[RFC PATCH] Support debuginfo and source file fetching via debuginfo server

[Christian Biesinger via gdb-patches]

On Tue, Aug 20, 2019 at 4:28 PM Aaron Merey <amerey@redhat.com> wrote:
> Debuginfo server is a lightweight web service that indexes debuginfo
> and source files by build-id and serves them over HTTP. Debuginfo server
> is able to index unpackaged, locally-built software in addition to RPM
> files. Debuginfo server is packaged with a shared library, libdbgserver,
> that provides a small set of client functions for fetching files from
> debuginfo server. This patch adds debuginfo server support to GDB. In
> case a source file or separate debuginfo file cannot be found locally,
> GDB can use libdbgserver to query debuginfo server for the file in
> question, if enabled to do so.
>
[...]
> @@ -1296,6 +1299,30 @@ elf_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
>           symbol_file_add_separate (debug_bfd.get (), debugfile.c_str (),
>                                     symfile_flags, objfile);
>         }
> +#if HAVE_LIBDBGSERVER
> +      else
> +        {
> +          const struct bfd_build_id *build_id;
> +          char *debugfile_path;
> +
> +          build_id = build_id_bfd_get (objfile->obfd);
> +          int fd = dbgserver_find_debuginfo (build_id->data,
> +                                             build_id->size,
> +                                             &debugfile_path);
> +
> +          if (fd >= 0)
> +            {
> +              /* debuginfo successfully retrieved from server, reopen
> +                 the file as a bfd instead.  */
> +              gdb_bfd_ref_ptr debug_bfd (symfile_bfd_open (debugfile_path));
> +
> +              symbol_file_add_separate(debug_bfd.get (), debugfile_path,
> +                                       symfile_flags, objfile);
> +              close(fd);
> +              free(debugfile_path);
> +            }
> +        }
> +#endif /* LIBDBGSERVER */
>      }
>  }
>

You wrote that the debuginfo server will download symbols over HTTP.
Does that mean that this call to dbgserver_find_debuginfo will block
as it downloads the file? (will ctrl+c work as it does that?)

If so, any way to do this download on a background thread?

Christian