Re: fchdir on mingw

[Eric Blake]

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According to Eric Blake on 8/31/2009 3:35 PM:
> One of the main reasons the fchdir module was added was so that the openat 
> module (and friends) would compile on mingw.  Well, it turns out that mingw 
> has 
> the (documented) limitation that open(dir,O_RDONLY) fails with EACCES, so 
> rpl_open was never registering an fd visiting a directory in the first place, 
> and the fchdir replacement (and thus openat and fts) failed to run on mingw.  
> The first patch improves things by adding a fchdir unit test, and teaches 
> rpl_open how to fake out opening a directory (the end result of 
> using "/dev/null" under the hood means that read() on the fd gives the same 
> EOF 
> results as on Linux; and replacing fstat() means we can hide the fact that we 
> used a dummy).

Pushed the first one; I'll wait a bit longer for any more review before
pushing the second (since it changes the implementation of fchdir) or the
subsequent fdopendir patches.

> Subject: [PATCH 1/2] fchdir: port to mingw
> 
> * m4/fchdir.m4 (gl_FUNC_FCHDIR): Check for mingw bug.
> * lib/open.c (open) [FCHDIR_REPLACEMENT]: If directories can't be
> opened, then use a substitute.
> * lib/sys_stat.in.h (fstat) [REPLACE_OPEN_DIRECTORY]: Declare
> replacement.
> * lib/fchdir.c (fstat) [REPLACE_OPEN_DIRECTORY]: Implement it.
> (_gl_register_fd): No need to check stat if open already filters
> all directories.
> (fchdir): Fix error condition to match POSIX.
> * modules/fchdir (Depends-on): Add sys_stat.
> * doc/posix-functions/open.texi (open): Document the limitation.
> * modules/fchdir-tests: New file.
> * tests/test-fchdir.c: Likewise.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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