[Crash-utility] 2.6.20 data structure changes

[Dave Anderson]

Just as a head's up, all of a sudden there are changes to
some crucial data structures in 2.6.20 that break several
commands, such as "vm", "files", "swap", "net -s", and probably
more...

I've fixed the "vm" and "swap" commands by recognizing
that the file structure's former "f_dentry" and "f_vfsmnt"
fields are now contained within the embedded "path"
structure.  That was simple enough...

One of the other changes is the removal of the "max_fdset"
field from the "fdtable" structure.  I'm not entirely clear how
best to handle it -- it almost seems that that if it doesn't exist,
the "max_fds" value can be used alone in all cases where
it used to be used in conjunction with "max_fdset"?  Any
filesystem-ophile out there that that can offer up a suggestion
would be appreciated...

I'll also fix the i386 "xgs" register addition to its pt_regs
structure.   Unfortunately the pt_regs register offsets have
been hardwired in crash since the beginning of time (i.e.,
long before gdb was embedded in crash) and it's screwing
up exception frame output...

Dave