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From: Junio C Hamano <gitster@pobox•com>
To: Alan Hourihane <alanh@fairlite•co.uk>
Cc: git@vger•kernel.org
Subject: Re: new platform & S_IFGITLINK problem
Date: Sat, 01 May 2010 19:33:26 -0700	[thread overview]
Message-ID: <7vfx2b2ft5.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <1272756555.13488.1314.camel@jetpack.demon.co.uk> (Alan Hourihane's message of "Sun\, 02 May 2010 00\:29\:15 +0100")

Alan Hourihane <alanh@fairlite•co.uk> writes:

> Just joined as I'm compiling git on a new platform and wondered if
> someone can help solve a problem with the definition of S_IFGITLINK.

Yikes.  The current codebase pretty much assumes that IFREG is 0100000,
IFDIR 0040000, and IFLNK 0120000, and the bits read from "struct stat" and
the mode bits we store in the index and tree objects are interchangeable.

Yes, that assumption is a gross POSIX violation but we so far haven't seen
any platform that matters in real life that assigns the IFMT bits
differently.

We would need to:

 (1) rename S_IFGITLINK to GIT_S_IFMODULE;

 (2) define GIT_S_IF{REG,DIR,LNK} as 0100000, 0040000, and 0120000;

 (3) write MODE_SYSTEM_TO_GIT() macro to convert from S_IF{REG,DIR,LNK} we
     read from struct stat to the "canonical" GIT_S_IF{REG,DIR,LNK}
     values; and

 (4) change all the code that read mode from struct stat and use it to
     first use MODE_SYSTEM_TO_GIT().

Currently 'git grep -e "S_IF[A-Z]" -e "struct stat"' reports around 250
hits, so it is not infeasible amount of work, but it is not a trivial and
mechanical replacement, either.  I or somebody need to set aside a block
of time to do this clean-up and audit the result.

Thanks for a report.

next prev parent reply	other threads:[~2010-05-02  2:56 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-01 23:29 new platform & S_IFGITLINK problem Alan Hourihane
2010-05-02  2:33 ` Junio C Hamano [this message]
2010-05-02  9:39   ` Alan Hourihane
2010-05-04  3:39   ` Linus Torvalds
2010-05-04  3:52     ` Linus Torvalds
2010-05-04  6:13       ` Andreas Ericsson
2010-05-04 14:34         ` Linus Torvalds
2010-05-04 15:29       ` Junio C Hamano
2010-05-04  7:21     ` Alan Hourihane
2010-07-22 16:23   ` Alan Hourihane
2010-07-25 17:29     ` Junio C Hamano
2010-07-25 18:00       ` Alan Hourihane
2010-08-02 16:11         ` Ævar Arnfjörð Bjarmason
2010-08-02 16:14           ` Alan Hourihane
2010-08-02 16:26             ` Ævar Arnfjörð Bjarmason
2010-05-05  2:29 ` Jonathan Nieder
2010-05-05  8:36   ` Alan Hourihane

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