计算机系信息处理实验室 Lecture 4 System Mechanisms (2) xlanchen@03/18/2005

计算机系•信息处理实验室

Lecture 4 System Mechanisms (2)

xlanchen@03/18/2005

xlanchen@03/18/2005 Understanding the Inside of Windows2000

2计算机系信息处理实验室

Contents

Trap dispatching

The executive object manager

Synchronization

System worker threads

Local procedure calls (LPCs)

Object manager

EXPERIMENT

Exploring the Object Manager

Uniform approach towards:

Object protection (C2 security)

Charging

Object naming

Object retention and garbage collection

Object access (via handles)

Standard object attributes

Standard object methods

Executive Objects Process

Memory Section

Object directory

Queues

Thread

Semaphore

Symbolic link

(registry) key

Executive objects that contain kernel objects

Object Structure

Object properties

OM deletes object when:

#open handles drops to zero

#knl refs drops to zero

Obj names

Support identification, finding, sharing

Hierarchic (per machine) name space

Symbolic links, e.g. “C:”

Type Objects

Process objects and the process type object

EXPERIMENT

Viewing the Type Objects

Type Object Attributes

Type name

Pool type

Default quota

Access types

Generic access rights mapping

Synchronization

Methods

Object Methods

Open--When an object handle is opened

Close--When an object handle is closed

Delete--Before the object manager deletes an object

Query--name When a thread requests the name of an object, such as a file, that exists in a secondary object domain

Parse--When the object manager is searching for an object name that exists in a secondary object domain

Security--When a process reads or changes the protection of an object, such as a file, that exists in a secondary object domain

Object Handles & Process Handle Table

EXPERIMENT

Viewing Open Handles with Nthandle

Structure of a handle table entry

EXPERIMENT Viewing the Handle Table with the Kernel Debugger

Handles and reference counts

Synchronization

Mutual exclusion

one, and only one, thread can access a particular resource at a time

Critical sections

Kernel Synchronization

Kernel critical sections

For single-processor

Simple operating systems: disable all interrupts

2K: raising the processor's IRQL

For a multiprocessor

spinlock

Using a spinlock

Executive Synchronization

Dispatcher objects

WaitForSingleObject

WaitForMultipleObjects

A thread in a Win32 application can synchronize with a Win32 process, thread, event, semaphore, mutex, waitable timer, I/O completion port, or file object

Executive resources

available only to kernel-mode code

aren't accessible from the Win32 API

Waiting on a dispatcher object

A thread can synchronize with a dispatcher object by waiting on the object's handle

Selected kernel dispatcher objects

Wait data structures

EXPERIMENT

Looking at Wait Queues

System worker threads

Three types

Delayed worker threads

Critical worker threads

hypercritical worker threads

EXPERIMENT Listing System Worker Threads

Windows 2000 Global Flags

NtGlobalFlag

Initialize

Gflags.exe

allows you to view and change the system global flags

Local procedure calls (LPCs)

An interprocess communication facility

For high-speed message passing

An internal mechanism available only to Windows 2000 operating system components

EXPERIMENT

Viewing LPC Port Objects

“ Internal” IPC between address spaces, e.g.

Transport for local RPC

Calls to Win32 subsystem

Variants:

n <= 256 bytes done inband

n > 256 bytes via shmem section

n > shmem section – addr-to-addr copy

Typically client-server

Client connects to servers well-known LPC port

Server opens new port and tells client its address

LPC端口的使用

计算机系信息处理实验室 Lecture 4 System Mechanisms (2) xlanchen@03/18/2005

Documents

Optimal Mechanisms

计算机系信息处理实验室 Lecture 9 Memory Management(1) xlanchen@04/15/2005

Mechanics of machines: Linkage Mechanisms

movement transformation mechanisms in spanish

Molecular mechanisms of the

Spasticity Mechanisms

计算机系信息处理实验室 Lecture 6 Management Mechanisms xlanchen@03/25/2005

Motion Planning Closed Chain Mechanisms

计算机系信息处理实验室 Lecture 8 Processes, Threads, and Jobs (2) xlanchen@04/08/2005

计算机系信息处理实验室 Lecture 12 I/O System xlanchen@05/13/2005

计算机系信息处理实验室 Lecture 5 Startup and Shutdown xlanchen@03/18/2005

Basic mechanisms of epigenetics

Andrew Abbott Mechanisms and Relations

Mechanisms of leukemia-‐induced immunosuppression

Analytical Mechanics: Link Mechanisms

Mechanisms of ocean-atmosphere interactions

CHARACTERISTICS AND MECHANISMS EMISSIONS

Litigating Cost Tracker Mechanisms

计算机系信息处理实验室 Lecture 14 Cache Manager xlanchen@05/27/2005

Statically Balanced Compliant Mechanisms

计算机系 信息处理实验室 Lecture 4 System Mechanisms (2) xlanchen@03/18/2005

计算机系信息处理实验室 Lecture 4 System Mechanisms (2) xlanchen@03/18/2005