cat /proc/registry/HKEY_PERFOMANCE_DATA/@ hangs

Dave Korn dk@artimi.com
Tue Jul 13 15:09:00 GMT 2004


> -----Original Message-----
> From: cygwin-owner On Behalf Of Igor Pechtchanski
> Sent: 13 July 2004 15:30
> To: Reini Urban

> On Tue, 13 Jul 2004, Reini Urban wrote:
> 
> > cat /proc/registry/HKEY_PERFOMANCE_DATA/@
> > hangs forever.
> 
> According to MSDN
> (<http://msdn.microsoft.com/library/en-us/perfmon/base/the_hke
y_performance_data_key.asp>):

[snip]

> This tells me that reading from HKEY_PERFORMANCE_DATA never 
> returns EOF,
> so that you have to terminate it explicitly from the outside.  So your
> behavior sounds absolutely normal.

  Reading a registry key isn't like reading a stream.  There's no file
position pointer and no EOF mark.  You read all (or as much as you want) of
the data in one operation.  I don't think this failure mode seems likely.

> > Win2K (no win98 OS)
> > Shouldn't HKEY_PERFOMANCE_DATA be disabled on NT systems, 
> or does it work?
> 
> If the key is present, it'll be in /proc/registry.  FWIW, the MSDN web
> page above doesn't mention any restrictions on the systems 
> that this key
> is present on.

Heh.  Check this:

dk@mace ~> cd /proc/registry/
dk@mace /proc/registry> ls
HKEY_CLASSES_ROOT    HKEY_CURRENT_USER  HKEY_LOCAL_MACHINE    HKEY_USERS
HKEY_CURRENT_CONFIG  HKEY_DYN_DATA      HKEY_PERFOMANCE_DATA
dk@mace /proc/registry> ls -la
Segmentation fault (core dumped)
dk@mace /proc/registry>

next I type 'ls' <space> <tab> to get

dk@mace /proc/registry> ls HKEY_

then I press P <tab> and the bash window vanishes !!


And check this too:

dk@mace /proc/registry> getfacl HKEY_PERFOMANCE_DATA
Segmentation fault (core dumped)
dk@mace /proc/registry> getfacl *
# file: HKEY_CLASSES_ROOT
# owner: Administrators
# group: SYSTEM
user::r-x
group::r-x
other:---
mask:rwx

# file: HKEY_CURRENT_CONFIG
# owner: Administrators
# group: SYSTEM
user::r-x
group::r-x
other:---
mask:rwx

# file: HKEY_CURRENT_USER
# owner: Administrators
# group: SYSTEM
user::r-x
group::r-x
other:---
mask:rwx

# file: HKEY_DYN_DATA
# owner: dk
# group: Domain Users
user::r-x
group::r-x
other:r-x
mask:rwx

# file: HKEY_LOCAL_MACHINE
# owner: Administrators
# group: SYSTEM
user::r-x
group::r-x
other:r--
mask:rwx
Segmentation fault (core dumped)
dk@mace /proc/registry>

  There's something badly wrong: it seems that any attempt to stat or
otherwise access it causes a segfault.

  Tell me, do you suppose the spelling mistake between HKEY_PERFOMANCE_DATA
and HKEY_PERFO*R*MANCE_DATA could be resulting in some internal routine in
cygwin's registry->filesystem mapping code getting called with a NULL
pointer?



    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....


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