How reproducible: Can it be reproduced? Yes How often? Everytime
Steps to Reproduce: Please  provide step by step instruction on how to reproduce the issue.

1.  Touch a new wtmp file as root
    touch /tmp/wtmp

2.  Run /usr/bin/sessreg from xorg-x11-server-utils-7.5.13.el6 (which uses sessreg-1.0.6)

/usr/bin/sessreg -a -w /tmp/wtmp -l ":0.0,1" -h test72 rbeldin

3.  Run last -f /tmp/wtmp to see the entry

Observe that there is no entry put in the /tmp/wtmp file specified on the
command line.

Repeat the test with the sessreg from xorg-x11-server-utils-7.5-5.2.el6.x86_64.rpm (which uses sessreg-1.0.5

last -f /tmp/wtmp will now display a line similar to:


[root@playero-1 old-xorg]# last -f /tmp/wtmp
rbeldin  :0.0,1       test72           Tue Jun 25 16:43   still logged in

Summary of actions taken to resolve/troubleshoot issue:

- source comparison of sessreg appears to show changes in sessreg.h and
  sessreg.c
- changes are introduction of new macro defines that control UTMP and UTMPX
- built the earlier version of sessreg with new Makefile and no changes there
- .h and .c changes go hand in hand

The problem is a mix of the macro definition and the way the code is written.

 98 #ifdef USE_UTMPX
 99 #ifdef HAVE_UPDWTMPX
100 static char *wtmpx_file = NULL;   <<<<< 
101 #endif

Since wtmpx_file is NULL, and never initialized, we never write the
entry.

343     if (!wtmp_none) {
344 #ifdef USE_UTMPX
345 # ifdef HAVE_UPDWTMPX
346         if (wtmpx_file != NULL) {  <<<< wtmpx_file is NULL at this point
347             updwtmpx(wtmpx_file, &utmpx_entry);
348         }
349 # endif
350 #else
351         wtmp = open (wtmp_file, O_WRONLY|O_APPEND);
352         if (wtmp != -1) {
353             sysnerr (write (wtmp, (char *) &utmp_entry, sizeof (utmp_entry))
354                         == sizeof (utmp_entry), "write wtmp entry");
355             close (wtmp);
356         }
357 #endif
358     }


I think the ifdef USE_UTMPX is incorrect and to restore the older
behavior, you would need to remove that but there is some logic here that
escapes.  Obviously, USE_UTMPX and HAVE_UPDWTMPX are set and we drop into the
code, but that is wrong if we want to keep the previous behavior.