cp: fix --link regarding the dereferencing of symbolic links

* src/copy.c (create_hard_link): Add a bool 'dereference' parameter,
and pass AT_SYMLINK_FOLLOW as 'flags' to linkat() when dereference
is true.
(should_dereference): Add new 'bool' function to determine if a
file should be dereferenced or not.
(copy_internal): Use the above new should_dereference() and remember
its return value in a new local bool 'dereference' variable.  Use that
in all three calls to create_hard_link().
* src/cp.c (main): after parsing the options, if x.dereference is
still DEFEF_UNDEFINED and the x.recursive is true, then only set
x.dereference to DEREF_NEVER iff --link was not specified.
* doc/coreutils.texi (cp invocation): Mention that cp(1) does not
follow symbolic links in the source when --link is specified.
Likewise in the description of the -R option when used together with
that option.
* tests/cp/same-file.sh: Adapt the expected results for the -fl,
the -bl and the -bfl tests.
* tests/cp/link-deref.sh: Add a new test.
* tests/local.mk (all_tests): Reference the above new test.
* NEWS (Changes in behavior): Mention the change.

This fixes http://bugs.gnu.org/15173

Co-authored-by: Bernhard Voelker <mail@bernhard-voelker.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/cp.c b/src/cp.c
index 7bc8630fb..78c0a0402 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -1135,7 +1135,7 @@ main (int argc, char **argv)
 
   if (x.dereference == DEREF_UNDEFINED)
     {
-      if (x.recursive)
+      if (x.recursive && ! x.hard_link)
         /* This is compatible with FreeBSD.  */
         x.dereference = DEREF_NEVER;
       else