Re: 'Undeleting' an open file

From: Ian Campbell (ijc_at_hellion.org.uk)
Date: 10/07/05

  • Next message: Al Viro: "Re: [PATCH] don't invalidate non-directory mountpoints" 
    To: Giuseppe Bilotta <bilotta78@hotpop.com>
Date:	Fri, 07 Oct 2005 15:30:00 +0100

    On Fri, 2005-10-07 at 16:14 +0200, Giuseppe Bilotta wrote:
    > On Wed, 5 Oct 2005 23:05:34 +0200 (CEST), Bodo Eggert wrote:
    >
    > > Files are deleted if the last reference is gone. If you play a music file
    > > and unlink it while it's playing, it won't be deleted untill the player
    > > closes the file, since an open filehandle is a reference.
    >
    > BTW, I've always wondered: is there a way to un-unlink such a file?

    Access via /proc/PID/fd/* seems to work:

    $ echo "Hello World" > testing
    $ exec 10>>testing
    $ rm testing
    $ ls -l /proc/self/fd/
    total 5
    lrwx------ 1 icampbell icampbell 64 Oct 7 15:28 0 -> /dev/pts/9
    lrwx------ 1 icampbell icampbell 64 Oct 7 15:28 1 -> /dev/pts/9
    l-wx------ 1 icampbell icampbell 64 Oct 7 15:28 10
    -> /home/icampbell/testing (deleted)
    lrwx------ 1 icampbell icampbell 64 Oct 7 15:28 2 -> /dev/pts/9
    lr-x------ 1 icampbell icampbell 64 Oct 7 15:28 3 -> /proc/31390/fd/
    $ cat /proc/self/fd/10
    Hello World
    $

    Ian. 

    -- 
Ian Campbell
Current Noise: Rotting Christ - In Domine Sathana
I may not be totally perfect, but parts of me are excellent.
		-- Ashleigh Brilliant
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