)
 346         return baudtab[i].code;
 347       else
 348         {
 349           /* check if it is in between valid values.  */
 350           if (rate < baudtab[i].rate)
 351             {
 352               if (i)
 353                 {
 354                   warning (_("Invalid baud rate %d.  "
 355                              "Closest values are %d and %d."),
 356                            rate, baudtab[i - 1].rate, baudtab[i].rate);
 357                 }
 358               else
 359                 {
 360                   warning (_("Invalid baud rate %d.  Minimum value is %d."),
 361                            rate, baudtab[0].rate);
 362                 }
 363               return -1;
 364             }
 365         }
 366     }
 367
 368   /* The requested speed was too large.  */
 369   warning (_("Invalid baud rate %d.  Maximum value is %d."),
 370             rate, baudtab[i - 1].rate);
 371   return -1;
 372 }
 373
 374 static int
 375 hardwire_setbaudrate (struct serial *scb, int rate)
 376 {
 377   struct hardwire_ttystate state;
 378   int baud_code = rate_to_code (rate);
 379
 380   if (baud_code < 0)
 381     {
 382       /* The baud rate was not valid.
 383          A warning has already been issued.  */
 384       errno = EINVAL;
 385       return -1;
 386     }
 387
 388   if (get_tty_state (scb, &state))
 389     return -1;
 390
 391   cfsetospeed (&state.termios, baud_code);
 392   cfsetispeed (&state.termios, baud_code);
 393
 394   return set_tty_state (scb, &state);
 395 }
 396
 397 static int
 398 hardwire_setstopbits (struct serial *scb, int num)
 399 {
 400   struct hardwire_ttystate state;
 401   int newbit;
 402
 403   if (get_tty_state (scb, &state))
 404     return -1;
 405
 406   switch (num)
 407     {
 408     case SERIAL_1_STOPBITS:
 409       newbit = 0;
 410       break;
 411     case SERIAL_1_AND_A_HALF_STOPBITS:
 412     case SERIAL_2_STOPBITS:
 413       newbit = 1;
 414       break;
 415     default:
 416       return 1;
 417     }
 418
 419   if (!newbit)
 420     state.termios.c_cflag &= ~CSTOPB;
 421   else
 422     state.termios.c_cflag |= CSTOPB;    /* two bits */
 423
 424   return set_tty_state (scb, &state);
 425 }
 426
 427 /* Implement the "setparity" serial_ops callback.  */
 428
 429 static int
 430 hardwire_setparity (struct serial *scb, int parity)
 431 {
 432   struct hardwire_ttystate state;
 433   int newparity = 0;
 434
 435   if (get_tty_state (scb, &state))
 436     return -1;
 437
 438   switch (parity)
 439     {
 440     case GDBPARITY_NONE:
 441       newparity = 0;
 442       break;
 443     case GDBPARITY_ODD:
 444       newparity = PARENB | PARODD;
 445       break;
 446     case GDBPARITY_EVEN:
 447       newparity = PARENB;
 448       break;
 449     default:
 450       internal_warning (__FILE__, __LINE__,
 451                         "Incorrect parity value: %d", parity);
 452       return -1;
 453     }
 454
 455   state.termios.c_cflag &= ~(PARENB | PARODD);
 456   state.termios.c_cflag |= newparity;
 457
 458   return set_tty_state (scb, &state);
 459 }
 460
 461
 462 static void
 463 hardwire_close (struct serial *scb)
 464 {
 465   if (scb->fd < 0)
 466     return;
 467
 468   close (scb->fd);
 469   scb->fd = -1;
 470 }
 471 \f
 472 \f
 473
 474 /* The hardwire ops.  */
 475
 476 static const struct serial_ops hardwire_ops =
 477 {
 478   "hardwire",
 479   hardwire_open,
 480   hardwire_close,
 481   NULL,
 482   ser_base_readchar,
 483   ser_base_write,
 484   hardwire_flush_output,
 485   hardwire_flush_input,
 486   hardwire_send_break,
 487   hardwire_raw,
 488   hardwire_get_tty_state,
 489   hardwire_copy_tty_state,
 490   hardwire_set_tty_state,
 491   hardwire_print_tty_state,
 492   hardwire_setbaudrate,
 493   hardwire_setstopbits,
 494   hardwire_setparity,
 495   hardwire_drain_output,
 496   ser_base_async,
 497   ser_unix_read_prim,
 498   ser_unix_write_prim
 499 };
 500
 501 void _initialize_ser_hardwire ();
 502 void
 503 _initialize_ser_hardwire ()
 504 {
 505   serial_add_interface (&hardwire_ops);
 506
 507 #ifdef CRTSCTS
 508   add_setshow_boolean_cmd ("remoteflow", no_class,
 509                            &serial_hwflow, _("\
 510 Set use of hardware flow control for remote serial I/O."), _("\
 511 Show use of hardware flow control for remote serial I/O."), _("\
 512 Enable or disable hardware flow control (RTS/CTS) on the serial port\n\
 513 when debugging using remote targets."),
 514                            NULL,
 515                            show_serial_hwflow,
 516                            &setlist, &showlist);
 517 #endif
 518 }
 519
 520 int
 521 ser_unix_read_prim (struct serial *scb, size_t count)
 522 {
 523   return read (scb->fd, scb->buf, count);
 524 }
 525
 526 int
 527 ser_unix_write_prim (struct serial *scb, const void *buf, size_t len)
 528 {
 529   return write (scb->fd, buf, len);
 530 }