Re: [PATCH 4/8] abg-elf-helpers: move some kernel helpers from abg-dwarf-reader

[Giuliano Procida <gprocida@google.com>]

On Mon, 20 Apr 2020 at 12:09, Matthias Maennich <maennich@google.com> wrote:
>
> Move some definitions from abg-dwarf-reader to abg-elf-helpers that are
> strictly only related to ELF.
>
>         * abg-dwarf-reader.cc(binary_is_linux_kernel): Move function out.
>         (binary_is_linux_kernel_module): Likewise.
>         (find_ksymtab_strings_section): Likewise.
>         * abg-elf-helpers.cc(binary_is_linux_kernel): Move function in.
>         (binary_is_linux_kernel_module): Likewise.
>         (find_ksymtab_strings_section): Likewise.

Next one should be .h.

>         * abg-elf-helpers.cc(binary_is_linux_kernel): Add declaration.
>         (binary_is_linux_kernel_module): Likewise.
>         (find_ksymtab_strings_section): Likewise.
>
> Signed-off-by: Matthias Maennich <maennich@google.com>
> ---
>  src/abg-dwarf-reader.cc | 46 -----------------------------------------
>  src/abg-elf-helpers.cc  | 45 ++++++++++++++++++++++++++++++++++++++++
>  src/abg-elf-helpers.h   | 14 +++++++++++++
>  3 files changed, 59 insertions(+), 46 deletions(-)
>
> diff --git a/src/abg-dwarf-reader.cc b/src/abg-dwarf-reader.cc
> index 303c1f8df4c2..3adb978b784b 100644
> --- a/src/abg-dwarf-reader.cc
> +++ b/src/abg-dwarf-reader.cc
> @@ -542,52 +542,6 @@ compare_dies(const read_context& ctxt,
>              bool update_canonical_dies_on_the_fly);
>
>
> -/// Test if the ELF binary denoted by a given ELF handle is a Linux
> -/// Kernel Module.
> -///
> -/// @param elf_handle the ELF handle to consider.
> -///
> -/// @return true iff the binary denoted by @p elf_handle is a Linux
> -/// kernel module.
> -static bool
> -binary_is_linux_kernel_module(Elf *elf_handle)
> -{
> -  return (find_section(elf_handle, ".modinfo", SHT_PROGBITS)
> -         && find_section(elf_handle,
> -                         ".gnu.linkonce.this_module",
> -                         SHT_PROGBITS));
> -}
> -
> -/// Test if the ELF binary denoted by a given ELF handle is a Linux
> -/// Kernel binary (either vmlinux or a kernel module).
> -///
> -/// @param elf_handle the ELF handle to consider.
> -///
> -/// @return true iff the binary denoted by @p elf_handle is a Linux
> -/// kernel binary
> -static bool
> -binary_is_linux_kernel(Elf *elf_handle)
> -{
> -  return (find_section(elf_handle,
> -                      "__ksymtab_strings",
> -                      SHT_PROGBITS)
> -         || binary_is_linux_kernel_module(elf_handle));
> -}
> -
> -/// Find the __ksymtab_strings section of a Linux kernel binary.
> -///
> -///
> -/// @return the find_ksymtab_strings_section of the linux kernel
> -/// binary denoted by @p elf_handle, or nil if such a section could
> -/// not be found.
> -static Elf_Scn*
> -find_ksymtab_strings_section(Elf *elf_handle)
> -{
> -  if (binary_is_linux_kernel(elf_handle))
> -    return find_section(elf_handle, "__ksymtab_strings", SHT_PROGBITS);
> -  return 0;
> -}
> -
>  /// Get the address at which a given binary is loaded in memory⋅
>  ///
>  /// @param elf_handle the elf handle for the binary to consider.
> diff --git a/src/abg-elf-helpers.cc b/src/abg-elf-helpers.cc
> index b7b868a332ec..ff0941dc6536 100644
> --- a/src/abg-elf-helpers.cc
> +++ b/src/abg-elf-helpers.cc
> @@ -548,6 +548,21 @@ get_symbol_versionning_sections(Elf*               elf_handle,
>    return false;
>  }
>
> +/// Find the __ksymtab_strings section of a Linux kernel binary.
> +///
> +/// @param elf_handle the elf handle to use.
> +///
> +/// @return the find_ksymtab_strings_section of the linux kernel
> +/// binary denoted by @p elf_handle, or nil if such a section could
> +/// not be found.
> +Elf_Scn*
> +find_ksymtab_strings_section(Elf *elf_handle)
> +{
> +  if (binary_is_linux_kernel(elf_handle))
> +    return find_section(elf_handle, "__ksymtab_strings", SHT_PROGBITS);
> +  return 0;
> +}
> +
>  /// Get the version definition (from the SHT_GNU_verdef section) of a
>  /// given symbol represented by a pointer to GElf_Versym.
>  ///
> @@ -750,7 +765,37 @@ get_version_for_symbol(Elf*                        elf_handle,
>    return false;
>  }
>
> +/// Test if the ELF binary denoted by a given ELF handle is a Linux
> +/// Kernel Module.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the binary denoted by @p elf_handle is a Linux
> +/// kernel module.
> +bool
> +binary_is_linux_kernel_module(Elf *elf_handle)
> +{
> +  return (find_section(elf_handle, ".modinfo", SHT_PROGBITS)
> +         && find_section(elf_handle,
> +                         ".gnu.linkonce.this_module",
> +                         SHT_PROGBITS));
> +}
>
> +/// Test if the ELF binary denoted by a given ELF handle is a Linux
> +/// Kernel binary (either vmlinux or a kernel module).
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the binary denoted by @p elf_handle is a Linux
> +/// kernel binary
> +bool
> +binary_is_linux_kernel(Elf *elf_handle)
> +{
> +  return (find_section(elf_handle,
> +                      "__ksymtab_strings",
> +                      SHT_PROGBITS)
> +         || binary_is_linux_kernel_module(elf_handle));
> +}
>
>  } // end namespace elf_helpers
>  } // end namespace abigail
> diff --git a/src/abg-elf-helpers.h b/src/abg-elf-helpers.h
> index 7e1c231ccc4e..33348126028c 100644
> --- a/src/abg-elf-helpers.h
> +++ b/src/abg-elf-helpers.h
> @@ -102,6 +102,9 @@ get_symbol_versionning_sections(Elf*                elf_handle,
>                                 Elf_Scn*&       verdef_section,
>                                 Elf_Scn*&       verneed_section);
>
> +Elf_Scn*
> +find_ksymtab_strings_section(Elf *elf_handle);
> +
>  //
>  // Helpers for symbol versioning
>  //
> @@ -124,6 +127,17 @@ get_version_for_symbol(Elf*                        elf_handle,
>                        bool                     get_def_version,
>                        elf_symbol::version&     version);
>
> +//
> +// Helpers for Linux Kernel Binaries
> +//
> +
> +bool
> +binary_is_linux_kernel_module(Elf *elf_handle);
> +
> +bool
> +binary_is_linux_kernel(Elf *elf_handle);
> +
> +
>  } // end namespace elf_helpers
>  } // end namespace abigail
>
> --
> 2.26.1.301.g55bc3eb7cb9-goog
>