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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 inline static LONG interlocked_inc( PLONG dest )
  41 {
  42     return interlocked_xchg_add( (int *)dest, 1 ) + 1;
  43 }
  44
  45 inline static LONG interlocked_dec( PLONG dest )
  46 {
  47     return interlocked_xchg_add( (int *)dest, -1 ) - 1;
  48 }
  49
  50 inline static 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 #else  /* linux */
  94
  95 static inline int futex_wait( int *addr, int val, struct timespec *timeout ) { return -ENOSYS; }
  96 static inline int futex_wake( int *addr, int val ) { return -ENOSYS; }
  97 static inline int use_futexes(void) { return 0; }
  98
  99 #endif
 100
 101 /***********************************************************************
 102  *           get_semaphore
 103  */
 104 static inline HANDLE get_semaphore( RTL_CRITICAL_SECTION *crit )
 105 {
 106     HANDLE ret = crit->LockSemaphore;
 107     if (!ret)
 108     {
 109         HANDLE sem;
 110         if (NtCreateSemaphore( &sem, SEMAPHORE_ALL_ACCESS, NULL, 0, 1 )) return 0;
 111         if (!(ret = (HANDLE)interlocked_cmpxchg_ptr( (PVOID *)&crit->LockSemaphore,
 112                                                      (PVOID)sem, 0 )))
 113             ret = sem;
 114         else
 115             NtClose(sem);  /* somebody beat us to it */
 116     }
 117     return ret;
 118 }
 119
 120 /***********************************************************************
 121  *           wait_semaphore
 122  */
 123 static inline NTSTATUS wait_semaphore( RTL_CRITICAL_SECTION *crit, int timeout )
 124 {
 125     if (use_futexes() && crit->DebugInfo)  /* debug info is cleared by MakeCriticalSectionGlobal */
 126     {
 127         int val;
 128         struct timespec timespec;
 129
 130         timespec.tv_sec  = timeout;
 131         timespec.tv_nsec = 0;
 132         while ((val = interlocked_cmpxchg( (int *)&crit->LockSemaphore, 0, 1 )) != 1)
 133         {
 134             /* note: this may wait longer than specified in case of signals or */
 135             /*       multiple wake-ups, but that shouldn't be a problem */
 136             if (futex_wait( (int *)&crit->LockSemaphore, val, &timespec ) == -ETIMEDOUT)
 137                 return STATUS_TIMEOUT;
 138         }
 139         return STATUS_WAIT_0;
 140     }
 141     else
 142     {
 143         HANDLE sem = get_semaphore( crit );
 144         LARGE_INTEGER time;
 145
 146         time.QuadPart = timeout * (LONGLONG)-10000000;
 147         return NtWaitForSingleObject( sem, FALSE, &time );
 148     }
 149 }
 150
 151 /***********************************************************************
 152  *           RtlInitializeCriticalSection   (NTDLL.@)
 153  *
 154  * Initialises a new critical section.
 155  *
 156  * PARAMS
 157  *  crit [O] Critical section to initialise
 158  *
 159  * RETURNS
 160  *  STATUS_SUCCESS.
 161  *
 162  * SEE
 163  *  RtlInitializeCriticalSectionAndSpinCount(), RtlDeleteCriticalSection(),
 164  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 165  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 166  */
 167 NTSTATUS WINAPI RtlInitializeCriticalSection( RTL_CRITICAL_SECTION *crit )
 168 {
 169     return RtlInitializeCriticalSectionAndSpinCount( crit, 0 );
 170 }
 171
 172 /***********************************************************************
 173  *           RtlInitializeCriticalSectionAndSpinCount   (NTDLL.@)
 174  *
 175  * Initialises a new critical section with a given spin count.
 176  *
 177  * PARAMS
 178  *   crit      [O] Critical section to initialise
 179  *   spincount [I] Spin count for crit
 180  *
 181  * RETURNS
 182  *  STATUS_SUCCESS.
 183  *
 184  * NOTES
 185  *  Available on NT4 SP3 or later.
 186  *
 187  * SEE
 188  *  RtlInitializeCriticalSection(), RtlDeleteCriticalSection(),
 189  *  RtlEnterCriticalSection(), RtlLeaveCriticalSection(),
 190  *  RtlTryEnterCriticalSection(), RtlSetCriticalSectionSpinCount()
 191  */
 192 NTSTATUS WINAPI RtlInitializeCriticalSectionAndSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 193 {
 194     crit->DebugInfo = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(RTL_CRITICAL_SECTION_DEBUG));
 195     if (crit->DebugInfo)
 196     {
 197         crit->DebugInfo->Type = 0;
 198         crit->DebugInfo->CreatorBackTraceIndex = 0;
 199         crit->DebugInfo->CriticalSection = crit;
 200         crit->DebugInfo->ProcessLocksList.Blink = &(crit->DebugInfo->ProcessLocksList);
 201         crit->DebugInfo->ProcessLocksList.Flink = &(crit->DebugInfo->ProcessLocksList);
 202         crit->DebugInfo->EntryCount = 0;
 203         crit->DebugInfo->ContentionCount = 0;
 204         memset( crit->DebugInfo->Spare, 0, sizeof(crit->DebugInfo->Spare) );
 205     }
 206     crit->LockCount      = -1;
 207     crit->RecursionCount = 0;
 208     crit->OwningThread   = 0;
 209     crit->LockSemaphore  = 0;
 210     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 211     crit->SpinCount = spincount & ~0x80000000;
 212     return STATUS_SUCCESS;
 213 }
 214
 215 /***********************************************************************
 216  *           RtlSetCriticalSectionSpinCount   (NTDLL.@)
 217  *
 218  * Sets the spin count of a critical section.
 219  *
 220  * PARAMS
 221  *   crit      [I/O] Critical section
 222  *   spincount [I] Spin count for crit
 223  *
 224  * RETURNS
 225  *  The previous spin count.
 226  *
 227  * NOTES
 228  *  If the system is not SMP, spincount is ignored and set to 0.
 229  *
 230  * SEE
 231  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 232  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 233  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 234  */
 235 ULONG WINAPI RtlSetCriticalSectionSpinCount( RTL_CRITICAL_SECTION *crit, ULONG spincount )
 236 {
 237     ULONG oldspincount = crit->SpinCount;
 238     if (NtCurrentTeb()->Peb->NumberOfProcessors <= 1) spincount = 0;
 239     crit->SpinCount = spincount;
 240     return oldspincount;
 241 }
 242
 243 /***********************************************************************
 244  *           RtlDeleteCriticalSection   (NTDLL.@)
 245  *
 246  * Frees the resources used by a critical section.
 247  *
 248  * PARAMS
 249  *  crit [I/O] Critical section to free
 250  *
 251  * RETURNS
 252  *  STATUS_SUCCESS.
 253  *
 254  * SEE
 255  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 256  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 257  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 258  */
 259 NTSTATUS WINAPI RtlDeleteCriticalSection( RTL_CRITICAL_SECTION *crit )
 260 {
 261     crit->LockCount      = -1;
 262     crit->RecursionCount = 0;
 263     crit->OwningThread   = 0;
 264     if (crit->LockSemaphore) NtClose( crit->LockSemaphore );
 265     crit->LockSemaphore  = 0;
 266     if (crit->DebugInfo)
 267     {
 268         /* only free the ones we made in here */
 269         if (!crit->DebugInfo->Spare[0])
 270         {
 271             RtlFreeHeap( GetProcessHeap(), 0, crit->DebugInfo );
 272             crit->DebugInfo = NULL;
 273         }
 274     }
 275     return STATUS_SUCCESS;
 276 }
 277
 278
 279 /***********************************************************************
 280  *           RtlpWaitForCriticalSection   (NTDLL.@)
 281  *
 282  * Waits for a busy critical section to become free.
 283  *
 284  * PARAMS
 285  *  crit [I/O] Critical section to wait for
 286  *
 287  * RETURNS
 288  *  STATUS_SUCCESS.
 289  *
 290  * NOTES
 291  *  Use RtlEnterCriticalSection() instead of this function as it is often much
 292  *  faster.
 293  *
 294  * SEE
 295  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 296  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 297  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 298  */
 299 NTSTATUS WINAPI RtlpWaitForCriticalSection( RTL_CRITICAL_SECTION *crit )
 300 {
 301     for (;;)
 302     {
 303         EXCEPTION_RECORD rec;
 304         NTSTATUS status = wait_semaphore( crit, 5 );
 305
 306         if ( status == STATUS_TIMEOUT )
 307         {
 308             const char *name = NULL;
 309             if (crit->DebugInfo) name = (char *)crit->DebugInfo->Spare[0];
 310             if (!name) name = "?";
 311             ERR( "section %p %s wait timed out in thread %04lx, blocked by %04lx, retrying (60 sec)\n",
 312                  crit, debugstr_a(name), GetCurrentThreadId(), (DWORD)crit->OwningThread );
 313             status = wait_semaphore( crit, 60 );
 314             if ( status == STATUS_TIMEOUT && TRACE_ON(relay) )
 315             {
 316                 ERR( "section %p %s wait timed out in thread %04lx, blocked by %04lx, retrying (5 min)\n",
 317                      crit, debugstr_a(name), GetCurrentThreadId(), (DWORD) crit->OwningThread );
 318                 status = wait_semaphore( crit, 300 );
 319             }
 320         }
 321         if (status == STATUS_WAIT_0) break;
 322
 323         /* Throw exception only for Wine internal locks */
 324         if ((!crit->DebugInfo) || (!crit->DebugInfo->Spare[0])) continue;
 325
 326         rec.ExceptionCode    = STATUS_POSSIBLE_DEADLOCK;
 327         rec.ExceptionFlags   = 0;
 328         rec.ExceptionRecord  = NULL;
 329         rec.ExceptionAddress = RtlRaiseException;  /* sic */
 330         rec.NumberParameters = 1;
 331         rec.ExceptionInformation[0] = (ULONG_PTR)crit;
 332         RtlRaiseException( &rec );
 333     }
 334     if (crit->DebugInfo) crit->DebugInfo->ContentionCount++;
 335     return STATUS_SUCCESS;
 336 }
 337
 338
 339 /***********************************************************************
 340  *           RtlpUnWaitCriticalSection   (NTDLL.@)
 341  *
 342  * Notifies other threads waiting on the busy critical section that it has
 343  * become free.
 344  *
 345  * PARAMS
 346  *  crit [I/O] Critical section
 347  *
 348  * RETURNS
 349  *  Success: STATUS_SUCCESS.
 350  *  Failure: Any error returned by NtReleaseSemaphore()
 351  *
 352  * NOTES
 353  *  Use RtlLeaveCriticalSection() instead of this function as it is often much
 354  *  faster.
 355  *
 356  * SEE
 357  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 358  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 359  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 360  */
 361 NTSTATUS WINAPI RtlpUnWaitCriticalSection( RTL_CRITICAL_SECTION *crit )
 362 {
 363     if (use_futexes() && crit->DebugInfo)  /* debug info is cleared by MakeCriticalSectionGlobal */
 364     {
 365         *(int *)&crit->LockSemaphore = 1;
 366         futex_wake( (int *)&crit->LockSemaphore, 1 );
 367         return STATUS_SUCCESS;
 368     }
 369     else
 370     {
 371         HANDLE sem = get_semaphore( crit );
 372         NTSTATUS res = NtReleaseSemaphore( sem, 1, NULL );
 373         if (res) RtlRaiseStatus( res );
 374         return res;
 375     }
 376 }
 377
 378
 379 /***********************************************************************
 380  *           RtlEnterCriticalSection   (NTDLL.@)
 381  *
 382  * Enters a critical section, waiting for it to become available if necessary.
 383  *
 384  * PARAMS
 385  *  crit [I/O] Critical section to enter
 386  *
 387  * RETURNS
 388  *  STATUS_SUCCESS. The critical section is held by the caller.
 389  *
 390  * SEE
 391  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 392  *  RtlDeleteCriticalSection(), RtlSetCriticalSectionSpinCount(),
 393  *  RtlLeaveCriticalSection(), RtlTryEnterCriticalSection()
 394  */
 395 NTSTATUS WINAPI RtlEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 396 {
 397     if (crit->SpinCount)
 398     {
 399         ULONG count;
 400
 401         if (RtlTryEnterCriticalSection( crit )) return STATUS_SUCCESS;
 402         for (count = crit->SpinCount; count > 0; count--)
 403         {
 404             if (crit->LockCount > 0) break;  /* more than one waiter, don't bother spinning */
 405             if (crit->LockCount == -1)       /* try again */
 406             {
 407                 if (interlocked_cmpxchg( (int *)&crit->LockCount, 0, -1 ) == -1) goto done;
 408             }
 409             small_pause();
 410         }
 411     }
 412
 413     if (interlocked_inc( &crit->LockCount ))
 414     {
 415         if (crit->OwningThread == (HANDLE)GetCurrentThreadId())
 416         {
 417             crit->RecursionCount++;
 418             return STATUS_SUCCESS;
 419         }
 420
 421         /* Now wait for it */
 422         RtlpWaitForCriticalSection( crit );
 423     }
 424 done:
 425     crit->OwningThread   = (HANDLE)GetCurrentThreadId();
 426     crit->RecursionCount = 1;
 427     return STATUS_SUCCESS;
 428 }
 429
 430
 431 /***********************************************************************
 432  *           RtlTryEnterCriticalSection   (NTDLL.@)
 433  *
 434  * Tries to enter a critical section without waiting.
 435  *
 436  * PARAMS
 437  *  crit [I/O] Critical section to enter
 438  *
 439  * RETURNS
 440  *  Success: TRUE. The critical section is held by the caller.
 441  *  Failure: FALSE. The critical section is currently held by another thread.
 442  *
 443  * SEE
 444  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 445  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 446  *  RtlLeaveCriticalSection(), RtlSetCriticalSectionSpinCount()
 447  */
 448 BOOL WINAPI RtlTryEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 449 {
 450     BOOL ret = FALSE;
 451     if (interlocked_cmpxchg( (int *)&crit->LockCount, 0, -1 ) == -1)
 452     {
 453         crit->OwningThread   = (HANDLE)GetCurrentThreadId();
 454         crit->RecursionCount = 1;
 455         ret = TRUE;
 456     }
 457     else if (crit->OwningThread == (HANDLE)GetCurrentThreadId())
 458     {
 459         interlocked_inc( &crit->LockCount );
 460         crit->RecursionCount++;
 461         ret = TRUE;
 462     }
 463     return ret;
 464 }
 465
 466
 467 /***********************************************************************
 468  *           RtlLeaveCriticalSection   (NTDLL.@)
 469  *
 470  * Leaves a critical section.
 471  *
 472  * PARAMS
 473  *  crit [I/O] Critical section to leave.
 474  *
 475  * RETURNS
 476  *  STATUS_SUCCESS.
 477  *
 478  * SEE
 479  *  RtlInitializeCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(),
 480  *  RtlDeleteCriticalSection(), RtlEnterCriticalSection(),
 481  *  RtlSetCriticalSectionSpinCount(), RtlTryEnterCriticalSection()
 482  */
 483 NTSTATUS WINAPI RtlLeaveCriticalSection( RTL_CRITICAL_SECTION *crit )
 484 {
 485     if (--crit->RecursionCount) interlocked_dec( &crit->LockCount );
 486     else
 487     {
 488         crit->OwningThread = 0;
 489         if (interlocked_dec( &crit->LockCount ) >= 0)
 490         {
 491             /* someone is waiting */
 492             RtlpUnWaitCriticalSection( crit );
 493         }
 494     }
 495     return STATUS_SUCCESS;
 496 }