elf.c

基于4个mips核的noc设计

	  {
	    ((*_bfd_error_handler)
	     (_("%s: invalid link %lu for reloc section %s (index %u)"),
	      bfd_get_filename (abfd), hdr->sh_link, name, shindex));
	    return _bfd_elf_make_section_from_shdr (abfd, hdr, name);
	  }

	/* For some incomprehensible reason Oracle distributes
	   libraries for Solaris in which some of the objects have
	   bogus sh_link fields.  It would be nice if we could just
	   reject them, but, unfortunately, some people need to use
	   them.  We scan through the section headers; if we find only
	   one suitable symbol table, we clobber the sh_link to point
	   to it.  I hope this doesn't break anything.  */
	if (elf_elfsections (abfd)[hdr->sh_link]->sh_type != SHT_SYMTAB
	    && elf_elfsections (abfd)[hdr->sh_link]->sh_type != SHT_DYNSYM)
	  {
	    int scan;
	    int found;

	    found = 0;
	    for (scan = 1; scan < ehdr->e_shnum; scan++)
	      {
		if (elf_elfsections (abfd)[scan]->sh_type == SHT_SYMTAB
		    || elf_elfsections (abfd)[scan]->sh_type == SHT_DYNSYM)
		  {
		    if (found != 0)
		      {
			found = 0;
			break;
		      }
		    found = scan;
		  }
	      }
	    if (found != 0)
	      hdr->sh_link = found;
	  }

	/* Get the symbol table.  */
	if (elf_elfsections (abfd)[hdr->sh_link]->sh_type == SHT_SYMTAB
	    && ! bfd_section_from_shdr (abfd, hdr->sh_link))
	  return false;

	/* If this reloc section does not use the main symbol table we
	   don't treat it as a reloc section.  BFD can't adequately
	   represent such a section, so at least for now, we don't
	   try.  We just present it as a normal section.  We also
	   can't use it as a reloc section if it points to the null
	   section.  */
	if (hdr->sh_link != elf_onesymtab (abfd) || hdr->sh_info == SHN_UNDEF)
	  return _bfd_elf_make_section_from_shdr (abfd, hdr, name);

	if (! bfd_section_from_shdr (abfd, hdr->sh_info))
	  return false;
	target_sect = bfd_section_from_elf_index (abfd, hdr->sh_info);
	if (target_sect == NULL)
	  return false;

	if ((target_sect->flags & SEC_RELOC) == 0
	    || target_sect->reloc_count == 0)
	  hdr2 = &elf_section_data (target_sect)->rel_hdr;
	else
	  {
	    BFD_ASSERT (elf_section_data (target_sect)->rel_hdr2 == NULL);
	    hdr2 = (Elf_Internal_Shdr *) bfd_alloc (abfd, sizeof (*hdr2));
	    elf_section_data (target_sect)->rel_hdr2 = hdr2;
	  }
	*hdr2 = *hdr;
	elf_elfsections (abfd)[shindex] = hdr2;
	target_sect->reloc_count += NUM_SHDR_ENTRIES (hdr);
	target_sect->flags |= SEC_RELOC;
	target_sect->relocation = NULL;
	target_sect->rel_filepos = hdr->sh_offset;
	/* In the section to which the relocations apply, mark whether
	   its relocations are of the REL or RELA variety.  */
	if (hdr->sh_size != 0)
	  elf_section_data (target_sect)->use_rela_p
	    = (hdr->sh_type == SHT_RELA);
	abfd->flags |= HAS_RELOC;
	return true;
      }
      break;

    case SHT_GNU_verdef:
      elf_dynverdef (abfd) = shindex;
      elf_tdata (abfd)->dynverdef_hdr = *hdr;
      return _bfd_elf_make_section_from_shdr (abfd, hdr, name);
      break;

    case SHT_GNU_versym:
      elf_dynversym (abfd) = shindex;
      elf_tdata (abfd)->dynversym_hdr = *hdr;
      return _bfd_elf_make_section_from_shdr (abfd, hdr, name);
      break;

    case SHT_GNU_verneed:
      elf_dynverref (abfd) = shindex;
      elf_tdata (abfd)->dynverref_hdr = *hdr;
      return _bfd_elf_make_section_from_shdr (abfd, hdr, name);
      break;

    case SHT_SHLIB:
      return true;

    default:
      /* Check for any processor-specific section types.  */
      {
	if (bed->elf_backend_section_from_shdr)
	  (*bed->elf_backend_section_from_shdr) (abfd, hdr, name);
      }
      break;
    }

  return true;
}

/* Given an ELF section number, retrieve the corresponding BFD
   section.  */

asection *
bfd_section_from_elf_index (abfd, index)
     bfd *abfd;
     unsigned int index;
{
  BFD_ASSERT (index > 0 && index < SHN_LORESERVE);
  if (index >= elf_elfheader (abfd)->e_shnum)
    return NULL;
  return elf_elfsections (abfd)[index]->bfd_section;
}

boolean
_bfd_elf_new_section_hook (abfd, sec)
     bfd *abfd;
     asection *sec;
{
  struct bfd_elf_section_data *sdata;

  sdata = (struct bfd_elf_section_data *) bfd_zalloc (abfd, sizeof (*sdata));
  if (!sdata)
    return false;
  sec->used_by_bfd = (PTR) sdata;

  /* Indicate whether or not this section should use RELA relocations.  */
  sdata->use_rela_p
    = get_elf_backend_data (abfd)->default_use_rela_p;

  return true;
}

/* Create a new bfd section from an ELF program header.

   Since program segments have no names, we generate a synthetic name
   of the form segment<NUM>, where NUM is generally the index in the
   program header table.  For segments that are split (see below) we
   generate the names segment<NUM>a and segment<NUM>b.

   Note that some program segments may have a file size that is different than
   (less than) the memory size.  All this means is that at execution the
   system must allocate the amount of memory specified by the memory size,
   but only initialize it with the first "file size" bytes read from the
   file.  This would occur for example, with program segments consisting
   of combined data+bss.

   To handle the above situation, this routine generates TWO bfd sections
   for the single program segment.  The first has the length specified by
   the file size of the segment, and the second has the length specified
   by the difference between the two sizes.  In effect, the segment is split
   into it's initialized and uninitialized parts.

 */

boolean
_bfd_elf_make_section_from_phdr (abfd, hdr, index, typename)
     bfd *abfd;
     Elf_Internal_Phdr *hdr;
     int index;
     const char *typename;
{
  asection *newsect;
  char *name;
  char namebuf[64];
  int split;

  split = ((hdr->p_memsz > 0)
	    && (hdr->p_filesz > 0)
	    && (hdr->p_memsz > hdr->p_filesz));
  sprintf (namebuf, "%s%d%s", typename, index, split ? "a" : "");
  name = bfd_alloc (abfd, strlen (namebuf) + 1);
  if (!name)
    return false;
  strcpy (name, namebuf);
  newsect = bfd_make_section (abfd, name);
  if (newsect == NULL)
    return false;
  newsect->vma = hdr->p_vaddr;
  newsect->lma = hdr->p_paddr;
  newsect->_raw_size = hdr->p_filesz;
  newsect->filepos = hdr->p_offset;
  newsect->flags |= SEC_HAS_CONTENTS;
  if (hdr->p_type == PT_LOAD)
    {
      newsect->flags |= SEC_ALLOC;
      newsect->flags |= SEC_LOAD;
      if (hdr->p_flags & PF_X)
	{
	  /* FIXME: all we known is that it has execute PERMISSION,
	     may be data.  */
	  newsect->flags |= SEC_CODE;
	}
    }
  if (!(hdr->p_flags & PF_W))
    {
      newsect->flags |= SEC_READONLY;
    }

  if (split)
    {
      sprintf (namebuf, "%s%db", typename, index);
      name = bfd_alloc (abfd, strlen (namebuf) + 1);
      if (!name)
	return false;
      strcpy (name, namebuf);
      newsect = bfd_make_section (abfd, name);
      if (newsect == NULL)
	return false;
      newsect->vma = hdr->p_vaddr + hdr->p_filesz;
      newsect->lma = hdr->p_paddr + hdr->p_filesz;
      newsect->_raw_size = hdr->p_memsz - hdr->p_filesz;
      if (hdr->p_type == PT_LOAD)
	{
	  newsect->flags |= SEC_ALLOC;
	  if (hdr->p_flags & PF_X)
	    newsect->flags |= SEC_CODE;
	}
      if (!(hdr->p_flags & PF_W))
	newsect->flags |= SEC_READONLY;
    }

  return true;
}

boolean
bfd_section_from_phdr (abfd, hdr, index)
     bfd *abfd;
     Elf_Internal_Phdr *hdr;
     int index;
{
  struct elf_backend_data *bed;

  switch (hdr->p_type)
    {
    case PT_NULL:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "null");

    case PT_LOAD:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "load");

    case PT_DYNAMIC:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "dynamic");

    case PT_INTERP:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "interp");

    case PT_NOTE:
      if (! _bfd_elf_make_section_from_phdr (abfd, hdr, index, "note"))
	return false;
      if (! elfcore_read_notes (abfd, hdr->p_offset, hdr->p_filesz))
	return false;
      return true;

    case PT_SHLIB:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "shlib");

    case PT_PHDR:
      return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "phdr");

    default:
      /* Check for any processor-specific program segment types.
         If no handler for them, default to making "segment" sections.  */
      bed = get_elf_backend_data (abfd);
      if (bed->elf_backend_section_from_phdr)
	return (*bed->elf_backend_section_from_phdr) (abfd, hdr, index);
      else
	return _bfd_elf_make_section_from_phdr (abfd, hdr, index, "segment");
    }
}

/* Initialize REL_HDR, the section-header for new section, containing
   relocations against ASECT.  If USE_RELA_P is true, we use RELA
   relocations; otherwise, we use REL relocations.  */

boolean
_bfd_elf_init_reloc_shdr (abfd, rel_hdr, asect, use_rela_p)
     bfd *abfd;
     Elf_Internal_Shdr *rel_hdr;
     asection *asect;
     boolean use_rela_p;
{
  char *name;
  struct elf_backend_data *bed;

  bed = get_elf_backend_data (abfd);
  name = bfd_alloc (abfd, sizeof ".rela" + strlen (asect->name));
  if (name == NULL)
    return false;
  sprintf (name, "%s%s", use_rela_p ? ".rela" : ".rel", asect->name);
  rel_hdr->sh_name =
    (unsigned int) _bfd_stringtab_add (elf_shstrtab (abfd), name,
				       true, false);
  if (rel_hdr->sh_name == (unsigned int) -1)
    return false;
  rel_hdr->sh_type = use_rela_p ? SHT_RELA : SHT_REL;
  rel_hdr->sh_entsize = (use_rela_p
			 ? bed->s->sizeof_rela
			 : bed->s->sizeof_rel);
  rel_hdr->sh_addralign = bed->s->file_align;
  rel_hdr->sh_flags = 0;
  rel_hdr->sh_addr = 0;
  rel_hdr->sh_size = 0;
  rel_hdr->sh_offset = 0;

  return true;
}

/* Set up an ELF internal section header for a section.  */

static void
elf_fake_sections (abfd, asect, failedptrarg)
     bfd *abfd;
     asection *asect;
     PTR failedptrarg;
{
  struct elf_backend_data *bed = get_elf_backend_data (abfd);
  boolean *failedptr = (boolean *) failedptrarg;
  Elf_Internal_Shdr *this_hdr;

  if (*failedptr)
    {
      /* We already failed; just get out of the bfd_map_over_sections
         loop.  */
      return;
    }

  this_hdr = &elf_section_data (asect)->this_hdr;

  this_hdr->sh_name = (unsigned long) _bfd_stringtab_add (elf_shstrtab (abfd),
							  asect->name,
							  true, false);
  if (this_hdr->sh_name == (unsigned long) -1)
    {
      *failedptr = true;
      return;
    }

  this_hdr->sh_flags = 0;

  if ((asect->flags & SEC_ALLOC) != 0
      || asect->user_set_vma)
    this_hdr->sh_addr = asect->vma;
  else
    this_hdr->sh_addr = 0;

  this_hdr->sh_offset = 0;
  this_hdr->sh_size = asect->_raw_size;
  this_hdr->sh_link = 0;
  this_hdr->sh_addralign = 1 << asect->alignment_power;
  /* The sh_entsize and sh_info fields may have been set already by
     copy_private_section_data.  */

  this_hdr->bfd_section = asect;
  this_hdr->contents = NULL;

  /* FIXME: This should not be based on section names.  */
  if (strcmp (asect->name, ".dynstr") == 0)
    this_hdr->sh_type = SHT_STRTAB;
  else if (strcmp (asect->name, ".hash") == 0)
    {
      this_hdr->sh_type = SHT_HASH;
      this_hdr->sh_entsize = bed->s->sizeof_hash_entry;
    }
  else if (strcmp (asect->name, ".dynsym") == 0)
    {
      this_hdr->sh_type = SHT_DYNSYM;
      this_hdr->sh_entsize = bed->s->sizeof_sym;
    }
  else if (strcmp (asect->name, ".dynamic") == 0)
    {
      this_hdr->sh_type = SHT_DYNAMIC;
      this_hdr->sh_entsize = bed->s->sizeof_dyn;
    }
  else if (strncmp (asect->name, ".rela", 5) == 0
	   && get_elf_backend_data (abfd)->may_use_rela_p)
    {
      this_hdr->sh_type = SHT_RELA;
      this_hdr->sh_entsize = bed->s->sizeof_rela;
    }
  else if (strncmp (asect->name, ".rel", 4) == 0
	   && get_elf_backend_data (abfd)->may_use_rel_p)
    {
      this_hdr->sh_type = SHT_REL;
      this_hdr->sh_entsize = bed->s->sizeof_rel;
    }
  else if (strncmp (asect->name, ".note", 5) == 0)
    this_hdr->sh_type = SHT_NOTE;
  else if (strncmp (asect->name, ".stab", 5) == 0
	   && strcmp (asect->name + strlen (asect->name) - 3, "str") == 0)
    this_hdr->sh_type = SHT_STRTAB;
  else if (strcmp (asect->name, ".gnu.version") == 0)
    {
      this_hdr->sh_type = SHT_GNU_versym;
      this_hdr->sh_entsize = sizeof (Elf_External_Versym);
    }
  else if (strcmp (asect->name, ".gnu.version_d") == 0)
    {
      this_hdr->sh_type = SHT_GNU_verdef;
      this_hdr->sh_entsize = 0;
      /* objcopy or strip will copy over sh_info, but may not set
         cverdefs.  The linker will set cverdefs, but sh_info will be
         zero.  */
      if (this_hdr->sh_info == 0)
	this_hdr->sh_info = elf_tdata (abfd)->cverdefs;
      else
	BFD_ASSERT (elf_tdata (abfd)->cverdefs == 0
		    || this_hdr->sh_info == elf_tdata (abfd)->cverdefs);
    }
  else if (strcmp (asect->name, ".gnu.version_r") == 0)
    {
      this_hdr->sh_type = SHT_GNU_verneed;
      this_hdr->sh_entsize = 0;
      /* objcopy or strip will copy over sh_info, but may not set
         cverrefs.  The linker will set cverrefs, but sh_info will be
         zero.  */
      if (this_hdr->sh_info == 0)
	this_hdr->sh_info = elf_tdata (abfd)->cverrefs;
      else
	BFD_ASSERT (elf_tdata (abfd)->cverrefs == 0
		    || this_hdr->sh_info == elf_tdata (abfd)->cverrefs);
    }
  else if ((asect->flags & SEC_ALLOC) != 0
	   && ((asect->flags & (SEC_LOAD | SEC_HAS_CONTENTS)) == 0))
    this_hdr->sh_type = SHT_NOBITS;
  else
    this_hdr->sh_type = SHT_PROGBITS;

  if ((asect->flags & SEC_ALLOC) != 0)
    this_hdr->sh_flags |= SHF_ALLOC;
  if ((asect->flags & SEC_READONLY) == 0)
    this_hdr->sh_flags |= SHF_WRITE;
  if ((asect->flags & SEC_CODE) != 0)
    this_hdr->sh_flags |= SHF_EXECINSTR;

  /* Check for processor-specific section types.  */
  if (bed->elf_backend_fake_sections)
    (*bed->elf_backend_fake_sections) (abfd, this_hdr, asect);