root/gc/win32_threads.c
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DEFINITIONS
This source file includes following definitions.
- GC_new_thread
- GC_get_max_thread_index
- GC_delete_gc_thread
- GC_delete_thread
- GC_lookup_thread
- GC_PROTO
- GC_stop_world
- GC_start_world
- GC_current_stackbottom
- GC_get_stack_min
- GC_push_all_stacks
- GC_get_next_stack
- GC_CreateThread
- thread_args
- GC_CreateThread
- thread_start
- main_thread_args
- WinMain
- main_thread_start
- GC_thr_init
- GC_pthread_join
- GC_pthread_create
- GC_start_routine
- GC_thread_exit_proc
- GC_pthread_sigmask
- GC_pthread_detach
- DllMain
1 #include "private/gc_priv.h"
2
3 #if defined(GC_WIN32_THREADS)
4
5 #include <windows.h>
6
7 #ifdef CYGWIN32
8 # include <errno.h>
9
10 /* Cygwin-specific forward decls */
11 # undef pthread_create
12 # undef pthread_sigmask
13 # undef pthread_join
14 # undef pthread_detach
15 # undef dlopen
16
17 # define DEBUG_CYGWIN_THREADS 0
18
19 void * GC_start_routine(void * arg);
20 void GC_thread_exit_proc(void *arg);
21
22 #endif
23
24 /* The type of the first argument to InterlockedExchange. */
25 /* Documented to be LONG volatile *, but at least gcc likes */
26 /* this better. */
27 typedef LONG * IE_t;
28
29 #ifndef MAX_THREADS
30 # define MAX_THREADS 256
31 /* FIXME: */
32 /* Things may get quite slow for large numbers of threads, */
33 /* since we look them up with sequential search. */
34 #endif
35
36 GC_bool GC_thr_initialized = FALSE;
37
38 DWORD GC_main_thread = 0;
39
40 struct GC_thread_Rep {
41 LONG in_use; /* Updated without lock. */
42 /* We assert that unused */
43 /* entries have invalid ids of */
44 /* zero and zero stack fields. */
45 DWORD id;
46 HANDLE handle;
47 ptr_t stack_base; /* The cold end of the stack. */
48 /* 0 ==> entry not valid. */
49 /* !in_use ==> stack_base == 0 */
50 GC_bool suspended;
51
52 # ifdef CYGWIN32
53 void *status; /* hold exit value until join in case it's a pointer */
54 pthread_t pthread_id;
55 short flags; /* Protected by GC lock. */
56 # define FINISHED 1 /* Thread has exited. */
57 # define DETACHED 2 /* Thread is intended to be detached. */
58 # endif
59 };
60
61 typedef volatile struct GC_thread_Rep * GC_thread;
62
63 /*
64 * We generally assume that volatile ==> memory ordering, at least among
65 * volatiles.
66 */
67
68 volatile GC_bool GC_please_stop = FALSE;
69
70 volatile struct GC_thread_Rep thread_table[MAX_THREADS];
71
72 volatile LONG GC_max_thread_index = 0; /* Largest index in thread_table */
73 /* that was ever used. */
74
75 extern LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info);
76
77 /*
78 * This may be called from DllMain, and hence operates under unusual
79 * constraints.
80 */
81 static GC_thread GC_new_thread(void) {
82 int i;
83 /* It appears to be unsafe to acquire a lock here, since this */
84 /* code is apparently not preeemptible on some systems. */
85 /* (This is based on complaints, not on Microsoft's official */
86 /* documentation, which says this should perform "only simple */
87 /* initialization tasks".) */
88 /* Hence we make do with nonblocking synchronization. */
89
90 /* The following should be a noop according to the win32 */
91 /* documentation. There is empirical evidence that it */
92 /* isn't. - HB */
93 # if defined(MPROTECT_VDB)
94 if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
95 # endif
96 /* cast away volatile qualifier */
97 for (i = 0; InterlockedExchange((IE_t)&thread_table[i].in_use,1) != 0; i++) {
98 /* Compare-and-swap would make this cleaner, but that's not */
99 /* supported before Windows 98 and NT 4.0. In Windows 2000, */
100 /* InterlockedExchange is supposed to be replaced by */
101 /* InterlockedExchangePointer, but that's not really what I */
102 /* want here. */
103 if (i == MAX_THREADS - 1)
104 ABORT("too many threads");
105 }
106 /* Update GC_max_thread_index if necessary. The following is safe, */
107 /* and unlike CompareExchange-based solutions seems to work on all */
108 /* Windows95 and later platforms. */
109 /* Unfortunately, GC_max_thread_index may be temporarily out of */
110 /* bounds, so readers have to compensate. */
111 while (i > GC_max_thread_index) {
112 InterlockedIncrement((IE_t)&GC_max_thread_index);
113 }
114 if (GC_max_thread_index >= MAX_THREADS) {
115 /* We overshot due to simultaneous increments. */
116 /* Setting it to MAX_THREADS-1 is always safe. */
117 GC_max_thread_index = MAX_THREADS - 1;
118 }
119
120 # ifdef CYGWIN32
121 thread_table[i].pthread_id = pthread_self();
122 # endif
123 if (!DuplicateHandle(GetCurrentProcess(),
124 GetCurrentThread(),
125 GetCurrentProcess(),
126 (HANDLE*)&thread_table[i].handle,
127 0,
128 0,
129 DUPLICATE_SAME_ACCESS)) {
130 DWORD last_error = GetLastError();
131 GC_printf1("Last error code: %lx\n", last_error);
132 ABORT("DuplicateHandle failed");
133 }
134 thread_table[i].stack_base = GC_get_stack_base();
135 /* Up until this point, GC_push_all_stacks considers this thread */
136 /* invalid. */
137 if (thread_table[i].stack_base == NULL)
138 ABORT("Failed to find stack base in GC_new_thread");
139 /* Up until this point, this entry is viewed as reserved but invalid */
140 /* by GC_delete_thread. */
141 thread_table[i].id = GetCurrentThreadId();
142 /* If this thread is being created while we are trying to stop */
143 /* the world, wait here. Hopefully this can't happen on any */
144 /* systems that don't allow us to block here. */
145 while (GC_please_stop) Sleep(20);
146 return thread_table + i;
147 }
148
149 /*
150 * GC_max_thread_index may temporarily be larger than MAX_THREADS.
151 * To avoid subscript errors, we check on access.
152 */
153 #ifdef __GNUC__
154 __inline__
155 #endif
156 LONG GC_get_max_thread_index()
157 {
158 LONG my_max = GC_max_thread_index;
159
160 if (my_max >= MAX_THREADS) return MAX_THREADS-1;
161 return my_max;
162 }
163
164 /* This is intended to be lock-free, though that */
165 /* assumes that the CloseHandle becomes visible before the */
166 /* in_use assignment. */
167 static void GC_delete_gc_thread(GC_thread thr)
168 {
169 CloseHandle(thr->handle);
170 /* cast away volatile qualifier */
171 thr->stack_base = 0;
172 thr->id = 0;
173 # ifdef CYGWIN32
174 thr->pthread_id = 0;
175 # endif /* CYGWIN32 */
176 thr->in_use = FALSE;
177 }
178
179 static void GC_delete_thread(DWORD thread_id) {
180 int i;
181 LONG my_max = GC_get_max_thread_index();
182
183 for (i = 0;
184 i <= my_max &&
185 (!thread_table[i].in_use || thread_table[i].id != thread_id);
186 /* Must still be in_use, since nobody else can store our thread_id. */
187 i++) {}
188 if (i > my_max) {
189 WARN("Removing nonexistent thread %ld\n", (GC_word)thread_id);
190 } else {
191 GC_delete_gc_thread(thread_table+i);
192 }
193 }
194
195
196 #ifdef CYGWIN32
197
198 /* Return a GC_thread corresponding to a given pthread_t. */
199 /* Returns 0 if it's not there. */
200 /* We assume that this is only called for pthread ids that */
201 /* have not yet terminated or are still joinable. */
202 static GC_thread GC_lookup_thread(pthread_t id)
203 {
204 int i;
205 LONG my_max = GC_get_max_thread_index();
206
207 for (i = 0;
208 i <= my_max &&
209 (!thread_table[i].in_use || thread_table[i].pthread_id != id
210 || !thread_table[i].in_use);
211 /* Must still be in_use, since nobody else can store our thread_id. */
212 i++);
213 if (i > my_max) return 0;
214 return thread_table + i;
215 }
216
217 #endif /* CYGWIN32 */
218
219 void GC_push_thread_structures GC_PROTO((void))
220 {
221 /* Unlike the other threads implementations, the thread table here */
222 /* contains no pointers to the collectable heap. Thus we have */
223 /* no private structures we need to preserve. */
224 # ifdef CYGWIN32
225 { int i; /* pthreads may keep a pointer in the thread exit value */
226 LONG my_max = GC_get_max_thread_index();
227
228 for (i = 0; i <= my_max; i++)
229 if (thread_table[i].in_use)
230 GC_push_all((ptr_t)&(thread_table[i].status),
231 (ptr_t)(&(thread_table[i].status)+1));
232 }
233 # endif
234 }
235
236 void GC_stop_world()
237 {
238 DWORD thread_id = GetCurrentThreadId();
239 int i;
240
241 if (!GC_thr_initialized) ABORT("GC_stop_world() called before GC_thr_init()");
242
243 GC_please_stop = TRUE;
244 for (i = 0; i <= GC_get_max_thread_index(); i++)
245 if (thread_table[i].stack_base != 0
246 && thread_table[i].id != thread_id) {
247 # ifdef MSWINCE
248 /* SuspendThread will fail if thread is running kernel code */
249 while (SuspendThread(thread_table[i].handle) == (DWORD)-1)
250 Sleep(10);
251 # else
252 /* Apparently the Windows 95 GetOpenFileName call creates */
253 /* a thread that does not properly get cleaned up, and */
254 /* SuspendThread on its descriptor may provoke a crash. */
255 /* This reduces the probability of that event, though it still */
256 /* appears there's a race here. */
257 DWORD exitCode;
258 if (GetExitCodeThread(thread_table[i].handle,&exitCode) &&
259 exitCode != STILL_ACTIVE) {
260 thread_table[i].stack_base = 0; /* prevent stack from being pushed */
261 # ifndef CYGWIN32
262 /* this breaks pthread_join on Cygwin, which is guaranteed to */
263 /* only see user pthreads */
264 thread_table[i].in_use = FALSE;
265 CloseHandle(thread_table[i].handle);
266 # endif
267 continue;
268 }
269 if (SuspendThread(thread_table[i].handle) == (DWORD)-1)
270 ABORT("SuspendThread failed");
271 # endif
272 thread_table[i].suspended = TRUE;
273 }
274 }
275
276 void GC_start_world()
277 {
278 DWORD thread_id = GetCurrentThreadId();
279 int i;
280 LONG my_max = GC_get_max_thread_index();
281
282 for (i = 0; i <= my_max; i++)
283 if (thread_table[i].stack_base != 0 && thread_table[i].suspended
284 && thread_table[i].id != thread_id) {
285 if (ResumeThread(thread_table[i].handle) == (DWORD)-1)
286 ABORT("ResumeThread failed");
287 thread_table[i].suspended = FALSE;
288 }
289 GC_please_stop = FALSE;
290 }
291
292 # ifdef _MSC_VER
293 # pragma warning(disable:4715)
294 # endif
295 ptr_t GC_current_stackbottom()
296 {
297 DWORD thread_id = GetCurrentThreadId();
298 int i;
299 LONG my_max = GC_get_max_thread_index();
300
301 for (i = 0; i <= my_max; i++)
302 if (thread_table[i].stack_base && thread_table[i].id == thread_id)
303 return thread_table[i].stack_base;
304 ABORT("no thread table entry for current thread");
305 }
306 # ifdef _MSC_VER
307 # pragma warning(default:4715)
308 # endif
309
310 # ifdef MSWINCE
311 /* The VirtualQuery calls below won't work properly on WinCE, but */
312 /* since each stack is restricted to an aligned 64K region of */
313 /* virtual memory we can just take the next lowest multiple of 64K. */
314 # define GC_get_stack_min(s) \
315 ((ptr_t)(((DWORD)(s) - 1) & 0xFFFF0000))
316 # else
317 static ptr_t GC_get_stack_min(ptr_t s)
318 {
319 ptr_t bottom;
320 MEMORY_BASIC_INFORMATION info;
321 VirtualQuery(s, &info, sizeof(info));
322 do {
323 bottom = info.BaseAddress;
324 VirtualQuery(bottom - 1, &info, sizeof(info));
325 } while ((info.Protect & PAGE_READWRITE)
326 && !(info.Protect & PAGE_GUARD));
327 return(bottom);
328 }
329 # endif
330
331 void GC_push_all_stacks()
332 {
333 DWORD thread_id = GetCurrentThreadId();
334 GC_bool found_me = FALSE;
335 int i;
336 int dummy;
337 ptr_t sp, stack_min;
338 GC_thread thread;
339 LONG my_max = GC_get_max_thread_index();
340
341 for (i = 0; i <= my_max; i++) {
342 thread = thread_table + i;
343 if (thread -> in_use && thread -> stack_base) {
344 if (thread -> id == thread_id) {
345 sp = (ptr_t) &dummy;
346 found_me = TRUE;
347 } else {
348 CONTEXT context;
349 context.ContextFlags = CONTEXT_INTEGER|CONTEXT_CONTROL;
350 if (!GetThreadContext(thread_table[i].handle, &context))
351 ABORT("GetThreadContext failed");
352
353 /* Push all registers that might point into the heap. Frame */
354 /* pointer registers are included in case client code was */
355 /* compiled with the 'omit frame pointer' optimisation. */
356 # define PUSH1(reg) GC_push_one((word)context.reg)
357 # define PUSH2(r1,r2) PUSH1(r1), PUSH1(r2)
358 # define PUSH4(r1,r2,r3,r4) PUSH2(r1,r2), PUSH2(r3,r4)
359 # if defined(I386)
360 PUSH4(Edi,Esi,Ebx,Edx), PUSH2(Ecx,Eax), PUSH1(Ebp);
361 sp = (ptr_t)context.Esp;
362 # elif defined(ARM32)
363 PUSH4(R0,R1,R2,R3),PUSH4(R4,R5,R6,R7),PUSH4(R8,R9,R10,R11),PUSH1(R12);
364 sp = (ptr_t)context.Sp;
365 # elif defined(SHx)
366 PUSH4(R0,R1,R2,R3), PUSH4(R4,R5,R6,R7), PUSH4(R8,R9,R10,R11);
367 PUSH2(R12,R13), PUSH1(R14);
368 sp = (ptr_t)context.R15;
369 # elif defined(MIPS)
370 PUSH4(IntAt,IntV0,IntV1,IntA0), PUSH4(IntA1,IntA2,IntA3,IntT0);
371 PUSH4(IntT1,IntT2,IntT3,IntT4), PUSH4(IntT5,IntT6,IntT7,IntS0);
372 PUSH4(IntS1,IntS2,IntS3,IntS4), PUSH4(IntS5,IntS6,IntS7,IntT8);
373 PUSH4(IntT9,IntK0,IntK1,IntS8);
374 sp = (ptr_t)context.IntSp;
375 # elif defined(PPC)
376 PUSH4(Gpr0, Gpr3, Gpr4, Gpr5), PUSH4(Gpr6, Gpr7, Gpr8, Gpr9);
377 PUSH4(Gpr10,Gpr11,Gpr12,Gpr14), PUSH4(Gpr15,Gpr16,Gpr17,Gpr18);
378 PUSH4(Gpr19,Gpr20,Gpr21,Gpr22), PUSH4(Gpr23,Gpr24,Gpr25,Gpr26);
379 PUSH4(Gpr27,Gpr28,Gpr29,Gpr30), PUSH1(Gpr31);
380 sp = (ptr_t)context.Gpr1;
381 # elif defined(ALPHA)
382 PUSH4(IntV0,IntT0,IntT1,IntT2), PUSH4(IntT3,IntT4,IntT5,IntT6);
383 PUSH4(IntT7,IntS0,IntS1,IntS2), PUSH4(IntS3,IntS4,IntS5,IntFp);
384 PUSH4(IntA0,IntA1,IntA2,IntA3), PUSH4(IntA4,IntA5,IntT8,IntT9);
385 PUSH4(IntT10,IntT11,IntT12,IntAt);
386 sp = (ptr_t)context.IntSp;
387 # else
388 # error "architecture is not supported"
389 # endif
390 }
391
392 stack_min = GC_get_stack_min(thread->stack_base);
393
394 if (sp >= stack_min && sp < thread->stack_base)
395 GC_push_all_stack(sp, thread->stack_base);
396 else {
397 WARN("Thread stack pointer 0x%lx out of range, pushing everything\n",
398 (unsigned long)sp);
399 GC_push_all_stack(stack_min, thread->stack_base);
400 }
401 }
402 }
403 if (!found_me) ABORT("Collecting from unknown thread.");
404 }
405
406 void GC_get_next_stack(char *start, char **lo, char **hi)
407 {
408 int i;
409 # define ADDR_LIMIT (char *)(-1L)
410 char * current_min = ADDR_LIMIT;
411 LONG my_max = GC_get_max_thread_index();
412
413 for (i = 0; i <= my_max; i++) {
414 char * s = (char *)thread_table[i].stack_base;
415
416 if (0 != s && s > start && s < current_min) {
417 current_min = s;
418 }
419 }
420 *hi = current_min;
421 if (current_min == ADDR_LIMIT) {
422 *lo = ADDR_LIMIT;
423 return;
424 }
425 *lo = GC_get_stack_min(current_min);
426 if (*lo < start) *lo = start;
427 }
428
429 #if !defined(CYGWIN32)
430
431 #if !defined(MSWINCE) && defined(GC_DLL)
432
433 /* We register threads from DllMain */
434
435 GC_API HANDLE WINAPI GC_CreateThread(
436 LPSECURITY_ATTRIBUTES lpThreadAttributes,
437 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
438 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId )
439 {
440 return CreateThread(lpThreadAttributes, dwStackSize, lpStartAddress,
441 lpParameter, dwCreationFlags, lpThreadId);
442 }
443
444 #else /* defined(MSWINCE) || !defined(GC_DLL)) */
445
446 /* We have no DllMain to take care of new threads. Thus we */
447 /* must properly intercept thread creation. */
448
449 typedef struct {
450 LPTHREAD_START_ROUTINE start;
451 LPVOID param;
452 } thread_args;
453
454 static DWORD WINAPI thread_start(LPVOID arg);
455
456 GC_API HANDLE WINAPI GC_CreateThread(
457 LPSECURITY_ATTRIBUTES lpThreadAttributes,
458 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
459 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId )
460 {
461 HANDLE thread_h = NULL;
462
463 thread_args *args;
464
465 if (!GC_is_initialized) GC_init();
466 /* make sure GC is initialized (i.e. main thread is attached) */
467
468 args = GC_malloc_uncollectable(sizeof(thread_args));
469 /* Handed off to and deallocated by child thread. */
470 if (0 == args) {
471 SetLastError(ERROR_NOT_ENOUGH_MEMORY);
472 return NULL;
473 }
474
475 /* set up thread arguments */
476 args -> start = lpStartAddress;
477 args -> param = lpParameter;
478
479 thread_h = CreateThread(lpThreadAttributes,
480 dwStackSize, thread_start,
481 args, dwCreationFlags,
482 lpThreadId);
483
484 return thread_h;
485 }
486
487 static DWORD WINAPI thread_start(LPVOID arg)
488 {
489 DWORD ret = 0;
490 thread_args *args = (thread_args *)arg;
491
492 GC_new_thread();
493
494 /* Clear the thread entry even if we exit with an exception. */
495 /* This is probably pointless, since an uncaught exception is */
496 /* supposed to result in the process being killed. */
497 #ifndef __GNUC__
498 __try {
499 #endif /* __GNUC__ */
500 ret = args->start (args->param);
501 #ifndef __GNUC__
502 } __finally {
503 #endif /* __GNUC__ */
504 GC_free(args);
505 GC_delete_thread(GetCurrentThreadId());
506 #ifndef __GNUC__
507 }
508 #endif /* __GNUC__ */
509
510 return ret;
511 }
512 #endif /* !defined(MSWINCE) && !(defined(__MINGW32__) && !defined(_DLL)) */
513
514 #endif /* !CYGWIN32 */
515
516 #ifdef MSWINCE
517
518 typedef struct {
519 HINSTANCE hInstance;
520 HINSTANCE hPrevInstance;
521 LPWSTR lpCmdLine;
522 int nShowCmd;
523 } main_thread_args;
524
525 DWORD WINAPI main_thread_start(LPVOID arg);
526
527 int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
528 LPWSTR lpCmdLine, int nShowCmd)
529 {
530 DWORD exit_code = 1;
531
532 main_thread_args args = {
533 hInstance, hPrevInstance, lpCmdLine, nShowCmd
534 };
535 HANDLE thread_h;
536 DWORD thread_id;
537
538 /* initialize everything */
539 GC_init();
540
541 /* start the main thread */
542 thread_h = GC_CreateThread(
543 NULL, 0, main_thread_start, &args, 0, &thread_id);
544
545 if (thread_h != NULL)
546 {
547 WaitForSingleObject (thread_h, INFINITE);
548 GetExitCodeThread (thread_h, &exit_code);
549 CloseHandle (thread_h);
550 }
551
552 GC_deinit();
553 DeleteCriticalSection(&GC_allocate_ml);
554
555 return (int) exit_code;
556 }
557
558 DWORD WINAPI main_thread_start(LPVOID arg)
559 {
560 main_thread_args * args = (main_thread_args *) arg;
561
562 return (DWORD) GC_WinMain (args->hInstance, args->hPrevInstance,
563 args->lpCmdLine, args->nShowCmd);
564 }
565
566 # else /* !MSWINCE */
567
568 /* Called by GC_init() - we hold the allocation lock. */
569 void GC_thr_init() {
570 if (GC_thr_initialized) return;
571 GC_main_thread = GetCurrentThreadId();
572 GC_thr_initialized = TRUE;
573
574 /* Add the initial thread, so we can stop it. */
575 GC_new_thread();
576 }
577
578 #ifdef CYGWIN32
579
580 struct start_info {
581 void *(*start_routine)(void *);
582 void *arg;
583 GC_bool detached;
584 };
585
586 int GC_pthread_join(pthread_t pthread_id, void **retval) {
587 int result;
588 int i;
589 GC_thread me;
590
591 # if DEBUG_CYGWIN_THREADS
592 GC_printf3("thread 0x%x(0x%x) is joining thread 0x%x.\n",
593 (int)pthread_self(), GetCurrentThreadId(), (int)pthread_id);
594 # endif
595
596 /* Thread being joined might not have registered itself yet. */
597 /* After the join,thread id may have been recycled. */
598 /* FIXME: It would be better if this worked more like */
599 /* pthread_support.c. */
600
601 while ((me = GC_lookup_thread(pthread_id)) == 0) Sleep(10);
602
603 result = pthread_join(pthread_id, retval);
604
605 GC_delete_gc_thread(me);
606
607 # if DEBUG_CYGWIN_THREADS
608 GC_printf3("thread 0x%x(0x%x) completed join with thread 0x%x.\n",
609 (int)pthread_self(), GetCurrentThreadId(), (int)pthread_id);
610 # endif
611
612 return result;
613 }
614
615 /* Cygwin-pthreads calls CreateThread internally, but it's not
616 * easily interceptible by us..
617 * so intercept pthread_create instead
618 */
619 int
620 GC_pthread_create(pthread_t *new_thread,
621 const pthread_attr_t *attr,
622 void *(*start_routine)(void *), void *arg) {
623 int result;
624 struct start_info * si;
625
626 if (!GC_is_initialized) GC_init();
627 /* make sure GC is initialized (i.e. main thread is attached) */
628
629 /* This is otherwise saved only in an area mmapped by the thread */
630 /* library, which isn't visible to the collector. */
631 si = GC_malloc_uncollectable(sizeof(struct start_info));
632 if (0 == si) return(EAGAIN);
633
634 si -> start_routine = start_routine;
635 si -> arg = arg;
636 if (attr != 0 &&
637 pthread_attr_getdetachstate(attr, &si->detached)
638 == PTHREAD_CREATE_DETACHED) {
639 si->detached = TRUE;
640 }
641
642 # if DEBUG_CYGWIN_THREADS
643 GC_printf2("About to create a thread from 0x%x(0x%x)\n",
644 (int)pthread_self(), GetCurrentThreadId);
645 # endif
646 result = pthread_create(new_thread, attr, GC_start_routine, si);
647
648 if (result) { /* failure */
649 GC_free(si);
650 }
651
652 return(result);
653 }
654
655 void * GC_start_routine(void * arg)
656 {
657 struct start_info * si = arg;
658 void * result;
659 void *(*start)(void *);
660 void *start_arg;
661 pthread_t pthread_id;
662 GC_thread me;
663 GC_bool detached;
664 int i;
665
666 # if DEBUG_CYGWIN_THREADS
667 GC_printf2("thread 0x%x(0x%x) starting...\n",(int)pthread_self(),
668 GetCurrentThreadId());
669 # endif
670
671 /* If a GC occurs before the thread is registered, that GC will */
672 /* ignore this thread. That's fine, since it will block trying to */
673 /* acquire the allocation lock, and won't yet hold interesting */
674 /* pointers. */
675 LOCK();
676 /* We register the thread here instead of in the parent, so that */
677 /* we don't need to hold the allocation lock during pthread_create. */
678 me = GC_new_thread();
679 UNLOCK();
680
681 start = si -> start_routine;
682 start_arg = si -> arg;
683 if (si-> detached) me -> flags |= DETACHED;
684 me -> pthread_id = pthread_id = pthread_self();
685
686 GC_free(si); /* was allocated uncollectable */
687
688 pthread_cleanup_push(GC_thread_exit_proc, (void *)me);
689 result = (*start)(start_arg);
690 me -> status = result;
691 pthread_cleanup_pop(0);
692
693 # if DEBUG_CYGWIN_THREADS
694 GC_printf2("thread 0x%x(0x%x) returned from start routine.\n",
695 (int)pthread_self(),GetCurrentThreadId());
696 # endif
697
698 return(result);
699 }
700
701 void GC_thread_exit_proc(void *arg)
702 {
703 GC_thread me = (GC_thread)arg;
704 int i;
705
706 # if DEBUG_CYGWIN_THREADS
707 GC_printf2("thread 0x%x(0x%x) called pthread_exit().\n",
708 (int)pthread_self(),GetCurrentThreadId());
709 # endif
710
711 LOCK();
712 if (me -> flags & DETACHED) {
713 GC_delete_thread(GetCurrentThreadId());
714 } else {
715 /* deallocate it as part of join */
716 me -> flags |= FINISHED;
717 }
718 UNLOCK();
719 }
720
721 /* nothing required here... */
722 int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) {
723 return pthread_sigmask(how, set, oset);
724 }
725
726 int GC_pthread_detach(pthread_t thread)
727 {
728 int result;
729 GC_thread thread_gc_id;
730
731 LOCK();
732 thread_gc_id = GC_lookup_thread(thread);
733 UNLOCK();
734 result = pthread_detach(thread);
735 if (result == 0) {
736 LOCK();
737 thread_gc_id -> flags |= DETACHED;
738 /* Here the pthread thread id may have been recycled. */
739 if (thread_gc_id -> flags & FINISHED) {
740 GC_delete_gc_thread(thread_gc_id);
741 }
742 UNLOCK();
743 }
744 return result;
745 }
746
747 #else /* !CYGWIN32 */
748
749 /*
750 * We avoid acquiring locks here, since this doesn't seem to be preemptable.
751 * Pontus Rydin suggests wrapping the thread start routine instead.
752 */
753 #ifdef GC_DLL
754 BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
755 {
756 switch (reason) {
757 case DLL_PROCESS_ATTACH:
758 GC_init(); /* Force initialization before thread attach. */
759 /* fall through */
760 case DLL_THREAD_ATTACH:
761 GC_ASSERT(GC_thr_initialized);
762 if (GC_main_thread != GetCurrentThreadId()) {
763 GC_new_thread();
764 } /* o.w. we already did it during GC_thr_init(), called by GC_init() */
765 break;
766
767 case DLL_THREAD_DETACH:
768 GC_delete_thread(GetCurrentThreadId());
769 break;
770
771 case DLL_PROCESS_DETACH:
772 {
773 int i;
774
775 LOCK();
776 for (i = 0; i <= GC_get_max_thread_index(); ++i)
777 {
778 if (thread_table[i].in_use)
779 GC_delete_gc_thread(thread_table + i);
780 }
781 UNLOCK();
782
783 GC_deinit();
784 DeleteCriticalSection(&GC_allocate_ml);
785 }
786 break;
787
788 }
789 return TRUE;
790 }
791 #endif /* GC_DLL */
792 #endif /* !CYGWIN32 */
793
794 # endif /* !MSWINCE */
795
796 #endif /* GC_WIN32_THREADS */