From: Wayne Davison <wayne@opencoder.net>
To: cygwin <cygwin@cygwin.com>
Subject: Re: /dev/fd/N not synonymous with file descriptor N; it is on Linux
Date: Sun, 16 Dec 2018 21:36:00 -0000 [thread overview]
Message-ID: <CAHSx_SvqFgi5stKvYSNCPwyyu98miPHyYcDKJL1-=KP8NE9+JQ@mail.gmail.com> (raw)
In-Reply-To: <20181216202847.GK28727@calimero.vinschen.de>
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 (note the dot-fd) before creating the normal
fd/0 symlink. Then, when a request came in to read /proc/$PID/fd/0, it
could check if the associated hard-link exists and read from that
instead. Or perhaps the "symlink" info could be stored elsewhere and
the fd/0 file could be the hard-link, requiring the stat code to be
tweaked to look up the pretend-symlink info?
..wayne..
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next prev parent reply other threads:[~2018-12-16 21:36 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 [this message]
2018-12-16 21:55 ` Corinna Vinschen
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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