readelf: simplify Xen string note printing

[tig_freebsdfoundation.org]

contrib/elftoolchain/readelf/readelf.c

3710

I noticed that this type==0 case didn't exist before. Is this needed? If not, I think you can get rid of the function pointer field in struct note_desc.

[markj]

contrib/elftoolchain/readelf/readelf.c

3685

Why don't we dump data in this case anymore?

3710

It's needed to ensure that loop iteration over xen_notes[] terminates. One common trick which eliminates the need for the nul terminator is to iterate using this pattern:

for (i = 0; i < sizeof(xen_notes) / sizeof(xen_notes[0]) /* sometimes written "nitems(xen_notes)" */; i++)

but existing practice in this code seems to be what Ed is doing, so I think it is ok.

I don't have a strong feeling about the function pointer. Indeed, it can be dropped, but if in the future a note is added that requires a custom print function, it'll need to be re-added.

[emaste]

contrib/elftoolchain/readelf/readelf.c

3685

returning false now falls through to the unknown: case in dump_notes_data and prints it as hex

3710

Yeah, my goal is to extend this to add custom print functions, and move all note printing to be done via tables like this.

[markj]

contrib/elftoolchain/readelf/readelf.c

3685

Oh, I mixed up the handling of nd->fp's return value.