dlls/ntdll/critsection.c

   1 /*
   2  * Win32 critical sections
   3  *
   4  * Copyright 1998 Alexandre Julliard
   5  */
   6
   7 #include <assert.h>
   8 #include <errno.h>
   9 #include <stdio.h>
  10 #include <sys/types.h>
  11 #include "winerror.h"
  12 #include "ntddk.h"
  13 #include "debugtools.h"
  14
  15 DEFAULT_DEBUG_CHANNEL(ntdll);
  16 DECLARE_DEBUG_CHANNEL(relay);
  17
  18 /* Define the atomic exchange/inc/dec functions.
  19  * These are available in kernel32.dll already,
  20  * but we don't want to import kernel32 from ntdll.
  21  */
  22
  23 #ifdef __i386__
  24
  25 # ifdef __GNUC__
  26
  27 inline static PVOID interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare )
  28 {
  29     PVOID ret;
  30     __asm__ __volatile__( "lock; cmpxchgl %2,(%1)"
  31                           : "=a" (ret) : "r" (dest), "r" (xchg), "0" (compare) : "memory" );
  32     return ret;
  33 }
  34 inline static LONG interlocked_inc( PLONG dest )
  35 {
  36     LONG ret;
  37     __asm__ __volatile__( "lock; xaddl %0,(%1)"
  38                           : "=r" (ret) : "r" (dest), "0" (1) : "memory" );
  39     return ret + 1;
  40 }
  41 inline static LONG interlocked_dec( PLONG dest )
  42 {
  43     LONG ret;
  44     __asm__ __volatile__( "lock; xaddl %0,(%1)"
  45                           : "=r" (ret) : "r" (dest), "0" (-1) : "memory" );
  46     return ret - 1;
  47 }
  48
  49 # else  /* __GNUC__ */
  50
  51 PVOID WINAPI interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare );
  52 __ASM_GLOBAL_FUNC(interlocked_cmpxchg,
  53                   "movl 12(%esp),%eax\n\t"
  54                   "movl 8(%esp),%ecx\n\t"
  55                   "movl 4(%esp),%edx\n\t"
  56                   "lock; cmpxchgl %ecx,(%edx)\n\t"
  57                   "ret $12");
  58 LONG WINAPI interlocked_inc( PLONG dest );
  59 __ASM_GLOBAL_FUNC(interlocked_inc,
  60                   "movl 4(%esp),%edx\n\t"
  61                   "movl $1,%eax\n\t"
  62                   "lock; xaddl %eax,(%edx)\n\t"
  63                   "incl %eax\n\t"
  64                   "ret $4");
  65 LONG WINAPI interlocked_dec( PLONG dest );
  66 __ASM_GLOBAL_FUNC(interlocked_dec,
  67                   "movl 4(%esp),%edx\n\t"
  68                   "movl $-1,%eax\n\t"
  69                   "lock; xaddl %eax,(%edx)\n\t"
  70                   "decl %eax\n\t"
  71                   "ret $4");
  72 # endif  /* __GNUC__ */
  73
  74 #elif defined(__sparc__) && defined(__sun__)
  75 /*
  76  * As the earlier Sparc processors lack necessary atomic instructions,
  77  * I'm simply falling back to the library-provided _lwp_mutex routines
  78  * to ensure mutual exclusion in a way appropriate for the current
  79  * architecture.
  80  *
  81  * FIXME:  If we have the compare-and-swap instruction (Sparc v9 and above)
  82  *         we could use this to speed up the Interlocked operations ...
  83  */
  84 #include <synch.h>
  85 static lwp_mutex_t interlocked_mutex = DEFAULTMUTEX;
  86
  87 static PVOID interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare )
  88 {
  89     _lwp_mutex_lock( &interlocked_mutex );
  90     if ( *dest == compare )
  91         *dest = xchg;
  92     else
  93         compare = *dest;
  94     _lwp_mutex_unlock( &interlocked_mutex );
  95     return compare;
  96 }
  97
  98 static LONG interlocked_inc( PLONG dest )
  99 {
 100     LONG retv;
 101     _lwp_mutex_lock( &interlocked_mutex );
 102     retv = ++*dest;
 103     _lwp_mutex_unlock( &interlocked_mutex );
 104     return retv;
 105 }
 106
 107 static LONG interlocked_dec( PLONG dest )
 108 {
 109     LONG retv;
 110     _lwp_mutex_lock( &interlocked_mutex );
 111     retv = --*dest;
 112     _lwp_mutex_unlock( &interlocked_mutex );
 113     return retv;
 114 }
 115 #else
 116 # error You must implement the interlocked* functions for your CPU
 117 #endif
 118
 119
 120 /***********************************************************************
 121  *           get_semaphore
 122  */
 123 static inline HANDLE get_semaphore( RTL_CRITICAL_SECTION *crit )
 124 {
 125     HANDLE ret = crit->LockSemaphore;
 126     if (!ret)
 127     {
 128         HANDLE sem;
 129         if (NtCreateSemaphore( &sem, SEMAPHORE_ALL_ACCESS, NULL, 0, 1 )) return 0;
 130         if (!(ret = (HANDLE)InterlockedCompareExchange( (PVOID *)&crit->LockSemaphore,
 131                                                         (PVOID)sem, 0 )))
 132             ret = sem;
 133         else
 134             NtClose(sem);  /* somebody beat us to it */
 135     }
 136     return ret;
 137 }
 138
 139 /***********************************************************************
 140  *           RtlInitializeCriticalSection   (NTDLL.@)
 141  */
 142 NTSTATUS WINAPI RtlInitializeCriticalSection( RTL_CRITICAL_SECTION *crit )
 143 {
 144     crit->LockCount      = -1;
 145     crit->RecursionCount = 0;
 146     crit->OwningThread   = 0;
 147     crit->LockSemaphore  = 0;
 148     return STATUS_SUCCESS;
 149 }
 150
 151 /***********************************************************************
 152  *           RtlInitializeCriticalSectionAndSpinCount   (NTDLL.@)
 153  * The InitializeCriticalSectionAndSpinCount (KERNEL32) function is
 154  * available on NT4SP3 or later, and Win98 or later.
 155  * I am assuming that this is the correct definition given the MSDN
 156  * docs for the kernel32 functions.
 157  */
 158 NTSTATUS WINAPI RtlInitializeCriticalSectionAndSpinCount( RTL_CRITICAL_SECTION *crit, DWORD spincount )
 159 {
 160     if(spincount) TRACE("critsection=%p: spincount=%ld not supported\n", crit, spincount);
 161     crit->SpinCount = spincount;
 162     return RtlInitializeCriticalSection( crit );
 163 }
 164
 165
 166 /***********************************************************************
 167  *           RtlDeleteCriticalSection   (NTDLL.@)
 168  */
 169 NTSTATUS WINAPI RtlDeleteCriticalSection( RTL_CRITICAL_SECTION *crit )
 170 {
 171     crit->LockCount      = -1;
 172     crit->RecursionCount = 0;
 173     crit->OwningThread   = 0;
 174     if (crit->LockSemaphore) NtClose( crit->LockSemaphore );
 175     crit->LockSemaphore  = 0;
 176     return STATUS_SUCCESS;
 177 }
 178
 179
 180 /***********************************************************************
 181  *           RtlpWaitForCriticalSection   (NTDLL.@)
 182  */
 183 NTSTATUS WINAPI RtlpWaitForCriticalSection( RTL_CRITICAL_SECTION *crit )
 184 {
 185     for (;;)
 186     {
 187         EXCEPTION_RECORD rec;
 188         HANDLE sem = get_semaphore( crit );
 189
 190         DWORD res = WaitForSingleObject( sem, 5000L );
 191         if ( res == WAIT_TIMEOUT )
 192         {
 193             ERR("Critical section %p wait timed out, retrying (60 sec) fs=%04x\n", crit, __get_fs() );
 194             res = WaitForSingleObject( sem, 60000L );
 195             if ( res == WAIT_TIMEOUT && TRACE_ON(relay) )
 196             {
 197                 ERR("Critical section %p wait timed out, retrying (5 min) fs=%04x\n", crit, __get_fs() );
 198                 res = WaitForSingleObject( sem, 300000L );
 199             }
 200         }
 201         if (res == STATUS_WAIT_0) return STATUS_SUCCESS;
 202
 203         rec.ExceptionCode    = EXCEPTION_CRITICAL_SECTION_WAIT;
 204         rec.ExceptionFlags   = 0;
 205         rec.ExceptionRecord  = NULL;
 206         rec.ExceptionAddress = RtlRaiseException;  /* sic */
 207         rec.NumberParameters = 1;
 208         rec.ExceptionInformation[0] = (DWORD)crit;
 209         RtlRaiseException( &rec );
 210     }
 211 }
 212
 213
 214 /***********************************************************************
 215  *           RtlpUnWaitCriticalSection   (NTDLL.@)
 216  */
 217 NTSTATUS WINAPI RtlpUnWaitCriticalSection( RTL_CRITICAL_SECTION *crit )
 218 {
 219     HANDLE sem = get_semaphore( crit );
 220     NTSTATUS res = NtReleaseSemaphore( sem, 1, NULL );
 221     if (res) RtlRaiseStatus( res );
 222     return res;
 223 }
 224
 225
 226 /***********************************************************************
 227  *           RtlEnterCriticalSection   (NTDLL.@)
 228  */
 229 NTSTATUS WINAPI RtlEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 230 {
 231     if (interlocked_inc( &crit->LockCount ))
 232     {
 233         if (crit->OwningThread == GetCurrentThreadId())
 234         {
 235             crit->RecursionCount++;
 236             return STATUS_SUCCESS;
 237         }
 238
 239         /* Now wait for it */
 240         RtlpWaitForCriticalSection( crit );
 241     }
 242     crit->OwningThread   = GetCurrentThreadId();
 243     crit->RecursionCount = 1;
 244     return STATUS_SUCCESS;
 245 }
 246
 247
 248 /***********************************************************************
 249  *           RtlTryEnterCriticalSection   (NTDLL.@)
 250  */
 251 BOOL WINAPI RtlTryEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
 252 {
 253     BOOL ret = FALSE;
 254     if (interlocked_cmpxchg( (PVOID *)&crit->LockCount, (PVOID)0L, (PVOID)-1L ) == (PVOID)-1L)
 255     {
 256         crit->OwningThread   = GetCurrentThreadId();
 257         crit->RecursionCount = 1;
 258         ret = TRUE;
 259     }
 260     else if (crit->OwningThread == GetCurrentThreadId())
 261     {
 262         interlocked_inc( &crit->LockCount );
 263         crit->RecursionCount++;
 264         ret = TRUE;
 265     }
 266     return ret;
 267 }
 268
 269
 270 /***********************************************************************
 271  *           RtlLeaveCriticalSection   (NTDLL.@)
 272  */
 273 NTSTATUS WINAPI RtlLeaveCriticalSection( RTL_CRITICAL_SECTION *crit )
 274 {
 275     if (--crit->RecursionCount) interlocked_dec( &crit->LockCount );
 276     else
 277     {
 278         crit->OwningThread = 0;
 279         if (interlocked_dec( &crit->LockCount ) >= 0)
 280         {
 281             /* someone is waiting */
 282             RtlpUnWaitCriticalSection( crit );
 283         }
 284     }
 285     return STATUS_SUCCESS;
 286 }