[ILUG] Configure

[Justin Mason]

"John P. Looney" said:

>  Here's an excerpt from a part of the script, similar to what I want to
> add. Can someone give a line by line explaination (I've tryed, and I'm not
> confident I'm right)..

OK -- I'll comment yr comments ;)

C
heck the autoconf documentation at gnu.org as well.
> # Seems to check for a --with-authpam arg.
> AC_ARG_WITH(authpam,
> [ --without-authpam                  Do not include the authpam module ],
>     doauthpam="$withval")

I think so.

> else # IF we have a --with-authpam, check for these headers (how?):
>     AC_CHECK_HEADERS(security/pam_appl.h Pam/pam_appl.h)

Configure builds a .c file to see if they exist.

>     saveLIBS="$LIBS"
>     LIBDL=""   # Does this check libdl for dlopen() ?

nope, it sets a value that'll be be substituted into the makefile by line
(a).

>     AC_CHECK_LIB(dl, dlopen, [ LIBDL="-ldl" ])
>     LIBS="$saveLIBS"
>     # Check libpam for pam_start()
>     AC_CHECK_LIB(pam, pam_start,
>         HAVE_PAM=1
>         LIBS="-lpam $LIBDL $LIBS"

>     # Why check again ?
>         AC_CHECK_FUNCS(pam_setcred),
>         HAVE_PAM=0,
>         $LIBDL)

To ensure that the libpam you're using is the right kind of libpam, and
not just the library which supplies pam_proper_alimentary_mechanisms
instead of authentication mechanisms or whatever.

>     LIBS="$saveLIBS"
> fi
> AC_SUBST(LIBDL) # Is this adding those flags to the LIBS line or something ?

Yes -- it means if LIBDL is mentioned in the Makefile.in or config.h.in
files it'll be substituted in with the value set above. This is line (a).

> AC_SUBST(HAVE_PAM)

Ditto. This one would be for config.h.in.

> AM_CONDITIONAL(HAVE_PAM, test "$HAVE_PAM" = 1)   # What these mean ?

dunno, that's a new one since I wrote an autoconf script...

> AUTHPAM=""
> if test "$HAVE_PAM" = 1
> then # I get lost here...
>     AUTHPAM=authpam
>     STATIC_LIST="$STATIC_LIST AUTHSTATIC(\"authpam\", auth_pam,
> auth_pam_pre)"
>     LIBAUTH="$LIBAUTH libauth-authpam.a"
> fi

Sorry mate, I'm lost on this one. :(

> AC_ARG_WITH(authpam-libraries,
> [ --with-authpam-libraries="libs"    Link 'libs' with authpam, this may be
>                                     required for FreeBSD 3.3],
>     authpamcrypt="$withval")
> 
> AUTHPAMCRYPT="$authpamcrypt"
> AC_SUBST(AUTHPAMCRYPT)

--j.