Mail Archives: cygwin/2005/05/17/23:08:35
On Wed, May 18, 2005 at 01:01:48PM +1000, Sonam Chauhan wrote:
>Reini:
>
>[Note, I'm no Cygwin expert, so please correct any misunderstandings.]
>
>> >>or fix it in this module XS. It's really easy with the cygwin provided
>> >>translation functions.
>> >> See http://sourceware.org/ml/cygwin/2005-02/msg00154.html
>...
>> > After all, Proc::ProcessTable misreports the PID and
>> > PPID only under certain conditions -- this would indicate a complex
>> issue in
>> > Proc::ProcessTable XS code, right?
>>
>> No. Just the translation is needed, but one has to specify somehow which
>> pid's he wants. The cygwin pid's or the winpid's.
>> Both have their merits and usecases.
>
>Why are two usecases needed? The code that builds the process table
>(returned by Proc::ProcessTable->table) should return the same PID and PPID
>that 'ps' reports - no exceptions - right?
>
>I had a look in Proc::ProcessTable's .xs and os/cygwin.c. There seem to be a
>problem with the process table data returned by this code in the
>OS_get_table() function:
>
>This defines an internal Cygwin query to return process information:
> cygwin_getinfo_types query = CW_GETPINFO_FULL;
>This executes the query within a for loop:
> p = (external_pinfo *) cygwin_internal (query, pid | CW_NEXTPID);
>
>From what I gather, the root problem is that for some processes (as
>demonstrated by my testcase script), the CW_GETPINFO_FULL query returns:
>1. Invalid PPIDs
Only PPIDs for cygwin processes are returned. Everything else should be 0.
Orphaned cygwin processes or processes started from the command line have
a PPID of 1.
>2. WINPID instead of Cygwin PID.
A cygwin pid can actually be spread across two processes. You see this with
"ps -W" if you do something like:
bash -c "exec sleep 20"
in one window and:
ps -W
in another window.
ps -W will also not always properly report on execed processes in
general. Since ps -W uses CW_GETPINFO_FULL, you can use that command to
see what is going on.
cgf
--
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Problem reports: http://cygwin.com/problems.html
Documentation: http://cygwin.com/docs.html
FAQ: http://cygwin.com/faq/
- Raw text -