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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
smsesnid.c
Abstract:
Session Manager Session ID Management
Author:
Mark Lucovsky (markl) 04-Oct-1989
Revision History:
--*/
#include "smsrvp.h"
#include <string.h>
ULONG
SmpAllocateSessionId(
IN PSMPKNOWNSUBSYS OwningSubsystem,
IN PSMPKNOWNSUBSYS CreatorSubsystem OPTIONAL
)
/*++
Routine Description:
This function allocates a session id.
Arguments:
OwningSubsystem - Supplies the address of the subsystem that should
become the owner of this session.
CreatorSubsystem - An optional parameter that if supplied supplies
the address of the subsystem requesting the creation of this
session. This subsystem is notified when the session completes.
Return Value:
This function returns the session id for this session.
--*/
{
ULONG SessionId;
PLIST_ENTRY SessionIdListInsertPoint;
PSMPSESSION Session;
RtlEnterCriticalSection(&SmpSessionListLock);
//
// SessionId's are allocated by incrementing a 32 bit counter.
// If the counter wraps, then session id's are allocated by
// scaning the sorted list of current session id's for a hole.
//
SessionId = SmpNextSessionId++;
SessionIdListInsertPoint = SmpSessionListHead.Blink;
if ( !SmpNextSessionIdScanMode ) {
if ( SmpNextSessionId == 0 ) {
//
// We have used up 32 bits worth of session id's so
// enable scan mode session id allocation.
//
SmpNextSessionIdScanMode = TRUE;
}
} else {
//
// Compute a session id by scanning the sorted session id list
// until a whole is found. When an id is found, then save it,
// and re-calculate the inster point.
//
DbgPrint("SMSS: SessionId's Wraped\n");
DbgBreakPoint();
}
Session = RtlAllocateHeap(SmpHeap, MAKE_TAG( SM_TAG ), sizeof(SMPSESSION));
Session->SessionId = SessionId;
Session->OwningSubsystem = OwningSubsystem;
Session->CreatorSubsystem = CreatorSubsystem;
InsertTailList(SessionIdListInsertPoint,&Session->SortedSessionIdListLinks);
RtlLeaveCriticalSection(&SmpSessionListLock);
return SessionId;
}
PSMPSESSION
SmpSessionIdToSession(
IN ULONG SessionId
)
/*++
Routine Description:
This function locates the session structure for the specified
session id.
It is assumed that the caller holds the session list lock.
Arguments:
SessionId - Supplies the session id whose session structure
located
Return Value:
NULL - No session matches the specified session
NON-NULL - Returns a pointer to the session structure associated with
the specified session id.
--*/
{
PLIST_ENTRY Next;
PSMPSESSION Session;
Next = SmpSessionListHead.Flink;
while ( Next != &SmpSessionListHead ) {
Session = CONTAINING_RECORD(Next, SMPSESSION, SortedSessionIdListLinks );
if ( Session->SessionId == SessionId ) {
return Session;
}
Next = Session->SortedSessionIdListLinks.Flink;
}
return NULL;
}
VOID
SmpDeleteSession(
IN ULONG SessionId,
IN BOOLEAN SendSessionComplete,
IN NTSTATUS SessionStatus
)
/*++
Routine Description:
This function locates and deletes a session id. If the
SendSessionComplete flag is true, then it also sends a session
complete message to the creator subsystem.
Arguments:
SessionId - Supplies the session id to delete.
SendSessionComplete - Specifies whether a session complete message
is to be sent to the creator subsystem (if one exists).
SessionStatus - Supplies the session completion status
Return Value:
--*/
{
PSMPSESSION Session;
PSMPKNOWNSUBSYS CreatorSubsystem;
RtlEnterCriticalSection(&SmpSessionListLock);
Session = SmpSessionIdToSession(SessionId);
if ( Session ) {
RemoveEntryList(&Session->SortedSessionIdListLinks);
RtlLeaveCriticalSection(&SmpSessionListLock);
CreatorSubsystem = Session->CreatorSubsystem;
RtlFreeHeap(SmpHeap,0,Session);
//
// If there is a creator subsystem, and if
// told to send a session complete message, then do it.
//
if ( CreatorSubsystem && SendSessionComplete ) {
//
// Foreign Session Complete
//
}
} else {
RtlLeaveCriticalSection(&SmpSessionListLock);
}
return;
//
// Make the compiler happy
//
SessionStatus;
}
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