According to the D(x) macro defined in pam_macros.h (source code) and used as follows:
D(("Hello PAM World"));
Where is this log located on CentOS7?
Note that I am using as flag debug in my pam.d conf file.
I tried also the following command:
grep -rnw '/var/log/' -e "Hello Pam World"
But with no success.
In the file you link, there are these lines at the top:
/*
* This is for debugging purposes ONLY. DO NOT use on live systems !!!
* You have been warned :-) - CG
*
* to get automated debugging to the log file, it must be created manually.
* _PAM_LOGFILE must exist, mode 666
*/
#ifndef _PAM_LOGFILE
#define _PAM_LOGFILE "/tmp/pam-debug.log"
#endif
So it looks like the output will be directed to /tmp/pam-debug.log, but you have to create it before, and give it full read-write permissions:
$ touch /tmp/pam-debug.log
$ chmod 666 /tmp/pam-debug.log
Looking to the Linux version of this file, it looks like it is written to /var/run/pam-debug.log, but only if it is compiled with PAM_DEBUG.
There a nice comment in configure.ac:
if test x"$enable_debug" = x"yes" ; then
AC_DEFINE([PAM_DEBUG],,
[lots of stuff gets written to /var/run/pam-debug.log])