atom.c File Reference

#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for atom.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
PRTL_ATOM_TABLE NTAPI	ExpGetGlobalAtomTable (VOID)
NTSTATUS NTAPI	NtAddAtom (IN PWSTR AtomName, IN ULONG AtomNameLength, OUT PRTL_ATOM Atom)
NTSTATUS NTAPI	NtDeleteAtom (IN RTL_ATOM Atom)
NTSTATUS NTAPI	NtFindAtom (IN PWSTR AtomName, IN ULONG AtomNameLength, OUT PRTL_ATOM Atom)
NTSTATUS NTAPI	NtQueryInformationAtom (RTL_ATOM Atom, ATOM_INFORMATION_CLASS AtomInformationClass, PVOID AtomInformation, ULONG AtomInformationLength, PULONG ReturnLength)

Variables
PRTL_ATOM_TABLE	GlobalAtomTable

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 13 of file atom.c.

Function Documentation

ExpGetGlobalAtomTable()

PRTL_ATOM_TABLE NTAPI ExpGetGlobalAtomTable

(

VOID

)

Definition at line 42 of file atom.c.

{
    NTSTATUS Status;
 
    /* Return it if we have one */
    if (GlobalAtomTable) return GlobalAtomTable;
 
    /* Create it */
    Status = RtlCreateAtomTable(37, &GlobalAtomTable);
 
    /* If we couldn't create it, return NULL */
    if (!NT_SUCCESS(Status)) return NULL;
 
    /* Return the newly created one */
    return GlobalAtomTable;
}

Referenced by NtAddAtom(), NtDeleteAtom(), NtFindAtom(), and NtQueryInformationAtom().

NtAddAtom()

NTSTATUS NTAPI NtAddAtom	(	IN PWSTR	AtomName,
		IN ULONG	AtomNameLength,
		OUT PRTL_ATOM	Atom
	)

Definition at line 86 of file atom.c.

{
    PRTL_ATOM_TABLE AtomTable = ExpGetGlobalAtomTable();
    NTSTATUS Status;
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    LPWSTR CapturedName;
    ULONG CapturedSize;
    RTL_ATOM SafeAtom;
    PAGED_CODE();
 
    /* Check for the table */
    if (AtomTable == NULL) return STATUS_ACCESS_DENIED;
 
    /* Check for valid name */
    if (AtomNameLength > (RTL_MAXIMUM_ATOM_LENGTH * sizeof(WCHAR)))
    {
        /* Fail */
        DPRINT1("Atom name too long\n");
        return STATUS_INVALID_PARAMETER;
    }
 
    /* Check if we're called from user-mode or kernel-mode */
    if (PreviousMode == KernelMode)
    {
        /* Re-use the given name if kernel mode */
        CapturedName = AtomName;
    }
    else
    {
        /* Check if we have a name */
        if (AtomName)
        {
            /* Allocate an aligned buffer + the null char */
            CapturedSize = ((AtomNameLength + sizeof(WCHAR)) &
                            ~(sizeof(WCHAR) -1));
            CapturedName = ExAllocatePoolWithTag(PagedPool,
                                                 CapturedSize,
                                                 TAG_ATOM);
 
            if (!CapturedName)
            {
                /* Fail the call */
                return STATUS_INSUFFICIENT_RESOURCES;
            }
 
            /* Enter SEH */
            _SEH2_TRY
            {
                /* Probe the atom */
                ProbeForRead(AtomName, AtomNameLength, sizeof(WCHAR));
 
                /* Copy the name and null-terminate it */
                RtlCopyMemory(CapturedName, AtomName, AtomNameLength);
                CapturedName[AtomNameLength / sizeof(WCHAR)] = UNICODE_NULL;
 
                /* Probe the atom too */
                if (Atom) ProbeForWriteUshort(Atom);
            }
            _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
            {
                /* Return the exception code */
                _SEH2_YIELD(return _SEH2_GetExceptionCode());
            }
            _SEH2_END;
        }
        else
        {
            /* No name */
            CapturedName = NULL;
        }
    }
 
    /* Call the runtime function */
    Status = RtlAddAtomToAtomTable(AtomTable, CapturedName, &SafeAtom);
    if (NT_SUCCESS(Status) && (Atom))
    {
        /* Success and caller wants the atom back.. .enter SEH */
        _SEH2_TRY
        {
            /* Return the atom */
            *Atom = SafeAtom;
        }
        _SEH2_EXCEPT(ExSystemExceptionFilter())
        {
            /* Get the exception code */
            Status = _SEH2_GetExceptionCode();
        }
        _SEH2_END;
    }
 
    /* If we captured anything, free it */
    if ((CapturedName != NULL) && (CapturedName != AtomName))
        ExFreePoolWithTag(CapturedName, TAG_ATOM);
 
    /* Return to caller */
    return Status;
}

Referenced by InitUserAtoms(), and InternalAddAtom().

NtDeleteAtom()

NTSTATUS NTAPI NtDeleteAtom

(

IN RTL_ATOM

Atom

)

Definition at line 206 of file atom.c.

{
    PRTL_ATOM_TABLE AtomTable = ExpGetGlobalAtomTable();
    PAGED_CODE();
 
    /* Check for valid table */
    if (AtomTable == NULL) return STATUS_ACCESS_DENIED;
 
    /* Call worker function */
    return RtlDeleteAtomFromAtomTable(AtomTable, Atom);
}

Referenced by InternalDeleteAtom().

NtFindAtom()

NTSTATUS NTAPI NtFindAtom	(	IN PWSTR	AtomName,
		IN ULONG	AtomNameLength,
		OUT PRTL_ATOM	Atom
	)

Definition at line 243 of file atom.c.

{
    PRTL_ATOM_TABLE AtomTable = ExpGetGlobalAtomTable();
    NTSTATUS Status;
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    _SEH2_VOLATILE LPWSTR CapturedName;
    ULONG CapturedSize;
    RTL_ATOM SafeAtom;
    PAGED_CODE();
 
    /* Check for the table */
    if (AtomTable == NULL) return STATUS_ACCESS_DENIED;
 
    /* Check for valid name */
    if (AtomNameLength > (RTL_MAXIMUM_ATOM_LENGTH * sizeof(WCHAR)))
    {
        /* Fail */
        DPRINT1("Atom name too long\n");
        return STATUS_INVALID_PARAMETER;
    }
 
    /* Re-use the given name if kernel mode or no atom name */
    CapturedName = AtomName;
 
    /* Check if we're called from user-mode*/
    if (PreviousMode != KernelMode)
    {
        /* Enter SEH */
        _SEH2_TRY
        {
            /* Check if we have a name */
            if (AtomName)
            {
                /* Probe the atom */
                ProbeForRead(AtomName, AtomNameLength, sizeof(WCHAR));
 
                /* Allocate an aligned buffer + the null char */
                CapturedSize = ((AtomNameLength + sizeof(WCHAR)) &~
                                (sizeof(WCHAR) -1));
                CapturedName = ExAllocatePoolWithQuotaTag(PagedPool,
                                                          CapturedSize,
                                                          TAG_ATOM);
                /* Copy the name and null-terminate it */
                RtlCopyMemory(CapturedName, AtomName, AtomNameLength);
                CapturedName[AtomNameLength / sizeof(WCHAR)] = UNICODE_NULL;
 
                /* Probe the atom too */
                if (Atom) ProbeForWriteUshort(Atom);
            }
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            if (CapturedName != AtomName)
            {
                ExFreePoolWithTag(CapturedName, TAG_ATOM);
            }
 
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
 
    /* Call the runtime function */
    Status = RtlLookupAtomInAtomTable(AtomTable, CapturedName, &SafeAtom);
    if (NT_SUCCESS(Status) && (Atom))
    {
        /* Success and caller wants the atom back... enter SEH */
        _SEH2_TRY
        {
            /* Return the atom */
            *Atom = SafeAtom;
        }
        _SEH2_EXCEPT(ExSystemExceptionFilter())
        {
            Status = _SEH2_GetExceptionCode();
        }
        _SEH2_END;
    }
 
    /* If we captured anything, free it */
    if ((CapturedName) && (CapturedName != AtomName))
        ExFreePoolWithTag(CapturedName, TAG_ATOM);
 
    /* Return to caller */
    return Status;
}

Referenced by InternalFindAtom().

NtQueryInformationAtom()

NTSTATUS NTAPI NtQueryInformationAtom	(	RTL_ATOM	Atom,
		ATOM_INFORMATION_CLASS	AtomInformationClass,
		PVOID	AtomInformation,
		ULONG	AtomInformationLength,
		PULONG	ReturnLength
	)

Definition at line 365 of file atom.c.

{
    PRTL_ATOM_TABLE AtomTable = ExpGetGlobalAtomTable();
    PATOM_BASIC_INFORMATION BasicInformation = AtomInformation;
    PATOM_TABLE_INFORMATION TableInformation = AtomInformation;
    NTSTATUS Status = STATUS_SUCCESS;
    ULONG Flags, UsageCount, NameLength, RequiredLength = 0;
    KPROCESSOR_MODE PreviousMode;
 
    PAGED_CODE();
 
    /* Check for valid table */
    if (AtomTable == NULL) return STATUS_ACCESS_DENIED;
 
    PreviousMode = ExGetPreviousMode();
 
    _SEH2_TRY
    {
        /* Probe the parameters */
        if (PreviousMode != KernelMode)
        {
            ProbeForWrite(AtomInformation,
                          AtomInformationLength,
                          sizeof(ULONG));
 
            if (ReturnLength != NULL)
            {
                ProbeForWriteUlong(ReturnLength);
            }
        }
 
        /* Choose class */
        switch (AtomInformationClass)
        {
            /* Caller requested info about an atom */
            case AtomBasicInformation:
 
                /* Size check */
                RequiredLength = FIELD_OFFSET(ATOM_BASIC_INFORMATION, Name);
                if (RequiredLength > AtomInformationLength)
                {
                    /* Fail */
                    DPRINT1("Buffer too small\n");
                    Status = STATUS_INFO_LENGTH_MISMATCH;
                    _SEH2_LEAVE;
                }
 
                /* Prepare query */
                UsageCount = 0;
                NameLength = AtomInformationLength - RequiredLength;
                BasicInformation->Name[0] = UNICODE_NULL;
 
                /* Query the data */
                Status = RtlQueryAtomInAtomTable(AtomTable,
                                                 Atom,
                                                 &UsageCount,
                                                 &Flags,
                                                 BasicInformation->Name,
                                                 &NameLength);
                if (NT_SUCCESS(Status))
                {
                    /* Return data */
                    BasicInformation->UsageCount = (USHORT)UsageCount;
                    BasicInformation->Flags = (USHORT)Flags;
                    BasicInformation->NameLength = (USHORT)NameLength;
                    RequiredLength += NameLength + sizeof(WCHAR);
                }
                break;
 
            /* Caller requested info about an Atom Table */
            case AtomTableInformation:
 
                /* Size check */
                RequiredLength = FIELD_OFFSET(ATOM_TABLE_INFORMATION, Atoms);
                if (RequiredLength > AtomInformationLength)
                {
                    /* Fail */
                    DPRINT1("Buffer too small\n");
                    Status = STATUS_INFO_LENGTH_MISMATCH;
                    _SEH2_LEAVE;
                }
 
                /* Query the data */
                Status = RtlQueryAtomListInAtomTable(AtomTable,
                                                     (AtomInformationLength - RequiredLength) /
                                                     sizeof(RTL_ATOM),
                                                     &TableInformation->NumberOfAtoms,
                                                     TableInformation->Atoms);
                if (NT_SUCCESS(Status))
                {
                    /* Update the return length */
                    RequiredLength += TableInformation->NumberOfAtoms * sizeof(RTL_ATOM);
                }
                break;
 
            /* Caller was on crack */
            default:
 
                /* Unrecognized class */
                Status = STATUS_INVALID_INFO_CLASS;
                break;
        }
 
        /* Return the required size */
        if (ReturnLength != NULL)
        {
            *ReturnLength = RequiredLength;
        }
    }
    _SEH2_EXCEPT(ExSystemExceptionFilter())
    {
        Status = _SEH2_GetExceptionCode();
    }
    _SEH2_END;
 
    /* Return to caller */
    return Status;
}

Referenced by InternalGetAtomName().

Variable Documentation

GlobalAtomTable

PRTL_ATOM_TABLE GlobalAtomTable

Definition at line 25 of file atom.c.

Referenced by ExpGetGlobalAtomTable().