Re: [PATCH 2/7 v3] gdb/debuginfod: Add debuginfod_section_query

[Andrew Burgess <aburgess@redhat.com>]

Aaron Merey <amerey@redhat.com> writes:

> v2: https://sourceware.org/pipermail/gdb-patches/2023-June/199985.html
>
> v3 has config/debuginfod.m4 changes moved into a separate patch.
>
> Commit message:
>
> Add new function debuginfod_section_query.  This function queries
> debuginfod servers for an individual ELF/DWARF section associated with
> a given build-id.
> ---
>  gdb/debuginfod-support.c | 60 ++++++++++++++++++++++++++++++++++++++++
>  gdb/debuginfod-support.h | 24 ++++++++++++++++
>  2 files changed, 84 insertions(+)
>
> diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
> index a41a4c95785..33bb9d9b7bc 100644
> --- a/gdb/debuginfod-support.c
> +++ b/gdb/debuginfod-support.c
> @@ -80,6 +80,15 @@ debuginfod_exec_query (const unsigned char *build_id,
>    return scoped_fd (-ENOSYS);
>  }
>  
> +scoped_fd
> +debuginfod_section_query (const unsigned char *build_id,
> +			  int build_id_len,
> +			  const char *filename,
> +			  const char *section_name,
> +			  gdb::unique_xmalloc_ptr<char> *destname)
> +{
> +  return scoped_fd (-ENOSYS);
> +}
>  #define NO_IMPL _("Support for debuginfod is not compiled into GDB.")
>  
>  #else
> @@ -412,6 +421,57 @@ debuginfod_exec_query (const unsigned char *build_id,
>  
>    return fd;
>  }
> +
> +/* See debuginfod-support.h  */
> +
> +scoped_fd
> +debuginfod_section_query (const unsigned char *build_id,
> +			  int build_id_len,
> +			  const char *filename,
> +			  const char *section_name,
> +			  gdb::unique_xmalloc_ptr<char> *destname)
> +{
> +#if !defined (HAVE_LIBDEBUGINFOD_FIND_SECTION)
> +  return scoped_fd (-ENOSYS);
> +#else
> +
> + if (!debuginfod_is_enabled ())

This line is under-indented by one space :)

Otherwise:

Approved-By: Andrew Burgess <aburgess@redhat.com>

Thanks,
Andrew


> +    return scoped_fd (-ENOSYS);
> +
> +  debuginfod_client *c = get_debuginfod_client ();
> +
> +  if (c == nullptr)
> +    return scoped_fd (-ENOMEM);
> +
> +  char *dname = nullptr;
> +  std::string desc = std::string ("section ") + section_name + " for";
> +  scoped_fd fd;
> +  gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
> +
> +  {
> +    user_data data (desc.c_str (), filename);
> +    debuginfod_set_user_data (c, &data);
> +    if (target_supports_terminal_ours ())
> +      {
> +	term_state.emplace ();
> +	target_terminal::ours ();
> +      }
> +
> +    fd = scoped_fd (debuginfod_find_section (c, build_id, build_id_len,
> +					     section_name, &dname));
> +    debuginfod_set_user_data (c, nullptr);
> +  }
> +
> +  print_outcome (fd.get (), desc.c_str (), filename);
> +  gdb_assert (destname != nullptr);
> +
> +  if (fd.get () >= 0)
> +    destname->reset (dname);
> +
> +  return fd;
> +#endif /* HAVE_LIBDEBUGINFOD_FIND_SECTION */
> +}
> +
>  #endif
>  
>  /* Set callback for "set debuginfod enabled".  */
> diff --git a/gdb/debuginfod-support.h b/gdb/debuginfod-support.h
> index 633600a79da..9701e3b4685 100644
> --- a/gdb/debuginfod-support.h
> +++ b/gdb/debuginfod-support.h
> @@ -81,4 +81,28 @@ extern scoped_fd debuginfod_exec_query (const unsigned char *build_id,
>  					const char *filename,
>  					gdb::unique_xmalloc_ptr<char>
>  					  *destname);
> +
> +/* Query debuginfod servers for the binary contents of a ELF/DWARF section
> +   from a file matching BUILD_ID.  BUILD_ID can be given as a binary blob
> +   or a null-terminated string.  If given as a binary blob, BUILD_ID_LEN
> +   should be the number of bytes.  If given as a null-terminated string,
> +   BUILD_ID_LEN should be 0.
> +
> +   FILENAME should be the name or path associated with the file matching
> +   BUILD_ID.  It is used for printing messages to the user.
> +
> +   SECTION_NAME should be the name of an ELF/DWARF section.
> +
> +   If the file is successfully retrieved, return a file descriptor and store
> +   the file's local path in DESTNAME.  If unsuccessful, print an error message
> +   and return a negative errno.  If GDB is not built with debuginfod or
> +   libdebuginfod does not support section queries, this function returns
> +   -ENOSYS.  */
> +
> +extern scoped_fd debuginfod_section_query (const unsigned char *build_id,
> +					   int build_id_len,
> +					   const char *filename,
> +					   const char *section_name,
> +					   gdb::unique_xmalloc_ptr<char>
> +					     *destname);
>  #endif /* DEBUGINFOD_SUPPORT_H */
> -- 
> 2.41.0