[PATCH] objcopy: Add elf header e_flags option in objcopy.

[PATCH] objcopy: Add elf header e_flags option in objcopy.

[liuzhensong]

Specify flags when copying binary to elf file.
This flags will be written to the e_flags of the elf header.

usage:
  objcopy -I binary -O target --alt-elf-eflags=val bin_file  elf_file

binutils/
  * objcopy.c
---
 binutils/objcopy.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 6fb31c8cac7..ae886a44619 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;
 
+/* Use alternative elf header e_flags?  */
+static bool alt_elf_eflags_set = false;
+static unsigned int alt_elf_eflags = 0;
+
 /* 150 isn't special; it's just an arbitrary non-ASCII char value.  */
 enum command_line_switch
 {
@@ -310,6 +314,7 @@ enum command_line_switch
   OPTION_ADD_GNU_DEBUGLINK,
   OPTION_ADD_SYMBOL,
   OPTION_ALT_MACH_CODE,
+  OPTION_ALT_ELF_EFLAGS,
   OPTION_CHANGE_ADDRESSES,
   OPTION_CHANGE_LEADING_CHAR,
   OPTION_CHANGE_SECTION_ADDRESS,
@@ -427,6 +432,7 @@ static struct option copy_options[] =
   {"adjust-vma", required_argument, 0, OPTION_CHANGE_ADDRESSES},
   {"adjust-warnings", no_argument, 0, OPTION_CHANGE_WARNINGS},
   {"alt-machine-code", required_argument, 0, OPTION_ALT_MACH_CODE},
+  {"alt-elf-eflags", required_argument, 0, OPTION_ALT_ELF_EFLAGS},
   {"binary-architecture", required_argument, 0, 'B'},
   {"byte", required_argument, 0, 'b'},
   {"change-addresses", required_argument, 0, OPTION_CHANGE_ADDRESSES},
@@ -660,6 +666,7 @@ copy_usage (FILE *stream, int exit_status)
      --weaken-symbols <file>       -W for all symbols listed in <file>\n\
      --add-symbol <name>=[<section>:]<value>[,<flags>]  Add a symbol\n\
      --alt-machine-code <index>    Use the target's <index>'th alternative machine\n\
+     --alt-elf-eflags=<value> 	   Use the alternative elf header e_flags\n\
      --writable-text               Mark the output text as writable\n\
      --readonly-text               Make the output text write protected\n\
      --pure                        Mark the output file as demand paged\n\
@@ -3496,6 +3503,11 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
 	}
     }
 
+  if (alt_elf_eflags_set)
+    {
+      elf_elfheader (obfd)->e_flags = alt_elf_eflags;
+    }
+
   return true;
 }
 
@@ -5863,6 +5875,11 @@ copy_main (int argc, char *argv[])
 	    fatal (_("verilog data width must be at least 1 byte"));
 	  break;
 
+	case OPTION_ALT_ELF_EFLAGS:
+	  alt_elf_eflags_set = true;
+	  alt_elf_eflags = parse_vma (optarg, "--alt-elf-eflags");
+	  break;
+
 	case 0:
 	  /* We've been given a long option.  */
 	  break;
-- 
2.31.1

Re: [PATCH] objcopy: Add elf header e_flags option in objcopy.

[Alan Modra]

On Thu, Apr 14, 2022 at 07:29:06PM +0800, liuzhensong wrote:
> @@ -660,6 +666,7 @@ copy_usage (FILE *stream, int exit_status)
>       --weaken-symbols <file>       -W for all symbols listed in <file>\n\
>       --add-symbol <name>=[<section>:]<value>[,<flags>]  Add a symbol\n\
>       --alt-machine-code <index>    Use the target's <index>'th alternative machine\n\
> +     --alt-elf-eflags=<value> 	   Use the alternative elf header e_flags\n\

Don't use tabs in help messages.

>       --writable-text               Mark the output text as writable\n\
>       --readonly-text               Make the output text write protected\n\
>       --pure                        Mark the output file as demand paged\n\
> @@ -3496,6 +3503,11 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
>  	}
>      }
>  
> +  if (alt_elf_eflags_set)
> +    {
> +      elf_elfheader (obfd)->e_flags = alt_elf_eflags;
> +    }
> +

Needs a check bfd_get_flavour (obfd) == bfd_target_elf_flavour before
writing a field only in ELF bfd, and no need for braces.

Also, please update binutils/doc.texi with the new objcopy option.

-- 
Alan Modra
Australia Development Lab, IBM

Re: [PATCH] objcopy: Add elf header e_flags option in objcopy.

[liuzhensong]

On 2022/4/15 上午10:03, Alan Modra wrote:
> On Thu, Apr 14, 2022 at 07:29:06PM +0800, liuzhensong wrote:
>> @@ -660,6 +666,7 @@ copy_usage (FILE *stream, int exit_status)
>>        --weaken-symbols <file>       -W for all symbols listed in <file>\n\
>>        --add-symbol <name>=[<section>:]<value>[,<flags>]  Add a symbol\n\
>>        --alt-machine-code <index>    Use the target's <index>'th alternative machine\n\
>> +     --alt-elf-eflags=<value> 	   Use the alternative elf header e_flags\n\
> Don't use tabs in help messages.
>
>>        --writable-text               Mark the output text as writable\n\
>>        --readonly-text               Make the output text write protected\n\
>>        --pure                        Mark the output file as demand paged\n\
>> @@ -3496,6 +3503,11 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
>>   	}
>>       }
>>   
>> +  if (alt_elf_eflags_set)
>> +    {
>> +      elf_elfheader (obfd)->e_flags = alt_elf_eflags;
>> +    }
>> +
> Needs a check bfd_get_flavour (obfd) == bfd_target_elf_flavour before
> writing a field only in ELF bfd, and no need for braces.
>
> Also, please update binutils/doc.texi with the new objcopy option.
>

I will send a v2 with the requested changes.
Thanks for the review.

--
liuzhensong