Objcopy problem

[Andrew STUBBS]

H.J. Lu wrote:
> How do you load a section with file size 0?

One does not. Here's the effect of this command in the old tools:

   $ sh4objcopy a.out a2.out --set-section-flags 
.post_text_reserve=contents,alloc,load,readonly,code
   $ sh4objdump -ph a2.out

a2.out:     file format elf32-shl

Program Header:
     LOAD off    0x00000080 vaddr 0x00000000 paddr 0x00000000 align 2**7
          filesz 0x0000016c memsz 0x0000016c flags rwx

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
   0 .text         0000000c  00000000  00000000  00000080  2**1
                   CONTENTS, ALLOC, LOAD, READONLY, CODE
   1 .post_text_reserve 00000160  0000000c  0000000c  0000008c  2**0
                   CONTENTS, ALLOC, LOAD, READONLY, CODE
   2 .comment      00000043  00000000  00000000  000001ec  2**0
                   CONTENTS, READONLY

As you can see, the section now _has_ a file size. This was the point of 
the exercise - the section contents may now be overwritten with the 
final data (in this case a digital signature used to verify the other 
sections).

The linker will not allow us to create a loadable section for which we 
do not yet know the contents. Therefore, this trick is used to convert 
the elf file into the form we need.

Andrew