From: Ken Brown <kbrown@cornell.edu>
To: cygwin@cygwin.com
Subject: Re: [PATCH] fhandler_pipe: add sanity limit to handle loops
Date: Thu, 13 Jan 2022 09:39:23 -0500 [thread overview]
Message-ID: <f9f51cfe-fa29-8918-3f54-50c963a150fa@cornell.edu> (raw)
In-Reply-To: <20220113195638.d64430e6b03159c70721fb45@nifty.ne.jp>
On 1/13/2022 5:56 AM, Takashi Yano wrote:
> Ken Brown wrote:
>> 2. You can use the ReturnLength parameter of NtQueryInformationProcess to see
>> how big a buffer is needed. This might be more efficient than repeatedly
>> doubling the buffer size.
>
> Even if ReturnLength is used, the first NtQueryInformationProcess()
> call and the second NtQueryInformationProcess() call will not be
> done in atomic, so retrying is still necessary. However, it may be
> more efficient as you mentioned.
>
> The similar is true also for NtQuerySystemInformation().
>
> Do you still think it is better to use ReturnLength rather than
> doubling the buffer?
I'm not sure. I only mentioned it because I saw that that's what Process Hacker
did, but still in a retry loop as you said.
I suspect it doesn't make a lot of difference in practice, since we call the
function once and then cache the value. Do whatever you think is best.
Thanks.
Ken
prev parent reply other threads:[~2022-01-13 14:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.BSO.2.21.2112231503400.11760@resin.csoft.net>
[not found] ` <f97bba17-16ab-d7be-01f6-1c057fb5f1a5@cornell.edu>
[not found] ` <alpine.BSO.2.21.2112231623490.11760@resin.csoft.net>
[not found] ` <c5115e9b-6475-d30e-04d3-cb84cfa92b3a@cornell.edu>
[not found] ` <alpine.BSO.2.21.2112241136160.11760@resin.csoft.net>
[not found] ` <622d3ac6-fa5d-965c-52da-db7a4463fffd@cornell.edu>
[not found] ` <alpine.BSO.2.21.2112241638280.11760@resin.csoft.net>
[not found] ` <20211225121902.54b82f1bb0d4f958d34a8bb7@nifty.ne.jp>
[not found] ` <alpine.BSO.2.21.2112241945060.11760@resin.csoft.net>
[not found] ` <20211225131242.adef568db53d561a6b134612@nifty.ne.jp>
[not found] ` <alpine.BSO.2.21.2112242101520.11760@resin.csoft.net>
[not found] ` <20211226021010.a2b2ad28f12df9ffb25b6584@nifty.ne.jp>
[not found] ` <alpine.BSO.2.21.2112251111580.11760@resin.csoft.net>
[not found] ` <alpine.BSO.2.21.2112251457480.11760@resin.csoft.net>
[not found] ` <8172019c-e048-4fe2-79c9-0b3262057d3e@cornell.edu>
[not found] ` <alpine.BSO.2.21.2112252054310.11760@resin.csoft.net>
[not found] ` <c7664703-0ec2-388f-64e3-8c46d4590b3e@cornell.edu>
2022-01-13 10:56 ` Takashi Yano
2022-01-13 14:39 ` Ken Brown [this message]
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