rtld parse_integer(): support octal and hex C notations

[des]

libexec/rtld-elf/rtld.c

6549

You might want to add a clause for binary (str[1] == 'b')

6571–6572

This can be greatly simplified if you just convert c to val first and then check that val < radix.

6573–6578

(you'll need <stdckdint.h>)

[kib]

libexec/rtld-elf/rtld.c

6571–6572

I did it for radixes <= 10, but it seems that for 16 it is simper, if not required, to keep existing structure.

6573–6578

Yes, it was discussed in D56151/7cfffe25da3fbc2db4bc, where the solution not utilizing non-freestanding features was proposed by dim. I prefer the current way due to that.

[kib]

Supoort binary numbers specification.
Restructure the valid character check and the digit value calculation.

[kib]

Add some tests

[des]

libexec/rtld-elf/rtld.c

6571–6572

Just do the conversion as if radix == 16 first, then check radix just once.

6573–6578

<stdckdint.h> is implemented using compiler builtins and the resulting code is much simpler to reason about.

[kib]

libexec/rtld-elf/rtld.c

6573–6578

This is an implementation detail, I want rtld do be as much self-contained as possible. The used pattern to avoid overflow is well known.

[kib]

Adjust the val calculation.

[dim]

LGTM.