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: Tue, 22 Jan 2019 09:07:00 -0000 [thread overview]
Message-ID: <20190122090725.GL2802@calimero.vinschen.de> (raw)
In-Reply-To: <20190122090240.GJ2802@calimero.vinschen.de>
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On Jan 22 10:02, Corinna Vinschen wrote:
> On Jan 22 09:50, Houder wrote:
> > On Sun, 6 Jan 2019 21:19:50, Corinna Vinschen wrote:
> > > > Also see:
> > > >
> > > > https://cygwin.com/ml/cygwin/2018-12/msg00028.html
> > > > ( Bash heredoc on FD 3 )
> > > >
> > > > Based on the output of strace on Linux, I composed an STC, that duplicates
> > > > the steps taken by bash (and cat).
> > >
> > > This should work in the latest developer snapshot uploaded to
> > > https://cygwin.com/snapshots/ Please give it a try.
> >
> > This solves: <program> -i /dev/fd/N N<<EOF (i.e. Steven Penny's problem)
> >
> > Howver ...
> > (and I sure that I am not telling you anything new)
> > [...]
> > 64-@@ rm aap.txt # hacker removing the logfile
> >
> > 64-@@ stat -L /proc/4120/fd/3
> > File: /proc/4120/fd/3
> > Size: 4 Blocks: 1 IO Block: 65536 regular file
> > Device: 33d91880h/869865600d Inode: 35747322042382612 Links: 0
> > Access: (0644/-rw-r--r--) Uid: ( 1000/ Henri) Gid: ( 513/ None)
> > Access: 2019-01-22 09:24:41.978178200 +0100
> > Modify: 2019-01-22 09:24:41.978178200 +0100
> > Change: 2019-01-22 09:26:25.021040800 +0100
> > Birth: 2019-01-22 09:24:41.978178200 +0100
> >
> > 64-@@ cp /proc/4120/fd/3 noot.txt # logfile rescue
> > 64-@@ cat noot.txt # empty! (however, this works on Linux)
> > 64-@@ cat /proc/4120/fd/3 # indeed, does not show contents
> > 64-@@
>
> Yes, this does not work under older systems. However, it works as
> desired at least with Windows 10 1709 due to changes in the OS in
> terms of handling of deleted files.
>
> I tested this with W8.1, W10 1709 and W10 1809. It fails on 8.1
... as expected ...
> but works fine on both W10 versions.
Corinna
--
Corinna Vinschen
Cygwin Maintainer
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prev parent reply other threads:[~2019-01-22 9:07 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
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 [this message]
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