dlls/ntdll/critsection.c

   1 /*
   2  * Win32 critical sections
   3  *
   4  * Copyright 1998 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <errno.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <sys/types.h>
  29 #include <time.h>
  30 #include "ntstatus.h"
  31 #define WIN32_NO_STATUS
  32 #include "windef.h"
  33 #include "winternl.h"
  34 #include "wine/debug.h"
  35 #include "ntdll_misc.h"
  36
  37 WINE_DEFAULT_DEBUG_CHANNEL(ntdll);
  38 WINE_DECLARE_DEBUG_CHANNEL(relay);
  39
  40 static inline LONG interlocked_inc( PLONG dest )
  41 {
  42     return interlocked_xchg_add( (int *)dest, 1 ) + 1;
  43 }
  44
  45 static inline LONG interlocked_dec( PLONG dest )
  46 {
  47     return interlocked_xchg_add( (int *)dest, -1 ) - 1;
  48 }
  49
  50 static inline void small_pause(void)
  51 {
  52 #ifdef __i386__
  53     __asm__ __volatile__( "rep;nop" : : : "memory" );
  54 #else
  55     __asm__ __volatile__( "" : : : "memory" );
  56 #endif
  57 }
  58
  59 #if defined(linux) && defined(__i386__)
  60
  61 static inline int futex_wait( int *addr, int val, struct timespec *timeout )
  62 {
  63     int res;
  64     __asm__ __volatile__( "xchgl %2,%%ebx\n\t"
  65                           "int $0x80\n\t"
  66                           "xchgl %2,%%ebx"
  67                           : "=a" (res)
  68                           : "0" (240) /* SYS_futex */, "D" (addr),
  69                             "c" (0) /* FUTEX_WAIT */, "d" (val), "S" (timeout) );
  70     return res;
  71 }
  72
  73 static inline int futex_wake( int *addr, int val )
  74 {
  75     int res;
  76     __asm__ __volatile__( "xchgl %2,%%ebx\n\t"
  77                           "int $0x80\n\t"
  78                           "xchgl %2,%%ebx"
  79                           : "=a" (res)
  80                           : "0" (240) /* SYS_futex */, "D" (addr),
  81                             "c" (1)  /* FUTEX_WAKE */, "d" (val) );
  82     return res;
  83 }
  84
  85 static inline int use_futexes(void)
  86 {
  87     static int supported = -1;
  88
  89     if (supported == -1) supported = (futex_wait( &supported, 10, NULL ) != -ENOSYS);
  90     return supported;
  91 }
  92
  93 static inline NTSTATUS fast_wait( RTL_CRITICAL_SECTION *crit, int timeout )
  94 {
  95     int val;
  96     struct timespec timespec;
  97
  98     if (!use_futexes()) return STATUS_NOT_IMPLEMENTED;
  99
 100     timespec.tv_sec  = timeout;
 101     timespec.tv_nsec = 0;
 102     while ((val = interlocked_cmpxchg( (int *)&crit->LockSemaphore, 0, 1 )) != 1)
 103     {
 104         /* note: this may wait longer than specified in case of signals or */
 105         /*       multiple wake-ups, but that shouldn't be a problem */
 106         if (futex_wait( (int *)&crit->LockSemaphore, val, &timespec ) == -ETIMEDOUT)
 107             return STATUS_TIMEOUT;
 108     }
 109     return STATUS_WAIT_0;
 110 }
 111
 112 static inline NTSTATUS fast_wake( RTL_CRITICAL_SECTION *crit )
 113 {
 114     if (!use_futexes()) return STATUS_NOT_IMPLEMENTED;
 115
 116     *(int *)&crit->LockSemaphore = 1;
 117     futex_wake( (int *)&crit->LockSemaphore, 1 );
 118     return STATUS_SUCCESS;
 119 }
 120
 121 static inline void close_semaphore( RTL_CRITICAL_SECTION *crit )
 122 {
 123     if (!use_futexes()) NtClose( crit->LockSemaphore );
 124 }
 125
 126 #elif defined(__APPLE__)
 127
 128 #include <mach/mach.h>
 129 #include <mach/task.h>
 130 #include <mach/semaphore.h>
 131
 132 static inline semaphore_t get_mach_semaphore( RTL_CRITICAL_SECTION *crit )
 133 {
 134     semaphore_t ret = *(int *)&crit->LockSemaphore;
 135     if (!ret)
 136     {
 137         semaphore_t sem;
 138         if (semaphore_create( mach_task_self(), &sem, SYNC_POLICY_FIFO, 0 )) return 0;
 139         if (!(ret = interlocked_cmpxchg( (int *)&crit->LockSemaphore, sem, 0 )))
 140             ret = sem;
 141         else
 142             semaphore_destroy( mach_task_self(), sem );  /* somebody beat us to it */
 143     }
 144     return ret;
 145 }
 146
 147 static inline NTSTATUS fast_wait( RTL_CRITICAL_SECTION *crit, int timeout )
 148 {
 149     mach_timespec_t timespec;
 150     semaphore_t sem = get_mach_semaphore( crit );
 151
 152     timespec.tv_sec = timeout;
 153     timespec.tv_nsec = 0;
 154     for (;;)
 155     {
 156         switch( semaphore_timedwait( sem, timespec ))
 157         {
 158         case KERN_SUCCESS:
 159             return STATUS_WAIT_0;
 160         case KERN_ABORTED:
 161             continue;  /* got a signal, restart */
 162         case KERN_OPERATION_TIMED_OUT:
 163             return STATUS_TIMEOUT;
 164         default:
 165             return STATUS_INVALID_HANDLE;
 166         }
 167     }
 168 }
 169
 170 static inline NTSTATUS fast_wake( RTL_CRITICAL_SECTION *crit )
 171 {
 172     semaphore_t sem = get_mach_semaphore( crit );
 173     semaphore_signal( sem );
 174     return STATUS_SUCCESS;
 175 }
 176
 177 static inline void close_semaphore( RTL_CRITICAL_SECTION *crit )
 178 {
 179     semaphore_destroy( mach_task_self(), *(int *)&crit->LockSemaphore );
 180 }
 181
 182 #else  /* __APPLE__ */
 183
 184 static inline NTSTATUS fast_wait( RTL_CRITICAL_SECTION *crit, int timeout )
 185 {
 186     return STATUS_NOT_IMPLEMENTED;
 187 }
 188
 189 static inline NTSTATUS fast_wake( RTL_CRITICAL_SECTION *crit )
 190 {
 191     return STATUS_NOT_IMPLEMENTED;
 192 }
 193
 194 static inline void close_semaphore( RTL_CRITICAL_SECTION *crit )
 195 {
 196     NtClose( crit->LockSemaphore );
 197 }
 198
 199 #endif
 200
 201 /***********************************************************************
 202  *           get_semaphore
 203  */
 204 static inline HANDLE get_semaphore( RTL_CRITICAL_SECTION *crit )
 205 {
 206     HANDLE ret = crit->LockSemaphore;
 207     if (!ret)
 208     {
 209         HANDLE sem;
 210         if (NtCreateSemaphore( &sem, SEMAPHORE_ALL_ACCESS, NULL, 0, 1 )) return 0;
 211         if (!(ret = (HANDLE)interlocked_cmpxchg_ptr( (PVOID *)&crit->LockSemaphore,
 212                                                      (PVOID)sem, 0 )))
 213             ret = sem;
 214         else
 215             NtClose(sem);  /* somebody beat us to it */
 216     }
 217     return ret;
 218 }
 219
 220 /***********************************************************************
 221  *           wait_semaphore
 222  */
 223 static inline NTSTATUS wait_semaphore( RTL_CRITICAL_SECTION *crit, int timeout )
 224 {
 225     NTSTATUS ret;
 226
 227     /* debug info is cleared by MakeCriticalSectionGlobal */
 228     if (!crit->DebugInfo || ((ret = fast_wait( crit, timeout )) == STATUS_NOT_IMPLEMENTED))
 229     {
 230         HANDLE sem = get_semaphore( crit );
 231         LARGE_INTEGER time;
 232
 233         time.QuadPart = timeout * (LONGLONG)-10000000;
 234         ret = NTDLL_wait_for_multiple_objects( 1, &sem, 0, &time, 0 );
 235     }
 236     return ret;
 237 }
 238
 239 /***********************************************************************
 240  *           RtlInitializeCriticalSection   (NTDLL.@)
 241  *
 242  * Initialises a new critical section.
 243  *
 244  * PARAMS
 245  *  crit [O] Critical section to initialise
 246  *
 247  * RETURNS
 248  *  STATUS_SUCCESS.
 249  *
 250  * SEE
 251  *  RtlInitializeCriticalSectionAndSpinCount(), RtlDeleteCriticalSection(),
 252  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 253  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 254  */
 255 NTSTATUS WINAPI RtlInitializeCriticalSection( RTL_CRITICAL_SECTION *crit )
 256 {
 257     return RtlInitializeCriticalSectionAndSpinCount( crit, 0 );
 258 }
 259
 260 /***********************************************************************
 261  *           RtlInitializeCriticalSectionAndSpinCount   (NTDLL.@)
 262  *
 263  * Initialises a new critical section with a given spin count.
 264  *
 265  * PARAMS
 266  *   crit      [O] Critical section to initialise
 267  *   spincount [I] Spin count for crit
 268  *
 269  * RETURNS
 270  *  STATUS_SUCCESS.
 271  *
 272  * NOTES
 273  *  Available on NT4 SP3 or later.
 274  *
 275  * SEE
 276  *  RtlInitializeCriticalSection(), RtlDeleteCriticalSection(),
 277  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 278  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 279  */
 280 NTSTATUS WINAPI RtlInitializeCriticalSectionAndSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 281 {
 282     crit->DebugInfo = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(RTL_CRITICAL_SECTION_DEBUG));
 283     if (crit->DebugInfo)
 284     {
 285         crit->DebugInfo->Type = 0;
 286         crit->DebugInfo->CreatorBackTraceIndex = 0;
 287         crit->DebugInfo->CriticalSection = crit;
 288         crit->DebugInfo->ProcessLocksList.Blink = &(crit->DebugInfo->ProcessLocksList);
 289         crit->DebugInfo->ProcessLocksList.Flink = &(crit->DebugInfo->ProcessLocksList);
 290         crit->DebugInfo->EntryCount = 0;
 291         crit->DebugInfo->ContentionCount = 0;
 292         memset( crit->DebugInfo->Spare, 0, sizeof(crit->DebugInfo->Spare) );
 293     }
 294     crit->LockCount      = -1;
 295     crit->RecursionCount = 0;
 296     crit->OwningThread   = 0;
 297     crit->LockSemaphore  = 0;
 298     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 299     crit->SpinCount = spincount & ~0x80000000;
 300     return STATUS_SUCCESS;
 301 }
 302
 303 /***********************************************************************
 304  *           RtlSetCriticalSectionSpinCount   (NTDLL.@)
 305  *
 306  * Sets the spin count of a critical section.
 307  *
 308  * PARAMS
 309  *   crit      [I/O] Critical section
 310  *   spincount [I] Spin count for crit
 311  *
 312  * RETURNS
 313  *  The previous spin count.
 314  *
 315  * NOTES
 316  *  If the system is not SMP, spincount is ignored and set to 0.
 317  *
 318  * SEE
 319  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 320  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 321  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 322  */
 323 ULONG WINAPI RtlSetCriticalSectionSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 324 {
 325     ULONG oldspincount = crit->SpinCount;
 326     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 327     crit->SpinCount = spincount;
 328     return oldspincount;
 329 }
 330
 331 /***********************************************************************
 332  *           RtlDeleteCriticalSection   (NTDLL.@)
 333  *
 334  * Frees the resources used by a critical section.
 335  *
 336  * PARAMS
 337  *  crit [I/O] Critical section to free
 338  *
 339  * RETURNS
 340  *  STATUS_SUCCESS.
 341  *
 342  * SEE
 343  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 344  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 345  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 346  */
 347 NTSTATUS WINAPI RtlDeleteCriticalSection( RTL_CRITICAL_SECTION *crit )
 348 {
 349     crit->LockCount      = -1;
 350     crit->RecursionCount = 0;
 351     crit->OwningThread   = 0;
 352     if (crit->DebugInfo)
 353     {
 354         /* only free the ones we made in here */
 355         if (!crit->DebugInfo->Spare[0])
 356         {
 357             RtlFreeHeap( GetProcessHeap(), 0, crit->DebugInfo );
 358             crit->DebugInfo = NULL;
 359         }
 360         close_semaphore( crit );
 361     }
 362     else NtClose( crit->LockSemaphore );
 363     crit->LockSemaphore = 0;
 364     return STATUS_SUCCESS;
 365 }
 366
 367
 368 /***********************************************************************
 369  *           RtlpWaitForCriticalSection   (NTDLL.@)
 370  *
 371  * Waits for a busy critical section to become free.
 372  *
 373  * PARAMS
 374  *  crit [I/O] Critical section to wait for
 375  *
 376  * RETURNS
 377  *  STATUS_SUCCESS.
 378  *
 379  * NOTES
 380  *  Use RtlEnterCriticalSection() instead of this function as it is often much
 381  *  faster.
 382  *
 383  * SEE
 384  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 385  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 386  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 387  */
 388 NTSTATUS WINAPI RtlpWaitForCriticalSection( RTL_CRITICAL_SECTION *crit )
 389 {
 390     for (;;)
 391     {
 392         EXCEPTION_RECORD rec;
 393         NTSTATUS status = wait_semaphore( crit, 5 );
 394
 395         if ( status == STATUS_TIMEOUT )
 396         {
 397             const char *name = NULL;
 398             if (crit->DebugInfo) name = (char *)crit->DebugInfo->Spare[0];
 399             if (!name) name = "?";
 400             ERR( "section %p %s wait timed out in thread %04x, blocked by %04x, retrying (60 sec)\n",
 401                  crit, debugstr_a(name), GetCurrentThreadId(), HandleToULong(crit->OwningThread) );
 402             status = wait_semaphore( crit, 60 );
 403             if ( status == STATUS_TIMEOUT && TRACE_ON(relay) )
 404             {
 405                 ERR( "section %p %s wait timed out in thread %04x, blocked by %04x, retrying (5 min)\n",
 406                      crit, debugstr_a(name), GetCurrentThreadId(), HandleToULong(crit->OwningThread) );
 407                 status = wait_semaphore( crit, 300 );
 408             }
 409         }
 410         if (status == STATUS_WAIT_0) break;
 411
 412         /* Throw exception only for Wine internal locks */
 413         if ((!crit->DebugInfo) || (!crit->DebugInfo->Spare[0])) continue;
 414
 415         rec.ExceptionCode    = STATUS_POSSIBLE_DEADLOCK;
 416         rec.ExceptionFlags   = 0;
 417         rec.ExceptionRecord  = NULL;
 418         rec.ExceptionAddress = RtlRaiseException;  /* sic */
 419         rec.NumberParameters = 1;
 420         rec.ExceptionInformation[0] = (ULONG_PTR)crit;
 421         RtlRaiseException( &rec );
 422     }
 423     if (crit->DebugInfo) crit->DebugInfo->ContentionCount++;
 424     return STATUS_SUCCESS;
 425 }
 426
 427
 428 /***********************************************************************
 429  *           RtlpUnWaitCriticalSection   (NTDLL.@)
 430  *
 431  * Notifies other threads waiting on the busy critical section that it has
 432  * become free.
 433  *
 434  * PARAMS
 435  *  crit [I/O] Critical section
 436  *
 437  * RETURNS
 438  *  Success: STATUS_SUCCESS.
 439  *  Failure: Any error returned by NtReleaseSemaphore()
 440  *
 441  * NOTES
 442  *  Use RtlLeaveCriticalSection() instead of this function as it is often much
 443  *  faster.
 444  *
 445  * SEE
 446  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 447  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 448  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 449  */
 450 NTSTATUS WINAPI RtlpUnWaitCriticalSection( RTL_CRITICAL_SECTION *crit )
 451 {
 452     NTSTATUS ret;
 453
 454     /* debug info is cleared by MakeCriticalSectionGlobal */
 455     if (!crit->DebugInfo || ((ret = fast_wake( crit )) == STATUS_NOT_IMPLEMENTED))
 456     {
 457         HANDLE sem = get_semaphore( crit );
 458         ret = NtReleaseSemaphore( sem, 1, NULL );
 459     }
 460     if (ret) RtlRaiseStatus( ret );
 461     return ret;
 462 }
 463
 464
 465 /***********************************************************************
 466  *           RtlEnterCriticalSection   (NTDLL.@)
 467  *
 468  * Enters a critical section, waiting for it to become available if necessary.
 469  *
 470  * PARAMS
 471  *  crit [I/O] Critical section to enter
 472  *
 473  * RETURNS
 474  *  STATUS_SUCCESS. The critical section is held by the caller.
 475  *
 476  * SEE
 477  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 478  *  RtlDeleteCriticalSection(), RtlSetCriticalSectionSpinCount(),
 479  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 480  */
 481 NTSTATUS WINAPI RtlEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 482 {
 483     if (crit->SpinCount)
 484     {
 485         ULONG count;
 486
 487         if (RtlTryEnterCriticalSection( crit )) return STATUS_SUCCESS;
 488         for (count = crit->SpinCount; count > 0; count--)
 489         {
 490             if (crit->LockCount > 0) break;  /* more than one waiter, don't bother spinning */
 491             if (crit->LockCount == -1)       /* try again */
 492             {
 493                 if (interlocked_cmpxchg( (int *)&crit->LockCount, 0, -1 ) == -1) goto done;
 494             }
 495             small_pause();
 496         }
 497     }
 498
 499     if (interlocked_inc( &crit->LockCount ))
 500     {
 501         if (crit->OwningThread == ULongToHandle(GetCurrentThreadId()))
 502         {
 503             crit->RecursionCount++;
 504             return STATUS_SUCCESS;
 505         }
 506
 507         /* Now wait for it */
 508         RtlpWaitForCriticalSection( crit );
 509     }
 510 done:
 511     crit->OwningThread   = ULongToHandle(GetCurrentThreadId());
 512     crit->RecursionCount = 1;
 513     return STATUS_SUCCESS;
 514 }
 515
 516
 517 /***********************************************************************
 518  *           RtlTryEnterCriticalSection   (NTDLL.@)
 519  *
 520  * Tries to enter a critical section without waiting.
 521  *
 522  * PARAMS
 523  *  crit [I/O] Critical section to enter
 524  *
 525  * RETURNS
 526  *  Success: TRUE. The critical section is held by the caller.
 527  *  Failure: FALSE. The critical section is currently held by another thread.
 528  *
 529  * SEE
 530  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 531  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 532  *  RtlLeaveCriticalSection(), RtlSetCriticalSectionSpinCount()
 533  */
 534 BOOL WINAPI RtlTryEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 535 {
 536     BOOL ret = FALSE;
 537     if (interlocked_cmpxchg( (int *)&crit->LockCount, 0, -1 ) == -1)
 538     {
 539         crit->OwningThread   = ULongToHandle(GetCurrentThreadId());
 540         crit->RecursionCount = 1;
 541         ret = TRUE;
 542     }
 543     else if (crit->OwningThread == ULongToHandle(GetCurrentThreadId()))
 544     {
 545         interlocked_inc( &crit->LockCount );
 546         crit->RecursionCount++;
 547         ret = TRUE;
 548     }
 549     return ret;
 550 }
 551
 552
 553 /***********************************************************************
 554  *           RtlLeaveCriticalSection   (NTDLL.@)
 555  *
 556  * Leaves a critical section.
 557  *
 558  * PARAMS
 559  *  crit [I/O] Critical section to leave.
 560  *
 561  * RETURNS
 562  *  STATUS_SUCCESS.
 563  *
 564  * SEE
 565  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 566  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 567  *  RtlSetCriticalSectionSpinCount(), RtlTryEnterCriticalSection()
 568  */
 569 NTSTATUS WINAPI RtlLeaveCriticalSection( RTL_CRITICAL_SECTION *crit )
 570 {
 571     if (--crit->RecursionCount) interlocked_dec( &crit->LockCount );
 572     else
 573     {
 574         crit->OwningThread = 0;
 575         if (interlocked_dec( &crit->LockCount ) >= 0)
 576         {
 577             /* someone is waiting */
 578             RtlpUnWaitCriticalSection( crit );
 579         }
 580     }
 581     return STATUS_SUCCESS;
 582 }