Re: prop_dictionary_internalize_from_file help

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Wed, 16 Dec 2009 10:37:48 -0500
    From:        matthew sporleder <msporleder%gmail.com@localhost>
    Message-ID:  
<b0459d5c0912160737y3b3911d8u7c620b4acccbd873%mail.gmail.com@localhost>

  | Yeah, I added that to try and get a hint.  Without it I don't even see
  | the attempt to open my plist.in ktruss.

That's very odd, I cannot see how adding that perror() could have caused
anything inside the library to change - does ktruss show the open now?

If it doesn't try ktrace/kdump instead (I think someone once said that
ktruss sometimes has "issues""")

If the file really isn't being opened - not even being attempted to be opened
(does it's access time get touched when you run your program) then from how
I read the source, the only possible failure is from malloc() - you'll get
NULL back if malloc() fails (and "no such file or directory" is a likely
errno value in that case, as malloc() is looking for its magic symlink
to help it decide how it should work, and that usually doesn't exist).

Most error retrns are immediately preceded by a call to free(), I'm
not sure if free() check's malloc's magic symlink file too - but if it
does, that could explain why you always just see "no such file or directory"
as the errno response (you might want to try making the magic symlink,
just make it point to "", as in

        ln -s "" /etc/malloc.conf

so the file does exist, and checking for it won't pollute errno.

  | Is there a good example of a minimal plist?

That's a question for someone else.

  | The one I started using was just copied from my mac
  | and I've been dropping stuff from it but I always get NULL.

What I'd do, is copy the proplib sources from src/common/lib/libprop
into your source directory, and compile them (and your test program)
with -g, and single step through, find out exactly what is failing.

That will work, you can override regular libc functions that way without
problems.   Of course, if the problem is deep inside somehere, it may
take a lot of patience to step far enough through to actually find what
is happening - but you can at least easiy set a breakpoint on the file
open, and see if it is ever called, and if so, whether it succeeds.

kre