grub-mkimage.c

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	    sym_addr = get_symbol_address (e, symtab_section,
					   ELF32_R_SYM (info));

	    switch (ELF32_R_TYPE (info))
	      {
	      case R_386_NONE:
		break;

	      case R_386_32:
		/* This is absolute.  */
		*target = grub_cpu_to_le32 (grub_le_to_cpu32 (*target)
					    + sym_addr);
		grub_util_info ("relocating an R_386_32 entry to 0x%x at the offset 0x%x",
				*target, offset);
		break;

	      case R_386_PC32:
		/* This is relative.  */
		*target = grub_cpu_to_le32 (grub_le_to_cpu32 (*target)
					    + sym_addr
					    - target_section_addr - offset);
		grub_util_info ("relocating an R_386_PC32 entry to 0x%x at the offset 0x%x",
				*target, offset);
		break;

	      default:
		grub_util_error ("unknown relocation type %d",
				 ELF32_R_TYPE (info));
		break;
	      }
	  }
      }
}

void
write_padding (FILE *out, size_t size)
{
  size_t i;

  for (i = 0; i < size; i++)
    if (fputc (0, out) == EOF)
      grub_util_error ("padding failed");
}

/* Add a PE32's fixup entry for a relocation. Return the resulting address
   after having written to the file OUT.  */
Elf32_Addr
add_fixup_entry (struct grub_pe32_fixup_block **block, grub_uint16_t type,
		 Elf32_Addr addr, int flush, Elf32_Addr current_address,
		 FILE *out)
{
  struct grub_pe32_fixup_block *b = *block;
  
  /* First, check if it is necessary to write out the current block.  */
  if (b)
    {
      if (flush || addr < b->page_rva || b->page_rva + 0x1000 <= addr)
	{
	  grub_uint32_t size;

	  if (flush)
	    {
	      /* Add as much padding as necessary to align the address
		 with a section boundary.  */
	      Elf32_Addr next_address;
	      unsigned padding_size;
              size_t index;
	      
	      next_address = current_address + b->block_size;
	      padding_size = ((align_pe32_section (next_address)
			       - next_address)
			      >> 1);
              index = ((b->block_size - sizeof (*b)) >> 1);
              grub_util_info ("adding %d padding fixup entries", padding_size);
	      while (padding_size--)
		{
		  b->entries[index++] = 0;
		  b->block_size += 2;
		}
	    }
          else if (b->block_size & (8 - 1))
            {
	      /* If not aligned with a 32-bit boundary, add
		 a padding entry.  */
              size_t index;

              grub_util_info ("adding a padding fixup entry");
              index = ((b->block_size - sizeof (*b)) >> 1);
              b->entries[index] = 0;
              b->block_size += 2;
            }

          /* Flush it.  */
          grub_util_info ("writing %d bytes of a fixup block starting at 0x%x",
                          b->block_size, b->page_rva);
          size = b->block_size;
	  current_address += size;
	  b->page_rva = grub_cpu_to_le32 (b->page_rva);
	  b->block_size = grub_cpu_to_le32 (b->block_size);
	  if (fwrite (b, size, 1, out) != 1)
	    grub_util_error ("write failed");
	  free (b);
	  *block = b = 0;
	}
    }

  if (! flush)
    {
      grub_uint16_t entry;
      size_t index;
      
      /* If not allocated yet, allocate a block with enough entries.  */
      if (! b)
	{
	  *block = b = xmalloc (sizeof (*b) + 2 * 0x1000);

	  /* The spec does not mention the requirement of a Page RVA.
	     Here, align the address with a 4K boundary for safety.  */
	  b->page_rva = (addr & ~(0x1000 - 1));
	  b->block_size = sizeof (*b);
	}

      /* Sanity check.  */
      if (b->block_size >= sizeof (*b) + 2 * 0x1000)
	grub_util_error ("too many fixup entries");

      /* Add a new entry.  */
      index = ((b->block_size - sizeof (*b)) >> 1);
      entry = GRUB_PE32_FIXUP_ENTRY (type, addr - b->page_rva);
      b->entries[index] = grub_cpu_to_le16 (entry);
      b->block_size += 2;
    }

  return current_address;
}

/* Write out zeros to make space for the header.  */
static Elf32_Addr
make_header_space (FILE *out)
{
  Elf32_Addr addr;
  
  addr = get_starting_section_address ();
  write_padding (out, addr);

  return addr;
}

/* Write text sections.  */
static Elf32_Addr
write_text_sections (FILE *out, Elf32_Addr current_address,
		     Elf32_Ehdr *e, Elf32_Shdr *sections,
		     Elf32_Half section_entsize, Elf32_Half num_sections,
		     const char *strtab)
{
  Elf32_Half i;
  Elf32_Shdr *s;
  Elf32_Addr addr;
  
  for (i = 0, s = sections;
       i < num_sections;
       i++, s = (Elf32_Shdr *) ((char *) s + section_entsize))
    if (is_text_section (s))
      {
	Elf32_Word align = grub_le_to_cpu32 (s->sh_addralign);
	Elf32_Off offset = grub_le_to_cpu32 (s->sh_offset);
	Elf32_Word size = grub_le_to_cpu32 (s->sh_size);
	const char *name = strtab + grub_le_to_cpu32 (s->sh_name);
	
	if (align)
	  {
	    addr = align_address (current_address, align);
	    if (current_address != addr)
	      {
		grub_util_info ("padding %d bytes for the ELF section alignment",
				addr - current_address);
		write_padding (out, addr - current_address);
		current_address = addr;
	      }
	  }
	
	grub_util_info ("writing the text section %s at 0x%x",
			name, current_address);
	
	if (fwrite ((char *) e + offset, size, 1, out) != 1)
	  grub_util_error ("write failed");
	
	current_address += size;
      }

  addr = align_pe32_section (current_address);
  if (addr != current_address)
    {
      grub_util_info ("padding %d bytes for the PE32 section alignment",
		      addr - current_address);
      write_padding (out, addr - current_address);
    }
  
  return addr;
}

/* Write data sections.  */
static Elf32_Addr
write_data_sections (FILE *out, Elf32_Addr current_address,
		     Elf32_Ehdr *e, Elf32_Shdr *sections,
		     Elf32_Half section_entsize, Elf32_Half num_sections,
		     const char *strtab)
{
  Elf32_Half i;
  Elf32_Shdr *s;
  Elf32_Addr addr;
  
  for (i = 0, s = sections;
       i < num_sections;
       i++, s = (Elf32_Shdr *) ((char *) s + section_entsize))
    if (is_data_section (s))
      {
	Elf32_Word align = grub_le_to_cpu32 (s->sh_addralign);
	Elf32_Off offset = grub_le_to_cpu32 (s->sh_offset);
	Elf32_Word size = grub_le_to_cpu32 (s->sh_size);
	const char *name = strtab + grub_le_to_cpu32 (s->sh_name);
	
	if (align)
	  {
	    addr = align_address (current_address, align);
	    if (current_address != addr)
	      {
		grub_util_info ("padding %d bytes for the ELF section alignment",
				addr - current_address);
		write_padding (out, addr - current_address);
		current_address = addr;
	      }
	  }
	
	grub_util_info ("writing the data section %s at 0x%x",
			name, current_address);
	
	if (s->sh_type == grub_cpu_to_le32 (SHT_NOBITS))
	  write_padding (out, size);
	else
	  if (fwrite ((char *) e + offset, size, 1, out) != 1)
	    grub_util_error ("write failed");
	
	current_address += size;
      }
  
  addr = align_pe32_section (current_address);
  if (addr != current_address)
    {
      grub_util_info ("padding %d bytes for the PE32 section alignment",
		      addr - current_address);
      write_padding (out, addr - current_address);
    }
  
  return addr;
}

/* Write modules.  */
static Elf32_Addr
make_mods_section (FILE *out, Elf32_Addr current_address,
		   const char *dir, char *mods[])
{
  struct grub_util_path_list *path_list;
  grub_size_t total_module_size;
  struct grub_util_path_list *p;
  struct grub_module_info modinfo;
  Elf32_Addr addr;

  path_list = grub_util_resolve_dependencies (dir, "moddep.lst", mods);
  
  total_module_size = sizeof (struct grub_module_info);
  for (p = path_list; p; p = p->next)
    {
      total_module_size += (grub_util_get_image_size (p->name)
			    + sizeof (struct grub_module_header));
    }

  grub_util_info ("the total module size is 0x%x", total_module_size);

  modinfo.magic = grub_cpu_to_le32 (GRUB_MODULE_MAGIC);
  modinfo.offset = grub_cpu_to_le32 (sizeof (modinfo));
  modinfo.size = grub_cpu_to_le32 (total_module_size);

  if (fwrite (&modinfo, sizeof (modinfo), 1, out) != 1)
    grub_util_error ("write failed");

  for (p = path_list; p; p = p->next)
    {
      struct grub_module_header header;
      size_t mod_size;
      char *mod_image;
      
      grub_util_info ("adding module %s", p->name);
      
      mod_size = grub_util_get_image_size (p->name);
      header.offset = grub_cpu_to_le32 (sizeof (header));
      header.size = grub_cpu_to_le32 (mod_size + sizeof (header));
      
      mod_image = grub_util_read_image (p->name);

      if (fwrite (&header, sizeof (header), 1, out) != 1
	  || fwrite (mod_image, mod_size, 1, out) != 1)
	grub_util_error ("write failed");

      free (mod_image);
    }
  
  for (p = path_list; p; )
    {
      struct grub_util_path_list *q;

      q = p->next;
      free (p);
      p = q;
    }
      
  current_address += total_module_size;
  
  addr = align_pe32_section (current_address);
  if (addr != current_address)
    {
      grub_util_info ("padding %d bytes for the PE32 section alignment",
		      addr - current_address);
      write_padding (out, addr - current_address);
    }

  return addr;
}

/* Make a .reloc section.  */
static Elf32_Addr
make_reloc_section (FILE *out, Elf32_Addr current_address, Elf32_Ehdr *e, 
		    Elf32_Addr *section_addresses, Elf32_Shdr *sections,
		    Elf32_Half section_entsize, Elf32_Half num_sections,
		    const char *strtab)
{
  Elf32_Half i;
  Elf32_Shdr *s;