PURPOSE of /CoreOS/coreutils/readlink-cannot-handle-recursive-symlinks

Description: Test for readlink cannot handle recursive symlinks

Author: Jan Scotka <jscotka@redhat.com>

Bug summary: readlink cannot handle recursive symlinks

Description:

Description of problem:

The readlink command fails with an error "Too many levels of symbolic links", even if there are only 2 levels.

The readlink command from RHEL 3 and RHEL 4 and from Fedora 11 all work fine.

Among other changes between RHEL 4 and RHEL 5, RHEL 5's coreutils added calls to cycle_check() in lib/canonicalize.c, but in upstream canonicalize.c (now in gnulib instead of coreutils), we see the comment:

          /* Detect loops.  We cannot use the cycle-check module here,

             since it's actually possible to encounter the same symlink

             more than once in a given traversal.  However, encountering

             the same symlink,NAME pair twice does indicate a loop.  */

http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/canonicalize.c;h=4f348398fd69ae516396313d18ac294a4ca3dde3;hb=b653eda3ac4864de205419d9f41eec267cb89eeb#l262

The latest canonicalize.c uses seen_triple() instead of cycle_check().

Version-Release number of selected component (if applicable):

coreutils-5.97-19.el5

How reproducible:

every time

Steps to Reproduce:

1. Create a directory with a symlink to itself

       mkdir /tmp/dir

       cd /tmp/dir

       ln -s ../dir dirlink

2. Run readlink using the 'dirlink' symlink recursively

       readlink -v -f dirlink

       readlink -v -f dirlink/dirlink

       readlink -v -f dirlink/dirlink/dirlink

Actual results:

The first readlink command on just dirlink succeeds, but the 2nd and 3rd commands fail with 

   readlink: dirlink/dirlink: Too many levels of symbolic links

Expected results:

$ readlink -v -f dirlink

/tmp/dir

$ readlink -v -f dirlink/dirlink

/tmp/dir

$ readlink -v -f dirlink/dirlink/dirlink

/tmp/dir

Additional info: