[debbugs-tracker] bug#31364: closed (cp -rfs: Fails to overwrite a symlink when it is on a different device)

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Your message dated Tue, 15 May 2018 10:01:20 -0700
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and subject line Re: bug#31364: cp -rfs: Fails to overwrite a symlink when it 
is on a different device
has caused the debbugs.gnu.org bug report #31364,
regarding cp -rfs: Fails to overwrite a symlink when it is on a different device
to be marked as done.

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31364: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=31364
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--- Begin Message --- Subject: cp -rfs: Fails to overwrite a symlink when it is on a different device Date: Fri, 04 May 2018 23:37:55 +0000

Hello,

I have found a bug in "cp -rfs".

Steps to reproduce:

1. Given "path1" and "path2" are on different devices.

2. $ touch "path1/file"

3. $ cd path2/; ln -s path1/file

4. $ cp --symbolic-link --force --recursive path1/file .

Expected:

The link is overwritten with an exact copy.

Actual result:

cp shows an error:

    cp: 'path1/file' and './file' are the same file 

This bug was introduced in

http://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=376967889ed7ed561e46ff6d88a66779db62737a

Specifically this hunk:

diff --git a/src/copy.c b/src/copy.c
index e3832c2..9dbd536 100644
--- a/src/copy.c
+++ b/src/copy.c

@@ -46,6 +46,7 @@

#include "file-set.h"

#include "filemode.h"

#include "filenamecat.h"

+#include "force-link.h"

#include "full-write.h"

#include "hash.h"

#include "hash-triple.h"

@@ -1623,11 +1624,13 @@ same_file_ok (char const *src_name, struct stat const *src_sb,

}

}

- /* It's ok to remove a destination symlink. But that works only when we

- unlink before opening the destination and when the source and destination

- files are on the same partition. */

- if (x->unlink_dest_before_opening

- && S_ISLNK (dst_sb_link->st_mode))

+ /* It's ok to remove a destination symlink. But that works only

+ when creating symbolic links, or when the source and destination

+ are on the same file system and when creating hard links or when

+ unlinking before opening the destination. */

+ if (x->symbolic_link

+ || ((x->hard_link || x->unlink_dest_before_opening)

+ && S_ISLNK (dst_sb_link->st_mode)))

return dst_sb_link->st_dev == src_sb_link->st_dev;

if (x->dereference == DEREF_NEVER)

Two patches that fix the issue are attached.

They are against the current master in https://github.com/coreutils/coreutils

The changes are also here:

https://github.com/coreutils/coreutils/compare/master...ilya-bobyr:master

Thank you, Illia Bobyr

0002-cp-Overwrite-symlinks-on-another-device.patch
Description: Text Data

0001-cp-No-dup-check-for-unlink_dest_after_failed_open.patch
Description: Text Data

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#31364: cp -rfs: Fails to overwrite a symlink when it is on a different device
>
>
>
>
> Date: 
>
> Tue, 15 May 2018 10:01:20 -0700
>
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> User-agent: 
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> Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0
>
>
>
>
> Pushed at 
> https://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=v8.29-36-gd3daa95
>
> marking this as done
>
> cheers,
> Pádraig.
>
>
>
> --- End Message ---