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( dest, 1 ) + 1;
  43 }
  44
  45 static inline LONG interlocked_dec( PLONG dest )
  46 {
  47     return interlocked_xchg_add( 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 = interlocked_cmpxchg_ptr( &crit->LockSemaphore, sem, 0 )))
 212             ret = sem;
 213         else
 214             NtClose(sem);  /* somebody beat us to it */
 215     }
 216     return ret;
 217 }
 218
 219 /***********************************************************************
 220  *           wait_semaphore
 221  */
 222 static inline NTSTATUS wait_semaphore( RTL_CRITICAL_SECTION *crit, int timeout )
 223 {
 224     NTSTATUS ret;
 225
 226     /* debug info is cleared by MakeCriticalSectionGlobal */
 227     if (!crit->DebugInfo || ((ret = fast_wait( crit, timeout )) == STATUS_NOT_IMPLEMENTED))
 228     {
 229         HANDLE sem = get_semaphore( crit );
 230         LARGE_INTEGER time;
 231
 232         time.QuadPart = timeout * (LONGLONG)-10000000;
 233         ret = NTDLL_wait_for_multiple_objects( 1, &sem, 0, &time, 0 );
 234     }
 235     return ret;
 236 }
 237
 238 /***********************************************************************
 239  *           RtlInitializeCriticalSection   (NTDLL.@)
 240  *
 241  * Initialises a new critical section.
 242  *
 243  * PARAMS
 244  *  crit [O] Critical section to initialise
 245  *
 246  * RETURNS
 247  *  STATUS_SUCCESS.
 248  *
 249  * SEE
 250  *  RtlInitializeCriticalSectionAndSpinCount(), RtlDeleteCriticalSection(),
 251  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 252  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 253  */
 254 NTSTATUS WINAPI RtlInitializeCriticalSection( RTL_CRITICAL_SECTION *crit )
 255 {
 256     return RtlInitializeCriticalSectionAndSpinCount( crit, 0 );
 257 }
 258
 259 /***********************************************************************
 260  *           RtlInitializeCriticalSectionAndSpinCount   (NTDLL.@)
 261  *
 262  * Initialises a new critical section with a given spin count.
 263  *
 264  * PARAMS
 265  *   crit      [O] Critical section to initialise
 266  *   spincount [I] Spin count for crit
 267  *
 268  * RETURNS
 269  *  STATUS_SUCCESS.
 270  *
 271  * NOTES
 272  *  Available on NT4 SP3 or later.
 273  *
 274  * SEE
 275  *  RtlInitializeCriticalSection(), RtlDeleteCriticalSection(),
 276  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 277  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 278  */
 279 NTSTATUS WINAPI RtlInitializeCriticalSectionAndSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 280 {
 281     crit->DebugInfo = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(RTL_CRITICAL_SECTION_DEBUG));
 282     if (crit->DebugInfo)
 283     {
 284         crit->DebugInfo->Type = 0;
 285         crit->DebugInfo->CreatorBackTraceIndex = 0;
 286         crit->DebugInfo->CriticalSection = crit;
 287         crit->DebugInfo->ProcessLocksList.Blink = &(crit->DebugInfo->ProcessLocksList);
 288         crit->DebugInfo->ProcessLocksList.Flink = &(crit->DebugInfo->ProcessLocksList);
 289         crit->DebugInfo->EntryCount = 0;
 290         crit->DebugInfo->ContentionCount = 0;
 291         memset( crit->DebugInfo->Spare, 0, sizeof(crit->DebugInfo->Spare) );
 292     }
 293     crit->LockCount      = -1;
 294     crit->RecursionCount = 0;
 295     crit->OwningThread   = 0;
 296     crit->LockSemaphore  = 0;
 297     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 298     crit->SpinCount = spincount & ~0x80000000;
 299     return STATUS_SUCCESS;
 300 }
 301
 302 /***********************************************************************
 303  *           RtlSetCriticalSectionSpinCount   (NTDLL.@)
 304  *
 305  * Sets the spin count of a critical section.
 306  *
 307  * PARAMS
 308  *   crit      [I/O] Critical section
 309  *   spincount [I] Spin count for crit
 310  *
 311  * RETURNS
 312  *  The previous spin count.
 313  *
 314  * NOTES
 315  *  If the system is not SMP, spincount is ignored and set to 0.
 316  *
 317  * SEE
 318  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 319  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 320  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 321  */
 322 ULONG WINAPI RtlSetCriticalSectionSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 323 {
 324     ULONG oldspincount = crit->SpinCount;
 325     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 326     crit->SpinCount = spincount;
 327     return oldspincount;
 328 }
 329
 330 /***********************************************************************
 331  *           RtlDeleteCriticalSection   (NTDLL.@)
 332  *
 333  * Frees the resources used by a critical section.
 334  *
 335  * PARAMS
 336  *  crit [I/O] Critical section to free
 337  *
 338  * RETURNS
 339  *  STATUS_SUCCESS.
 340  *
 341  * SEE
 342  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 343  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 344  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 345  */
 346 NTSTATUS WINAPI RtlDeleteCriticalSection( RTL_CRITICAL_SECTION *crit )
 347 {
 348     crit->LockCount      = -1;
 349     crit->RecursionCount = 0;
 350     crit->OwningThread   = 0;
 351     if (crit->DebugInfo)
 352     {
 353         /* only free the ones we made in here */
 354         if (!crit->DebugInfo->Spare[0])
 355         {
 356             RtlFreeHeap( GetProcessHeap(), 0, crit->DebugInfo );
 357             crit->DebugInfo = NULL;
 358         }
 359         close_semaphore( crit );
 360     }
 361     else NtClose( crit->LockSemaphore );
 362     crit->LockSemaphore = 0;
 363     return STATUS_SUCCESS;
 364 }
 365
 366
 367 /***********************************************************************
 368  *           RtlpWaitForCriticalSection   (NTDLL.@)
 369  *
 370  * Waits for a busy critical section to become free.
 371  *
 372  * PARAMS
 373  *  crit [I/O] Critical section to wait for
 374  *
 375  * RETURNS
 376  *  STATUS_SUCCESS.
 377  *
 378  * NOTES
 379  *  Use RtlEnterCriticalSection() instead of this function as it is often much
 380  *  faster.
 381  *
 382  * SEE
 383  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 384  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 385  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 386  */
 387 NTSTATUS WINAPI RtlpWaitForCriticalSection( RTL_CRITICAL_SECTION *crit )
 388 {
 389     for (;;)
 390     {
 391         EXCEPTION_RECORD rec;
 392         NTSTATUS status = wait_semaphore( crit, 5 );
 393
 394         if ( status == STATUS_TIMEOUT )
 395         {
 396             const char *name = NULL;
 397             if (crit->DebugInfo) name = (char *)crit->DebugInfo->Spare[0];
 398             if (!name) name = "?";
 399             ERR( "section %p %s wait timed out in thread %04x, blocked by %04x, retrying (60 sec)\n",
 400                  crit, debugstr_a(name), GetCurrentThreadId(), HandleToULong(crit->OwningThread) );
 401             status = wait_semaphore( crit, 60 );
 402             if ( status == STATUS_TIMEOUT && TRACE_ON(relay) )
 403             {
 404                 ERR( "section %p %s wait timed out in thread %04x, blocked by %04x, retrying (5 min)\n",
 405                      crit, debugstr_a(name), GetCurrentThreadId(), HandleToULong(crit->OwningThread) );
 406                 status = wait_semaphore( crit, 300 );
 407             }
 408         }
 409         if (status == STATUS_WAIT_0) break;
 410
 411         /* Throw exception only for Wine internal locks */
 412         if ((!crit->DebugInfo) || (!crit->DebugInfo->Spare[0])) continue;
 413
 414         rec.ExceptionCode    = STATUS_POSSIBLE_DEADLOCK;
 415         rec.ExceptionFlags   = 0;
 416         rec.ExceptionRecord  = NULL;
 417         rec.ExceptionAddress = RtlRaiseException;  /* sic */
 418         rec.NumberParameters = 1;
 419         rec.ExceptionInformation[0] = (ULONG_PTR)crit;
 420         RtlRaiseException( &rec );
 421     }
 422     if (crit->DebugInfo) crit->DebugInfo->ContentionCount++;
 423     return STATUS_SUCCESS;
 424 }
 425
 426
 427 /***********************************************************************
 428  *           RtlpUnWaitCriticalSection   (NTDLL.@)
 429  *
 430  * Notifies other threads waiting on the busy critical section that it has
 431  * become free.
 432  *
 433  * PARAMS
 434  *  crit [I/O] Critical section
 435  *
 436  * RETURNS
 437  *  Success: STATUS_SUCCESS.
 438  *  Failure: Any error returned by NtReleaseSemaphore()
 439  *
 440  * NOTES
 441  *  Use RtlLeaveCriticalSection() instead of this function as it is often much
 442  *  faster.
 443  *
 444  * SEE
 445  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 446  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 447  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 448  */
 449 NTSTATUS WINAPI RtlpUnWaitCriticalSection( RTL_CRITICAL_SECTION *crit )
 450 {
 451     NTSTATUS ret;
 452
 453     /* debug info is cleared by MakeCriticalSectionGlobal */
 454     if (!crit->DebugInfo || ((ret = fast_wake( crit )) == STATUS_NOT_IMPLEMENTED))
 455     {
 456         HANDLE sem = get_semaphore( crit );
 457         ret = NtReleaseSemaphore( sem, 1, NULL );
 458     }
 459     if (ret) RtlRaiseStatus( ret );
 460     return ret;
 461 }
 462
 463
 464 /***********************************************************************
 465  *           RtlEnterCriticalSection   (NTDLL.@)
 466  *
 467  * Enters a critical section, waiting for it to become available if necessary.
 468  *
 469  * PARAMS
 470  *  crit [I/O] Critical section to enter
 471  *
 472  * RETURNS
 473  *  STATUS_SUCCESS. The critical section is held by the caller.
 474  *
 475  * SEE
 476  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 477  *  RtlDeleteCriticalSection(), RtlSetCriticalSectionSpinCount(),
 478  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 479  */
 480 NTSTATUS WINAPI RtlEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 481 {
 482     if (crit->SpinCount)
 483     {
 484         ULONG count;
 485
 486         if (RtlTryEnterCriticalSection( crit )) return STATUS_SUCCESS;
 487         for (count = crit->SpinCount; count > 0; count--)
 488         {
 489             if (crit->LockCount > 0) break;  /* more than one waiter, don't bother spinning */
 490             if (crit->LockCount == -1)       /* try again */
 491             {
 492                 if (interlocked_cmpxchg( &crit->LockCount, 0, -1 ) == -1) goto done;
 493             }
 494             small_pause();
 495         }
 496     }
 497
 498     if (interlocked_inc( &crit->LockCount ))
 499     {
 500         if (crit->OwningThread == ULongToHandle(GetCurrentThreadId()))
 501         {
 502             crit->RecursionCount++;
 503             return STATUS_SUCCESS;
 504         }
 505
 506         /* Now wait for it */
 507         RtlpWaitForCriticalSection( crit );
 508     }
 509 done:
 510     crit->OwningThread   = ULongToHandle(GetCurrentThreadId());
 511     crit->RecursionCount = 1;
 512     return STATUS_SUCCESS;
 513 }
 514
 515
 516 /***********************************************************************
 517  *           RtlTryEnterCriticalSection   (NTDLL.@)
 518  *
 519  * Tries to enter a critical section without waiting.
 520  *
 521  * PARAMS
 522  *  crit [I/O] Critical section to enter
 523  *
 524  * RETURNS
 525  *  Success: TRUE. The critical section is held by the caller.
 526  *  Failure: FALSE. The critical section is currently held by another thread.
 527  *
 528  * SEE
 529  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 530  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 531  *  RtlLeaveCriticalSection(), RtlSetCriticalSectionSpinCount()
 532  */
 533 BOOL WINAPI RtlTryEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 534 {
 535     BOOL ret = FALSE;
 536     if (interlocked_cmpxchg( &crit->LockCount, 0, -1 ) == -1)
 537     {
 538         crit->OwningThread   = ULongToHandle(GetCurrentThreadId());
 539         crit->RecursionCount = 1;
 540         ret = TRUE;
 541     }
 542     else if (crit->OwningThread == ULongToHandle(GetCurrentThreadId()))
 543     {
 544         interlocked_inc( &crit->LockCount );
 545         crit->RecursionCount++;
 546         ret = TRUE;
 547     }
 548     return ret;
 549 }
 550
 551
 552 /***********************************************************************
 553  *           RtlLeaveCriticalSection   (NTDLL.@)
 554  *
 555  * Leaves a critical section.
 556  *
 557  * PARAMS
 558  *  crit [I/O] Critical section to leave.
 559  *
 560  * RETURNS
 561  *  STATUS_SUCCESS.
 562  *
 563  * SEE
 564  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 565  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 566  *  RtlSetCriticalSectionSpinCount(), RtlTryEnterCriticalSection()
 567  */
 568 NTSTATUS WINAPI RtlLeaveCriticalSection( RTL_CRITICAL_SECTION *crit )
 569 {
 570     if (--crit->RecursionCount) interlocked_dec( &crit->LockCount );
 571     else
 572     {
 573         crit->OwningThread = 0;
 574         if (interlocked_dec( &crit->LockCount ) >= 0)
 575         {
 576             /* someone is waiting */
 577             RtlpUnWaitCriticalSection( crit );
 578         }
 579     }
 580     return STATUS_SUCCESS;
 581 }