Bug 1006221

Description of problem:
The version of 'tail' that ships with RHEL6.4 appears to be mishandling dead symlinks. 

Version-Release number of selected component (if applicable):
coreutils-8.4-19.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
Please follow these precise steps in order to reproduce the errant behavior.  I've prefixed each command with T1 or T2, to indicate whether that command should be run in the first terminal (T1) or the second (T2).  The commands should be run in this precise order.

T1: touch logfile
T1: ln -s logfile logfile-link
T2: tail -F logfile-link
T1: echo "line 1" >> logfile
T2: observe "line 1" from tail
T1: rm logfile
T2: observe "tail: `logfile-link' has become inaccessible: No such file or directory"
T1: echo "line 2" >> logfile
T2: observe that tail is no longer tracking the contents of 'logfile'

Here is the terminal demonstration.

~~~~~~~~~~~~~~~~~~~~~
On Red Hat Enterprise Linux 5:
~~~~~~~~~~~~~~~~~~~~~

Terminal#1:

[root@dhcp223-183 ~]# mkdir /tmp/test
[root@dhcp223-183 ~]# cd /tmp/test
[root@dhcp223-183 test]# touch logfile
[root@dhcp223-183 test]# 
[root@dhcp223-183 test]# ln -s logfile logfile-link
[root@dhcp223-183 test]# echo "line 1" >> logfile
[root@dhcp223-183 test]# rm -rf logfile
[root@dhcp223-183 test]# echo "line 2" >> logfile

Terminal#2:

[root@dhcp223-183 ~]# cd /tmp/test/
[root@dhcp223-183 test]# tail -F logfile-link 
line 1
tail: `logfile-link' has become inaccessible: No such file or directory
line 2

It started appending the new lines.

~~~~~~~~~~~~~~~~~~~~~
Whereas on Red Hat Enterprise Linux 6:
~~~~~~~~~~~~~~~~~~~~~

Terminal#1:

[root@dhcp223-116 ~]# mkdir /tmp/test
[root@dhcp223-116 ~]# cd /tmp/test
[root@dhcp223-116 test]# touch logfile
[root@dhcp223-116 test]# ln -s logfile logfile-link
[root@dhcp223-116 test]# echo "line 1" >> logfile
[root@dhcp223-116 test]# rm logfile
rm: remove regular file `logfile'? y
[root@dhcp223-116 test]# echo "line 2" >> logfile
[root@dhcp223-116 test]# ls
logfile  logfile-link
[root@dhcp223-116 test]# echo "line 2" >> logfile
[root@dhcp223-116 test]# ll
total 4
-rw-r--r-- 1 root root 14 Sep  6 10:53 logfile
lrwxrwxrwx 1 root root  7 Sep  6 10:47 logfile-link -> logfile

Terminal#2:

[root@dhcp223-116 ~]# cd /tmp/test
[root@dhcp223-116 test]# tail -F logfile-link
line 1
tail: `logfile-link' has become inaccessible: No such file or directory


^C

Here the new incoming text was not appended in tail -F output on terminal 2.


Actual results:
Tail should notice when it's monitoring a dead symlink, and "wake up" when the symlink is no longer dead, and monitor the referent's content.

Expected results:
Its not monitoring it.

Additional info:
This works on Red Hat Enterprise Linux 5 as expected.