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1 /* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
2  *
3  * Permission is hereby granted, free of charge, to any person obtaining a copy
4  * of this software and associated documentation files (the "Software"), to
5  * deal in the Software without restriction, including without limitation the
6  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
7  * sell copies of the Software, and to permit persons to whom the Software is
8  * furnished to do so, subject to the following conditions:
9  *
10  * The above copyright notice and this permission notice shall be included in
11  * all copies or substantial portions of the Software.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
19  * IN THE SOFTWARE.
20  */
21 
22 #include <assert.h>
23 #include <limits.h>
24 #include <stdlib.h>
25 
26 #if defined(__MINGW64_VERSION_MAJOR)
27 /* MemoryBarrier expands to __mm_mfence in some cases (x86+sse2), which may
28  * require this header in some versions of mingw64. */
29 #include <intrin.h>
30 #endif
31 
32 #include "uv.h"
33 #include "internal.h"
34 
uv__once_inner(uv_once_t * guard,void (* callback)(void))35 static void uv__once_inner(uv_once_t* guard, void (*callback)(void)) {
36   DWORD result;
37   HANDLE existing_event, created_event;
38 
39   created_event = CreateEvent(NULL, 1, 0, NULL);
40   if (created_event == 0) {
41     /* Could fail in a low-memory situation? */
42     uv_fatal_error(GetLastError(), "CreateEvent");
43   }
44 
45   existing_event = InterlockedCompareExchangePointer(&guard->event,
46                                                      created_event,
47                                                      NULL);
48 
49   if (existing_event == NULL) {
50     /* We won the race */
51     callback();
52 
53     result = SetEvent(created_event);
54     assert(result);
55     guard->ran = 1;
56 
57   } else {
58     /* We lost the race. Destroy the event we created and wait for the existing
59      * one to become signaled. */
60     CloseHandle(created_event);
61     result = WaitForSingleObject(existing_event, INFINITE);
62     assert(result == WAIT_OBJECT_0);
63   }
64 }
65 
66 
uv_once(uv_once_t * guard,void (* callback)(void))67 void uv_once(uv_once_t* guard, void (*callback)(void)) {
68   /* Fast case - avoid WaitForSingleObject. */
69   if (guard->ran) {
70     return;
71   }
72 
73   uv__once_inner(guard, callback);
74 }
75 
76 
77 /* Verify that uv_thread_t can be stored in a TLS slot. */
78 STATIC_ASSERT(sizeof(uv_thread_t) <= sizeof(void*));
79 
80 static uv_key_t uv__current_thread_key;
81 static uv_once_t uv__current_thread_init_guard = UV_ONCE_INIT;
82 
83 
uv__init_current_thread_key(void)84 static void uv__init_current_thread_key(void) {
85   if (uv_key_create(&uv__current_thread_key))
86     abort();
87 }
88 
89 
90 struct thread_ctx {
91   void (*entry)(void* arg);
92   void* arg;
93   uv_thread_t self;
94 };
95 
96 
uv__thread_start(void * arg)97 static UINT __stdcall uv__thread_start(void* arg) {
98   struct thread_ctx *ctx_p;
99   struct thread_ctx ctx;
100 
101   ctx_p = arg;
102   ctx = *ctx_p;
103   uv__free(ctx_p);
104 
105   uv_once(&uv__current_thread_init_guard, uv__init_current_thread_key);
106   uv_key_set(&uv__current_thread_key, ctx.self);
107 
108   ctx.entry(ctx.arg);
109 
110   return 0;
111 }
112 
113 
uv_thread_create(uv_thread_t * tid,void (* entry)(void * arg),void * arg)114 int uv_thread_create(uv_thread_t *tid, void (*entry)(void *arg), void *arg) {
115   uv_thread_options_t params;
116   params.flags = UV_THREAD_NO_FLAGS;
117   return uv_thread_create_ex(tid, &params, entry, arg);
118 }
119 
uv_thread_create_ex(uv_thread_t * tid,const uv_thread_options_t * params,void (* entry)(void * arg),void * arg)120 int uv_thread_create_ex(uv_thread_t* tid,
121                         const uv_thread_options_t* params,
122                         void (*entry)(void *arg),
123                         void *arg) {
124   struct thread_ctx* ctx;
125   int err;
126   HANDLE thread;
127   SYSTEM_INFO sysinfo;
128   size_t stack_size;
129   size_t pagesize;
130 
131   stack_size =
132       params->flags & UV_THREAD_HAS_STACK_SIZE ? params->stack_size : 0;
133 
134   if (stack_size != 0) {
135     GetNativeSystemInfo(&sysinfo);
136     pagesize = (size_t)sysinfo.dwPageSize;
137     /* Round up to the nearest page boundary. */
138     stack_size = (stack_size + pagesize - 1) &~ (pagesize - 1);
139 
140     if ((unsigned)stack_size != stack_size)
141       return UV_EINVAL;
142   }
143 
144   ctx = uv__malloc(sizeof(*ctx));
145   if (ctx == NULL)
146     return UV_ENOMEM;
147 
148   ctx->entry = entry;
149   ctx->arg = arg;
150 
151   /* Create the thread in suspended state so we have a chance to pass
152    * its own creation handle to it */
153   thread = (HANDLE) _beginthreadex(NULL,
154                                    (unsigned)stack_size,
155                                    uv__thread_start,
156                                    ctx,
157                                    CREATE_SUSPENDED,
158                                    NULL);
159   if (thread == NULL) {
160     err = errno;
161     uv__free(ctx);
162   } else {
163     err = 0;
164     *tid = thread;
165     ctx->self = thread;
166     ResumeThread(thread);
167   }
168 
169   switch (err) {
170     case 0:
171       return 0;
172     case EACCES:
173       return UV_EACCES;
174     case EAGAIN:
175       return UV_EAGAIN;
176     case EINVAL:
177       return UV_EINVAL;
178   }
179 
180   return UV_EIO;
181 }
182 
183 
uv_thread_self(void)184 uv_thread_t uv_thread_self(void) {
185   uv_thread_t key;
186   uv_once(&uv__current_thread_init_guard, uv__init_current_thread_key);
187   key = uv_key_get(&uv__current_thread_key);
188   if (key == NULL) {
189       /* If the thread wasn't started by uv_thread_create (such as the main
190        * thread), we assign an id to it now. */
191       if (!DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
192                            GetCurrentProcess(), &key, 0,
193                            FALSE, DUPLICATE_SAME_ACCESS)) {
194           uv_fatal_error(GetLastError(), "DuplicateHandle");
195       }
196       uv_key_set(&uv__current_thread_key, key);
197   }
198   return key;
199 }
200 
201 
uv_thread_join(uv_thread_t * tid)202 int uv_thread_join(uv_thread_t *tid) {
203   if (WaitForSingleObject(*tid, INFINITE))
204     return uv_translate_sys_error(GetLastError());
205   else {
206     CloseHandle(*tid);
207     *tid = 0;
208     MemoryBarrier();  /* For feature parity with pthread_join(). */
209     return 0;
210   }
211 }
212 
213 
uv_thread_equal(const uv_thread_t * t1,const uv_thread_t * t2)214 int uv_thread_equal(const uv_thread_t* t1, const uv_thread_t* t2) {
215   return *t1 == *t2;
216 }
217 
218 
uv_mutex_init(uv_mutex_t * mutex)219 int uv_mutex_init(uv_mutex_t* mutex) {
220   InitializeCriticalSection(mutex);
221   return 0;
222 }
223 
224 
uv_mutex_init_recursive(uv_mutex_t * mutex)225 int uv_mutex_init_recursive(uv_mutex_t* mutex) {
226   return uv_mutex_init(mutex);
227 }
228 
229 
uv_mutex_destroy(uv_mutex_t * mutex)230 void uv_mutex_destroy(uv_mutex_t* mutex) {
231   DeleteCriticalSection(mutex);
232 }
233 
234 
uv_mutex_lock(uv_mutex_t * mutex)235 void uv_mutex_lock(uv_mutex_t* mutex) {
236   EnterCriticalSection(mutex);
237 }
238 
239 
uv_mutex_trylock(uv_mutex_t * mutex)240 int uv_mutex_trylock(uv_mutex_t* mutex) {
241   if (TryEnterCriticalSection(mutex))
242     return 0;
243   else
244     return UV_EBUSY;
245 }
246 
247 
uv_mutex_unlock(uv_mutex_t * mutex)248 void uv_mutex_unlock(uv_mutex_t* mutex) {
249   LeaveCriticalSection(mutex);
250 }
251 
252 /* Ensure that the ABI for this type remains stable in v1.x */
253 #ifdef _WIN64
254 STATIC_ASSERT(sizeof(uv_rwlock_t) == 80);
255 #else
256 STATIC_ASSERT(sizeof(uv_rwlock_t) == 48);
257 #endif
258 
uv_rwlock_init(uv_rwlock_t * rwlock)259 int uv_rwlock_init(uv_rwlock_t* rwlock) {
260   memset(rwlock, 0, sizeof(*rwlock));
261   InitializeSRWLock(&rwlock->read_write_lock_);
262 
263   return 0;
264 }
265 
266 
uv_rwlock_destroy(uv_rwlock_t * rwlock)267 void uv_rwlock_destroy(uv_rwlock_t* rwlock) {
268   /* SRWLock does not need explicit destruction so long as there are no waiting threads
269      See: https://docs.microsoft.com/windows/win32/api/synchapi/nf-synchapi-initializesrwlock#remarks */
270 }
271 
272 
uv_rwlock_rdlock(uv_rwlock_t * rwlock)273 void uv_rwlock_rdlock(uv_rwlock_t* rwlock) {
274   AcquireSRWLockShared(&rwlock->read_write_lock_);
275 }
276 
277 
uv_rwlock_tryrdlock(uv_rwlock_t * rwlock)278 int uv_rwlock_tryrdlock(uv_rwlock_t* rwlock) {
279   if (!TryAcquireSRWLockShared(&rwlock->read_write_lock_))
280     return UV_EBUSY;
281 
282   return 0;
283 }
284 
285 
uv_rwlock_rdunlock(uv_rwlock_t * rwlock)286 void uv_rwlock_rdunlock(uv_rwlock_t* rwlock) {
287   ReleaseSRWLockShared(&rwlock->read_write_lock_);
288 }
289 
290 
uv_rwlock_wrlock(uv_rwlock_t * rwlock)291 void uv_rwlock_wrlock(uv_rwlock_t* rwlock) {
292   AcquireSRWLockExclusive(&rwlock->read_write_lock_);
293 }
294 
295 
uv_rwlock_trywrlock(uv_rwlock_t * rwlock)296 int uv_rwlock_trywrlock(uv_rwlock_t* rwlock) {
297   if (!TryAcquireSRWLockExclusive(&rwlock->read_write_lock_))
298     return UV_EBUSY;
299 
300   return 0;
301 }
302 
303 
uv_rwlock_wrunlock(uv_rwlock_t * rwlock)304 void uv_rwlock_wrunlock(uv_rwlock_t* rwlock) {
305   ReleaseSRWLockExclusive(&rwlock->read_write_lock_);
306 }
307 
308 
uv_sem_init(uv_sem_t * sem,unsigned int value)309 int uv_sem_init(uv_sem_t* sem, unsigned int value) {
310   *sem = CreateSemaphore(NULL, value, INT_MAX, NULL);
311   if (*sem == NULL)
312     return uv_translate_sys_error(GetLastError());
313   else
314     return 0;
315 }
316 
317 
uv_sem_destroy(uv_sem_t * sem)318 void uv_sem_destroy(uv_sem_t* sem) {
319   if (!CloseHandle(*sem))
320     abort();
321 }
322 
323 
uv_sem_post(uv_sem_t * sem)324 void uv_sem_post(uv_sem_t* sem) {
325   if (!ReleaseSemaphore(*sem, 1, NULL))
326     abort();
327 }
328 
329 
uv_sem_wait(uv_sem_t * sem)330 void uv_sem_wait(uv_sem_t* sem) {
331   if (WaitForSingleObject(*sem, INFINITE) != WAIT_OBJECT_0)
332     abort();
333 }
334 
335 
uv_sem_trywait(uv_sem_t * sem)336 int uv_sem_trywait(uv_sem_t* sem) {
337   DWORD r = WaitForSingleObject(*sem, 0);
338 
339   if (r == WAIT_OBJECT_0)
340     return 0;
341 
342   if (r == WAIT_TIMEOUT)
343     return UV_EAGAIN;
344 
345   abort();
346   return -1; /* Satisfy the compiler. */
347 }
348 
349 
uv_cond_init(uv_cond_t * cond)350 int uv_cond_init(uv_cond_t* cond) {
351   InitializeConditionVariable(&cond->cond_var);
352   return 0;
353 }
354 
355 
uv_cond_destroy(uv_cond_t * cond)356 void uv_cond_destroy(uv_cond_t* cond) {
357   /* nothing to do */
358   (void) &cond;
359 }
360 
361 
uv_cond_signal(uv_cond_t * cond)362 void uv_cond_signal(uv_cond_t* cond) {
363   WakeConditionVariable(&cond->cond_var);
364 }
365 
366 
uv_cond_broadcast(uv_cond_t * cond)367 void uv_cond_broadcast(uv_cond_t* cond) {
368   WakeAllConditionVariable(&cond->cond_var);
369 }
370 
371 
uv_cond_wait(uv_cond_t * cond,uv_mutex_t * mutex)372 void uv_cond_wait(uv_cond_t* cond, uv_mutex_t* mutex) {
373   if (!SleepConditionVariableCS(&cond->cond_var, mutex, INFINITE))
374     abort();
375 }
376 
uv_cond_timedwait(uv_cond_t * cond,uv_mutex_t * mutex,uint64_t timeout)377 int uv_cond_timedwait(uv_cond_t* cond, uv_mutex_t* mutex, uint64_t timeout) {
378   if (SleepConditionVariableCS(&cond->cond_var, mutex, (DWORD)(timeout / 1e6)))
379     return 0;
380   if (GetLastError() != ERROR_TIMEOUT)
381     abort();
382   return UV_ETIMEDOUT;
383 }
384 
385 
uv_barrier_init(uv_barrier_t * barrier,unsigned int count)386 int uv_barrier_init(uv_barrier_t* barrier, unsigned int count) {
387   int err;
388 
389   barrier->n = count;
390   barrier->count = 0;
391 
392   err = uv_mutex_init(&barrier->mutex);
393   if (err)
394     return err;
395 
396   err = uv_sem_init(&barrier->turnstile1, 0);
397   if (err)
398     goto error2;
399 
400   err = uv_sem_init(&barrier->turnstile2, 1);
401   if (err)
402     goto error;
403 
404   return 0;
405 
406 error:
407   uv_sem_destroy(&barrier->turnstile1);
408 error2:
409   uv_mutex_destroy(&barrier->mutex);
410   return err;
411 
412 }
413 
414 
uv_barrier_destroy(uv_barrier_t * barrier)415 void uv_barrier_destroy(uv_barrier_t* barrier) {
416   uv_sem_destroy(&barrier->turnstile2);
417   uv_sem_destroy(&barrier->turnstile1);
418   uv_mutex_destroy(&barrier->mutex);
419 }
420 
421 
uv_barrier_wait(uv_barrier_t * barrier)422 int uv_barrier_wait(uv_barrier_t* barrier) {
423   int serial_thread;
424 
425   uv_mutex_lock(&barrier->mutex);
426   if (++barrier->count == barrier->n) {
427     uv_sem_wait(&barrier->turnstile2);
428     uv_sem_post(&barrier->turnstile1);
429   }
430   uv_mutex_unlock(&barrier->mutex);
431 
432   uv_sem_wait(&barrier->turnstile1);
433   uv_sem_post(&barrier->turnstile1);
434 
435   uv_mutex_lock(&barrier->mutex);
436   serial_thread = (--barrier->count == 0);
437   if (serial_thread) {
438     uv_sem_wait(&barrier->turnstile1);
439     uv_sem_post(&barrier->turnstile2);
440   }
441   uv_mutex_unlock(&barrier->mutex);
442 
443   uv_sem_wait(&barrier->turnstile2);
444   uv_sem_post(&barrier->turnstile2);
445   return serial_thread;
446 }
447 
448 
uv_key_create(uv_key_t * key)449 int uv_key_create(uv_key_t* key) {
450   key->tls_index = TlsAlloc();
451   if (key->tls_index == TLS_OUT_OF_INDEXES)
452     return UV_ENOMEM;
453   return 0;
454 }
455 
456 
uv_key_delete(uv_key_t * key)457 void uv_key_delete(uv_key_t* key) {
458   if (TlsFree(key->tls_index) == FALSE)
459     abort();
460   key->tls_index = TLS_OUT_OF_INDEXES;
461 }
462 
463 
uv_key_get(uv_key_t * key)464 void* uv_key_get(uv_key_t* key) {
465   void* value;
466 
467   value = TlsGetValue(key->tls_index);
468   if (value == NULL)
469     if (GetLastError() != ERROR_SUCCESS)
470       abort();
471 
472   return value;
473 }
474 
475 
uv_key_set(uv_key_t * key,void * value)476 void uv_key_set(uv_key_t* key, void* value) {
477   if (TlsSetValue(key->tls_index, value) == FALSE)
478     abort();
479 }
480