[PATCH v2] gdbserver: Check r_version < 1 for Linux debugger interface
H.J. Lu
hjl.tools@gmail.com
Tue Aug 17 14:04:25 GMT 2021
On Tue, Aug 17, 2021 at 6:48 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu via Gdb-patches:
>
> > Set r_version == 2 breaks GDB due to
> >
> > static CORE_ADDR
> > solib_svr4_r_ldsomap (struct svr4_info *info)
> > {
> > struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
> > struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
> > enum bfd_endian byte_order = type_byte_order (ptr_type);
> > ULONGEST version = 0;
> >
> > try
> > {
> > /* Check version, and return zero if `struct r_debug' doesn't have
> > the r_ldsomap member. */
> > version
> > = read_memory_unsigned_integer (info->debug_base +
> > lmo->r_version_offset,
> > lmo->r_version_size, byte_order);
> > }
> > catch (const gdb_exception_error &ex)
> > {
> > exception_print (gdb_stderr, ex);
> > }
> >
> > if (version < 2 || lmo->r_ldsomap_offset == -1)
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > glibc doesn't have r_ldsomap. But r_ldsomap_offset is set
> > unconditionally. Shouldn't it be set only if the target debugger
> > interface has it?
>
> glibc should add r_ldsomap_offset and switch its own version number to
> 3, I think.
We can add an OS flavor field to struct link_map_offsets for this.
--
H.J.
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