release/src/router/dnscrypt/src/libevent-modified/evthread_win32.c

   1 /*
   2  * Copyright 2009-2012 Niels Provos and Nick Mathewson
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote products
  13  *    derived from this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 #include "event2/event-config.h"
  27
  28 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
  29
  30 #ifdef WIN32
  31 #ifndef _WIN32_WINNT
  32 /* Minimum required for InitializeCriticalSectionAndSpinCount */
  33 #define _WIN32_WINNT 0x0403
  34 #endif
  35 #include <winsock2.h>
  36 #define WIN32_LEAN_AND_MEAN
  37 #include <windows.h>
  38 #undef WIN32_LEAN_AND_MEAN
  39 #include <sys/locking.h>
  40 #endif
  41
  42 struct event_base;
  43 #include "event2/thread.h"
  44
  45 #include "mm-internal.h"
  46 #include "evthread-internal.h"
  47
  48 #define SPIN_COUNT 2000
  49
  50 static void *
  51 evthread_win32_lock_create(unsigned locktype)
  52 {
  53         CRITICAL_SECTION *lock = mm_malloc(sizeof(CRITICAL_SECTION));
  54         if (!lock)
  55                 return NULL;
  56         if (InitializeCriticalSectionAndSpinCount(lock, SPIN_COUNT) == 0) {
  57                 mm_free(lock);
  58                 return NULL;
  59         }
  60         return lock;
  61 }
  62
  63 static void
  64 evthread_win32_lock_free(void *_lock, unsigned locktype)
  65 {
  66         CRITICAL_SECTION *lock = _lock;
  67         DeleteCriticalSection(lock);
  68         mm_free(lock);
  69 }
  70
  71 static int
  72 evthread_win32_lock(unsigned mode, void *_lock)
  73 {
  74         CRITICAL_SECTION *lock = _lock;
  75         if ((mode & EVTHREAD_TRY)) {
  76                 return ! TryEnterCriticalSection(lock);
  77         } else {
  78                 EnterCriticalSection(lock);
  79                 return 0;
  80         }
  81 }
  82
  83 static int
  84 evthread_win32_unlock(unsigned mode, void *_lock)
  85 {
  86         CRITICAL_SECTION *lock = _lock;
  87         LeaveCriticalSection(lock);
  88         return 0;
  89 }
  90
  91 static unsigned long
  92 evthread_win32_get_id(void)
  93 {
  94         return (unsigned long) GetCurrentThreadId();
  95 }
  96
  97 #ifdef WIN32_HAVE_CONDITION_VARIABLES
  98 static void WINAPI (*InitializeConditionVariable_fn)(PCONDITION_VARIABLE)
  99         = NULL;
 100 static BOOL WINAPI (*SleepConditionVariableCS_fn)(
 101         PCONDITION_VARIABLE, PCRITICAL_SECTION, DWORD) = NULL;
 102 static void WINAPI (*WakeAllConditionVariable_fn)(PCONDITION_VARIABLE) = NULL;
 103 static void WINAPI (*WakeConditionVariable_fn)(PCONDITION_VARIABLE) = NULL;
 104
 105 static int
 106 evthread_win32_condvar_init(void)
 107 {
 108         HANDLE lib;
 109
 110         lib = GetModuleHandle(TEXT("kernel32.dll"));
 111         if (lib == NULL)
 112                 return 0;
 113
 114 #define LOAD(name)                              \
 115         name##_fn = GetProcAddress(lib, #name)
 116         LOAD(InitializeConditionVariable);
 117         LOAD(SleepConditionVariableCS);
 118         LOAD(WakeAllConditionVariable);
 119         LOAD(WakeConditionVariable);
 120
 121         return InitializeConditionVariable_fn && SleepConditionVariableCS_fn &&
 122             WakeAllConditionVariable_fn && WakeConditionVariable_fn;
 123 }
 124
 125 /* XXXX Even if we can build this, we don't necessarily want to: the functions
 126  * in question didn't exist before Vista, so we'd better LoadProc them. */
 127 static void *
 128 evthread_win32_condvar_alloc(unsigned condflags)
 129 {
 130         CONDITION_VARIABLE *cond = mm_malloc(sizeof(CONDITION_VARIABLE));
 131         if (!cond)
 132                 return NULL;
 133         InitializeConditionVariable_fn(cond);
 134         return cond;
 135 }
 136
 137 static void
 138 evthread_win32_condvar_free(void *_cond)
 139 {
 140         CONDITION_VARIABLE *cond = _cond;
 141         /* There doesn't _seem_ to be a cleaup fn here... */
 142         mm_free(cond);
 143 }
 144
 145 static int
 146 evthread_win32_condvar_signal(void *_cond, int broadcast)
 147 {
 148         CONDITION_VARIABLE *cond = _cond;
 149         if (broadcast)
 150                 WakeAllConditionVariable_fn(cond);
 151         else
 152                 WakeConditionVariable_fn(cond);
 153         return 0;
 154 }
 155
 156 static int
 157 evthread_win32_condvar_wait(void *_cond, void *_lock, const struct timeval *tv)
 158 {
 159         CONDITION_VARIABLE *cond = _cond;
 160         CRITICAL_SECTION *lock = _lock;
 161         DWORD ms, err;
 162         BOOL result;
 163
 164         if (tv)
 165                 ms = evutil_tv_to_msec(tv);
 166         else
 167                 ms = INFINITE;
 168         result = SleepConditionVariableCS_fn(cond, lock, ms);
 169         if (result) {
 170                 if (GetLastError() == WAIT_TIMEOUT)
 171                         return 1;
 172                 else
 173                         return -1;
 174         } else {
 175                 return 0;
 176         }
 177 }
 178 #endif
 179
 180 struct evthread_win32_cond {
 181         HANDLE event;
 182
 183         CRITICAL_SECTION lock;
 184         int n_waiting;
 185         int n_to_wake;
 186         int generation;
 187 };
 188
 189 static void *
 190 evthread_win32_cond_alloc(unsigned flags)
 191 {
 192         struct evthread_win32_cond *cond;
 193         if (!(cond = mm_malloc(sizeof(struct evthread_win32_cond))))
 194                 return NULL;
 195         if (InitializeCriticalSectionAndSpinCount(&cond->lock, SPIN_COUNT)==0) {
 196                 mm_free(cond);
 197                 return NULL;
 198         }
 199         if ((cond->event = CreateEvent(NULL,TRUE,FALSE,NULL)) == NULL) {
 200                 DeleteCriticalSection(&cond->lock);
 201                 mm_free(cond);
 202                 return NULL;
 203         }
 204         cond->n_waiting = cond->n_to_wake = cond->generation = 0;
 205         return cond;
 206 }
 207
 208 static void
 209 evthread_win32_cond_free(void *_cond)
 210 {
 211         struct evthread_win32_cond *cond = _cond;
 212         DeleteCriticalSection(&cond->lock);
 213         CloseHandle(cond->event);
 214         mm_free(cond);
 215 }
 216
 217 static int
 218 evthread_win32_cond_signal(void *_cond, int broadcast)
 219 {
 220         struct evthread_win32_cond *cond = _cond;
 221         EnterCriticalSection(&cond->lock);
 222         if (broadcast)
 223                 cond->n_to_wake = cond->n_waiting;
 224         else
 225                 ++cond->n_to_wake;
 226         cond->generation++;
 227         SetEvent(cond->event);
 228         LeaveCriticalSection(&cond->lock);
 229         return 0;
 230 }
 231
 232 static int
 233 evthread_win32_cond_wait(void *_cond, void *_lock, const struct timeval *tv)
 234 {
 235         struct evthread_win32_cond *cond = _cond;
 236         CRITICAL_SECTION *lock = _lock;
 237         int generation_at_start;
 238         int waiting = 1;
 239         int result = -1;
 240         DWORD ms = INFINITE, ms_orig = INFINITE, startTime, endTime;
 241         if (tv)
 242                 ms_orig = ms = evutil_tv_to_msec(tv);
 243
 244         EnterCriticalSection(&cond->lock);
 245         ++cond->n_waiting;
 246         generation_at_start = cond->generation;
 247         LeaveCriticalSection(&cond->lock);
 248
 249         LeaveCriticalSection(lock);
 250
 251         startTime = GetTickCount();
 252         do {
 253                 DWORD res;
 254                 res = WaitForSingleObject(cond->event, ms);
 255                 EnterCriticalSection(&cond->lock);
 256                 if (cond->n_to_wake &&
 257                     cond->generation != generation_at_start) {
 258                         --cond->n_to_wake;
 259                         --cond->n_waiting;
 260                         result = 0;
 261                         waiting = 0;
 262                         goto out;
 263                 } else if (res != WAIT_OBJECT_0) {
 264                         result = (res==WAIT_TIMEOUT) ? 1 : -1;
 265                         --cond->n_waiting;
 266                         waiting = 0;
 267                         goto out;
 268                 } else if (ms != INFINITE) {
 269                         endTime = GetTickCount();
 270                         if (startTime + ms_orig <= endTime) {
 271                                 result = 1; /* Timeout */
 272                                 --cond->n_waiting;
 273                                 waiting = 0;
 274                                 goto out;
 275                         } else {
 276                                 ms = startTime + ms_orig - endTime;
 277                         }
 278                 }
 279                 /* If we make it here, we are still waiting. */
 280                 if (cond->n_to_wake == 0) {
 281                         /* There is nobody else who should wake up; reset
 282                          * the event. */
 283                         ResetEvent(cond->event);
 284                 }
 285         out:
 286                 LeaveCriticalSection(&cond->lock);
 287         } while (waiting);
 288
 289         EnterCriticalSection(lock);
 290
 291         EnterCriticalSection(&cond->lock);
 292         if (!cond->n_waiting)
 293                 ResetEvent(cond->event);
 294         LeaveCriticalSection(&cond->lock);
 295
 296         return result;
 297 }
 298
 299 int
 300 evthread_use_windows_threads(void)
 301 {
 302         struct evthread_lock_callbacks cbs = {
 303                 EVTHREAD_LOCK_API_VERSION,
 304                 EVTHREAD_LOCKTYPE_RECURSIVE,
 305                 evthread_win32_lock_create,
 306                 evthread_win32_lock_free,
 307                 evthread_win32_lock,
 308                 evthread_win32_unlock
 309         };
 310
 311
 312         struct evthread_condition_callbacks cond_cbs = {
 313                 EVTHREAD_CONDITION_API_VERSION,
 314                 evthread_win32_cond_alloc,
 315                 evthread_win32_cond_free,
 316                 evthread_win32_cond_signal,
 317                 evthread_win32_cond_wait
 318         };
 319 #ifdef WIN32_HAVE_CONDITION_VARIABLES
 320         struct evthread_condition_callbacks condvar_cbs = {
 321                 EVTHREAD_CONDITION_API_VERSION,
 322                 evthread_win32_condvar_alloc,
 323                 evthread_win32_condvar_free,
 324                 evthread_win32_condvar_signal,
 325                 evthread_win32_condvar_wait
 326         };
 327 #endif
 328
 329         evthread_set_lock_callbacks(&cbs);
 330         evthread_set_id_callback(evthread_win32_get_id);
 331 #ifdef WIN32_HAVE_CONDITION_VARIABLES
 332         if (evthread_win32_condvar_init()) {
 333                 evthread_set_condition_callbacks(&condvar_cbs);
 334                 return 0;
 335         }
 336 #endif
 337         evthread_set_condition_callbacks(&cond_cbs);
 338
 339         return 0;
 340 }
 341
 342 #endif