[9fans] devfs.c and configuration files

[mirtchov@cpsc.ucalgary.ca]

I tried putting the devfs configuration on disk, but ran into major
problems reading it back from there.  The diff included fixes a few of
those:

	1.  The config file _must_ begin with "fsdev:\n".  This
	feature is undocumented and not really necessary -- for
	example it makes the man page example

		cp /dev/fs/ctl /dev/fd0disk

	not work at all.  I've left it in because I don't know why it
	was there in the first place.

	2.  A double free in rdconf()

	3.  The parser doesn't deal with empty lines -- it will flag
	an error, the error handling routine will sed 'configed = 1',
	so the next "bind -a '#k' /dev" will work, just not the first
	one.  We all know how important it is for other Plan 9
	utilities that configuration files and scripts end in a
	newline, so I've changed it to handle it properly.

andrey

------


plan9% yesterday -d /sys/src/9/port/devfs.c
diff /n/dump/2003/1016/sys/src/9/port/devfs.c /sys/src/9/port/devfs.c
270c270
< 		error("Bad config");
---
> 		error("Bad config: should begin with: fsdev\\n");
276a277,280
> 		if (e == p) {
> 			e++;
> 			continue;
> 		}
280d283
< 	free(s);
plan9%