[PATCH v3] objcopy: Add ELF header e_flags option in objcopy.

[H.J. Lu]

On Sun, Apr 17, 2022, 1:25 AM liuzhensong <liuzhensong@loongson.cn> wrote:

> Specify flags when copying binary to ELF.
> The flags is treated as an absolute number to be
> stored in the e_flags field of the ELF header.
>
> Usage:
>   objcopy -I binary -O target --elf-eflags=val bin_file  elf_file
>
> binutils/
>   * objcopy.c
>   * doc/binutils.texi:Add the new objcopy option.
> ---
>  binutils/doc/binutils.texi |  7 +++++++
>  binutils/objcopy.c         | 16 ++++++++++++++++
>  2 files changed, 23 insertions(+)
>
> diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
> index 2c234c682aa..65230775b29 100644
> --- a/binutils/doc/binutils.texi
> +++ b/binutils/doc/binutils.texi
> @@ -1326,6 +1326,7 @@ objcopy [@option{-F}
> @var{bfdname}|@option{--target=}@var{bfdname}]
>          [@option{--merge-notes}]
>          [@option{--no-merge-notes}]
>          [@option{--verilog-data-width=@var{val}}]
> +        [@option{--elf-eflags=}@var{value}]
>          [@option{-v}|@option{--verbose}]
>          [@option{-V}|@option{--version}]
>          [@option{--help}] [@option{--info}]
> @@ -2187,6 +2188,12 @@ For Verilog output, this options controls the
> number of bytes
>  converted for each output data element.  The input target controls the
>  endianness of the conversion.
>
> +@item --elf-eflags=@var{value}
> +Meaningful only for ELF output.  Use @var{value} as e_flags of the
> +output.  This is useful for changing the e_flags of an existing binary.
> +The @var{value} is treated as an absolute number to be stored in the
> +e_flags field of the ELF header.
> +
>  @item -v
>  @itemx --verbose
>  Verbose output: list all object files modified.  In the case of
> diff --git a/binutils/objcopy.c b/binutils/objcopy.c
> index 6fb31c8cac7..3c1eaf5ec1a 100644
> --- a/binutils/objcopy.c
> +++ b/binutils/objcopy.c
> @@ -303,6 +303,10 @@ enum long_section_name_handling
>     This is also the only behaviour for 'strip'.  */
>  static enum long_section_name_handling long_section_names = KEEP;
>
> +/* Specify ELF header e_flags?  */
> +static bool elf_eflags_set = false;
> +static unsigned int elf_eflags = 0;
> +
>  /* 150 isn't special; it's just an arbitrary non-ASCII char value.  */
>  enum command_line_switch
>  {
> @@ -321,6 +325,7 @@ enum command_line_switch
>    OPTION_DEBUGGING,
>    OPTION_DECOMPRESS_DEBUG_SECTIONS,
>    OPTION_DUMP_SECTION,
> +  OPTION_ELF_EFLAGS,
>    OPTION_ELF_STT_COMMON,
>    OPTION_EXTRACT_DWO,
>    OPTION_EXTRACT_SYMBOL,
> @@ -443,6 +448,7 @@ static struct option copy_options[] =
>    {"discard-all", no_argument, 0, 'x'},
>    {"discard-locals", no_argument, 0, 'X'},
>    {"dump-section", required_argument, 0, OPTION_DUMP_SECTION},
> +  {"elf-eflags", required_argument, 0, OPTION_ELF_EFLAGS},
>    {"elf-stt-common", required_argument, 0, OPTION_ELF_STT_COMMON},
>    {"enable-deterministic-archives", no_argument, 0, 'D'},
>    {"extract-dwo", no_argument, 0, OPTION_EXTRACT_DWO},
> @@ -684,6 +690,7 @@ copy_usage (FILE *stream, int exit_status)
>       --elf-stt-common=[yes|no]     Generate ELF common symbols with
> STT_COMMON\n\
>                                       type\n\
>       --verilog-data-width <number> Specifies data width, in bytes, for
> verilog output\n\
> +     --elf-eflags=<value>          Set e_flags to <value> for ELF
> output\n\
>    -M  --merge-notes                Remove redundant entries in note
> sections\n\
>        --no-merge-notes             Do not attempt to remove redundant
> notes (default)\n\
>    -v --verbose                     List all object files modified\n\
> @@ -3496,6 +3503,10 @@ copy_object (bfd *ibfd, bfd *obfd, const
> bfd_arch_info_type *input_arch)
>         }
>      }
>
> +  if (bfd_get_flavour (obfd) == bfd_target_elf_flavour
> +      && elf_eflags_set)
> +    elf_elfheader (obfd)->e_flags = elf_eflags;
> +
>    return true;
>  }
>
> @@ -5863,6 +5874,11 @@ copy_main (int argc, char *argv[])
>             fatal (_("verilog data width must be at least 1 byte"));
>           break;
>
> +       case OPTION_ELF_EFLAGS:
> +         elf_eflags_set = true;
> +         elf_eflags = parse_vma (optarg, "--elf-eflags");
> +         break;
> +
>         case 0:
>           /* We've been given a long option.  */
>           break;
> --
> 2.31.1


>
Should we extend elfedit instead?

H.J.