From: Brian Inglis <Brian.Inglis@Shaw.ca>
To: cygwin@cygwin.com
Cc: Martin Wege <martin.l.wege@gmail.com>
Subject: Re: Cygwin pathconf() query filesystem kernel data? Re: How does Cygwin detect MSFT NFSv3 file system? Re: Weird (path) problems with cygwin test release 3.5.0-0.384.g9939aa7d0945.x86_64 ...
Date: Sat, 19 Aug 2023 11:50:38 -0600 [thread overview]
Message-ID: <f0a61e5d-ca45-4145-a33d-78c3c9a0b345@Shaw.ca> (raw)
In-Reply-To: <CANH4o6P0XfmqjiiG+4eGmiz=4Vj8420Q6GSCz-PAwfnUUF-tzw@mail.gmail.com>
On 2023-08-18 07:09, Martin Wege via Cygwin wrote:
> On Fri, Aug 18, 2023 at 10:44 AM Corinna Vinschen via Cygwin
> <cygwin@cygwin.com> wrote:
>>
>> On Aug 17 20:49, Martin Wege via Cygwin wrote:
>>> On Mon, Aug 14, 2023 at 10:56 PM Corinna Vinschen via Cygwin
>>> <cygwin@cygwin.com> wrote:
>>>> and the result is the same. Note that Cygwin supports MSFT NFSv3 but
>>>> not CITI NFSv4.1 internally. No gurantee that Cygwin always does what
>>>> is necessary for that other NFS.
>>>
>>> 1. How does Cygwin detect whether something is a MSFT NFSv3, or not?
>>> Cygwin /bin/mount lists the CITI NFSv4.1 as 'nfs', so there *IS*
>>> something which detects that?
>>
>> The filesystem name returned by NtQueryVolumeInformationFile is "NFS".
>> If any other NFS returns the same filesystem name, it will be treated
>> just like MSFT NFSv3.
>>
>>> 2. Are Cygwin soft link handing depend on MSFT NFSv3 or not, i.e. does
>>> the Cygwin soft link code behave differently for MSFT NFSv3 file
>>> systems?
>>
>> Yes. NFS doesn't support symlink creation and symlink reading via
>> the usual functions, because Windows symlinks are created as reparse
>> points. NFS doesn't support reparse points. So the developers of
>> the MSFT NFS client had to invent their own way to create and
>> read NFS symlinks:
>>
>> https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/path.cc;hb=HEAD#l1719
>>
>> https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/path.cc;hb=HEAD#l2750
>>
>>> 3. Does Cygwin implement the pathconf() api?
>>
>> Yes. Surprisingly, you can check this yourself by just calling the
>> function and trying to compile your code.
>
> Apologies, how do we say in German? "Ich sollte meine Frage konkretisieren:"
>
> Does the Cygwin implementation of pathconf() support query data of the
> underlying filesystem based on data from the kernel, as UNIX does? So
> pathconf() returns different values for NTFS, ReFS, or Windows builtin
> NFSv3?
>
> I am asking, because as far as I know the Linux implementation is not
> a syscall, and instead glibc guesses values based on builtin static
> data, and whatever fstatfs() has to offer. Compared to that UNIX
> (Solaris, AIX, HPUX, ...) have pathconf() as a syscall, and actually
> ask the filesystem itself.
Many library functions are implemented as documented either in the Cygwin
packages cygwin-doc and man-pages-posix available for installation; and use as
e.g. `man 3p fpathconf`, also available online at:
https://pubs.opengroup.org/onlinepubs/9699919799/functions/fpathconf.html or
https://man7.org/linux/man-pages/man3/fpathconf.3p.html
and for comparison and reference we make Cygwin package man-pages-linux
available for installation; and use as e.g. `man -m linux 3 fpathconf`, also
available online at:
https://man7.org/linux/man-pages/man3/fpathconf.3.html
suggestions for setup are in the package announcements made every 9-12 weeks
when the latest Linux man-pages package is released and updated on Cygwin.
Please also note that the getconf(1) program is installed as part of Cygwin and
can access f/pathconf variables associated with a pathname argument, as shown in
getconf(1) `man 1 getconf` and getconf(1p) `man 1p getconf`.
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut
-- Antoine de Saint-Exupéry
next prev parent reply other threads:[~2023-08-19 17:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <a0f1e420-ae48-49a3-9300-c56f1948ad9b.8d485f54-9f47-42b0-bdcb-9635fbf663c3.6697971f-86bc-49dc-8072-c37095eed858@emailsignatures365.codetwo.com>
[not found] ` <a0f1e420-ae48-49a3-9300-c56f1948ad9b.93e247b8-206a-49dd-b71c-9240681180cb.7748cdc6-d053-4197-9372-3b4751ae3949@emailsignatures365.codetwo.com>
[not found] ` <a0f1e420-ae48-49a3-9300-c56f1948ad9b.e52b7f5f-5a09-4346-99f8-a6591191169c.10af45d3-4cfc-48f7-a293-b6d9fa78cdd1@emailsignatures365.codetwo.com>
2023-08-11 13:36 ` Mainz, Roland
2023-08-14 10:21 ` Corinna Vinschen
2023-08-14 16:25 ` Roland Mainz
2023-08-14 17:29 ` Roland Mainz
2023-08-14 19:42 ` Martin Wege
2023-08-14 20:57 ` Corinna Vinschen
2023-08-14 20:56 ` Corinna Vinschen
2023-08-17 18:49 ` How does Cygwin detect MSFT NFSv3 file system? " Martin Wege
2023-08-18 8:44 ` Corinna Vinschen
2023-08-18 13:09 ` Cygwin pathconf() query filesystem kernel data? " Martin Wege
2023-08-19 17:50 ` Brian Inglis [this message]
2023-08-21 12:03 ` Martin Wege
2023-08-21 22:07 ` Brian Inglis
2023-08-24 16:27 ` Martin Wege
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