I was building Pulseaudio on Solaris 8, and I found a problem with module loading. When the module is loaded, the argument field of the module struct is set to a NULL pointer (instead of a null string). While on Linux, this would not generate a problem, it does on Solaris when the module list is printed.
An example:
On Linux, running the list-modules command from the Pulseaudio command line:
...
index: 10
name: <module-x11-publish>
argument: <(null)>
used: -1
auto unload: no
...
On Solaris 8, it segfaults (on a strlen function inside vsnprintf)
Note the '(null)' as the value of the argument field. I traced the actual call to generate this text:
from pulsecore/cli-text.c, line 57 (only relevant portion listed)
pa_strbuf_printf(s, " ...argument: <%s>\n...", ..., m->argument,...);
The problem is when any one of the C strings in the argument list to the pa_strbuf_printf call is a NULL pointer.
The Solaris man pages for printf list the behavior as "undefined" when a NULL pointer is passed as a string argument. It looks like the behavior persists in OpenSolaris (on purpose).
See See http://developers.sun.com/solaris/articles/portingUNIXapps.html for more info on Solaris' take on dealing with NULL pointers.
I think there are a few options for fixing this:
1. Fix the pa_strbuf_printf function to go through the format string, and for every %s, check and correct any NULL pointer. I'm not sure how to do this one.
2. Fix each call to pa_strbuf_printf. This is not difficult, but would be tedious, as there are quite a few of these calls (example in cli-text.patch)
3. Change pa_xstrdup to return an empty string if it's given a NULL pointer. While not an exact duplication of a NULL pointer, it would be much cleaner, and more portable (example in xmalloc.patch)
I would recommend option 3, as it permanently adjusts the NULL strings before they propogate anywhere. There would be no need to correct any calls to pa_strbuf_printf, provided that ONLY strings created from pa_xstrdup were used.
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