Package: coreutils;
Reported by: Gian Piero Carrubba <gpiero <at> rm-rf.it>
Date: Mon, 4 Nov 2013 23:38:02 UTC
Severity: wishlist
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From: Gian Piero Carrubba <gpiero <at> rm-rf.it> To: Jim Meyering <jim <at> meyering.net> Cc: 15806 <at> debbugs.gnu.org Subject: bug#15806: [cp] -R modifies dereferencing settings Date: Fri, 8 Nov 2013 17:45:40 +0100
* [Tue, Nov 05, 2013 at 12:37:06AM +0100] Gian Piero Carrubba:
>1. leave `cp -R` acting as it currently does...
>
>...but properly document it. The texinfo doc already cites this
>behaviour, but both the man page and the help (imo, the two most used
>sources while searching for an option) don't. I would suggest adding
>"Implies '--no-dereference'" to the description of the -r/-R option.
...except that it's not exactly true. If '-r' implied '-P', `cp -rL`
would dereference and `cp -Lr` would not. Actually they both
dereference, so a better wording is needed. Something along the line:
"By default, does not dereference symbolic links in the source".
>= tests/cp/special-f.sh [2]
>This is unexpected. At a first look, the failure should be caused by
>the following test not being fully inclusive:
>
> -- src/copy.c:1930
> else if (! S_ISDIR (dst_sb.st_mode)
> /* Never unlink dst_name when in move mode. */
> && ! x->move_mode
> && (x->unlink_dest_before_opening
> || (x->preserve_links && 1 < dst_sb.st_nlink)
> || (x->dereference == DEREF_NEVER
> && ! S_ISREG (src_sb.st_mode))
> ))
>
>I hadn't the time for investigate further, will do in the next days.
>At the moment, however, I suspect the previous dereference settings was
>simply masking and underlying issue.
Will diverge to another report, as imho it is a bug by itself.
>[2] A side note about this test. The comment seems to contradict the
>code:
>
> -- tests/cp/special-f.sh:28
> # Without -f, expect it to fail
> cp -R fifo e || fail=1
>
>As for my impression, it also contradicts POSIX specifications (w/o
>-f it should fail). Anyway this belongs to another bug report.
mmh, no... a better reading of the specs was enough to understand that
it should NOT fail, so the test is right (but the comment is
misleading).
* [Thu, Nov 07, 2013 at 09:27:41AM -0800] Jim Meyering:
>My first reaction is that it would take a strong argument to justify
>changing the existing semantics. Have you compared the semantics
>of any other cp implementations?
I have to admit I have no strong argument, and I suspect I cannot obtain
one just by comparing different implementations, given that this
behaviour is "implementation dependant" (so different implementations
differ in this regard).
Just for reference, both cp implementations on Solaris 10 dereference:
$ echo TEST > file ; ln -s file link
$ for o in "" -R -r -PR -Pr -RP -rP ; do /usr/bin/cp $o link cp$o ;
/usr/xpg4/bin/cp $o link cp-xpg4$o ; done
$ ls -liog
678491 -rw-r--r-- 1 5 Nov 8 16:55 cp
678499 lrwxrwxrwx 1 4 Nov 8 16:55 cp-Pr -> file
678497 lrwxrwxrwx 1 4 Nov 8 16:55 cp-PR -> file
678495 -rw-r--r-- 1 5 Nov 8 16:55 cp-r
678493 -rw-r--r-- 1 5 Nov 8 16:55 cp-R
678503 lrwxrwxrwx 1 4 Nov 8 16:55 cp-rP -> file
678501 lrwxrwxrwx 1 4 Nov 8 16:55 cp-RP -> file
678492 -rw-r--r-- 1 5 Nov 8 16:55 cp-xpg4
678500 lrwxrwxrwx 1 4 Nov 8 16:55 cp-xpg4-Pr -> file
678498 lrwxrwxrwx 1 4 Nov 8 16:55 cp-xpg4-PR -> file
678496 -rw-r--r-- 1 5 Nov 8 16:55 cp-xpg4-r
678494 -rw-r--r-- 1 5 Nov 8 16:55 cp-xpg4-R
678504 lrwxrwxrwx 1 4 Nov 8 16:55 cp-xpg4-rP -> file
678502 lrwxrwxrwx 1 4 Nov 8 16:55 cp-xpg4-RP -> file
678489 -rw-r--r-- 1 5 Nov 8 16:54 file
678490 lrwxrwxrwx 1 4 Nov 8 16:54 link -> file
The same is true for AIX 6.1:
$ for o in "" -R -r -P -PR -Pr -RP -rP ; do cp $o link cp$o ; done
$ ls -liog
32831 -rw-r--r-- 1 5 Nov 08 16:53 cp
32834 lrwxrwxrwx 1 4 Nov 08 16:53 cp-P
32835 lrwxrwxrwx 1 4 Nov 08 16:53 cp-PR
32836 lrwxrwxrwx 1 4 Nov 08 16:53 cp-Pr
32832 -rw-r--r-- 1 5 Nov 08 16:53 cp-R
32837 lrwxrwxrwx 1 4 Nov 08 16:53 cp-RP
32833 -rw-r--r-- 1 5 Nov 08 16:53 cp-r
32838 lrwxrwxrwx 1 4 Nov 08 16:53 cp-rP
32829 -rw-r--r-- 1 5 Nov 08 16:50 file
32830 lrwxrwxrwx 1 4 Nov 08 16:50 link
On the other hand, if I recall correctly, the FreeBSD implementation
acts like the coreutils one (doesn't dereference). Don't know about
other implementations.
Ciao,
Gian Piero.
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