384 lines
15 KiB
C
384 lines
15 KiB
C
|
/*++
|
||
|
|
Copyright (c) 1989 Microsoft Corporation
|
||
|
|
|
||
|
|
Module Name:
|
||
|
|
semphore.c
|
||
|
|
|
||
|
|
Abstract:
|
||
|
|
This module implements the executive semaphore object. Functions are
|
||
|
|
provided to create, open, release, and query semaphore objects.
|
||
|
|
|
||
|
|
Author:
|
||
|
|
David N. Cutler (davec) 8-May-1989
|
||
|
|
|
||
|
|
Environment:
|
||
|
|
Kernel mode only.
|
||
|
|
|
||
|
|
Revision History:
|
||
|
|
--*/
|
||
|
|
|
||
|
|
#include "exp.h"
|
||
|
|
|
||
|
|
|
||
|
|
// Temporary so boost is patchable
|
||
|
|
ULONG ExpSemaphoreBoost = SEMAPHORE_INCREMENT;
|
||
|
|
|
||
|
|
|
||
|
|
// Address of semaphore object type descriptor.
|
||
|
|
POBJECT_TYPE ExSemaphoreObjectType;
|
||
|
|
|
||
|
|
|
||
|
|
// Structure that describes the mapping of generic access rights to object
|
||
|
|
// specific access rights for semaphore objects.
|
||
|
|
GENERIC_MAPPING ExpSemaphoreMapping = {
|
||
|
|
STANDARD_RIGHTS_READ | SEMAPHORE_QUERY_STATE,
|
||
|
|
STANDARD_RIGHTS_WRITE | SEMAPHORE_MODIFY_STATE,
|
||
|
|
STANDARD_RIGHTS_EXECUTE | SYNCHRONIZE,
|
||
|
|
SEMAPHORE_ALL_ACCESS
|
||
|
|
};
|
||
|
|
|
||
|
|
#ifdef ALLOC_PRAGMA
|
||
|
|
#pragma alloc_text(INIT, ExpSemaphoreInitialization)
|
||
|
|
#pragma alloc_text(PAGE, NtCreateSemaphore)
|
||
|
|
#pragma alloc_text(PAGE, NtOpenSemaphore)
|
||
|
|
#pragma alloc_text(PAGE, NtQuerySemaphore)
|
||
|
|
#pragma alloc_text(PAGE, NtReleaseSemaphore)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
BOOLEAN ExpSemaphoreInitialization ()
|
||
|
|
/*++
|
||
|
|
Routine Description:
|
||
|
|
This function creates the semaphore object type descriptor at system
|
||
|
|
initialization and stores the address of the object type descriptor in local static storage.
|
||
|
|
Arguments:
|
||
|
|
None.
|
||
|
|
Return Value:
|
||
|
|
A value of TRUE is returned if the semaphore object type descriptor is successfully created. Otherwise a value of FALSE is returned.
|
||
|
|
--*/
|
||
|
|
{
|
||
|
|
OBJECT_TYPE_INITIALIZER ObjectTypeInitializer;
|
||
|
|
NTSTATUS Status;
|
||
|
|
UNICODE_STRING TypeName;
|
||
|
|
|
||
|
|
// Initialize string descriptor.
|
||
|
|
RtlInitUnicodeString(&TypeName, L"Semaphore");
|
||
|
|
|
||
|
|
// Create semaphore object type descriptor.
|
||
|
|
RtlZeroMemory(&ObjectTypeInitializer, sizeof(ObjectTypeInitializer));
|
||
|
|
ObjectTypeInitializer.Length = sizeof(ObjectTypeInitializer);
|
||
|
|
ObjectTypeInitializer.InvalidAttributes = OBJ_OPENLINK;
|
||
|
|
ObjectTypeInitializer.GenericMapping = ExpSemaphoreMapping;
|
||
|
|
ObjectTypeInitializer.PoolType = NonPagedPool;
|
||
|
|
ObjectTypeInitializer.DefaultNonPagedPoolCharge = sizeof(KSEMAPHORE);
|
||
|
|
ObjectTypeInitializer.ValidAccessMask = SEMAPHORE_ALL_ACCESS;
|
||
|
|
Status = ObCreateObjectType(&TypeName, &ObjectTypeInitializer, (PSECURITY_DESCRIPTOR)NULL, &ExSemaphoreObjectType);
|
||
|
|
|
||
|
|
// If the semaphore object type descriptor was successfully created, then
|
||
|
|
// return a value of TRUE. Otherwise return a value of FALSE.
|
||
|
|
return (BOOLEAN)(NT_SUCCESS(Status));
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
NTSTATUS NtCreateSemaphore (IN PHANDLE SemaphoreHandle,
|
||
|
|
IN ACCESS_MASK DesiredAccess,
|
||
|
|
IN POBJECT_ATTRIBUTES ObjectAttributes OPTIONAL,
|
||
|
|
IN LONG InitialCount,
|
||
|
|
IN LONG MaximumCount
|
||
|
|
)
|
||
|
|
/*++
|
||
|
|
Routine Description:
|
||
|
|
This function creates a semaphore object, sets its initial count to the
|
||
|
|
specified value, sets its maximum count to the specified value, and opens
|
||
|
|
a handle to the object with the specified desired access.
|
||
|
|
Arguments:
|
||
|
|
SemaphoreHandle - Supplies a pointer to a variable that will receive the semaphore object handle.
|
||
|
|
DesiredAccess - Supplies the desired types of access for the semaphore object.
|
||
|
|
ObjectAttributes - Supplies a pointer to an object attributes structure.
|
||
|
|
InitialCount - Supplies the initial count of the semaphore object.
|
||
|
|
MaximumCount - Supplies the maximum count of the semaphore object.
|
||
|
|
Return Value:
|
||
|
|
TBS
|
||
|
|
--*/
|
||
|
|
{
|
||
|
|
HANDLE Handle;
|
||
|
|
KPROCESSOR_MODE PreviousMode;
|
||
|
|
PVOID Semaphore;
|
||
|
|
NTSTATUS Status;
|
||
|
|
|
||
|
|
// Establish an exception handler, probe the output handle address, and
|
||
|
|
// attempt to create a semaphore object. If the probe fails, then return
|
||
|
|
// the exception code as the service status. Otherwise return the status
|
||
|
|
// value returned by the object insertion routine.
|
||
|
|
try {
|
||
|
|
// Get previous processor mode and probe output handle address if necessary.
|
||
|
|
PreviousMode = KeGetPreviousMode();
|
||
|
|
if (PreviousMode != KernelMode) {
|
||
|
|
ProbeForWriteHandle(SemaphoreHandle);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check argument validity.
|
||
|
|
if ((MaximumCount <= 0) || (InitialCount < 0) || (InitialCount > MaximumCount)) {
|
||
|
|
return STATUS_INVALID_PARAMETER;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Allocate semaphore object.
|
||
|
|
Status = ObCreateObject(PreviousMode,
|
||
|
|
ExSemaphoreObjectType,
|
||
|
|
ObjectAttributes,
|
||
|
|
PreviousMode,
|
||
|
|
NULL,
|
||
|
|
sizeof(KSEMAPHORE),
|
||
|
|
0,
|
||
|
|
0,
|
||
|
|
(PVOID *)&Semaphore);
|
||
|
|
|
||
|
|
// If the semaphore object was successfully allocated, then initialize
|
||
|
|
// the semaphore object and attempt to insert the semaphore object in the current process' handle table.
|
||
|
|
if (NT_SUCCESS(Status)) {
|
||
|
|
KeInitializeSemaphore((PKSEMAPHORE)Semaphore, InitialCount, MaximumCount);
|
||
|
|
Status = ObInsertObject(Semaphore, NULL, DesiredAccess, 0, (PVOID *)NULL, &Handle);
|
||
|
|
|
||
|
|
// If the semaphore object was successfully inserted in the current
|
||
|
|
// process' handle table, then attempt to write the semaphore handle
|
||
|
|
// value. If the write attempt fails, then do not report an error.
|
||
|
|
// When the caller attempts to access the handle value, an access violation will occur.
|
||
|
|
if (NT_SUCCESS(Status)) {
|
||
|
|
try {
|
||
|
|
*SemaphoreHandle = Handle;
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If an exception occurs during the probe of the output handle address,
|
||
|
|
// then always handle the exception and return the exception code as the status value.
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
return GetExceptionCode();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return service status.
|
||
|
|
return Status;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
NTSTATUS NtOpenSemaphore (OUT PHANDLE SemaphoreHandle, IN ACCESS_MASK DesiredAccess, IN POBJECT_ATTRIBUTES ObjectAttributes)
|
||
|
|
/*++
|
||
|
|
Routine Description:
|
||
|
|
This function opens a handle to a semaphore object with the specified desired access.
|
||
|
|
Arguments:
|
||
|
|
SemaphoreHandle - Supplies a pointer to a variable that will receive the semaphore object handle.
|
||
|
|
DesiredAccess - Supplies the desired types of access for the semaphore object.
|
||
|
|
ObjectAttributes - Supplies a pointer to an object attributes structure.
|
||
|
|
Return Value:
|
||
|
|
TBS
|
||
|
|
--*/
|
||
|
|
{
|
||
|
|
HANDLE Handle;
|
||
|
|
KPROCESSOR_MODE PreviousMode;
|
||
|
|
NTSTATUS Status;
|
||
|
|
|
||
|
|
// Establish an exception handler, probe the output handle address, and
|
||
|
|
// attempt to open a semaphore object. If the probe fails, then return
|
||
|
|
// the exception code as the service status. Otherwise return the status
|
||
|
|
// value returned by the object open routine.
|
||
|
|
try {
|
||
|
|
// Get previous processor mode and probe output handle address if necessary.
|
||
|
|
PreviousMode = KeGetPreviousMode();
|
||
|
|
if (PreviousMode != KernelMode) {
|
||
|
|
ProbeForWriteHandle(SemaphoreHandle);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Open handle to the semaphore object with the specified desired access.
|
||
|
|
Status = ObOpenObjectByName(ObjectAttributes,
|
||
|
|
ExSemaphoreObjectType,
|
||
|
|
PreviousMode,
|
||
|
|
NULL,
|
||
|
|
DesiredAccess,
|
||
|
|
NULL,
|
||
|
|
&Handle);
|
||
|
|
|
||
|
|
// If the open was successful, then attempt to write the semaphore
|
||
|
|
// object handle value. If the write attempt fails, then do not report
|
||
|
|
// an error. When the caller attempts to access the handle value, an access violation will occur.
|
||
|
|
if (NT_SUCCESS(Status)) {
|
||
|
|
try {
|
||
|
|
*SemaphoreHandle = Handle;
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If an exception occurs during the probe of the output handle address,
|
||
|
|
// then always handle the exception and return the exception code as the status value.
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
return GetExceptionCode();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return service status.
|
||
|
|
return Status;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
NTSTATUS
|
||
|
|
NtQuerySemaphore (
|
||
|
|
IN HANDLE SemaphoreHandle,
|
||
|
|
IN SEMAPHORE_INFORMATION_CLASS SemaphoreInformationClass,
|
||
|
|
OUT PVOID SemaphoreInformation,
|
||
|
|
IN ULONG SemaphoreInformationLength,
|
||
|
|
OUT PULONG ReturnLength OPTIONAL
|
||
|
|
)
|
||
|
|
/*++
|
||
|
|
Routine Description:
|
||
|
|
This function queries the state of a semaphore object and returns the requested information in the specified record structure.
|
||
|
|
Arguments:
|
||
|
|
SemaphoreHandle - Supplies a handle to a semaphore object.
|
||
|
|
SemaphoreInformationClass - Supplies the class of information being requested.
|
||
|
|
SemaphoreInformation - Supplies a pointer to a record that is to receive the requested information.
|
||
|
|
SemaphoreInformationLength - Supplies the length of the record that is to receive the requested information.
|
||
|
|
ReturnLength - Supplies an optional pointer to a variable that will receive the actual length of the information that is returned.
|
||
|
|
Return Value:
|
||
|
|
TBS
|
||
|
|
--*/
|
||
|
|
{
|
||
|
|
PVOID Semaphore;
|
||
|
|
LONG Count;
|
||
|
|
LONG Maximum;
|
||
|
|
KPROCESSOR_MODE PreviousMode;
|
||
|
|
NTSTATUS Status;
|
||
|
|
|
||
|
|
// Establish an exception handler, probe the output arguments, reference
|
||
|
|
// the semaphore object, and return the specified information. If the probe
|
||
|
|
// fails, then return the exception code as the service status. Otherwise
|
||
|
|
// return the status value returned by the reference object by handle routine.
|
||
|
|
try {
|
||
|
|
// Get previous processor mode and probe output arguments if necessary.
|
||
|
|
PreviousMode = KeGetPreviousMode();
|
||
|
|
if (PreviousMode != KernelMode) {
|
||
|
|
ProbeForWrite(SemaphoreInformation, sizeof(SEMAPHORE_BASIC_INFORMATION), sizeof(ULONG));
|
||
|
|
if (ARGUMENT_PRESENT(ReturnLength)) {
|
||
|
|
ProbeForWriteUlong(ReturnLength);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check argument validity.
|
||
|
|
if (SemaphoreInformationClass != SemaphoreBasicInformation) {
|
||
|
|
return STATUS_INVALID_INFO_CLASS;
|
||
|
|
}
|
||
|
|
if (SemaphoreInformationLength != sizeof(SEMAPHORE_BASIC_INFORMATION)) {
|
||
|
|
return STATUS_INFO_LENGTH_MISMATCH;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Reference semaphore object by handle.
|
||
|
|
Status = ObReferenceObjectByHandle(SemaphoreHandle,
|
||
|
|
SEMAPHORE_QUERY_STATE,
|
||
|
|
ExSemaphoreObjectType,
|
||
|
|
PreviousMode,
|
||
|
|
&Semaphore,
|
||
|
|
NULL);
|
||
|
|
|
||
|
|
// If the reference was successful, then read the current state and
|
||
|
|
// maximum count of the semaphore object, dereference semaphore object,
|
||
|
|
// fill in the information structure, and return the length of the
|
||
|
|
// information structure if specified. If the write of the semaphore
|
||
|
|
// information or the return length fails, then do not report an error.
|
||
|
|
// When the caller accesses the information structure or length an access violation will occur.
|
||
|
|
if (NT_SUCCESS(Status)) {
|
||
|
|
Count = KeReadStateSemaphore((PKSEMAPHORE)Semaphore);
|
||
|
|
Maximum = ((PKSEMAPHORE)Semaphore)->Limit;
|
||
|
|
ObDereferenceObject(Semaphore);
|
||
|
|
try {
|
||
|
|
((PSEMAPHORE_BASIC_INFORMATION)SemaphoreInformation)->CurrentCount = Count;
|
||
|
|
((PSEMAPHORE_BASIC_INFORMATION)SemaphoreInformation)->MaximumCount = Maximum;
|
||
|
|
if (ARGUMENT_PRESENT(ReturnLength)) {
|
||
|
|
*ReturnLength = sizeof(SEMAPHORE_BASIC_INFORMATION);
|
||
|
|
}
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If an exception occurs during the probe of the output arguments, then
|
||
|
|
// always handle the exception and return the exception code as the status value.
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
return GetExceptionCode();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return service status.
|
||
|
|
return Status;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
NTSTATUS NtReleaseSemaphore (IN HANDLE SemaphoreHandle, IN LONG ReleaseCount, OUT PLONG PreviousCount OPTIONAL)
|
||
|
|
/*++
|
||
|
|
Routine Description:
|
||
|
|
This function releases a semaphore object by adding the specified release count to the current value.
|
||
|
|
Arguments:
|
||
|
|
Semaphore - Supplies a handle to a semaphore object.
|
||
|
|
ReleaseCount - Supplies the release count that is to be added to the current semaphore count.
|
||
|
|
PreviousCount - Supplies an optional pointer to a variable that will receive the previous semaphore count.
|
||
|
|
Return Value:
|
||
|
|
TBS
|
||
|
|
--*/
|
||
|
|
{
|
||
|
|
LONG Count;
|
||
|
|
PVOID Semaphore;
|
||
|
|
KPROCESSOR_MODE PreviousMode;
|
||
|
|
NTSTATUS Status;
|
||
|
|
|
||
|
|
// Establish an exception handler, probe the previous count address if
|
||
|
|
// specified, reference the semaphore object, and release the semaphore
|
||
|
|
// object. If the probe fails, then return the exception code as the
|
||
|
|
// service status. Otherwise return the status value returned by the
|
||
|
|
// reference object by handle routine.
|
||
|
|
try {
|
||
|
|
// Get previous processor mode and probe previous count address if necessary.
|
||
|
|
PreviousMode = KeGetPreviousMode();
|
||
|
|
if ((PreviousMode != KernelMode) && (ARGUMENT_PRESENT(PreviousCount))) {
|
||
|
|
ProbeForWriteLong(PreviousCount);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check argument validity.
|
||
|
|
if (ReleaseCount <= 0) {
|
||
|
|
return STATUS_INVALID_PARAMETER;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Reference semaphore object by handle.
|
||
|
|
Status = ObReferenceObjectByHandle(SemaphoreHandle,
|
||
|
|
SEMAPHORE_MODIFY_STATE,
|
||
|
|
ExSemaphoreObjectType,
|
||
|
|
PreviousMode,
|
||
|
|
&Semaphore,
|
||
|
|
NULL);
|
||
|
|
|
||
|
|
// If the reference was successful, then release the semaphore object.
|
||
|
|
// If an exception occurs because the maximum count of the semaphore
|
||
|
|
// has been exceeded, then dereference the semaphore object and return
|
||
|
|
// the exception code as the service status. Otherwise write the previous
|
||
|
|
// count value if specified. If the write of the previous count fails,
|
||
|
|
// then do not report an error. When the caller attempts to access the
|
||
|
|
// previous count value, an access violation will occur.
|
||
|
|
if (NT_SUCCESS(Status)) {
|
||
|
|
try {
|
||
|
|
Count = KeReleaseSemaphore((PKSEMAPHORE)Semaphore, ExpSemaphoreBoost, ReleaseCount, FALSE);
|
||
|
|
ObDereferenceObject(Semaphore);
|
||
|
|
if (ARGUMENT_PRESENT(PreviousCount)) {
|
||
|
|
try {
|
||
|
|
*PreviousCount = Count;
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
}
|
||
|
|
}
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
ObDereferenceObject(Semaphore);
|
||
|
|
return GetExceptionCode();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If an exception occurs during the probe of the previous count, then
|
||
|
|
// always handle the exception and return the exception code as the status value.
|
||
|
|
} except(ExSystemExceptionFilter()) {
|
||
|
|
return GetExceptionCode();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return service status.
|
||
|
|
return Status;
|
||
|
|
}
|