The document discusses the role and functions of the process manager in Windows XP, detailing its responsibilities in process creation, deletion, and management using threads and jobs. It explains the Win32 API's createprocess() function, asynchronous procedure calls (APCs), and the support for POSIX processes. Additionally, it covers how the process manager facilitates impersonation for client-server computing to operate under various security contexts.

1. PROCESS MANAGER

2. PRCS MNGR IN XP Arct.

3. 
 CREATING
 DELETING
 USES THREADS , PROCESSES & JOBS
 PRIORITIES & AFFINITIES IN PROCESSES &THREADS WHEN
CREATED
× KNOWLEDGE OF PARENT/CHILD RELATIONSHIPS
× PROCESS HIERARCHIES
× SCHEDULING OF PROCESSES
PROs & CONs

4.  A win32 API appl calls CreateProcess()
 A msg sent to win32API subsystem to notify
that process is created
 CreateProcess() originally calls an API in PM
to create a process
 PM calls Obj Mngr >> process obj returns obj
handler toWin32 API.

5. Win XP API’S :
API’s for manipulating Virtual mem & Threads & for
duplicating handles takes a process handle, so sub
systems can perform operations on behalf of new
process without executing directly in the new process
context.

6. APC’s (Asynchronous procd calls)
• Once a process is created, initial thread is created & APC is
delivered to thread to prompt the start of the execution in
user-mode loader.
• The loader is an ‘ntdll.dll’ is a link lib mapped to every
process automatically when created.
• WIN XP also supports UNIX fork() to support the POSIX
environmental sub system to create a process
• WIN32 API envrmt calls the PM but POSIX uses cross-
process nature of WIN XP API’s to create a process from
with in the subsystem process

7. APC’s (contd…)
• PM also implements queuing & delivery of APC’s
to threads.
• APC’s are used by sys to
> Initiate thread exe
> Complete I/O
> Terminate threads and processes
> Attach debugger
• To support POSIX, PM provides API’s that sends
alerts to threads that unblock from sys calls.

8. PM API’s :
There are also PM API’s that get & set a thread’s
register context and access another process’s
Virtual mem.
With in EXECUTIVE, the existing threads can
temp’ly attach to another process.

9. IMPERSONATION
• PM also supports Impersonation
Ex:- A thread running in a process with a security
token belonging to another user.
• This facility is fundamental to client-server computing
model, where the services needs to act on behalf of the
variety of clients with diff security ID,s.

10. THANK YOU
by DAVID