[PATCH 02/13] elf: switch _dl_map_segment() to anonymous mapping

[stsp]

30.03.2023 00:17, Adhemerval Zanella Netto пишет:
> On 29/03/23 15:46, stsp wrote:
>
>> Would MAP_COPY be a good choice for
>> explicitly anonymous mapping? If so -
>> can change.
> It avoid code duplication.

Queued for v10.

>>
>> Ah, that seems to be a "hole" are
>> between segments. I actually think
>> my handling is much better. Without
>> my patch, such holes are filled with
>> actually the _random_ page from the
>> original file mapping. Just whatever
>> page happened to have that offset.
>> Do you think the random page from
>> the file is a good idea for tooling/debugging?
> It seems to be a gdb limitation that is showing some wrong information.  But again,
> I really don't see *why* this change is needed: the current algorithms already
> maps the ELF segments correctly and have random data on the hole does not really
> matter (it would be mapped as PROT_NONE).
Its only for dlmem().
In dlmem() you need to do anonymous
mmap at the relocation address, and
after that we shouldn't skip the first
segment.
I can remove this patch if you insist, but
the cost will likely be quite high, as I'll
need then to propagate some flag up to
_dl_map_segments() to tell if we can
skip the first segment or not, and if
we should call _dl_map_segment() or
a premap callback.