|
|
|
Modern Operating Systems by Herbert Bos and Andrew S. Tanenb...
Modern_Operating_Systems_by_Herbert_Bos_and_Andrew_S._Tanenbaum_4th_Ed.pdf
Showing 900 out of 1137
Modern Operating Systems by Herbert Bos and Andrew...
Modern_Operating_Systems_by_Herbert_Bos_and_Andrew_S._Tanenbaum_4th_Ed.pdf-M ODERN O PERATING S YSTEMS
Modern Operating Systems by Herbert...
Modern_Operating_Systems_by_Herbert_Bos_and_Andrew_S._Tanenbaum_4th_Ed.pdf-M ODERN O PERATING S YSTEMS
Page 900
SEC. 11.2
PROGRAMMING WINDOWS
869
access requested.
When handles are duplicated between processes, new access
restrictions can be added that are specific to the duplicated handle.
Thus, a process
can duplicate a read-write handle and turn it into a read-only version in the target
process.
Not all system-created data structures are objects and not all objects are kernel-
mode objects.
The only ones that are true kernel-mode objects are those that need
to be named, protected, or shared in some way.
Usually, they represent some kind
of programming abstraction implemented in the kernel. Every kernel-mode object
has a system-defined type, has well-defined operations on it, and occupies storage
in kernel memory.
Although user-mode programs can perform the operations (by
making system calls), they cannot get at the data directly.
Figure 11-7 shows a sampling of the native APIs, all of which use explicit
handles to manipulate kernel-mode objects such as processes, threads, IPC ports,
and
sections
(which are used to describe memory objects that can be mapped into
address spaces).
NtCreateProcess
returns a handle to a newly created process ob-
ject, representing an executing instance of the program represented by the
Section-
Handle
.
DebugPortHandle
is used to communicate with a debugger when giving it
control of the process after an exception (e.g., dividing by zero or accessing invalid
memory).
ExceptPortHandle
is used to communicate with a subsystem process
when errors occur and are not handled by an attached debugger.
NtCreateProcess(&ProcHandle, Access, SectionHandle, DebugPortHandle, ExceptPortHandle, ...)
NtCreateThread(&ThreadHandle, ProcHandle, Access, ThreadContext, CreateSuspended, ...)
NtAllocateVirtualMemory(ProcHandle, Addr, Size, Type, Protection, ...)
NtMapViewOfSection(SectHandle, ProcHandle, Addr, Size, Protection, ...)
NtReadVirtualMemory(ProcHandle, Addr, Size, ...)
NtWriteVirtualMemory(ProcHandle, Addr, Size, ...)
NtCreateFile(&FileHandle, FileNameDescriptor, Access, ...)
NtDuplicateObject(srcProcHandle, srcObjHandle, dstProcHandle, dstObjHandle, ...)
Figure 11-7.
Examples of native NT API calls that use handles to manipulate ob-
jects across process boundaries.
NtCreateThread
takes
ProcHandle
because it can create a thread in any process
for which the calling process has a handle (with sufficient access rights).
Simi-
larly,
NtAllocateVirtualMemory
,
NtMapViewOfSection
,
NtReadVirtualMemory,
and
NtWriteVirtualMemory
allow one process not only to operate on its own address
space, but also to allocate virtual addresses, map sections, and read or write virtual
memory in other processes.
NtCreateFile
is the native API call for creating a new
file or opening an existing one.
NtDuplicateObject
is the API call for duplicating
handles from one process to another.
Kernel-mode objects are, of course, not unique to Windows. UNIX systems
also support a variety of kernel-mode objects, such as files, network sockets, pipes,
Ace your assessments! Get Better Grades
Browse thousands of Study Materials & Solutions from your Favorite Schools
Concordia University
Concordia_University
School:
Operating_Systems
Course:
Great resource for chem class. Had all the past labs and assignments
Leland P.
Santa Clara University
Introducing Study Plan
Using AI Tools to Help you understand and remember your course concepts better and faster than any other resource.
Find the best videos to learn every concept in that course from Youtube and Tiktok without searching.
Save All Relavent Videos & Materials and access anytime and anywhere
Prepare Smart and Guarantee better grades
Know more
Students also viewed documents
lab 18.docx
lab_18.docx
Course
Course
3
Module5QuizSTA2023.d...
Module5QuizSTA2023.docx.docx
Course
Course
10
Week 7 Test Math302....
Week_7_Test_Math302.docx.docx
Course
Course
30
Chapter 1 Assigment ...
Chapter_1_Assigment_Questions.docx.docx
Course
Course
5
Week 4 tests.docx.do...
Week_4_tests.docx.docx
Course
Course
23
Week 6 tests.docx.do...
Week_6_tests.docx.docx
Course
Course
106
