handle.c

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/*
 * COPYRIGHT:   See COPYING in the top level directory
 * PROJECT:     ReactOS WinSock 2 DLL
 * FILE:        misc/handle.c
 * PURPOSE:     Provider handle management
 * PROGRAMMERS: Casper S. Hornstrup (chorns@users.sourceforge.net)
 * REVISIONS:
 *   CSH 01/09-2000 Created
 */

#include "ws2_32.h"

PPROVIDER_HANDLE_BLOCK ProviderHandleTable;
CRITICAL_SECTION ProviderHandleTableLock;

PPROVIDER_HANDLE
GetProviderByHandle(PPROVIDER_HANDLE_BLOCK HandleTable,
                    HANDLE Handle)
/*
 * FUNCTION: Get the data structure for a handle
 * ARGUMENTS:
 *     HandleTable = Pointer to handle table
 *     Handle      = Handle to get data structure for
 * RETURNS:
 *     Pointer to the data structure identified by the handle on success,
 *     NULL on failure
 */
{
    PPROVIDER_HANDLE_BLOCK Current;
    PLIST_ENTRY CurrentEntry;
    ULONG i;

    WS_DbgPrint(MAX_TRACE, ("HandleTable (0x%X)  Handle (0x%X).\n", HandleTable, Handle));

    CurrentEntry = HandleTable->Entry.Flink;

    while (CurrentEntry != &HandleTable->Entry)
    {
        Current = CONTAINING_RECORD(CurrentEntry, PROVIDER_HANDLE_BLOCK, Entry);

        for (i = 0; i < HANDLE_BLOCK_ENTRIES; i++)
        {
            if ((Current->Handles[i].Provider != NULL) &&
                (Current->Handles[i].Handle == Handle))
            {
                return &Current->Handles[i];
            }
        }
        CurrentEntry = CurrentEntry->Flink;
    }

    return NULL;
}


VOID
CloseAllHandles(PPROVIDER_HANDLE_BLOCK HandleTable)
{
    PPROVIDER_HANDLE_BLOCK Current;
    PLIST_ENTRY CurrentEntry;
    PCATALOG_ENTRY Provider;
    ULONG i;

    WS_DbgPrint(MAX_TRACE, ("HandleTable (0x%X).\n", HandleTable));

    CurrentEntry = HandleTable->Entry.Flink;

    while (CurrentEntry != &HandleTable->Entry)
    {
        Current = CONTAINING_RECORD(CurrentEntry, PROVIDER_HANDLE_BLOCK, Entry);

        for (i = 0; i < HANDLE_BLOCK_ENTRIES; i++)
        {
            Provider = Current->Handles[i].Provider;
            if (Provider != NULL)
            {
                DereferenceProviderByPointer(Provider);
                Current->Handles[i].Handle   = (HANDLE)0;
                Current->Handles[i].Provider = NULL;
            }
        }
        CurrentEntry = CurrentEntry->Flink;
    }
}


VOID
DeleteHandleTable(PPROVIDER_HANDLE_BLOCK HandleTable)
{
    PPROVIDER_HANDLE_BLOCK Current;
    PLIST_ENTRY CurrentEntry;

    CloseAllHandles(HandleTable);

    CurrentEntry = RemoveHeadList(&HandleTable->Entry);

    while (CurrentEntry != &HandleTable->Entry)
    {
        Current = CONTAINING_RECORD(CurrentEntry,
                                    PROVIDER_HANDLE_BLOCK,
                                    Entry);

        HeapFree(GlobalHeap, 0, Current);

        CurrentEntry = RemoveHeadList(&HandleTable->Entry);
    }
}


PCATALOG_ENTRY
DeleteProviderHandle(PPROVIDER_HANDLE_BLOCK HandleTable,
                     HANDLE Handle)
{
    PPROVIDER_HANDLE Entry;
    PCATALOG_ENTRY Provider;

    WS_DbgPrint(MAX_TRACE, ("HandleTable (0x%X)  Handle (0x%X).\n", HandleTable, Handle));

    Entry = GetProviderByHandle(HandleTable, Handle);
    if (!Entry)
        return NULL;

    Provider = Entry->Provider;
    Entry->Handle = (HANDLE)0;
    Entry->Provider = NULL;

    return Provider;
}


HANDLE
CreateProviderHandleTable(PPROVIDER_HANDLE_BLOCK HandleTable,
                          HANDLE Handle,
                          PCATALOG_ENTRY Provider)
{
    PPROVIDER_HANDLE_BLOCK NewBlock;
    PLIST_ENTRY CurrentEntry;
    ULONG i;

    WS_DbgPrint(MAX_TRACE, ("HandleTable (0x%X)  Handle (0x%X)  Provider (0x%X).\n",
    HandleTable, Handle, Provider));

    /* Scan through the currently allocated handle blocks looking for a free slot */
    CurrentEntry = HandleTable->Entry.Flink;
    while (CurrentEntry != &HandleTable->Entry)
    {
        PPROVIDER_HANDLE_BLOCK Block = CONTAINING_RECORD(CurrentEntry,
                                                         PROVIDER_HANDLE_BLOCK,
                                                         Entry);

        for (i = 0; i < HANDLE_BLOCK_ENTRIES; i++)
        {
            WS_DbgPrint(MAX_TRACE, ("Considering slot %ld containing 0x%X.\n",
                        i,
                        Block->Handles[i].Provider));
            if (Block->Handles[i].Provider == NULL)
            {
                Block->Handles[i].Handle   = Handle;
                Block->Handles[i].Provider = Provider;
                return Handle;
            }
        }
        CurrentEntry = CurrentEntry->Flink;
    }

    /* Add a new handle block to the end of the list */
    NewBlock = (PPROVIDER_HANDLE_BLOCK)HeapAlloc(GlobalHeap,
                                                 0,
                                                 sizeof(PROVIDER_HANDLE_BLOCK));

    WS_DbgPrint(MID_TRACE,("using table entry %x\n", NewBlock));

    if (!NewBlock)
        return (HANDLE)0;

    ZeroMemory(NewBlock, sizeof(PROVIDER_HANDLE_BLOCK));
    InsertTailList(&HandleTable->Entry,
                   &NewBlock->Entry);

    NewBlock->Handles[0].Handle   = Handle;
    NewBlock->Handles[0].Provider = Provider;

    return Handle;
}


HANDLE
CreateProviderHandle(HANDLE Handle,
                     PCATALOG_ENTRY Provider)
{
    HANDLE h;

    EnterCriticalSection(&ProviderHandleTableLock);

    h = CreateProviderHandleTable(ProviderHandleTable,
                                  Handle,
                                  Provider);

    LeaveCriticalSection(&ProviderHandleTableLock);

    if (h != NULL)
        ReferenceProviderByPointer(Provider);

    return h;
}


BOOL
ReferenceProviderByHandle(HANDLE Handle,
                          PCATALOG_ENTRY* Provider)
/*
 * FUNCTION: Increments the reference count for a provider and returns a pointer to it
 * ARGUMENTS:
 *     Handle   = Handle for the provider
 *     Provider = Address of buffer to place pointer to provider
 * RETURNS:
 *     TRUE if handle was valid, FALSE if not
 */
{
    PPROVIDER_HANDLE ProviderHandle;

    WS_DbgPrint(MID_TRACE, ("Handle (0x%X)  Provider (0x%X).\n", Handle, Provider));

    EnterCriticalSection(&ProviderHandleTableLock);

    ProviderHandle = GetProviderByHandle(ProviderHandleTable,
                                         Handle);

    WS_DbgPrint(MID_TRACE, ("ProviderHandle is %x\n", ProviderHandle));

    LeaveCriticalSection(&ProviderHandleTableLock);

    if (ProviderHandle)
    {
        ReferenceProviderByPointer(ProviderHandle->Provider);
        *Provider = ProviderHandle->Provider;
    }

    return (ProviderHandle != NULL);
}


BOOL
CloseProviderHandle(HANDLE Handle)
{
    PCATALOG_ENTRY Provider;

    WS_DbgPrint(MAX_TRACE, ("Handle (0x%X).\n", Handle));

    EnterCriticalSection(&ProviderHandleTableLock);

    Provider = DeleteProviderHandle(ProviderHandleTable,
                                    Handle);
    if (!Provider)
        return FALSE;

    LeaveCriticalSection(&ProviderHandleTableLock);

    DereferenceProviderByPointer(Provider);

    return TRUE;
}


BOOL
InitProviderHandleTable(VOID)
{
    ProviderHandleTable =
        (PPROVIDER_HANDLE_BLOCK)HeapAlloc(GlobalHeap,
                                          0,
                                          sizeof(PROVIDER_HANDLE_BLOCK));
    if (!ProviderHandleTable)
        return FALSE;

    WS_DbgPrint(MID_TRACE,("Called\n"));

    ZeroMemory(ProviderHandleTable,
               sizeof(PROVIDER_HANDLE_BLOCK));

    InitializeListHead(&ProviderHandleTable->Entry);

    InitializeCriticalSection(&ProviderHandleTableLock);

    return TRUE;
}


VOID
FreeProviderHandleTable(VOID)
{
    DeleteHandleTable(ProviderHandleTable);

    DeleteCriticalSection(&ProviderHandleTableLock);
}

/* EOF */