Sweden-Number/dlls/ntdll/critsection.c

292 lines
8.6 KiB
C

/*
* Win32 critical sections
*
* Copyright 1998 Alexandre Julliard
*/
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include "winerror.h"
#include "ntddk.h"
#include "debugtools.h"
DEFAULT_DEBUG_CHANNEL(ntdll);
DECLARE_DEBUG_CHANNEL(relay);
/* Define the atomic exchange/inc/dec functions.
* These are available in kernel32.dll already,
* but we don't want to import kernel32 from ntdll.
*/
#ifdef __i386__
# ifdef __GNUC__
inline static PVOID interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare )
{
PVOID ret;
__asm__ __volatile__( "lock; cmpxchgl %2,(%1)"
: "=a" (ret) : "r" (dest), "r" (xchg), "0" (compare) : "memory" );
return ret;
}
inline static LONG interlocked_inc( PLONG dest )
{
LONG ret;
__asm__ __volatile__( "lock; xaddl %0,(%1)"
: "=r" (ret) : "r" (dest), "0" (1) : "memory" );
return ret + 1;
}
inline static LONG interlocked_dec( PLONG dest )
{
LONG ret;
__asm__ __volatile__( "lock; xaddl %0,(%1)"
: "=r" (ret) : "r" (dest), "0" (-1) : "memory" );
return ret - 1;
}
# else /* __GNUC__ */
PVOID WINAPI interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare );
__ASM_GLOBAL_FUNC(interlocked_cmpxchg,
"movl 12(%esp),%eax\n\t"
"movl 8(%esp),%ecx\n\t"
"movl 4(%esp),%edx\n\t"
"lock; cmpxchgl %ecx,(%edx)\n\t"
"ret $12");
LONG WINAPI interlocked_inc( PLONG dest );
__ASM_GLOBAL_FUNC(interlocked_inc,
"movl 4(%esp),%edx\n\t"
"movl $1,%eax\n\t"
"lock; xaddl %eax,(%edx)\n\t"
"incl %eax\n\t"
"ret $4");
LONG WINAPI interlocked_dec( PLONG dest );
__ASM_GLOBAL_FUNC(interlocked_dec,
"movl 4(%esp),%edx\n\t"
"movl $-1,%eax\n\t"
"lock; xaddl %eax,(%edx)\n\t"
"decl %eax\n\t"
"ret $4");
# endif /* __GNUC__ */
#elif defined(__sparc__) && defined(__sun__)
/*
* As the earlier Sparc processors lack necessary atomic instructions,
* I'm simply falling back to the library-provided _lwp_mutex routines
* to ensure mutual exclusion in a way appropriate for the current
* architecture.
*
* FIXME: If we have the compare-and-swap instruction (Sparc v9 and above)
* we could use this to speed up the Interlocked operations ...
*/
#include <synch.h>
static lwp_mutex_t interlocked_mutex = DEFAULTMUTEX;
static PVOID interlocked_cmpxchg( PVOID *dest, PVOID xchg, PVOID compare )
{
_lwp_mutex_lock( &interlocked_mutex );
if ( *dest == compare )
*dest = xchg;
else
compare = *dest;
_lwp_mutex_unlock( &interlocked_mutex );
return compare;
}
static LONG interlocked_inc( PLONG dest )
{
LONG retv;
_lwp_mutex_lock( &interlocked_mutex );
retv = ++*dest;
_lwp_mutex_unlock( &interlocked_mutex );
return retv;
}
static LONG interlocked_dec( PLONG dest )
{
LONG retv;
_lwp_mutex_lock( &interlocked_mutex );
retv = --*dest;
_lwp_mutex_unlock( &interlocked_mutex );
return retv;
}
#else
# error You must implement the interlocked* functions for your CPU
#endif
/***********************************************************************
* get_semaphore
*/
static inline HANDLE get_semaphore( RTL_CRITICAL_SECTION *crit )
{
HANDLE ret = crit->LockSemaphore;
if (!ret)
{
HANDLE sem;
if (NtCreateSemaphore( &sem, SEMAPHORE_ALL_ACCESS, NULL, 0, 1 )) return 0;
if (!(ret = (HANDLE)interlocked_cmpxchg( (PVOID *)&crit->LockSemaphore,
(PVOID)sem, 0 )))
ret = sem;
else
NtClose(sem); /* somebody beat us to it */
}
return ret;
}
/***********************************************************************
* RtlInitializeCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlInitializeCriticalSection( RTL_CRITICAL_SECTION *crit )
{
crit->DebugInfo = NULL;
crit->LockCount = -1;
crit->RecursionCount = 0;
crit->OwningThread = 0;
crit->LockSemaphore = 0;
return STATUS_SUCCESS;
}
/***********************************************************************
* RtlInitializeCriticalSectionAndSpinCount (NTDLL.@)
* The InitializeCriticalSectionAndSpinCount (KERNEL32) function is
* available on NT4SP3 or later, and Win98 or later.
* I am assuming that this is the correct definition given the MSDN
* docs for the kernel32 functions.
*/
NTSTATUS WINAPI RtlInitializeCriticalSectionAndSpinCount( RTL_CRITICAL_SECTION *crit, DWORD spincount )
{
if(spincount) TRACE("critsection=%p: spincount=%ld not supported\n", crit, spincount);
crit->SpinCount = spincount;
return RtlInitializeCriticalSection( crit );
}
/***********************************************************************
* RtlDeleteCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlDeleteCriticalSection( RTL_CRITICAL_SECTION *crit )
{
crit->LockCount = -1;
crit->RecursionCount = 0;
crit->OwningThread = 0;
if (crit->LockSemaphore) NtClose( crit->LockSemaphore );
crit->LockSemaphore = 0;
return STATUS_SUCCESS;
}
/***********************************************************************
* RtlpWaitForCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlpWaitForCriticalSection( RTL_CRITICAL_SECTION *crit )
{
for (;;)
{
EXCEPTION_RECORD rec;
HANDLE sem = get_semaphore( crit );
DWORD res = WaitForSingleObject( sem, 5000L );
if ( res == WAIT_TIMEOUT )
{
const char *name = (char *)crit->DebugInfo;
if (!name || IsBadStringPtrA(name,80)) name = "?";
ERR( "section %p %s wait timed out, retrying (60 sec) fs=%04x\n",
crit, debugstr_a(name), __get_fs() );
res = WaitForSingleObject( sem, 60000L );
if ( res == WAIT_TIMEOUT && TRACE_ON(relay) )
{
ERR( "section %p %s wait timed out, retrying (5 min) fs=%04x\n",
crit, debugstr_a(name), __get_fs() );
res = WaitForSingleObject( sem, 300000L );
}
}
if (res == STATUS_WAIT_0) return STATUS_SUCCESS;
rec.ExceptionCode = EXCEPTION_CRITICAL_SECTION_WAIT;
rec.ExceptionFlags = 0;
rec.ExceptionRecord = NULL;
rec.ExceptionAddress = RtlRaiseException; /* sic */
rec.NumberParameters = 1;
rec.ExceptionInformation[0] = (DWORD)crit;
RtlRaiseException( &rec );
}
}
/***********************************************************************
* RtlpUnWaitCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlpUnWaitCriticalSection( RTL_CRITICAL_SECTION *crit )
{
HANDLE sem = get_semaphore( crit );
NTSTATUS res = NtReleaseSemaphore( sem, 1, NULL );
if (res) RtlRaiseStatus( res );
return res;
}
/***********************************************************************
* RtlEnterCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
{
if (interlocked_inc( &crit->LockCount ))
{
if (crit->OwningThread == GetCurrentThreadId())
{
crit->RecursionCount++;
return STATUS_SUCCESS;
}
/* Now wait for it */
RtlpWaitForCriticalSection( crit );
}
crit->OwningThread = GetCurrentThreadId();
crit->RecursionCount = 1;
return STATUS_SUCCESS;
}
/***********************************************************************
* RtlTryEnterCriticalSection (NTDLL.@)
*/
BOOL WINAPI RtlTryEnterCriticalSection( RTL_CRITICAL_SECTION *crit )
{
BOOL ret = FALSE;
if (interlocked_cmpxchg( (PVOID *)&crit->LockCount, (PVOID)0L, (PVOID)-1L ) == (PVOID)-1L)
{
crit->OwningThread = GetCurrentThreadId();
crit->RecursionCount = 1;
ret = TRUE;
}
else if (crit->OwningThread == GetCurrentThreadId())
{
interlocked_inc( &crit->LockCount );
crit->RecursionCount++;
ret = TRUE;
}
return ret;
}
/***********************************************************************
* RtlLeaveCriticalSection (NTDLL.@)
*/
NTSTATUS WINAPI RtlLeaveCriticalSection( RTL_CRITICAL_SECTION *crit )
{
if (--crit->RecursionCount) interlocked_dec( &crit->LockCount );
else
{
crit->OwningThread = 0;
if (interlocked_dec( &crit->LockCount ) >= 0)
{
/* someone is waiting */
RtlpUnWaitCriticalSection( crit );
}
}
return STATUS_SUCCESS;
}