Re: placing data into a section

[Nick Clifton <nickc at redhat dot com>]

Hi Bahadir,

> When I am linking an elf executable, I would like to place some bulk
> data (e.g. a zip file or some other binary file) into a section in the
> final executable. How can I achieve this with ld commands and the
> linker script?

As has already been mentioned this is probably easier to do using the 
assembler's .incbin directive or the objcopy program's --add-section 
switch.  But if you do want to use a linker script...

> .data :
>    {
>    /* Some other data go here ... */
>
>    bulk_data_start = .;
>    *(.bulk_data)
>    bulk_data_end = .;
>    }
> }
>
> But how can I put a file into a .bulk_data section like that?

By explicitly mentioning the file name:

     bulk_data_start = .;
     bulk_data.o(.data)
     bulk_data_end = . ;

I am assuming here that you want the .data section from your bulk_data.o 
file.  If however you wanted the .bulk_data section, assuming that it 
exists, then the script would be:

     bulk_data_start = .;
     bulk_data.o(.bulk_data)
     bulk_data_end = . ;

Note however that if you want this data to come *after* the normal data 
(and assuming that it is in a section called .data) then you have to be 
a little bit more careful.  This, for example will not work:

  .data :
   {
     *(.data)
     bulk_data_start = .;
     bulk_data.o(.data)
     bulk_data_end = .;
   }

This is because the first "*(.data)" will match the .data section in all 
the input files, including .bulk_data.o.  So you have to exclude the 
bulk data from the ordinary data, like this:

  .data :
   {
     *(EXCLUDE_FILE (bulk_data.o) .data)
     bulk_data_start = .;
     bulk_data.o(.data)
     bulk_data_end = .;
   }

This is all documented in the linker manual.  I strongly recommend that 
you read it.

Cheers
  Nick

PS.  The above examples assume that you will be passing "bulk_data.o" as 
a filename on the linker command line.