| 1 | /* Generic serial interface functions. |
| 2 | |
| 3 | Copyright (C) 1992-2013 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 "event-loop.h" |
| 24 | |
| 25 | #include "gdb_select.h" |
| 26 | #include "gdb_string.h" |
| 27 | #include "gdb_assert.h" |
| 28 | #include <sys/time.h> |
| 29 | #ifdef USE_WIN32API |
| 30 | #include <winsock2.h> |
| 31 | #endif |
| 32 | |
| 33 | |
| 34 | static timer_handler_func push_event; |
| 35 | static handler_func fd_event; |
| 36 | |
| 37 | /* Event handling for ASYNC serial code. |
| 38 | |
| 39 | At any time the SERIAL device either: has an empty FIFO and is |
| 40 | waiting on a FD event; or has a non-empty FIFO/error condition and |
| 41 | is constantly scheduling timer events. |
| 42 | |
| 43 | ASYNC only stops pestering its client when it is de-async'ed or it |
| 44 | is told to go away. */ |
| 45 | |
| 46 | /* Value of scb->async_state: */ |
| 47 | enum { |
| 48 | /* >= 0 (TIMER_SCHEDULED) */ |
| 49 | /* The ID of the currently scheduled timer event. This state is |
| 50 | rarely encountered. Timer events are one-off so as soon as the |
| 51 | event is delivered the state is shanged to NOTHING_SCHEDULED. */ |
| 52 | FD_SCHEDULED = -1, |
| 53 | /* The fd_event() handler is scheduled. It is called when ever the |
| 54 | file descriptor becomes ready. */ |
| 55 | NOTHING_SCHEDULED = -2 |
| 56 | /* Either no task is scheduled (just going into ASYNC mode) or a |
| 57 | timer event has just gone off and the current state has been |
| 58 | forced into nothing scheduled. */ |
| 59 | }; |
| 60 | |
| 61 | /* Identify and schedule the next ASYNC task based on scb->async_state |
| 62 | and scb->buf* (the input FIFO). A state machine is used to avoid |
| 63 | the need to make redundant calls into the event-loop - the next |
| 64 | scheduled task is only changed when needed. */ |
| 65 | |
| 66 | static void |
| 67 | reschedule (struct serial *scb) |
| 68 | { |
| 69 | if (serial_is_async_p (scb)) |
| 70 | { |
| 71 | int next_state; |
| 72 | |
| 73 | switch (scb->async_state) |
| 74 | { |
| 75 | case FD_SCHEDULED: |
| 76 | if (scb->bufcnt == 0) |
| 77 | next_state = FD_SCHEDULED; |
| 78 | else |
| 79 | { |
| 80 | delete_file_handler (scb->fd); |
| 81 | next_state = create_timer (0, push_event, scb); |
| 82 | } |
| 83 | break; |
| 84 | case NOTHING_SCHEDULED: |
| 85 | if (scb->bufcnt == 0) |
| 86 | { |
| 87 | add_file_handler (scb->fd, fd_event, scb); |
| 88 | next_state = FD_SCHEDULED; |
| 89 | } |
| 90 | else |
| 91 | { |
| 92 | next_state = create_timer (0, push_event, scb); |
| 93 | } |
| 94 | break; |
| 95 | default: /* TIMER SCHEDULED */ |
| 96 | if (scb->bufcnt == 0) |
| 97 | { |
| 98 | delete_timer (scb->async_state); |
| 99 | add_file_handler (scb->fd, fd_event, scb); |
| 100 | next_state = FD_SCHEDULED; |
| 101 | } |
| 102 | else |
| 103 | next_state = scb->async_state; |
| 104 | break; |
| 105 | } |
| 106 | if (serial_debug_p (scb)) |
| 107 | { |
| 108 | switch (next_state) |
| 109 | { |
| 110 | case FD_SCHEDULED: |
| 111 | if (scb->async_state != FD_SCHEDULED) |
| 112 | fprintf_unfiltered (gdb_stdlog, "[fd%d->fd-scheduled]\n", |
| 113 | scb->fd); |
| 114 | break; |
| 115 | default: /* TIMER SCHEDULED */ |
| 116 | if (scb->async_state == FD_SCHEDULED) |
| 117 | fprintf_unfiltered (gdb_stdlog, "[fd%d->timer-scheduled]\n", |
| 118 | scb->fd); |
| 119 | break; |
| 120 | } |
| 121 | } |
| 122 | scb->async_state = next_state; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | /* Run the SCB's async handle, and reschedule, if the handler doesn't |
| 127 | close SCB. */ |
| 128 | |
| 129 | static void |
| 130 | run_async_handler_and_reschedule (struct serial *scb) |
| 131 | { |
| 132 | int is_open; |
| 133 | |
| 134 | /* Take a reference, so a serial_close call within the handler |
| 135 | doesn't make SCB a dangling pointer. */ |
| 136 | serial_ref (scb); |
| 137 | |
| 138 | /* Run the handler. */ |
| 139 | scb->async_handler (scb, scb->async_context); |
| 140 | |
| 141 | is_open = serial_is_open (scb); |
| 142 | serial_unref (scb); |
| 143 | |
| 144 | /* Get ready for more, if not already closed. */ |
| 145 | if (is_open) |
| 146 | reschedule (scb); |
| 147 | } |
| 148 | |
| 149 | /* FD_EVENT: This is scheduled when the input FIFO is empty (and there |
| 150 | is no pending error). As soon as data arrives, it is read into the |
| 151 | input FIFO and the client notified. The client should then drain |
| 152 | the FIFO using readchar(). If the FIFO isn't immediatly emptied, |
| 153 | push_event() is used to nag the client until it is. */ |
| 154 | |
| 155 | static void |
| 156 | fd_event (int error, void *context) |
| 157 | { |
| 158 | struct serial *scb = context; |
| 159 | if (error != 0) |
| 160 | { |
| 161 | scb->bufcnt = SERIAL_ERROR; |
| 162 | } |
| 163 | else if (scb->bufcnt == 0) |
| 164 | { |
| 165 | /* Prime the input FIFO. The readchar() function is used to |
| 166 | pull characters out of the buffer. See also |
| 167 | generic_readchar(). */ |
| 168 | int nr; |
| 169 | nr = scb->ops->read_prim (scb, BUFSIZ); |
| 170 | if (nr == 0) |
| 171 | { |
| 172 | scb->bufcnt = SERIAL_EOF; |
| 173 | } |
| 174 | else if (nr > 0) |
| 175 | { |
| 176 | scb->bufcnt = nr; |
| 177 | scb->bufp = scb->buf; |
| 178 | } |
| 179 | else |
| 180 | { |
| 181 | scb->bufcnt = SERIAL_ERROR; |
| 182 | } |
| 183 | } |
| 184 | run_async_handler_and_reschedule (scb); |
| 185 | } |
| 186 | |
| 187 | /* PUSH_EVENT: The input FIFO is non-empty (or there is a pending |
| 188 | error). Nag the client until all the data has been read. In the |
| 189 | case of errors, the client will need to close or de-async the |
| 190 | device before naging stops. */ |
| 191 | |
| 192 | static void |
| 193 | push_event (void *context) |
| 194 | { |
| 195 | struct serial *scb = context; |
| 196 | |
| 197 | scb->async_state = NOTHING_SCHEDULED; /* Timers are one-off */ |
| 198 | run_async_handler_and_reschedule (scb); |
| 199 | } |
| 200 | |
| 201 | /* Wait for input on scb, with timeout seconds. Returns 0 on success, |
| 202 | otherwise SERIAL_TIMEOUT or SERIAL_ERROR. */ |
| 203 | |
| 204 | static int |
| 205 | ser_base_wait_for (struct serial *scb, int timeout) |
| 206 | { |
| 207 | while (1) |
| 208 | { |
| 209 | int numfds; |
| 210 | struct timeval tv; |
| 211 | fd_set readfds, exceptfds; |
| 212 | |
| 213 | /* NOTE: Some OS's can scramble the READFDS when the select() |
| 214 | call fails (ex the kernel with Red Hat 5.2). Initialize all |
| 215 | arguments before each call. */ |
| 216 | |
| 217 | tv.tv_sec = timeout; |
| 218 | tv.tv_usec = 0; |
| 219 | |
| 220 | FD_ZERO (&readfds); |
| 221 | FD_ZERO (&exceptfds); |
| 222 | FD_SET (scb->fd, &readfds); |
| 223 | FD_SET (scb->fd, &exceptfds); |
| 224 | |
| 225 | if (timeout >= 0) |
| 226 | numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, &tv); |
| 227 | else |
| 228 | numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, 0); |
| 229 | |
| 230 | if (numfds <= 0) |
| 231 | { |
| 232 | if (numfds == 0) |
| 233 | return SERIAL_TIMEOUT; |
| 234 | else if (errno == EINTR) |
| 235 | continue; |
| 236 | else |
| 237 | return SERIAL_ERROR; /* Got an error from select or |
| 238 | poll. */ |
| 239 | } |
| 240 | |
| 241 | return 0; |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | /* Read any error output we might have. */ |
| 246 | |
| 247 | static void |
| 248 | ser_base_read_error_fd (struct serial *scb, int close_fd) |
| 249 | { |
| 250 | if (scb->error_fd != -1) |
| 251 | { |
| 252 | ssize_t s; |
| 253 | char buf[GDB_MI_MSG_WIDTH + 1]; |
| 254 | |
| 255 | for (;;) |
| 256 | { |
| 257 | char *current; |
| 258 | char *newline; |
| 259 | int to_read = GDB_MI_MSG_WIDTH; |
| 260 | int num_bytes = -1; |
| 261 | |
| 262 | if (scb->ops->avail) |
| 263 | num_bytes = (scb->ops->avail)(scb, scb->error_fd); |
| 264 | |
| 265 | if (num_bytes != -1) |
| 266 | to_read = (num_bytes < to_read) ? num_bytes : to_read; |
| 267 | |
| 268 | if (to_read == 0) |
| 269 | break; |
| 270 | |
| 271 | s = read (scb->error_fd, &buf, to_read); |
| 272 | if ((s == -1) || (s == 0 && !close_fd)) |
| 273 | break; |
| 274 | |
| 275 | if (s == 0 && close_fd) |
| 276 | { |
| 277 | /* End of file. */ |
| 278 | close (scb->error_fd); |
| 279 | scb->error_fd = -1; |
| 280 | break; |
| 281 | } |
| 282 | |
| 283 | /* In theory, embedded newlines are not a problem. |
| 284 | But for MI, we want each output line to have just |
| 285 | one newline for legibility. So output things |
| 286 | in newline chunks. */ |
| 287 | gdb_assert (s > 0 && s <= GDB_MI_MSG_WIDTH); |
| 288 | buf[s] = '\0'; |
| 289 | current = buf; |
| 290 | while ((newline = strstr (current, "\n")) != NULL) |
| 291 | { |
| 292 | *newline = '\0'; |
| 293 | fputs_unfiltered (current, gdb_stderr); |
| 294 | fputs_unfiltered ("\n", gdb_stderr); |
| 295 | current = newline + 1; |
| 296 | } |
| 297 | |
| 298 | fputs_unfiltered (current, gdb_stderr); |
| 299 | } |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | /* Read a character with user-specified timeout. TIMEOUT is number of seconds |
| 304 | to wait, or -1 to wait forever. Use timeout of 0 to effect a poll. Returns |
| 305 | char if successful. Returns -2 if timeout expired, EOF if line dropped |
| 306 | dead, or -3 for any other error (see errno in that case). */ |
| 307 | |
| 308 | static int |
| 309 | do_ser_base_readchar (struct serial *scb, int timeout) |
| 310 | { |
| 311 | int status; |
| 312 | int delta; |
| 313 | |
| 314 | /* We have to be able to keep the GUI alive here, so we break the |
| 315 | original timeout into steps of 1 second, running the "keep the |
| 316 | GUI alive" hook each time through the loop. |
| 317 | |
| 318 | Also, timeout = 0 means to poll, so we just set the delta to 0, |
| 319 | so we will only go through the loop once. */ |
| 320 | |
| 321 | delta = (timeout == 0 ? 0 : 1); |
| 322 | while (1) |
| 323 | { |
| 324 | /* N.B. The UI may destroy our world (for instance by calling |
| 325 | remote_stop,) in which case we want to get out of here as |
| 326 | quickly as possible. It is not safe to touch scb, since |
| 327 | someone else might have freed it. The |
| 328 | deprecated_ui_loop_hook signals that we should exit by |
| 329 | returning 1. */ |
| 330 | |
| 331 | if (deprecated_ui_loop_hook) |
| 332 | { |
| 333 | if (deprecated_ui_loop_hook (0)) |
| 334 | return SERIAL_TIMEOUT; |
| 335 | } |
| 336 | |
| 337 | status = ser_base_wait_for (scb, delta); |
| 338 | if (timeout > 0) |
| 339 | timeout -= delta; |
| 340 | |
| 341 | /* If we got a character or an error back from wait_for, then we can |
| 342 | break from the loop before the timeout is completed. */ |
| 343 | if (status != SERIAL_TIMEOUT) |
| 344 | break; |
| 345 | |
| 346 | /* If we have exhausted the original timeout, then generate |
| 347 | a SERIAL_TIMEOUT, and pass it out of the loop. */ |
| 348 | else if (timeout == 0) |
| 349 | { |
| 350 | status = SERIAL_TIMEOUT; |
| 351 | break; |
| 352 | } |
| 353 | |
| 354 | /* We also need to check and consume the stderr because it could |
| 355 | come before the stdout for some stubs. If we just sit and wait |
| 356 | for stdout, we would hit a deadlock for that case. */ |
| 357 | ser_base_read_error_fd (scb, 0); |
| 358 | } |
| 359 | |
| 360 | if (status < 0) |
| 361 | return status; |
| 362 | |
| 363 | status = scb->ops->read_prim (scb, BUFSIZ); |
| 364 | |
| 365 | if (status <= 0) |
| 366 | { |
| 367 | if (status == 0) |
| 368 | return SERIAL_EOF; |
| 369 | else |
| 370 | /* Got an error from read. */ |
| 371 | return SERIAL_ERROR; |
| 372 | } |
| 373 | |
| 374 | scb->bufcnt = status; |
| 375 | scb->bufcnt--; |
| 376 | scb->bufp = scb->buf; |
| 377 | return *scb->bufp++; |
| 378 | } |
| 379 | |
| 380 | /* Perform operations common to both old and new readchar. */ |
| 381 | |
| 382 | /* Return the next character from the input FIFO. If the FIFO is |
| 383 | empty, call the SERIAL specific routine to try and read in more |
| 384 | characters. |
| 385 | |
| 386 | Initially data from the input FIFO is returned (fd_event() |
| 387 | pre-reads the input into that FIFO. Once that has been emptied, |
| 388 | further data is obtained by polling the input FD using the device |
| 389 | specific readchar() function. Note: reschedule() is called after |
| 390 | every read. This is because there is no guarentee that the lower |
| 391 | level fd_event() poll_event() code (which also calls reschedule()) |
| 392 | will be called. */ |
| 393 | |
| 394 | int |
| 395 | generic_readchar (struct serial *scb, int timeout, |
| 396 | int (do_readchar) (struct serial *scb, int timeout)) |
| 397 | { |
| 398 | int ch; |
| 399 | if (scb->bufcnt > 0) |
| 400 | { |
| 401 | ch = *scb->bufp; |
| 402 | scb->bufcnt--; |
| 403 | scb->bufp++; |
| 404 | } |
| 405 | else if (scb->bufcnt < 0) |
| 406 | { |
| 407 | /* Some errors/eof are are sticky. */ |
| 408 | ch = scb->bufcnt; |
| 409 | } |
| 410 | else |
| 411 | { |
| 412 | ch = do_readchar (scb, timeout); |
| 413 | if (ch < 0) |
| 414 | { |
| 415 | switch ((enum serial_rc) ch) |
| 416 | { |
| 417 | case SERIAL_EOF: |
| 418 | case SERIAL_ERROR: |
| 419 | /* Make the error/eof stick. */ |
| 420 | scb->bufcnt = ch; |
| 421 | break; |
| 422 | case SERIAL_TIMEOUT: |
| 423 | scb->bufcnt = 0; |
| 424 | break; |
| 425 | } |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | /* Read any error output we might have. */ |
| 430 | ser_base_read_error_fd (scb, 1); |
| 431 | |
| 432 | reschedule (scb); |
| 433 | return ch; |
| 434 | } |
| 435 | |
| 436 | int |
| 437 | ser_base_readchar (struct serial *scb, int timeout) |
| 438 | { |
| 439 | return generic_readchar (scb, timeout, do_ser_base_readchar); |
| 440 | } |
| 441 | |
| 442 | int |
| 443 | ser_base_write (struct serial *scb, const char *str, int len) |
| 444 | { |
| 445 | int cc; |
| 446 | |
| 447 | while (len > 0) |
| 448 | { |
| 449 | cc = scb->ops->write_prim (scb, str, len); |
| 450 | |
| 451 | if (cc < 0) |
| 452 | return 1; |
| 453 | len -= cc; |
| 454 | str += cc; |
| 455 | } |
| 456 | return 0; |
| 457 | } |
| 458 | |
| 459 | int |
| 460 | ser_base_flush_output (struct serial *scb) |
| 461 | { |
| 462 | return 0; |
| 463 | } |
| 464 | |
| 465 | int |
| 466 | ser_base_flush_input (struct serial *scb) |
| 467 | { |
| 468 | if (scb->bufcnt >= 0) |
| 469 | { |
| 470 | scb->bufcnt = 0; |
| 471 | scb->bufp = scb->buf; |
| 472 | return 0; |
| 473 | } |
| 474 | else |
| 475 | return SERIAL_ERROR; |
| 476 | } |
| 477 | |
| 478 | int |
| 479 | ser_base_send_break (struct serial *scb) |
| 480 | { |
| 481 | return 0; |
| 482 | } |
| 483 | |
| 484 | int |
| 485 | ser_base_drain_output (struct serial *scb) |
| 486 | { |
| 487 | return 0; |
| 488 | } |
| 489 | |
| 490 | void |
| 491 | ser_base_raw (struct serial *scb) |
| 492 | { |
| 493 | return; /* Always in raw mode. */ |
| 494 | } |
| 495 | |
| 496 | serial_ttystate |
| 497 | ser_base_get_tty_state (struct serial *scb) |
| 498 | { |
| 499 | /* Allocate a dummy. */ |
| 500 | return (serial_ttystate) XMALLOC (int); |
| 501 | } |
| 502 | |
| 503 | serial_ttystate |
| 504 | ser_base_copy_tty_state (struct serial *scb, serial_ttystate ttystate) |
| 505 | { |
| 506 | /* Allocate another dummy. */ |
| 507 | return (serial_ttystate) XMALLOC (int); |
| 508 | } |
| 509 | |
| 510 | int |
| 511 | ser_base_set_tty_state (struct serial *scb, serial_ttystate ttystate) |
| 512 | { |
| 513 | return 0; |
| 514 | } |
| 515 | |
| 516 | int |
| 517 | ser_base_noflush_set_tty_state (struct serial *scb, |
| 518 | serial_ttystate new_ttystate, |
| 519 | serial_ttystate old_ttystate) |
| 520 | { |
| 521 | return 0; |
| 522 | } |
| 523 | |
| 524 | void |
| 525 | ser_base_print_tty_state (struct serial *scb, |
| 526 | serial_ttystate ttystate, |
| 527 | struct ui_file *stream) |
| 528 | { |
| 529 | /* Nothing to print. */ |
| 530 | return; |
| 531 | } |
| 532 | |
| 533 | int |
| 534 | ser_base_setbaudrate (struct serial *scb, int rate) |
| 535 | { |
| 536 | return 0; /* Never fails! */ |
| 537 | } |
| 538 | |
| 539 | int |
| 540 | ser_base_setstopbits (struct serial *scb, int num) |
| 541 | { |
| 542 | return 0; /* Never fails! */ |
| 543 | } |
| 544 | |
| 545 | /* Put the SERIAL device into/out-of ASYNC mode. */ |
| 546 | |
| 547 | void |
| 548 | ser_base_async (struct serial *scb, |
| 549 | int async_p) |
| 550 | { |
| 551 | if (async_p) |
| 552 | { |
| 553 | /* Force a re-schedule. */ |
| 554 | scb->async_state = NOTHING_SCHEDULED; |
| 555 | if (serial_debug_p (scb)) |
| 556 | fprintf_unfiltered (gdb_stdlog, "[fd%d->asynchronous]\n", |
| 557 | scb->fd); |
| 558 | reschedule (scb); |
| 559 | } |
| 560 | else |
| 561 | { |
| 562 | if (serial_debug_p (scb)) |
| 563 | fprintf_unfiltered (gdb_stdlog, "[fd%d->synchronous]\n", |
| 564 | scb->fd); |
| 565 | /* De-schedule whatever tasks are currently scheduled. */ |
| 566 | switch (scb->async_state) |
| 567 | { |
| 568 | case FD_SCHEDULED: |
| 569 | delete_file_handler (scb->fd); |
| 570 | break; |
| 571 | case NOTHING_SCHEDULED: |
| 572 | break; |
| 573 | default: /* TIMER SCHEDULED */ |
| 574 | delete_timer (scb->async_state); |
| 575 | break; |
| 576 | } |
| 577 | } |
| 578 | } |