Open a file with Rolling IRPs

NTFSD
1

Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

2

There are some implementations of generating IRP_MJ_CREATE freely available
on Internet. However they use undocumented functions and utilize
undocumented fields of FILE_OBJECT, so I suppose you’ll have portability
issues if you try to use it. Moreover the implementations I found slightly
differ from each other and there is no way to get to know which of them is
more correct.

The most difficult part is to build the file object. Probably you can find
samples of doing this in fastfat example from IFS Kit

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

3

Anurag Sarin wrote:

Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

My advice would be to forget it.

I tried to “roll my own create”, and get it right, a few years ago USING
undocumented APIS. I was not successful in consistently getting it right.

The access state structure is particularly difficult.

If you’ve ever read the code in the Create path, you’ll know how
complicated and case-specific it is.

Seriously, this isn’t something you want to spend your time on.

Peter
OSR

4

I managed to write a routine that created a file on all of the systems
available in our company (and my home systems as well). But the solution was
so much complicated and yet fragile, that I switched to using shadow devices
which is a much-much more stable solution. And implementing shadow devices
takes just a few days including testing.

–htfv

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

5

Thanks for ur help I found the below function code for every bodys
benefit …

NTSTATUS FsSimpleOpen(PUNICODE_STRING pstrName, ACCESS_MASK
DesiredAccess,
PDEVICE_OBJECT pVolume, PDEVICE_OBJECT pRealDevice, PFILE_OBJECT
pParent,
PFILE_OBJECT *ppFile)

But what to pass in
PDEVICE_OBJECT pVolume ,
PDEVICE_OBJECT pRealDevice and PFILE_OBJECT pParent

I read : pVolume is the driver at the bottom of the file system stack,
pParent should be the driver at the top of the FS stack, pRealDevice
should be the FILE_DEVICE_DISK on which the volume is mounted.

Can any body vive an an example… How to get these values in WIN 2k
Filke system filter Driver.

anurag

-----Original Message-----
From: Roman Kudinov [mailto:xxxxx@rbcmail.ru]
Sent: Monday, January 24, 2005 12:49 PM
To: Windows File Systems Devs Interest List
Subject: Re:[ntfsd] Open a file with Rolling IRPs

There are some implementations of generating IRP_MJ_CREATE freely
available on Internet. However they use undocumented functions and
utilize undocumented fields of FILE_OBJECT, so I suppose you’ll have
portability issues if you try to use it. Moreover the implementations I
found slightly differ from each other and there is no way to get to know
which of them is more correct.

The most difficult part is to build the file object. Probably you can
find samples of doing this in fastfat example from IFS Kit

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd… Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@divassoftware.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

6

Try searching on osronline for this function, I saw a thread which discussed
this a couple of years ago

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Thanks for ur help I found the below function code for every bodys
benefit …

NTSTATUS FsSimpleOpen(PUNICODE_STRING pstrName, ACCESS_MASK
DesiredAccess,
PDEVICE_OBJECT pVolume, PDEVICE_OBJECT pRealDevice, PFILE_OBJECT
pParent,
PFILE_OBJECT *ppFile)

But what to pass in
PDEVICE_OBJECT pVolume ,
PDEVICE_OBJECT pRealDevice and PFILE_OBJECT pParent

I read : pVolume is the driver at the bottom of the file system stack,
pParent should be the driver at the top of the FS stack, pRealDevice
should be the FILE_DEVICE_DISK on which the volume is mounted.

Can any body vive an an example… How to get these values in WIN 2k
Filke system filter Driver.

anurag

-----Original Message-----
From: Roman Kudinov [mailto:xxxxx@rbcmail.ru]
Sent: Monday, January 24, 2005 12:49 PM
To: Windows File Systems Devs Interest List
Subject: Re:[ntfsd] Open a file with Rolling IRPs

There are some implementations of generating IRP_MJ_CREATE freely
available on Internet. However they use undocumented functions and
utilize undocumented fields of FILE_OBJECT, so I suppose you’ll have
portability issues if you try to use it. Moreover the implementations I
found slightly differ from each other and there is no way to get to know
which of them is more correct.

The most difficult part is to build the file object. Probably you can
find samples of doing this in fastfat example from IFS Kit

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd… Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@divassoftware.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

7

I am a beginner could you tell me what are shadow devices and how can I
implement them.
Or could you guide me to an article…

Thanks
Anurag
-----Original Message-----
From: Alexey Logachyov [mailto:xxxxx@mail.ru]
Sent: Monday, January 24, 2005 9:18 PM
To: Windows File Systems Devs Interest List
Subject: Re:[ntfsd] Open a file with Rolling IRPs

I managed to write a routine that created a file on all of the systems
available in our company (and my home systems as well). But the solution
was
so much complicated and yet fragile, that I switched to using shadow
devices
which is a much-much more stable solution. And implementing shadow
devices
takes just a few days including testing.

–htfv

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@divassoftware.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

8

Can I ask for some code using shadow devices for opening a file.

-----Original Message-----
From: Alexey Logachyov [mailto:xxxxx@mail.ru]
Sent: Monday, January 24, 2005 9:18 PM
To: Windows File Systems Devs Interest List
Subject: Re:[ntfsd] Open a file with Rolling IRPs

I managed to write a routine that created a file on all of the systems
available in our company (and my home systems as well). But the solution
was
so much complicated and yet fragile, that I switched to using shadow
devices
which is a much-much more stable solution. And implementing shadow
devices
takes just a few days including testing.

–htfv

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@divassoftware.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

9

Search the list - it was discussed in details about a year ago. (Or it was
more than a year ago? My memory’s got leaking)

–htfv

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Can I ask for some code using shadow devices for opening a file.

-----Original Message-----
From: Alexey Logachyov [mailto:xxxxx@mail.ru]
Sent: Monday, January 24, 2005 9:18 PM
To: Windows File Systems Devs Interest List
Subject: Re:[ntfsd] Open a file with Rolling IRPs

I managed to write a routine that created a file on all of the systems
available in our company (and my home systems as well). But the solution
was
so much complicated and yet fragile, that I switched to using shadow
devices
which is a much-much more stable solution. And implementing shadow
devices
takes just a few days including testing.

–htfv

“Anurag Sarin” wrote in message
news:xxxxx@ntfsd…
Working on WIN2k - File system filter driver.

I want to Open a file using Building IRPs Method.

1>How to get file object by the given File Name?
2>Can some body explain me as how these parameters need to be given
values or can I ignore them.
IrpSp->Parameters.Create.SecurityContext->AccessState
IrpSp->Parameters.Create.SecurityContext->DesiredAccess

Regards
Anurag

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@divassoftware.com To
unsubscribe send a blank email to xxxxx@lists.osr.com