From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: /dev/fd/N not synonymous with file descriptor N; it is on Linux
Date: Sun, 16 Dec 2018 21:55:00 -0000 [thread overview]
Message-ID: <20181216215549.GO28727@calimero.vinschen.de> (raw)
In-Reply-To: <CAHSx_SvqFgi5stKvYSNCPwyyu98miPHyYcDKJL1-=KP8NE9+JQ@mail.gmail.com>
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On Dec 16 13:36, Wayne Davison wrote:
> On Sun, Dec 16, 2018 at 12:29 PM Corinna Vinschen wrote:
> > In contrast to Linux the symlinks are not just faked symlinks with the underlying OS having direct access to the file descriptors.
>
> Yeah, Linux is more like a fuse where the open filehandles are used
> directly on open, and the stat calls return pretend symlinks with the
> lsof info.
>
> > The way it's implemented in Cygwin uses the actual file path resolution and then either works or fails as above.
>
> If Cygwin can't be changed into a fuse idiom, perhaps a hard-link
> idiom could be used? For instance, when the /proc/$PID/fd/0 symlink is
> being created, the code could try to hard-link the file to
> /proc/$PID/.fd/0 first
Nice try, but hardlinks don't cross FS borders. /proc is a filesystem
on its own with its own inode numbers.
I'm mulling over adding some hack to open(). It could try to recognize
the special case of opening a processes' own descriptor symlink within
/proc and then warp the open() call into dup(). No idea how tricky
or even feasible that is, though...
Corinna
--
Corinna Vinschen
Cygwin Maintainer
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next prev parent reply other threads:[~2018-12-16 21:55 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-16 16:31 Houder
2018-12-16 20:28 ` Corinna Vinschen
2018-12-16 20:31 ` Corinna Vinschen
2018-12-16 21:36 ` Wayne Davison
2018-12-16 21:55 ` Corinna Vinschen [this message]
2018-12-17 4:30 ` Houder
2018-12-17 9:25 ` Corinna Vinschen
2018-12-17 11:26 ` Corinna Vinschen
2019-01-02 13:56 ` Houder
2018-12-17 3:41 ` Houder
2019-01-06 20:19 ` Corinna Vinschen
2019-01-22 8:50 ` Houder
2019-01-22 8:57 ` Houder
2019-01-22 9:06 ` Corinna Vinschen
2019-01-22 9:25 ` Houder
2019-01-22 9:42 ` Corinna Vinschen
2019-01-22 10:20 ` Houder
2019-01-22 10:39 ` Corinna Vinschen
2019-01-27 18:39 ` Houder
2019-01-27 21:57 ` Corinna Vinschen
2019-01-27 22:12 ` Corinna Vinschen
2019-01-28 14:15 ` Houder
2019-01-28 16:51 ` Corinna Vinschen
2019-01-22 9:02 ` Corinna Vinschen
2019-01-22 9:07 ` Corinna Vinschen
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