1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850
|
/*
* tclEpollNotfy.c --
*
* This file contains the implementation of the epoll()-based
* Linux-specific notifier, which is the lowest-level part of the Tcl
* event loop. This file works together with generic/tclNotify.c.
*
* Copyright © 1995-1997 Sun Microsystems, Inc.
* Copyright © 2016 Lucio Andrés Illanes Albornoz <l.illanes@gmx.de>
*
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*/
#include "tclInt.h"
#ifndef HAVE_COREFOUNDATION /* Darwin/Mac OS X CoreFoundation notifier is
* in tclMacOSXNotify.c */
#if defined(NOTIFIER_EPOLL) && TCL_THREADS
#ifndef _GNU_SOURCE
# define _GNU_SOURCE /* For pipe2(2) */
#endif
#include <fcntl.h>
#include <signal.h>
#include <sys/epoll.h>
#ifdef HAVE_EVENTFD
#include <sys/eventfd.h>
#endif /* HAVE_EVENTFD */
#include <sys/queue.h>
/*
* This structure is used to keep track of the notifier info for a registered
* file.
*/
struct PlatformEventData;
typedef struct FileHandler {
int fd;
int mask; /* Mask of desired events: TCL_READABLE,
* etc. */
int readyMask; /* Mask of events that have been seen since
* the last time file handlers were invoked
* for this file. */
Tcl_FileProc *proc; /* Function to call, in the style of
* Tcl_CreateFileHandler. */
void *clientData; /* Argument to pass to proc. */
struct FileHandler *nextPtr;/* Next in list of all files we care about. */
LIST_ENTRY(FileHandler) readyNode;
/* Next/previous in list of FileHandlers asso-
* ciated with regular files (S_IFREG) that are
* ready for I/O. */
struct PlatformEventData *pedPtr;
/* Pointer to PlatformEventData associating this
* FileHandler with epoll(7) events. */
} FileHandler;
/*
* The following structure associates a FileHandler and the thread that owns
* it with the file descriptors of interest and their event masks passed to
* epoll_ctl(2) and their corresponding event(s) returned by epoll_wait(2).
*/
struct ThreadSpecificData;
struct PlatformEventData {
FileHandler *filePtr;
struct ThreadSpecificData *tsdPtr;
};
/*
* The following structure is what is added to the Tcl event queue when file
* handlers are ready to fire.
*/
typedef struct {
Tcl_Event header; /* Information that is standard for all
* events. */
int fd; /* File descriptor that is ready. Used to find
* the FileHandler structure for the file
* (can't point directly to the FileHandler
* structure because it could go away while
* the event is queued). */
} FileHandlerEvent;
/*
* The following static structure contains the state information for the
* epoll based implementation of the Tcl notifier. One of these structures is
* created for each thread that is using the notifier.
*/
LIST_HEAD(PlatformReadyFileHandlerList, FileHandler);
typedef struct ThreadSpecificData {
FileHandler *triggerFilePtr;
FileHandler *firstFileHandlerPtr;
/* Pointer to head of file handler list. */
struct PlatformReadyFileHandlerList firstReadyFileHandlerPtr;
/* Pointer to head of list of FileHandlers
* associated with regular files (S_IFREG)
* that are ready for I/O. */
pthread_mutex_t notifierMutex;
/* Mutex protecting notifier termination in
* TclpFinalizeNotifier. */
#ifdef HAVE_EVENTFD
int triggerEventFd; /* eventfd(2) used by other threads to wake
* up this thread for inter-thread IPC. */
#else
int triggerPipe[2]; /* pipe(2) used by other threads to wake
* up this thread for inter-thread IPC. */
#endif /* HAVE_EVENTFD */
int eventsFd; /* epoll(7) file descriptor used to wait for
* fds */
struct epoll_event *readyEvents;
/* Pointer to at most maxReadyEvents events
* returned by epoll_wait(2). */
size_t maxReadyEvents; /* Count of epoll_events in readyEvents. */
int asyncPending; /* True when signal triggered thread. */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;
/*
* Forward declarations.
*/
static void PlatformEventsControl(FileHandler *filePtr,
ThreadSpecificData *tsdPtr, int op, int isNew);
static void PlatformEventsInit(void);
static int PlatformEventsTranslate(struct epoll_event *event);
static int PlatformEventsWait(struct epoll_event *events,
size_t numEvents, struct timeval *timePtr);
/*
* Incorporate the base notifier implementation.
*/
#include "tclUnixNotfy.c"
/*
*----------------------------------------------------------------------
*
* TclpInitNotifier --
*
* Initializes the platform specific notifier state.
*
* Results:
* Returns a handle to the notifier state for this thread.
*
* Side effects:
* If no initNotifierProc notifier hook exists, PlatformEventsInit is
* called.
*
*----------------------------------------------------------------------
*/
void *
TclpInitNotifier(void)
{
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
PlatformEventsInit();
return tsdPtr;
}
/*
*----------------------------------------------------------------------
*
* PlatformEventsControl --
*
* This function registers interest for the file descriptor and the mask
* of TCL_* bits associated with filePtr on the epoll file descriptor
* associated with tsdPtr.
*
* Future calls to epoll_wait will return filePtr and tsdPtr alongside
* with the event registered here via the PlatformEventData struct.
*
* Results:
* None.
*
* Side effects:
* - If adding a new file descriptor, a PlatformEventData struct will be
* allocated and associated with filePtr.
* - fstat is called on the file descriptor; if it is associated with a
* regular file (S_IFREG,) filePtr is considered to be ready for I/O
* and added to or deleted from the corresponding list in tsdPtr.
* - If it is not associated with a regular file, the file descriptor is
* added, modified concerning its mask of events of interest, or
* deleted from the epoll file descriptor of the calling thread.
*
*----------------------------------------------------------------------
*/
static void
PlatformEventsControl(
FileHandler *filePtr,
ThreadSpecificData *tsdPtr,
int op,
int isNew)
{
struct epoll_event newEvent;
struct PlatformEventData *newPedPtr;
Tcl_StatBuf fdStat;
newEvent.events = 0;
if (filePtr->mask & (TCL_READABLE | TCL_EXCEPTION)) {
newEvent.events |= EPOLLIN;
}
if (filePtr->mask & TCL_WRITABLE) {
newEvent.events |= EPOLLOUT;
}
if (isNew) {
newPedPtr = (struct PlatformEventData *)
Tcl_Alloc(sizeof(struct PlatformEventData));
newPedPtr->filePtr = filePtr;
newPedPtr->tsdPtr = tsdPtr;
filePtr->pedPtr = newPedPtr;
}
newEvent.data.ptr = filePtr->pedPtr;
/*
* N.B. As discussed in Tcl_WaitForEvent(), epoll(7) does not support
* regular files (S_IFREG). Therefore, filePtr is in these cases simply
* added or deleted from the list of FileHandlers associated with regular
* files belonging to tsdPtr.
*/
if (TclOSfstat(filePtr->fd, &fdStat) == -1) {
/*
* The tclEpollNotfy PlatformEventsControl function panics if the TclOSfstat
* call returns -1, which occurs when using a websocket to a browser and the
* browser page is refreshed. It seems the fstat call isn't doing anything
* useful, in particular the contents of the statbuf aren't examined afterwards
* on success and at best it changes the panic message. Instead we avoid the
* panic at the cost of a memory leak. See [010d8f38]
*/
return;
} else if (epoll_ctl(tsdPtr->eventsFd, op, filePtr->fd, &newEvent) == -1) {
switch (errno) {
case EPERM:
switch (op) {
case EPOLL_CTL_ADD:
if (isNew) {
LIST_INSERT_HEAD(&tsdPtr->firstReadyFileHandlerPtr, filePtr,
readyNode);
}
break;
case EPOLL_CTL_DEL:
LIST_REMOVE(filePtr, readyNode);
break;
}
break;
default:
Tcl_Panic("epoll_ctl: %s", strerror(errno));
}
}
return;
}
/*
*----------------------------------------------------------------------
*
* TclpFinalizeNotifier --
*
* This function closes the eventfd and the epoll file descriptor and
* frees the epoll_event structs owned by the thread of the caller. The
* above operations are protected by tsdPtr->notifierMutex, which is
* destroyed thereafter.
*
* Results:
* None.
*
* Side effects:
* While tsdPtr->notifierMutex is held:
* - The per-thread eventfd(2) is closed, if non-zero, and set to -1.
* - The per-thread epoll(7) fd is closed, if non-zero, and set to 0.
* - The per-thread epoll_event structs are freed, if any, and set to 0.
*
* tsdPtr->notifierMutex is destroyed.
*
*----------------------------------------------------------------------
*/
void
TclpFinalizeNotifier(
TCL_UNUSED(void *))
{
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
pthread_mutex_lock(&tsdPtr->notifierMutex);
#ifdef HAVE_EVENTFD
if (tsdPtr->triggerEventFd) {
close(tsdPtr->triggerEventFd);
tsdPtr->triggerEventFd = -1;
}
#else /* !HAVE_EVENTFD */
if (tsdPtr->triggerPipe[0]) {
close(tsdPtr->triggerPipe[0]);
tsdPtr->triggerPipe[0] = -1;
}
if (tsdPtr->triggerPipe[1]) {
close(tsdPtr->triggerPipe[1]);
tsdPtr->triggerPipe[1] = -1;
}
#endif /* HAVE_EVENTFD */
Tcl_Free(tsdPtr->triggerFilePtr->pedPtr);
Tcl_Free(tsdPtr->triggerFilePtr);
if (tsdPtr->eventsFd > 0) {
close(tsdPtr->eventsFd);
tsdPtr->eventsFd = 0;
}
if (tsdPtr->readyEvents) {
Tcl_Free(tsdPtr->readyEvents);
tsdPtr->maxReadyEvents = 0;
}
pthread_mutex_unlock(&tsdPtr->notifierMutex);
if ((errno = pthread_mutex_destroy(&tsdPtr->notifierMutex))) {
Tcl_Panic("pthread_mutex_destroy: %s", strerror(errno));
}
}
/*
*----------------------------------------------------------------------
*
* PlatformEventsInit --
*
* This function abstracts creating a kqueue fd via the epoll_create
* system call and allocating memory for the epoll_event structs in
* tsdPtr for the thread of the caller.
*
* Results:
* None.
*
* Side effects:
* The following per-thread entities are initialised:
* - notifierMutex is initialised.
* - The eventfd(2) is created w/ EFD_CLOEXEC and EFD_NONBLOCK.
* - The epoll(7) fd is created w/ EPOLL_CLOEXEC.
* - A FileHandler struct is allocated and initialised for the
* eventfd(2), registering interest for TCL_READABLE on it via
* PlatformEventsControl().
* - readyEvents and maxReadyEvents are initialised with 512
* epoll_events.
*
*----------------------------------------------------------------------
*/
static void
PlatformEventsInit(void)
{
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
FileHandler *filePtr;
errno = pthread_mutex_init(&tsdPtr->notifierMutex, NULL);
if (errno) {
Tcl_Panic("Tcl_InitNotifier: %s", "could not create mutex");
}
filePtr = (FileHandler *) Tcl_Alloc(sizeof(FileHandler));
#ifdef HAVE_EVENTFD
tsdPtr->triggerEventFd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (tsdPtr->triggerEventFd <= 0) {
Tcl_Panic("Tcl_InitNotifier: %s", "could not create trigger eventfd");
}
filePtr->fd = tsdPtr->triggerEventFd;
#else /* !HAVE_EVENTFD */
if (pipe2(tsdPtr->triggerPipe, O_CLOEXEC | O_NONBLOCK) != 0) {
Tcl_Panic("Tcl_InitNotifier: %s", "could not create trigger pipe");
}
filePtr->fd = tsdPtr->triggerPipe[0];
#endif /* HAVE_EVENTFD */
tsdPtr->triggerFilePtr = filePtr;
if ((tsdPtr->eventsFd = epoll_create1(EPOLL_CLOEXEC)) == -1) {
Tcl_Panic("epoll_create1: %s", strerror(errno));
}
filePtr->mask = TCL_READABLE;
PlatformEventsControl(filePtr, tsdPtr, EPOLL_CTL_ADD, 1);
if (!tsdPtr->readyEvents) {
tsdPtr->maxReadyEvents = 512;
tsdPtr->readyEvents = (struct epoll_event *) Tcl_Alloc(
tsdPtr->maxReadyEvents * sizeof(tsdPtr->readyEvents[0]));
}
LIST_INIT(&tsdPtr->firstReadyFileHandlerPtr);
}
/*
*----------------------------------------------------------------------
*
* PlatformEventsTranslate --
*
* This function translates the platform-specific mask of returned events
* in eventPtr to a mask of TCL_* bits.
*
* Results:
* Returns the translated mask.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static int
PlatformEventsTranslate(
struct epoll_event *eventPtr)
{
int mask;
mask = 0;
if (eventPtr->events & (EPOLLIN | EPOLLHUP)) {
mask |= TCL_READABLE;
}
if (eventPtr->events & EPOLLOUT) {
mask |= TCL_WRITABLE;
}
if (eventPtr->events & EPOLLERR) {
mask |= TCL_EXCEPTION;
}
return mask;
}
/*
*----------------------------------------------------------------------
*
* PlatformEventsWait --
*
* This function abstracts waiting for I/O events via epoll_wait.
*
* Results:
* Returns -1 if epoll_wait failed. Returns 0 if polling and if no events
* became available whilst polling. Returns a pointer to and the count of
* all returned events in all other cases.
*
* Side effects:
* gettimeofday(2), epoll_wait(2), and gettimeofday(2) are called, in the
* specified order.
* If timePtr specifies a positive value, it is updated to reflect the
* amount of time that has passed; if its value would {under, over}flow,
* it is set to zero.
*
*----------------------------------------------------------------------
*/
static int
PlatformEventsWait(
struct epoll_event *events,
size_t numEvents,
struct timeval *timePtr)
{
int numFound;
struct timeval tv0, tv1, tv_delta;
int timeout;
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
/*
* If timePtr is NULL, epoll_wait(2) will wait indefinitely. If it
* specifies a timeout of {0,0}, epoll_wait(2) will poll. Otherwise, the
* timeout will simply be converted to milliseconds.
*/
if (!timePtr) {
timeout = -1;
} else if (!timePtr->tv_sec && !timePtr->tv_usec) {
timeout = 0;
} else {
timeout = (int) timePtr->tv_sec * 1000;
if (timePtr->tv_usec) {
timeout += (int) timePtr->tv_usec / 1000;
}
}
/*
* Call (and possibly block on) epoll_wait(2) and substract the delta of
* gettimeofday(2) before and after the call from timePtr if the latter is
* not NULL. Return the number of events returned by epoll_wait(2).
*/
gettimeofday(&tv0, NULL);
numFound = epoll_wait(tsdPtr->eventsFd, events, (int) numEvents, timeout);
gettimeofday(&tv1, NULL);
if (timePtr && (timePtr->tv_sec && timePtr->tv_usec)) {
timersub(&tv1, &tv0, &tv_delta);
if (!timercmp(&tv_delta, timePtr, >)) {
timersub(timePtr, &tv_delta, timePtr);
} else {
timePtr->tv_sec = 0;
timePtr->tv_usec = 0;
}
}
if (tsdPtr->asyncPending) {
tsdPtr->asyncPending = 0;
TclAsyncMarkFromNotifier();
}
return numFound;
}
/*
*----------------------------------------------------------------------
*
* TclpCreateFileHandler --
*
* This function registers a file handler with the epoll notifier of the
* thread of the caller.
*
* Results:
* None.
*
* Side effects:
* Creates a new file handler structure.
* PlatformEventsControl() is called for the new file handler structure.
*
*----------------------------------------------------------------------
*/
void
TclpCreateFileHandler(
int fd, /* Handle of stream to watch. */
int mask, /* OR'ed combination of TCL_READABLE,
* TCL_WRITABLE, and TCL_EXCEPTION: indicates
* conditions under which proc should be
* called. */
Tcl_FileProc *proc, /* Function to call for each selected
* event. */
void *clientData) /* Arbitrary data to pass to proc. */
{
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
FileHandler *filePtr = LookUpFileHandler(tsdPtr, fd, NULL);
int isNew = (filePtr == NULL);
if (isNew) {
filePtr = (FileHandler *) Tcl_Alloc(sizeof(FileHandler));
filePtr->fd = fd;
filePtr->readyMask = 0;
filePtr->nextPtr = tsdPtr->firstFileHandlerPtr;
tsdPtr->firstFileHandlerPtr = filePtr;
}
filePtr->proc = proc;
filePtr->clientData = clientData;
filePtr->mask = mask;
PlatformEventsControl(filePtr, tsdPtr,
isNew ? EPOLL_CTL_ADD : EPOLL_CTL_MOD, isNew);
}
/*
*----------------------------------------------------------------------
*
* TclpDeleteFileHandler --
*
* Cancel a previously-arranged callback arrangement for a file on the
* epoll file descriptor of the thread of the caller.
*
* Results:
* None.
*
* Side effects:
* If a callback was previously registered on file, remove it.
* PlatformEventsControl() is called for the file handler structure.
* The PlatformEventData struct associated with the new file handler
* structure is freed.
*
*----------------------------------------------------------------------
*/
void
TclpDeleteFileHandler(
int fd) /* Stream id for which to remove callback
* function. */
{
FileHandler *filePtr, *prevPtr;
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
/*
* Find the entry for the given file (and return if there isn't one).
*/
filePtr = LookUpFileHandler(tsdPtr, fd, &prevPtr);
if (filePtr == NULL) {
return;
}
/*
* Update the check masks for this file.
*/
PlatformEventsControl(filePtr, tsdPtr, EPOLL_CTL_DEL, 0);
if (filePtr->pedPtr) {
Tcl_Free(filePtr->pedPtr);
}
/*
* Clean up information in the callback record.
*/
if (prevPtr == NULL) {
tsdPtr->firstFileHandlerPtr = filePtr->nextPtr;
} else {
prevPtr->nextPtr = filePtr->nextPtr;
}
Tcl_Free(filePtr);
}
/*
*----------------------------------------------------------------------
*
* TclpWaitForEvent --
*
* This function is called by Tcl_DoOneEvent to wait for new events on
* the message queue. If the block time is 0, then TclpWaitForEvent just
* polls without blocking.
*
* The waiting logic is implemented in PlatformEventsWait.
*
* Results:
* Returns -1 if PlatformEventsWait() would block forever, otherwise
* returns 0.
*
* Side effects:
* Queues file events that are detected by PlatformEventsWait().
*
*----------------------------------------------------------------------
*/
int
TclpWaitForEvent(
const Tcl_Time *timePtr) /* Maximum block time, or NULL. */
{
FileHandler *filePtr;
Tcl_Time vTime;
struct timeval timeout, *timeoutPtr;
/* Impl. notes: timeout & timeoutPtr are used
* if, and only if threads are not enabled.
* They are the arguments for the regular
* epoll_wait() used when the core is not
* thread-enabled. */
int mask, numFound, numEvent;
struct PlatformEventData *pedPtr;
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
int numQueued;
ssize_t i;
/*
* Set up the timeout structure. Note that if there are no events to check
* for, we return with a negative result rather than blocking forever.
*/
if (timePtr != NULL) {
/*
* TIP #233 (Virtualized Time). Is virtual time in effect? And do we
* actually have something to scale? If yes to both then we call the
* handler to do this scaling.
*/
if (timePtr->sec != 0 || timePtr->usec != 0) {
vTime = *timePtr;
TclScaleTime(&vTime);
timePtr = &vTime;
}
timeout.tv_sec = timePtr->sec;
timeout.tv_usec = timePtr->usec;
timeoutPtr = &timeout;
} else {
timeoutPtr = NULL;
}
/*
* Walk the list of FileHandlers associated with regular files (S_IFREG)
* belonging to tsdPtr, queue Tcl events for them, and update their mask
* of events of interest.
*
* As epoll(7) does not support regular files, the behaviour of
* {select,poll}(2) is simply simulated here: fds associated with regular
* files are added to this list by PlatformEventsControl() and processed
* here before calling (and possibly blocking) on PlatformEventsWait().
*/
numQueued = 0;
LIST_FOREACH(filePtr, &tsdPtr->firstReadyFileHandlerPtr, readyNode) {
mask = 0;
if (filePtr->mask & TCL_READABLE) {
mask |= TCL_READABLE;
}
if (filePtr->mask & TCL_WRITABLE) {
mask |= TCL_WRITABLE;
}
/*
* Don't bother to queue an event if the mask was previously non-zero
* since an event must still be on the queue.
*/
if (filePtr->readyMask == 0) {
FileHandlerEvent *fileEvPtr = (FileHandlerEvent *)
Tcl_Alloc(sizeof(FileHandlerEvent));
fileEvPtr->header.proc = FileHandlerEventProc;
fileEvPtr->fd = filePtr->fd;
Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
numQueued++;
}
filePtr->readyMask = mask;
}
/*
* If any events were queued in the above loop, force PlatformEventsWait()
* to poll as there already are events that need to be processed at this
* point.
*/
if (numQueued) {
timeout.tv_sec = 0;
timeout.tv_usec = 0;
timeoutPtr = &timeout;
}
/*
* Wait or poll for new events, queue Tcl events for the FileHandlers
* corresponding to them, and update the FileHandlers' mask of events of
* interest registered by the last call to Tcl_CreateFileHandler().
*
* Events for the eventfd(2)/trigger pipe are processed here in order to
* facilitate inter-thread IPC. If another thread intends to wake up this
* thread whilst it's blocking on PlatformEventsWait(), it write(2)s to
* the eventfd(2)/trigger pipe (see Tcl_AlertNotifier(),) which in turn
* will cause PlatformEventsWait() to return immediately.
*/
numFound = PlatformEventsWait(tsdPtr->readyEvents,
tsdPtr->maxReadyEvents, timeoutPtr);
for (numEvent = 0; numEvent < numFound; numEvent++) {
pedPtr = (struct PlatformEventData *)
tsdPtr->readyEvents[numEvent].data.ptr;
filePtr = pedPtr->filePtr;
mask = PlatformEventsTranslate(&tsdPtr->readyEvents[numEvent]);
#ifdef HAVE_EVENTFD
if (filePtr->fd == tsdPtr->triggerEventFd) {
uint64_t eventFdVal;
i = read(tsdPtr->triggerEventFd, &eventFdVal, sizeof(eventFdVal));
if ((i != sizeof(eventFdVal)) && (errno != EAGAIN)) {
Tcl_Panic("%s: read from %p->triggerEventFd: %s",
"Tcl_WaitForEvent", tsdPtr, strerror(errno));
}
continue;
}
#else /* !HAVE_EVENTFD */
if (filePtr->fd == tsdPtr->triggerPipe[0]) {
char triggerPipeVal;
i = read(tsdPtr->triggerPipe[0], &triggerPipeVal,
sizeof(triggerPipeVal));
if ((i != sizeof(triggerPipeVal)) && (errno != EAGAIN)) {
Tcl_Panic("%s: read from %p->triggerPipe[0]: %s",
"Tcl_WaitForEvent", tsdPtr, strerror(errno));
}
continue;
}
#endif /* HAVE_EVENTFD */
if (!mask) {
continue;
}
/*
* Don't bother to queue an event if the mask was previously non-zero
* since an event must still be on the queue.
*/
if (filePtr->readyMask == 0) {
FileHandlerEvent *fileEvPtr = (FileHandlerEvent *)
Tcl_Alloc(sizeof(FileHandlerEvent));
fileEvPtr->header.proc = FileHandlerEventProc;
fileEvPtr->fd = filePtr->fd;
Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
}
filePtr->readyMask = mask;
}
return 0;
}
/*
*----------------------------------------------------------------------
*
* TclAsyncNotifier --
*
* This procedure sets the async mark of an async handler to a
* given value, if it is called from the target thread.
*
* Result:
* True, when the handler will be marked, false otherwise.
*
* Side effects:
* The signal may be resent to the target thread.
*
*----------------------------------------------------------------------
*/
int
TclAsyncNotifier(
int sigNumber, /* Signal number. */
Tcl_ThreadId threadId, /* Target thread. */
void *clientData, /* Notifier data. */
int *flagPtr, /* Flag to mark. */
int value) /* Value of mark. */
{
#if TCL_THREADS
/*
* WARNING:
* This code most likely runs in a signal handler. Thus,
* only few async-signal-safe system calls are allowed,
* e.g. pthread_self(), sem_post(), write().
*/
if (pthread_equal(pthread_self(), (pthread_t) threadId)) {
ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;
*flagPtr = value;
if (tsdPtr != NULL && !tsdPtr->asyncPending) {
tsdPtr->asyncPending = 1;
TclpAlertNotifier(tsdPtr);
return 1;
}
return 0;
}
/*
* Re-send the signal to the proper target thread.
*/
pthread_kill((pthread_t) threadId, sigNumber);
#else
(void)sigNumber;
(void)threadId;
(void)clientData;
(void)flagPtr;
(void)value;
#endif
return 0;
}
#endif /* NOTIFIER_EPOLL && TCL_THREADS */
#else
TCL_MAC_EMPTY_FILE(unix_tclEpollNotfy_c)
#endif /* !HAVE_COREFOUNDATION */
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
|