In standards such as LoPAPR, property names in excess of the usual 31
characters exist.
This breaks property traversal.
While in IEEE 1275-1994, nextprop is defined explicitly to work with a
32-byte region of memory, using a larger buffer should be fine. There is
actually no way to pass a buffer length to the nextprop call in the OF
client interface, so SLOF actually just blindly overflows the buffer.
So we have to defensively make the buffer larger, to avoid memory
corruption when reading out long properties on live OF systems.
Note also that on real-mode OF, things are pretty tight because we are
allocating against a static bounce buffer in low memory, so we can't just
use a huge buffer to work around this without it being wasteful of our
limited amount of 32-bit physical memory.
This allows a patched ofwdump to operate properly on SLOF (i.e. pseries)
systems, as well as any other PowerPC systems with overlength properties.
Reviewed by: jhibbits
MFC after: 2 weeks
Sponsored by: Tag1 Consulting, Inc.
Differential Revision: https://reviews.freebsd.org/D26669
- Make the code use the new OFIOCMAXVALUE instead of defining the maximum
length of property values locally.
- Move the application specific parts from ofw_util.c to ofwdump.c in
order to make ofw_util.c more library-like. While ofw_dump_properties()
could be made non-specific to ofwdump(8) it's currently optimized for
use in ofwdump(8) and making it a library-like function would just
complicate the code unnecessarily.
- Minor clean-up in ofw_util.c, e.g. make its use of getopt(3) the way
it's described in style(9), make its usage() static, etc.
- Add a comment in ofw_util.c about why it doesn't call usage() when
neither the "-a" option nor a node-name where given.
- Add ofw_optnode() and ofw_setprop(), helper functions for the
OFIOCGETOPTNODE and OFIOCSET ioctls respectively, to ofw_util.[c,h].
- Be consistent with the use of 'const' in ofw_util.[c,h] and add 'const'
to the function arguments that are acutally const but weren't declared
as such.
- Mark WARNS=6 clean.
Approved by: tmm
