ls --color: Don't stat symlinks when neither ORPHAN nor MISSING attribute has a color.

* src/ls.c (main): Don't set check_symlink_color when C_EXEC is
colored, unless ln=target (aka color_symlink_as_referent) is set.
(gobble_file): Set f->linkok = true also when !check_symlink_color.
http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/10608/focus=10927
Reported by Jeremy Maitin-Shepard.
* tests/strace: New file, contents extracted from...
* tests/mv/atomic: ...here.  Source strace.
* tests/ls/stat-free-symlinks: New file.  Test for the above.
Use strace to ensure that in this corner case, ls does not call stat.
* tests/ls/Makefile.am (TESTS): Add stat-free-symlinks.
* tests/Makefile.am (EXTRA_DIST): Add strace.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/ls.c b/src/ls.c
index 751dc3d1d..204341cd4 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -1168,7 +1168,7 @@ main (int argc, char **argv)
     {
       /* Avoid following symbolic links when possible.  */
       if (is_colored (C_ORPHAN)
-	  || is_colored (C_EXEC)
+	  || (is_colored (C_EXEC) && color_symlink_as_referent)
 	  || (is_colored (C_MISSING) && format == long_format))
 	check_symlink_color = true;
 
@@ -2713,6 +2713,12 @@ gobble_file (char const *name, enum filetype type, ino_t inode,
 	  free (linkname);
 	}
 
+      /* When not distinguishing types of symlinks, pretend we know that
+	 it is stat'able, so that it will be colored as a regular symlink,
+	 and not as an orphan.  */
+      if (S_ISLNK (f->stat.st_mode) && !check_symlink_color)
+	f->linkok = true;
+
       if (S_ISLNK (f->stat.st_mode))
 	f->filetype = symbolic_link;
       else if (S_ISDIR (f->stat.st_mode))