Steps to Reproduce:
1. cd /tmp
2. mkdir sandboxpids.tmp
3. emerge something
4. watch very confusing error message
(steps 1, 2 and 4 done as any user, need to be root for step 3)
Calculating dependencies ...done!
>>> emerge (1 of 1) some-cat/something to /
>>> md5 src_uri ;-) something.tar.gz
>>> /tmp/sandboxpids.tmp is not a regular file>>> pids file write: Bad address
to bring down emerge should not be made that easy
!!! Emerge seems to test if sandboxpids.tmp is a regular file only. If it is
!!! hard link to existing file, existing file is empty when emerge is done.
!!! Very dangerous.
This is pretty major -- a newsgroup poster just pointed this one out. Any Gentoo system can trivially be damaged extremely badly with this one, as far as I can tell.
*** This bug has been marked as a duplicate of 21923 ***