| 1 | /* Event loop machinery for GDB, the GNU debugger. |
| 2 | Copyright (C) 1999-2020 Free Software Foundation, Inc. |
| 3 | Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions. |
| 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 "gdbsupport/common-defs.h" |
| 21 | #include "gdbsupport/event-loop.h" |
| 22 | |
| 23 | #include <chrono> |
| 24 | |
| 25 | #ifdef HAVE_POLL |
| 26 | #if defined (HAVE_POLL_H) |
| 27 | #include <poll.h> |
| 28 | #elif defined (HAVE_SYS_POLL_H) |
| 29 | #include <sys/poll.h> |
| 30 | #endif |
| 31 | #endif |
| 32 | |
| 33 | #include <sys/types.h> |
| 34 | #include "gdbsupport/gdb_sys_time.h" |
| 35 | #include "gdbsupport/gdb_select.h" |
| 36 | |
| 37 | /* Tell create_file_handler what events we are interested in. |
| 38 | This is used by the select version of the event loop. */ |
| 39 | |
| 40 | #define GDB_READABLE (1<<1) |
| 41 | #define GDB_WRITABLE (1<<2) |
| 42 | #define GDB_EXCEPTION (1<<3) |
| 43 | |
| 44 | /* Information about each file descriptor we register with the event |
| 45 | loop. */ |
| 46 | |
| 47 | typedef struct file_handler |
| 48 | { |
| 49 | int fd; /* File descriptor. */ |
| 50 | int mask; /* Events we want to monitor: POLLIN, etc. */ |
| 51 | int ready_mask; /* Events that have been seen since |
| 52 | the last time. */ |
| 53 | handler_func *proc; /* Procedure to call when fd is ready. */ |
| 54 | gdb_client_data client_data; /* Argument to pass to proc. */ |
| 55 | int error; /* Was an error detected on this fd? */ |
| 56 | struct file_handler *next_file; /* Next registered file descriptor. */ |
| 57 | } |
| 58 | file_handler; |
| 59 | |
| 60 | /* Gdb_notifier is just a list of file descriptors gdb is interested in. |
| 61 | These are the input file descriptor, and the target file |
| 62 | descriptor. We have two flavors of the notifier, one for platforms |
| 63 | that have the POLL function, the other for those that don't, and |
| 64 | only support SELECT. Each of the elements in the gdb_notifier list is |
| 65 | basically a description of what kind of events gdb is interested |
| 66 | in, for each fd. */ |
| 67 | |
| 68 | /* As of 1999-04-30 only the input file descriptor is registered with the |
| 69 | event loop. */ |
| 70 | |
| 71 | /* Do we use poll or select ? */ |
| 72 | #ifdef HAVE_POLL |
| 73 | #define USE_POLL 1 |
| 74 | #else |
| 75 | #define USE_POLL 0 |
| 76 | #endif /* HAVE_POLL */ |
| 77 | |
| 78 | static unsigned char use_poll = USE_POLL; |
| 79 | |
| 80 | #ifdef USE_WIN32API |
| 81 | #include <windows.h> |
| 82 | #include <io.h> |
| 83 | #endif |
| 84 | |
| 85 | static struct |
| 86 | { |
| 87 | /* Ptr to head of file handler list. */ |
| 88 | file_handler *first_file_handler; |
| 89 | |
| 90 | /* Next file handler to handle, for the select variant. To level |
| 91 | the fairness across event sources, we serve file handlers in a |
| 92 | round-robin-like fashion. The number and order of the polled |
| 93 | file handlers may change between invocations, but this is good |
| 94 | enough. */ |
| 95 | file_handler *next_file_handler; |
| 96 | |
| 97 | #ifdef HAVE_POLL |
| 98 | /* Ptr to array of pollfd structures. */ |
| 99 | struct pollfd *poll_fds; |
| 100 | |
| 101 | /* Next file descriptor to handle, for the poll variant. To level |
| 102 | the fairness across event sources, we poll the file descriptors |
| 103 | in a round-robin-like fashion. The number and order of the |
| 104 | polled file descriptors may change between invocations, but |
| 105 | this is good enough. */ |
| 106 | int next_poll_fds_index; |
| 107 | |
| 108 | /* Timeout in milliseconds for calls to poll(). */ |
| 109 | int poll_timeout; |
| 110 | #endif |
| 111 | |
| 112 | /* Masks to be used in the next call to select. |
| 113 | Bits are set in response to calls to create_file_handler. */ |
| 114 | fd_set check_masks[3]; |
| 115 | |
| 116 | /* What file descriptors were found ready by select. */ |
| 117 | fd_set ready_masks[3]; |
| 118 | |
| 119 | /* Number of file descriptors to monitor (for poll). */ |
| 120 | /* Number of valid bits (highest fd value + 1) (for select). */ |
| 121 | int num_fds; |
| 122 | |
| 123 | /* Time structure for calls to select(). */ |
| 124 | struct timeval select_timeout; |
| 125 | |
| 126 | /* Flag to tell whether the timeout should be used. */ |
| 127 | int timeout_valid; |
| 128 | } |
| 129 | gdb_notifier; |
| 130 | |
| 131 | /* Structure associated with a timer. PROC will be executed at the |
| 132 | first occasion after WHEN. */ |
| 133 | struct gdb_timer |
| 134 | { |
| 135 | std::chrono::steady_clock::time_point when; |
| 136 | int timer_id; |
| 137 | struct gdb_timer *next; |
| 138 | timer_handler_func *proc; /* Function to call to do the work. */ |
| 139 | gdb_client_data client_data; /* Argument to async_handler_func. */ |
| 140 | }; |
| 141 | |
| 142 | /* List of currently active timers. It is sorted in order of |
| 143 | increasing timers. */ |
| 144 | static struct |
| 145 | { |
| 146 | /* Pointer to first in timer list. */ |
| 147 | struct gdb_timer *first_timer; |
| 148 | |
| 149 | /* Id of the last timer created. */ |
| 150 | int num_timers; |
| 151 | } |
| 152 | timer_list; |
| 153 | |
| 154 | static void create_file_handler (int fd, int mask, handler_func *proc, |
| 155 | gdb_client_data client_data); |
| 156 | static int gdb_wait_for_event (int); |
| 157 | static int update_wait_timeout (void); |
| 158 | static int poll_timers (void); |
| 159 | \f |
| 160 | /* Process one high level event. If nothing is ready at this time, |
| 161 | wait for something to happen (via gdb_wait_for_event), then process |
| 162 | it. Returns >0 if something was done otherwise returns <0 (this |
| 163 | can happen if there are no event sources to wait for). */ |
| 164 | |
| 165 | int |
| 166 | gdb_do_one_event (void) |
| 167 | { |
| 168 | static int event_source_head = 0; |
| 169 | const int number_of_sources = 3; |
| 170 | int current = 0; |
| 171 | |
| 172 | /* First let's see if there are any asynchronous signal handlers |
| 173 | that are ready. These would be the result of invoking any of the |
| 174 | signal handlers. */ |
| 175 | if (invoke_async_signal_handlers ()) |
| 176 | return 1; |
| 177 | |
| 178 | /* To level the fairness across event sources, we poll them in a |
| 179 | round-robin fashion. */ |
| 180 | for (current = 0; current < number_of_sources; current++) |
| 181 | { |
| 182 | int res; |
| 183 | |
| 184 | switch (event_source_head) |
| 185 | { |
| 186 | case 0: |
| 187 | /* Are any timers that are ready? */ |
| 188 | res = poll_timers (); |
| 189 | break; |
| 190 | case 1: |
| 191 | /* Are there events already waiting to be collected on the |
| 192 | monitored file descriptors? */ |
| 193 | res = gdb_wait_for_event (0); |
| 194 | break; |
| 195 | case 2: |
| 196 | /* Are there any asynchronous event handlers ready? */ |
| 197 | res = check_async_event_handlers (); |
| 198 | break; |
| 199 | default: |
| 200 | internal_error (__FILE__, __LINE__, |
| 201 | "unexpected event_source_head %d", |
| 202 | event_source_head); |
| 203 | } |
| 204 | |
| 205 | event_source_head++; |
| 206 | if (event_source_head == number_of_sources) |
| 207 | event_source_head = 0; |
| 208 | |
| 209 | if (res > 0) |
| 210 | return 1; |
| 211 | } |
| 212 | |
| 213 | /* Block waiting for a new event. If gdb_wait_for_event returns -1, |
| 214 | we should get out because this means that there are no event |
| 215 | sources left. This will make the event loop stop, and the |
| 216 | application exit. */ |
| 217 | |
| 218 | if (gdb_wait_for_event (1) < 0) |
| 219 | return -1; |
| 220 | |
| 221 | /* If gdb_wait_for_event has returned 1, it means that one event has |
| 222 | been handled. We break out of the loop. */ |
| 223 | return 1; |
| 224 | } |
| 225 | |
| 226 | \f |
| 227 | |
| 228 | /* Wrapper function for create_file_handler, so that the caller |
| 229 | doesn't have to know implementation details about the use of poll |
| 230 | vs. select. */ |
| 231 | void |
| 232 | add_file_handler (int fd, handler_func * proc, gdb_client_data client_data) |
| 233 | { |
| 234 | #ifdef HAVE_POLL |
| 235 | struct pollfd fds; |
| 236 | #endif |
| 237 | |
| 238 | if (use_poll) |
| 239 | { |
| 240 | #ifdef HAVE_POLL |
| 241 | /* Check to see if poll () is usable. If not, we'll switch to |
| 242 | use select. This can happen on systems like |
| 243 | m68k-motorola-sys, `poll' cannot be used to wait for `stdin'. |
| 244 | On m68k-motorola-sysv, tty's are not stream-based and not |
| 245 | `poll'able. */ |
| 246 | fds.fd = fd; |
| 247 | fds.events = POLLIN; |
| 248 | if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL)) |
| 249 | use_poll = 0; |
| 250 | #else |
| 251 | internal_error (__FILE__, __LINE__, |
| 252 | _("use_poll without HAVE_POLL")); |
| 253 | #endif /* HAVE_POLL */ |
| 254 | } |
| 255 | if (use_poll) |
| 256 | { |
| 257 | #ifdef HAVE_POLL |
| 258 | create_file_handler (fd, POLLIN, proc, client_data); |
| 259 | #else |
| 260 | internal_error (__FILE__, __LINE__, |
| 261 | _("use_poll without HAVE_POLL")); |
| 262 | #endif |
| 263 | } |
| 264 | else |
| 265 | create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, |
| 266 | proc, client_data); |
| 267 | } |
| 268 | |
| 269 | /* Add a file handler/descriptor to the list of descriptors we are |
| 270 | interested in. |
| 271 | |
| 272 | FD is the file descriptor for the file/stream to be listened to. |
| 273 | |
| 274 | For the poll case, MASK is a combination (OR) of POLLIN, |
| 275 | POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND: |
| 276 | these are the events we are interested in. If any of them occurs, |
| 277 | proc should be called. |
| 278 | |
| 279 | For the select case, MASK is a combination of READABLE, WRITABLE, |
| 280 | EXCEPTION. PROC is the procedure that will be called when an event |
| 281 | occurs for FD. CLIENT_DATA is the argument to pass to PROC. */ |
| 282 | |
| 283 | static void |
| 284 | create_file_handler (int fd, int mask, handler_func * proc, |
| 285 | gdb_client_data client_data) |
| 286 | { |
| 287 | file_handler *file_ptr; |
| 288 | |
| 289 | /* Do we already have a file handler for this file? (We may be |
| 290 | changing its associated procedure). */ |
| 291 | for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL; |
| 292 | file_ptr = file_ptr->next_file) |
| 293 | { |
| 294 | if (file_ptr->fd == fd) |
| 295 | break; |
| 296 | } |
| 297 | |
| 298 | /* It is a new file descriptor. Add it to the list. Otherwise, just |
| 299 | change the data associated with it. */ |
| 300 | if (file_ptr == NULL) |
| 301 | { |
| 302 | file_ptr = XNEW (file_handler); |
| 303 | file_ptr->fd = fd; |
| 304 | file_ptr->ready_mask = 0; |
| 305 | file_ptr->next_file = gdb_notifier.first_file_handler; |
| 306 | gdb_notifier.first_file_handler = file_ptr; |
| 307 | |
| 308 | if (use_poll) |
| 309 | { |
| 310 | #ifdef HAVE_POLL |
| 311 | gdb_notifier.num_fds++; |
| 312 | if (gdb_notifier.poll_fds) |
| 313 | gdb_notifier.poll_fds = |
| 314 | (struct pollfd *) xrealloc (gdb_notifier.poll_fds, |
| 315 | (gdb_notifier.num_fds |
| 316 | * sizeof (struct pollfd))); |
| 317 | else |
| 318 | gdb_notifier.poll_fds = |
| 319 | XNEW (struct pollfd); |
| 320 | (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd; |
| 321 | (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask; |
| 322 | (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0; |
| 323 | #else |
| 324 | internal_error (__FILE__, __LINE__, |
| 325 | _("use_poll without HAVE_POLL")); |
| 326 | #endif /* HAVE_POLL */ |
| 327 | } |
| 328 | else |
| 329 | { |
| 330 | if (mask & GDB_READABLE) |
| 331 | FD_SET (fd, &gdb_notifier.check_masks[0]); |
| 332 | else |
| 333 | FD_CLR (fd, &gdb_notifier.check_masks[0]); |
| 334 | |
| 335 | if (mask & GDB_WRITABLE) |
| 336 | FD_SET (fd, &gdb_notifier.check_masks[1]); |
| 337 | else |
| 338 | FD_CLR (fd, &gdb_notifier.check_masks[1]); |
| 339 | |
| 340 | if (mask & GDB_EXCEPTION) |
| 341 | FD_SET (fd, &gdb_notifier.check_masks[2]); |
| 342 | else |
| 343 | FD_CLR (fd, &gdb_notifier.check_masks[2]); |
| 344 | |
| 345 | if (gdb_notifier.num_fds <= fd) |
| 346 | gdb_notifier.num_fds = fd + 1; |
| 347 | } |
| 348 | } |
| 349 | |
| 350 | file_ptr->proc = proc; |
| 351 | file_ptr->client_data = client_data; |
| 352 | file_ptr->mask = mask; |
| 353 | } |
| 354 | |
| 355 | /* Return the next file handler to handle, and advance to the next |
| 356 | file handler, wrapping around if the end of the list is |
| 357 | reached. */ |
| 358 | |
| 359 | static file_handler * |
| 360 | get_next_file_handler_to_handle_and_advance (void) |
| 361 | { |
| 362 | file_handler *curr_next; |
| 363 | |
| 364 | /* The first time around, this is still NULL. */ |
| 365 | if (gdb_notifier.next_file_handler == NULL) |
| 366 | gdb_notifier.next_file_handler = gdb_notifier.first_file_handler; |
| 367 | |
| 368 | curr_next = gdb_notifier.next_file_handler; |
| 369 | gdb_assert (curr_next != NULL); |
| 370 | |
| 371 | /* Advance. */ |
| 372 | gdb_notifier.next_file_handler = curr_next->next_file; |
| 373 | /* Wrap around, if necessary. */ |
| 374 | if (gdb_notifier.next_file_handler == NULL) |
| 375 | gdb_notifier.next_file_handler = gdb_notifier.first_file_handler; |
| 376 | |
| 377 | return curr_next; |
| 378 | } |
| 379 | |
| 380 | /* Remove the file descriptor FD from the list of monitored fd's: |
| 381 | i.e. we don't care anymore about events on the FD. */ |
| 382 | void |
| 383 | delete_file_handler (int fd) |
| 384 | { |
| 385 | file_handler *file_ptr, *prev_ptr = NULL; |
| 386 | int i; |
| 387 | #ifdef HAVE_POLL |
| 388 | int j; |
| 389 | struct pollfd *new_poll_fds; |
| 390 | #endif |
| 391 | |
| 392 | /* Find the entry for the given file. */ |
| 393 | |
| 394 | for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL; |
| 395 | file_ptr = file_ptr->next_file) |
| 396 | { |
| 397 | if (file_ptr->fd == fd) |
| 398 | break; |
| 399 | } |
| 400 | |
| 401 | if (file_ptr == NULL) |
| 402 | return; |
| 403 | |
| 404 | if (use_poll) |
| 405 | { |
| 406 | #ifdef HAVE_POLL |
| 407 | /* Create a new poll_fds array by copying every fd's information |
| 408 | but the one we want to get rid of. */ |
| 409 | |
| 410 | new_poll_fds = (struct pollfd *) |
| 411 | xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd)); |
| 412 | |
| 413 | for (i = 0, j = 0; i < gdb_notifier.num_fds; i++) |
| 414 | { |
| 415 | if ((gdb_notifier.poll_fds + i)->fd != fd) |
| 416 | { |
| 417 | (new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd; |
| 418 | (new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events; |
| 419 | (new_poll_fds + j)->revents |
| 420 | = (gdb_notifier.poll_fds + i)->revents; |
| 421 | j++; |
| 422 | } |
| 423 | } |
| 424 | xfree (gdb_notifier.poll_fds); |
| 425 | gdb_notifier.poll_fds = new_poll_fds; |
| 426 | gdb_notifier.num_fds--; |
| 427 | #else |
| 428 | internal_error (__FILE__, __LINE__, |
| 429 | _("use_poll without HAVE_POLL")); |
| 430 | #endif /* HAVE_POLL */ |
| 431 | } |
| 432 | else |
| 433 | { |
| 434 | if (file_ptr->mask & GDB_READABLE) |
| 435 | FD_CLR (fd, &gdb_notifier.check_masks[0]); |
| 436 | if (file_ptr->mask & GDB_WRITABLE) |
| 437 | FD_CLR (fd, &gdb_notifier.check_masks[1]); |
| 438 | if (file_ptr->mask & GDB_EXCEPTION) |
| 439 | FD_CLR (fd, &gdb_notifier.check_masks[2]); |
| 440 | |
| 441 | /* Find current max fd. */ |
| 442 | |
| 443 | if ((fd + 1) == gdb_notifier.num_fds) |
| 444 | { |
| 445 | gdb_notifier.num_fds--; |
| 446 | for (i = gdb_notifier.num_fds; i; i--) |
| 447 | { |
| 448 | if (FD_ISSET (i - 1, &gdb_notifier.check_masks[0]) |
| 449 | || FD_ISSET (i - 1, &gdb_notifier.check_masks[1]) |
| 450 | || FD_ISSET (i - 1, &gdb_notifier.check_masks[2])) |
| 451 | break; |
| 452 | } |
| 453 | gdb_notifier.num_fds = i; |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | /* Deactivate the file descriptor, by clearing its mask, |
| 458 | so that it will not fire again. */ |
| 459 | |
| 460 | file_ptr->mask = 0; |
| 461 | |
| 462 | /* If this file handler was going to be the next one to be handled, |
| 463 | advance to the next's next, if any. */ |
| 464 | if (gdb_notifier.next_file_handler == file_ptr) |
| 465 | { |
| 466 | if (file_ptr->next_file == NULL |
| 467 | && file_ptr == gdb_notifier.first_file_handler) |
| 468 | gdb_notifier.next_file_handler = NULL; |
| 469 | else |
| 470 | get_next_file_handler_to_handle_and_advance (); |
| 471 | } |
| 472 | |
| 473 | /* Get rid of the file handler in the file handler list. */ |
| 474 | if (file_ptr == gdb_notifier.first_file_handler) |
| 475 | gdb_notifier.first_file_handler = file_ptr->next_file; |
| 476 | else |
| 477 | { |
| 478 | for (prev_ptr = gdb_notifier.first_file_handler; |
| 479 | prev_ptr->next_file != file_ptr; |
| 480 | prev_ptr = prev_ptr->next_file) |
| 481 | ; |
| 482 | prev_ptr->next_file = file_ptr->next_file; |
| 483 | } |
| 484 | xfree (file_ptr); |
| 485 | } |
| 486 | |
| 487 | /* Handle the given event by calling the procedure associated to the |
| 488 | corresponding file handler. */ |
| 489 | |
| 490 | static void |
| 491 | handle_file_event (file_handler *file_ptr, int ready_mask) |
| 492 | { |
| 493 | int mask; |
| 494 | #ifdef HAVE_POLL |
| 495 | int error_mask; |
| 496 | #endif |
| 497 | |
| 498 | { |
| 499 | { |
| 500 | /* With poll, the ready_mask could have any of three events |
| 501 | set to 1: POLLHUP, POLLERR, POLLNVAL. These events |
| 502 | cannot be used in the requested event mask (events), but |
| 503 | they can be returned in the return mask (revents). We |
| 504 | need to check for those event too, and add them to the |
| 505 | mask which will be passed to the handler. */ |
| 506 | |
| 507 | /* See if the desired events (mask) match the received |
| 508 | events (ready_mask). */ |
| 509 | |
| 510 | if (use_poll) |
| 511 | { |
| 512 | #ifdef HAVE_POLL |
| 513 | /* POLLHUP means EOF, but can be combined with POLLIN to |
| 514 | signal more data to read. */ |
| 515 | error_mask = POLLHUP | POLLERR | POLLNVAL; |
| 516 | mask = ready_mask & (file_ptr->mask | error_mask); |
| 517 | |
| 518 | if ((mask & (POLLERR | POLLNVAL)) != 0) |
| 519 | { |
| 520 | /* Work in progress. We may need to tell somebody |
| 521 | what kind of error we had. */ |
| 522 | if (mask & POLLERR) |
| 523 | warning (_("Error detected on fd %d"), file_ptr->fd); |
| 524 | if (mask & POLLNVAL) |
| 525 | warning (_("Invalid or non-`poll'able fd %d"), |
| 526 | file_ptr->fd); |
| 527 | file_ptr->error = 1; |
| 528 | } |
| 529 | else |
| 530 | file_ptr->error = 0; |
| 531 | #else |
| 532 | internal_error (__FILE__, __LINE__, |
| 533 | _("use_poll without HAVE_POLL")); |
| 534 | #endif /* HAVE_POLL */ |
| 535 | } |
| 536 | else |
| 537 | { |
| 538 | if (ready_mask & GDB_EXCEPTION) |
| 539 | { |
| 540 | warning (_("Exception condition detected on fd %d"), |
| 541 | file_ptr->fd); |
| 542 | file_ptr->error = 1; |
| 543 | } |
| 544 | else |
| 545 | file_ptr->error = 0; |
| 546 | mask = ready_mask & file_ptr->mask; |
| 547 | } |
| 548 | |
| 549 | /* If there was a match, then call the handler. */ |
| 550 | if (mask != 0) |
| 551 | (*file_ptr->proc) (file_ptr->error, file_ptr->client_data); |
| 552 | } |
| 553 | } |
| 554 | } |
| 555 | |
| 556 | /* Wait for new events on the monitored file descriptors. Run the |
| 557 | event handler if the first descriptor that is detected by the poll. |
| 558 | If BLOCK and if there are no events, this function will block in |
| 559 | the call to poll. Return 1 if an event was handled. Return -1 if |
| 560 | there are no file descriptors to monitor. Return 1 if an event was |
| 561 | handled, otherwise returns 0. */ |
| 562 | |
| 563 | static int |
| 564 | gdb_wait_for_event (int block) |
| 565 | { |
| 566 | file_handler *file_ptr; |
| 567 | int num_found = 0; |
| 568 | |
| 569 | /* Make sure all output is done before getting another event. */ |
| 570 | flush_streams (); |
| 571 | |
| 572 | if (gdb_notifier.num_fds == 0) |
| 573 | return -1; |
| 574 | |
| 575 | if (block) |
| 576 | update_wait_timeout (); |
| 577 | |
| 578 | if (use_poll) |
| 579 | { |
| 580 | #ifdef HAVE_POLL |
| 581 | int timeout; |
| 582 | |
| 583 | if (block) |
| 584 | timeout = gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1; |
| 585 | else |
| 586 | timeout = 0; |
| 587 | |
| 588 | num_found = poll (gdb_notifier.poll_fds, |
| 589 | (unsigned long) gdb_notifier.num_fds, timeout); |
| 590 | |
| 591 | /* Don't print anything if we get out of poll because of a |
| 592 | signal. */ |
| 593 | if (num_found == -1 && errno != EINTR) |
| 594 | perror_with_name (("poll")); |
| 595 | #else |
| 596 | internal_error (__FILE__, __LINE__, |
| 597 | _("use_poll without HAVE_POLL")); |
| 598 | #endif /* HAVE_POLL */ |
| 599 | } |
| 600 | else |
| 601 | { |
| 602 | struct timeval select_timeout; |
| 603 | struct timeval *timeout_p; |
| 604 | |
| 605 | if (block) |
| 606 | timeout_p = gdb_notifier.timeout_valid |
| 607 | ? &gdb_notifier.select_timeout : NULL; |
| 608 | else |
| 609 | { |
| 610 | memset (&select_timeout, 0, sizeof (select_timeout)); |
| 611 | timeout_p = &select_timeout; |
| 612 | } |
| 613 | |
| 614 | gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0]; |
| 615 | gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1]; |
| 616 | gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2]; |
| 617 | num_found = gdb_select (gdb_notifier.num_fds, |
| 618 | &gdb_notifier.ready_masks[0], |
| 619 | &gdb_notifier.ready_masks[1], |
| 620 | &gdb_notifier.ready_masks[2], |
| 621 | timeout_p); |
| 622 | |
| 623 | /* Clear the masks after an error from select. */ |
| 624 | if (num_found == -1) |
| 625 | { |
| 626 | FD_ZERO (&gdb_notifier.ready_masks[0]); |
| 627 | FD_ZERO (&gdb_notifier.ready_masks[1]); |
| 628 | FD_ZERO (&gdb_notifier.ready_masks[2]); |
| 629 | |
| 630 | /* Dont print anything if we got a signal, let gdb handle |
| 631 | it. */ |
| 632 | if (errno != EINTR) |
| 633 | perror_with_name (("select")); |
| 634 | } |
| 635 | } |
| 636 | |
| 637 | /* Avoid looking at poll_fds[i]->revents if no event fired. */ |
| 638 | if (num_found <= 0) |
| 639 | return 0; |
| 640 | |
| 641 | /* Run event handlers. We always run just one handler and go back |
| 642 | to polling, in case a handler changes the notifier list. Since |
| 643 | events for sources we haven't consumed yet wake poll/select |
| 644 | immediately, no event is lost. */ |
| 645 | |
| 646 | /* To level the fairness across event descriptors, we handle them in |
| 647 | a round-robin-like fashion. The number and order of descriptors |
| 648 | may change between invocations, but this is good enough. */ |
| 649 | if (use_poll) |
| 650 | { |
| 651 | #ifdef HAVE_POLL |
| 652 | int i; |
| 653 | int mask; |
| 654 | |
| 655 | while (1) |
| 656 | { |
| 657 | if (gdb_notifier.next_poll_fds_index >= gdb_notifier.num_fds) |
| 658 | gdb_notifier.next_poll_fds_index = 0; |
| 659 | i = gdb_notifier.next_poll_fds_index++; |
| 660 | |
| 661 | gdb_assert (i < gdb_notifier.num_fds); |
| 662 | if ((gdb_notifier.poll_fds + i)->revents) |
| 663 | break; |
| 664 | } |
| 665 | |
| 666 | for (file_ptr = gdb_notifier.first_file_handler; |
| 667 | file_ptr != NULL; |
| 668 | file_ptr = file_ptr->next_file) |
| 669 | { |
| 670 | if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd) |
| 671 | break; |
| 672 | } |
| 673 | gdb_assert (file_ptr != NULL); |
| 674 | |
| 675 | mask = (gdb_notifier.poll_fds + i)->revents; |
| 676 | handle_file_event (file_ptr, mask); |
| 677 | return 1; |
| 678 | #else |
| 679 | internal_error (__FILE__, __LINE__, |
| 680 | _("use_poll without HAVE_POLL")); |
| 681 | #endif /* HAVE_POLL */ |
| 682 | } |
| 683 | else |
| 684 | { |
| 685 | /* See comment about even source fairness above. */ |
| 686 | int mask = 0; |
| 687 | |
| 688 | do |
| 689 | { |
| 690 | file_ptr = get_next_file_handler_to_handle_and_advance (); |
| 691 | |
| 692 | if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0])) |
| 693 | mask |= GDB_READABLE; |
| 694 | if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1])) |
| 695 | mask |= GDB_WRITABLE; |
| 696 | if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2])) |
| 697 | mask |= GDB_EXCEPTION; |
| 698 | } |
| 699 | while (mask == 0); |
| 700 | |
| 701 | handle_file_event (file_ptr, mask); |
| 702 | return 1; |
| 703 | } |
| 704 | return 0; |
| 705 | } |
| 706 | \f |
| 707 | /* Create a timer that will expire in MS milliseconds from now. When |
| 708 | the timer is ready, PROC will be executed. At creation, the timer |
| 709 | is added to the timers queue. This queue is kept sorted in order |
| 710 | of increasing timers. Return a handle to the timer struct. */ |
| 711 | |
| 712 | int |
| 713 | create_timer (int ms, timer_handler_func *proc, |
| 714 | gdb_client_data client_data) |
| 715 | { |
| 716 | using namespace std::chrono; |
| 717 | struct gdb_timer *timer_ptr, *timer_index, *prev_timer; |
| 718 | |
| 719 | steady_clock::time_point time_now = steady_clock::now (); |
| 720 | |
| 721 | timer_ptr = new gdb_timer (); |
| 722 | timer_ptr->when = time_now + milliseconds (ms); |
| 723 | timer_ptr->proc = proc; |
| 724 | timer_ptr->client_data = client_data; |
| 725 | timer_list.num_timers++; |
| 726 | timer_ptr->timer_id = timer_list.num_timers; |
| 727 | |
| 728 | /* Now add the timer to the timer queue, making sure it is sorted in |
| 729 | increasing order of expiration. */ |
| 730 | |
| 731 | for (timer_index = timer_list.first_timer; |
| 732 | timer_index != NULL; |
| 733 | timer_index = timer_index->next) |
| 734 | { |
| 735 | if (timer_index->when > timer_ptr->when) |
| 736 | break; |
| 737 | } |
| 738 | |
| 739 | if (timer_index == timer_list.first_timer) |
| 740 | { |
| 741 | timer_ptr->next = timer_list.first_timer; |
| 742 | timer_list.first_timer = timer_ptr; |
| 743 | |
| 744 | } |
| 745 | else |
| 746 | { |
| 747 | for (prev_timer = timer_list.first_timer; |
| 748 | prev_timer->next != timer_index; |
| 749 | prev_timer = prev_timer->next) |
| 750 | ; |
| 751 | |
| 752 | prev_timer->next = timer_ptr; |
| 753 | timer_ptr->next = timer_index; |
| 754 | } |
| 755 | |
| 756 | gdb_notifier.timeout_valid = 0; |
| 757 | return timer_ptr->timer_id; |
| 758 | } |
| 759 | |
| 760 | /* There is a chance that the creator of the timer wants to get rid of |
| 761 | it before it expires. */ |
| 762 | void |
| 763 | delete_timer (int id) |
| 764 | { |
| 765 | struct gdb_timer *timer_ptr, *prev_timer = NULL; |
| 766 | |
| 767 | /* Find the entry for the given timer. */ |
| 768 | |
| 769 | for (timer_ptr = timer_list.first_timer; timer_ptr != NULL; |
| 770 | timer_ptr = timer_ptr->next) |
| 771 | { |
| 772 | if (timer_ptr->timer_id == id) |
| 773 | break; |
| 774 | } |
| 775 | |
| 776 | if (timer_ptr == NULL) |
| 777 | return; |
| 778 | /* Get rid of the timer in the timer list. */ |
| 779 | if (timer_ptr == timer_list.first_timer) |
| 780 | timer_list.first_timer = timer_ptr->next; |
| 781 | else |
| 782 | { |
| 783 | for (prev_timer = timer_list.first_timer; |
| 784 | prev_timer->next != timer_ptr; |
| 785 | prev_timer = prev_timer->next) |
| 786 | ; |
| 787 | prev_timer->next = timer_ptr->next; |
| 788 | } |
| 789 | delete timer_ptr; |
| 790 | |
| 791 | gdb_notifier.timeout_valid = 0; |
| 792 | } |
| 793 | |
| 794 | /* Convert a std::chrono duration to a struct timeval. */ |
| 795 | |
| 796 | template<typename Duration> |
| 797 | static struct timeval |
| 798 | duration_cast_timeval (const Duration &d) |
| 799 | { |
| 800 | using namespace std::chrono; |
| 801 | seconds sec = duration_cast<seconds> (d); |
| 802 | microseconds msec = duration_cast<microseconds> (d - sec); |
| 803 | |
| 804 | struct timeval tv; |
| 805 | tv.tv_sec = sec.count (); |
| 806 | tv.tv_usec = msec.count (); |
| 807 | return tv; |
| 808 | } |
| 809 | |
| 810 | /* Update the timeout for the select() or poll(). Returns true if the |
| 811 | timer has already expired, false otherwise. */ |
| 812 | |
| 813 | static int |
| 814 | update_wait_timeout (void) |
| 815 | { |
| 816 | if (timer_list.first_timer != NULL) |
| 817 | { |
| 818 | using namespace std::chrono; |
| 819 | steady_clock::time_point time_now = steady_clock::now (); |
| 820 | struct timeval timeout; |
| 821 | |
| 822 | if (timer_list.first_timer->when < time_now) |
| 823 | { |
| 824 | /* It expired already. */ |
| 825 | timeout.tv_sec = 0; |
| 826 | timeout.tv_usec = 0; |
| 827 | } |
| 828 | else |
| 829 | { |
| 830 | steady_clock::duration d = timer_list.first_timer->when - time_now; |
| 831 | timeout = duration_cast_timeval (d); |
| 832 | } |
| 833 | |
| 834 | /* Update the timeout for select/ poll. */ |
| 835 | if (use_poll) |
| 836 | { |
| 837 | #ifdef HAVE_POLL |
| 838 | gdb_notifier.poll_timeout = timeout.tv_sec * 1000; |
| 839 | #else |
| 840 | internal_error (__FILE__, __LINE__, |
| 841 | _("use_poll without HAVE_POLL")); |
| 842 | #endif /* HAVE_POLL */ |
| 843 | } |
| 844 | else |
| 845 | { |
| 846 | gdb_notifier.select_timeout.tv_sec = timeout.tv_sec; |
| 847 | gdb_notifier.select_timeout.tv_usec = timeout.tv_usec; |
| 848 | } |
| 849 | gdb_notifier.timeout_valid = 1; |
| 850 | |
| 851 | if (timer_list.first_timer->when < time_now) |
| 852 | return 1; |
| 853 | } |
| 854 | else |
| 855 | gdb_notifier.timeout_valid = 0; |
| 856 | |
| 857 | return 0; |
| 858 | } |
| 859 | |
| 860 | /* Check whether a timer in the timers queue is ready. If a timer is |
| 861 | ready, call its handler and return. Update the timeout for the |
| 862 | select() or poll() as well. Return 1 if an event was handled, |
| 863 | otherwise returns 0.*/ |
| 864 | |
| 865 | static int |
| 866 | poll_timers (void) |
| 867 | { |
| 868 | if (update_wait_timeout ()) |
| 869 | { |
| 870 | struct gdb_timer *timer_ptr = timer_list.first_timer; |
| 871 | timer_handler_func *proc = timer_ptr->proc; |
| 872 | gdb_client_data client_data = timer_ptr->client_data; |
| 873 | |
| 874 | /* Get rid of the timer from the beginning of the list. */ |
| 875 | timer_list.first_timer = timer_ptr->next; |
| 876 | |
| 877 | /* Delete the timer before calling the callback, not after, in |
| 878 | case the callback itself decides to try deleting the timer |
| 879 | too. */ |
| 880 | delete timer_ptr; |
| 881 | |
| 882 | /* Call the procedure associated with that timer. */ |
| 883 | (proc) (client_data); |
| 884 | |
| 885 | return 1; |
| 886 | } |
| 887 | |
| 888 | return 0; |
| 889 | } |