Sweden-Number/scheduler/critsection.c

315 lines
9.0 KiB
C

/*
* Win32 critical sections
*
* Copyright 1998 Alexandre Julliard
*/
/* Note: critical sections are not implemented exactly the same way
* than under NT (LockSemaphore should be a real semaphore handle).
* But since they are even more different under Win95, it probably
* doesn't matter...
*/
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/sem.h>
#include "debug.h"
#include "windows.h"
#include "winerror.h"
#include "winbase.h"
#include "heap.h"
#include "k32obj.h"
#include "debug.h"
#include "thread.h"
typedef struct
{
K32OBJ header;
THREAD_QUEUE wait_queue;
BOOL32 signaled;
} CRIT_SECTION;
/* On some systems this is supposed to be defined in the program */
#ifndef HAVE_UNION_SEMUN
union semun {
int val;
struct semid_ds *buf;
ushort *array;
};
#endif
static BOOL32 CRIT_SECTION_Signaled( K32OBJ *obj, DWORD thread_id );
static BOOL32 CRIT_SECTION_Satisfied( K32OBJ *obj, DWORD thread_id );
static void CRIT_SECTION_AddWait( K32OBJ *obj, DWORD thread_id );
static void CRIT_SECTION_RemoveWait( K32OBJ *obj, DWORD thread_id );
static void CRIT_SECTION_Destroy( K32OBJ *obj );
const K32OBJ_OPS CRITICAL_SECTION_Ops =
{
CRIT_SECTION_Signaled, /* signaled */
CRIT_SECTION_Satisfied, /* satisfied */
CRIT_SECTION_AddWait, /* add_wait */
CRIT_SECTION_RemoveWait, /* remove_wait */
NULL, /* read */
NULL, /* write */
CRIT_SECTION_Destroy /* destroy */
};
/***********************************************************************
* InitializeCriticalSection (KERNEL32.472) (NTDLL.406)
*/
void WINAPI InitializeCriticalSection( CRITICAL_SECTION *crit )
{
CRIT_SECTION *obj;
crit->LockCount = -1;
crit->RecursionCount = 0;
crit->OwningThread = 0;
crit->LockSemaphore = 0;
if (SystemHeap)
{
if (!(obj = (CRIT_SECTION *)HeapAlloc( SystemHeap, 0, sizeof(*obj) )))
return; /* No way to return an error... */
obj->header.type = K32OBJ_CRITICAL_SECTION;
obj->header.refcount = 1;
obj->wait_queue = NULL;
obj->signaled = FALSE;
crit->LockSemaphore = (HANDLE32)obj;
crit->Reserved = (DWORD)-1;
}
else
{
union semun val;
crit->Reserved = (DWORD)semget( IPC_PRIVATE, 1, IPC_CREAT | 0777 );
if (crit->Reserved == (DWORD)-1)
{
perror( "semget" );
return;
}
val.val = 0;
semctl( (int)crit->Reserved, 0, SETVAL, val );
}
}
/***********************************************************************
* DeleteCriticalSection (KERNEL32.185) (NTDLL.327)
*/
void WINAPI DeleteCriticalSection( CRITICAL_SECTION *crit )
{
CRIT_SECTION *obj = (CRIT_SECTION *)crit->LockSemaphore;
if (obj)
{
if (crit->RecursionCount) /* Should not happen */
MSG("Deleting owned critical section (%p)\n", crit );
crit->LockCount = -1;
crit->RecursionCount = 0;
crit->OwningThread = 0;
crit->LockSemaphore = 0;
K32OBJ_DecCount( &obj->header );
}
else if (crit->Reserved != (DWORD)-1)
{
semctl( (int)crit->Reserved, 0, IPC_RMID, (union semun)0 );
}
}
/***********************************************************************
* EnterCriticalSection (KERNEL32.195) (NTDLL.344)
*/
void WINAPI EnterCriticalSection( CRITICAL_SECTION *crit )
{
if ((crit->Reserved==-1) && !(crit->LockSemaphore)) {
FIXME(win32,"entering uninitialized section(%p)?\n",crit);
InitializeCriticalSection(crit);
}
if (InterlockedIncrement( &crit->LockCount ))
{
if (crit->OwningThread == GetCurrentThreadId())
{
crit->RecursionCount++;
return;
}
/* Now wait for it */
if (crit->LockSemaphore)
{
WAIT_STRUCT *wait = &THREAD_Current()->wait_struct;
SYSTEM_LOCK();
wait->count = 1;
wait->signaled = WAIT_FAILED;
wait->wait_all = FALSE;
wait->objs[0] = (K32OBJ *)crit->LockSemaphore;
K32OBJ_IncCount( wait->objs[0] );
SYNC_WaitForCondition( wait, INFINITE32 );
K32OBJ_DecCount( wait->objs[0] );
SYSTEM_UNLOCK();
}
else if (crit->Reserved != (DWORD)-1)
{
int ret;
struct sembuf sop;
sop.sem_num = 0;
sop.sem_op = -1;
sop.sem_flg = SEM_UNDO;
do
{
ret = semop( (int)crit->Reserved, &sop, 1 );
} while ((ret == -1) && (errno == EINTR));
}
else
{
MSG( "Uninitialized critical section (%p)\n", crit );
return;
}
}
crit->OwningThread = GetCurrentThreadId();
crit->RecursionCount = 1;
}
/***********************************************************************
* TryEnterCriticalSection (KERNEL32.898) (NTDLL.969)
*/
BOOL32 WINAPI TryEnterCriticalSection( CRITICAL_SECTION *crit )
{
if (InterlockedIncrement( &crit->LockCount ))
{
if (crit->OwningThread == GetCurrentThreadId())
{
crit->RecursionCount++;
return TRUE;
}
/* FIXME: this doesn't work */
InterlockedDecrement( &crit->LockCount );
return FALSE;
}
crit->OwningThread = GetCurrentThreadId();
crit->RecursionCount = 1;
return TRUE;
}
/***********************************************************************
* LeaveCriticalSection (KERNEL32.494) (NTDLL.426)
*/
void WINAPI LeaveCriticalSection( CRITICAL_SECTION *crit )
{
if (crit->OwningThread != GetCurrentThreadId()) return;
if (--crit->RecursionCount)
{
InterlockedDecrement( &crit->LockCount );
return;
}
crit->OwningThread = 0;
if (InterlockedDecrement( &crit->LockCount ) >= 0)
{
/* Someone is waiting */
if (crit->LockSemaphore)
{
CRIT_SECTION *obj = (CRIT_SECTION *)crit->LockSemaphore;
SYSTEM_LOCK();
obj->signaled = TRUE;
SYNC_WakeUp( &obj->wait_queue, 1 );
SYSTEM_UNLOCK();
}
else if (crit->Reserved != (DWORD)-1)
{
struct sembuf sop;
sop.sem_num = 0;
sop.sem_op = 1;
sop.sem_flg = SEM_UNDO;
semop( (int)crit->Reserved, &sop, 1 );
}
}
}
/***********************************************************************
* MakeCriticalSectionGlobal (KERNEL32.515)
*/
void WINAPI MakeCriticalSectionGlobal( CRITICAL_SECTION *crit )
{
/* Nothing to do: a critical section is always global */
}
/***********************************************************************
* ReinitializeCriticalSection (KERNEL32.581)
*/
void WINAPI ReinitializeCriticalSection( CRITICAL_SECTION *crit )
{
DeleteCriticalSection( crit );
InitializeCriticalSection( crit );
}
/***********************************************************************
* CRIT_SECTION_Signaled
*/
static BOOL32 CRIT_SECTION_Signaled( K32OBJ *obj, DWORD thread_id )
{
CRIT_SECTION *crit = (CRIT_SECTION *)obj;
assert( obj->type == K32OBJ_CRITICAL_SECTION );
return crit->signaled;
}
/***********************************************************************
* CRIT_SECTION_Satisfied
*
* Wait on this object has been satisfied.
*/
static BOOL32 CRIT_SECTION_Satisfied( K32OBJ *obj, DWORD thread_id )
{
CRIT_SECTION *crit = (CRIT_SECTION *)obj;
assert( obj->type == K32OBJ_CRITICAL_SECTION );
/* Only one thread is allowed to wake up */
crit->signaled = FALSE;
return FALSE; /* Not abandoned */
}
/***********************************************************************
* CRIT_SECTION_AddWait
*
* Add thread to object wait queue.
*/
static void CRIT_SECTION_AddWait( K32OBJ *obj, DWORD thread_id )
{
CRIT_SECTION *crit = (CRIT_SECTION *)obj;
assert( obj->type == K32OBJ_CRITICAL_SECTION );
THREAD_AddQueue( &crit->wait_queue, THREAD_ID_TO_THDB(thread_id) );
}
/***********************************************************************
* CRIT_SECTION_RemoveWait
*
* Remove current thread from object wait queue.
*/
static void CRIT_SECTION_RemoveWait( K32OBJ *obj, DWORD thread_id )
{
CRIT_SECTION *crit = (CRIT_SECTION *)obj;
assert( obj->type == K32OBJ_CRITICAL_SECTION );
THREAD_RemoveQueue( &crit->wait_queue, THREAD_ID_TO_THDB(thread_id) );
}
/***********************************************************************
* CRIT_SECTION_Destroy
*/
static void CRIT_SECTION_Destroy( K32OBJ *obj )
{
CRIT_SECTION *crit = (CRIT_SECTION *)obj;
assert( obj->type == K32OBJ_CRITICAL_SECTION );
/* There cannot be any thread on the list since the ref count is 0 */
assert( crit->wait_queue == NULL );
obj->type = K32OBJ_UNKNOWN;
HeapFree( SystemHeap, 0, crit );
}