/src/binutils-gdb/bfd/elf-properties.c

Source
/* ELF program property support.
   Copyright (C) 2017-2026 Free Software Foundation, Inc.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

/* GNU program property draft is at:

   https://github.com/hjl-tools/linux-abi/wiki/property-draft.pdf
 */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "elf-bfd.h"

/* Find a property.  */
elf_property_list *
_bfd_elf_find_property (elf_property_list *l,
      unsigned int type,
      elf_property_list **prev)
{
  if (prev != NULL)
    *prev = NULL;

  /* The properties are supposed to be sorted in the list.  */
  for (elf_property_list *n = l; n != NULL; n = n->next)
    {
      if (type == n->property.pr_type)
  return n;
      else if (type < n->property.pr_type)
  break;
      else if (prev != NULL)
  *prev = n;
    }
  return NULL;
}

/* Insert a property into the list after prev.  */
static elf_property_list *
_bfd_elf_insert_property (elf_property_list *l,
        elf_property_list *what,
        elf_property_list *prev)
{
  if (l == NULL) // First node.
    return what;

  if (prev == NULL) // Prepend.
    {
      what->next = l;
      return what;
    }

  what->next = prev->next;
  prev->next = what;
  return l;
}

/* Remove a property from the list after prev.  */
static elf_property_list *
_bfd_elf_remove_property (elf_property_list *l,
        elf_property_list *what,
        elf_property_list *prev)
{
  if (l == NULL)
    return l;

  if (prev == NULL) // Pop front
    {
      BFD_ASSERT (what == l);
      l = what->next;
    }
  else
    prev->next = what->next;

  what->next = NULL;
  return l;
}

/* Get a property, allocate a new one if needed.  */

elf_property *
_bfd_elf_get_property (bfd *abfd, unsigned int type, unsigned int datasz)
{
  if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
    {
      /* Never should happen.  */
      abort ();
    }

  elf_property_list *prev;
  elf_property_list *p =
    _bfd_elf_find_property (elf_properties (abfd), type, &prev);
  if (p != NULL)  /* Reuse the existing entry.  */
    {
      if (datasz > p->property.pr_datasz)
  {
    /* This can happen when mixing 32-bit and 64-bit objects.  */
    p->property.pr_datasz = datasz;
  }
      return &p->property;
    }

  p = (elf_property_list *) bfd_alloc (abfd, sizeof (*p));
  if (p == NULL)
    {
      _bfd_error_handler (_("%pB: out of memory in _bfd_elf_get_property"),
        abfd);
      _exit (EXIT_FAILURE);
    }

  memset (p, 0, sizeof (*p));
  p->property.pr_type = type;
  p->property.pr_datasz = datasz;

  elf_properties (abfd) =
    _bfd_elf_insert_property (elf_properties (abfd), p, prev);

  return &p->property;
}

/* Parse GNU properties.  */

bool
_bfd_elf_parse_gnu_properties (bfd *abfd, Elf_Internal_Note *note)
{
  elf_backend_data *bed = get_elf_backend_data (abfd);
  unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;
  bfd_byte *ptr = (bfd_byte *) note->descdata;
  bfd_byte *ptr_end = ptr + note->descsz;

  if (note->descsz < 8 || (note->descsz % align_size) != 0)
    {
    bad_size:
      _bfd_error_handler
  (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx"),
   abfd, note->type, note->descsz);
      return false;
    }

  while (ptr != ptr_end)
    {
      unsigned int type;
      unsigned int datasz;
      elf_property *prop;

      if ((size_t) (ptr_end - ptr) < 8)
  goto bad_size;

      type = bfd_h_get_32 (abfd, ptr);
      datasz = bfd_h_get_32 (abfd, ptr + 4);
      ptr += 8;

      if (datasz > (size_t) (ptr_end - ptr))
  {
    _bfd_error_handler
      (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x"),
       abfd, note->type, type, datasz);
    /* Clear all properties.  */
    elf_properties (abfd) = NULL;
    return false;
  }

      if (type >= GNU_PROPERTY_LOPROC)
  {
    if (bed->elf_machine_code == EM_NONE)
      {
        /* Ignore processor-specific properties with generic ELF
     target vector.  They should be handled by the matching
     ELF target vector.  */
        goto next;
      }
    else if (type < GNU_PROPERTY_LOUSER
       && bed->parse_gnu_properties)
      {
        enum elf_property_kind kind
    = bed->parse_gnu_properties (abfd, type, ptr, datasz);
        if (kind == property_corrupt)
    {
      /* Clear all properties.  */
      elf_properties (abfd) = NULL;
      return false;
    }
        else if (kind != property_ignored)
    goto next;
      }
  }
      else
  {
    switch (type)
      {
      case GNU_PROPERTY_STACK_SIZE:
        if (datasz != align_size)
    {
      _bfd_error_handler
        (_("warning: %pB: corrupt stack size: 0x%x"),
         abfd, datasz);
      /* Clear all properties.  */
      elf_properties (abfd) = NULL;
      return false;
    }
        prop = _bfd_elf_get_property (abfd, type, datasz);
        if (datasz == 8)
    prop->u.number = bfd_h_get_64 (abfd, ptr);
        else
    prop->u.number = bfd_h_get_32 (abfd, ptr);
        prop->pr_kind = property_number;
        goto next;

      case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
        if (datasz != 0)
    {
      _bfd_error_handler
        (_("warning: %pB: corrupt no copy on protected size: 0x%x"),
         abfd, datasz);
      /* Clear all properties.  */
      elf_properties (abfd) = NULL;
      return false;
    }
        prop = _bfd_elf_get_property (abfd, type, datasz);
        elf_has_no_copy_on_protected (abfd) = true;
        prop->pr_kind = property_number;
        goto next;

      case GNU_PROPERTY_MEMORY_SEAL:
        if (datasz != 0)
    {
      _bfd_error_handler
        (_("warning: %pB: corrupt memory sealing size: 0x%x"),
         abfd, datasz);
      /* Clear all properties.  */
      elf_properties (abfd) = NULL;
      return false;
    }
        prop = _bfd_elf_get_property (abfd, type, datasz);
        prop->pr_kind = property_number;
        goto next;

      default:
        if ((type >= GNU_PROPERTY_UINT32_AND_LO
       && type <= GNU_PROPERTY_UINT32_AND_HI)
      || (type >= GNU_PROPERTY_UINT32_OR_LO
          && type <= GNU_PROPERTY_UINT32_OR_HI))
    {
      if (datasz != 4)
        {
          _bfd_error_handler
      (_("error: %pB: <corrupt property (0x%x) size: 0x%x>"),
       abfd, type, datasz);
          /* Clear all properties.  */
          elf_properties (abfd) = NULL;
          return false;
        }
      prop = _bfd_elf_get_property (abfd, type, datasz);
      prop->u.number |= bfd_h_get_32 (abfd, ptr);
      prop->pr_kind = property_number;
      if (type == GNU_PROPERTY_1_NEEDED
          && ((prop->u.number
         & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
        != 0))
        {
          elf_has_indirect_extern_access (abfd) = true;
          /* GNU_PROPERTY_NO_COPY_ON_PROTECTED is implied.  */
          elf_has_no_copy_on_protected (abfd) = true;
        }
      goto next;
    }
        break;
      }
  }

      _bfd_error_handler
  (_("warning: %pB: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x"),
   abfd, note->type, type);

    next:
      ptr += (datasz + (align_size - 1)) & ~ (align_size - 1);
    }

  return true;
}

/* Merge GNU property BPROP with APROP.  If APROP isn't NULL, return TRUE
   if APROP is updated.  Otherwise, return TRUE if BPROP should be merged
   with ABFD.  */

static bool
elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd, bfd *bbfd,
        elf_property *aprop, elf_property *bprop)
{
  elf_backend_data *bed = get_elf_backend_data (abfd);
  unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type;
  unsigned int number;
  bool updated;

  if (bed->merge_gnu_properties != NULL
      && pr_type >= GNU_PROPERTY_LOPROC
      && pr_type < GNU_PROPERTY_LOUSER)
    return bed->merge_gnu_properties (info, abfd, bbfd, aprop, bprop);

  switch (pr_type)
    {
    case GNU_PROPERTY_STACK_SIZE:
      if (aprop != NULL && bprop != NULL)
  {
    if (bprop->u.number > aprop->u.number)
      {
        aprop->u.number = bprop->u.number;
        return true;
      }
    break;
  }
      /* FALLTHROUGH */

    case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
    case GNU_PROPERTY_MEMORY_SEAL:
      /* Return TRUE if APROP is NULL to indicate that BPROP should
   be added to ABFD.  */
      return aprop == NULL;

    default:
      updated = false;
      if (pr_type >= GNU_PROPERTY_UINT32_OR_LO
    && pr_type <= GNU_PROPERTY_UINT32_OR_HI)
  {
    if (aprop != NULL && bprop != NULL)
      {
        number = aprop->u.number;
        aprop->u.number = number | bprop->u.number;
        /* Remove the property if all bits are empty.  */
        if (aprop->u.number == 0)
    {
      aprop->pr_kind = property_remove;
      updated = true;
    }
        else
    updated = number != (unsigned int) aprop->u.number;
      }
    else
      {
        /* Only one of APROP and BPROP can be NULL.  */
        if (aprop != NULL)
    {
      if (aprop->u.number == 0)
        {
          /* Remove APROP if all bits are empty.  */
          aprop->pr_kind = property_remove;
          updated = true;
        }
    }
        else
    {
      /* Return TRUE if APROP is NULL and all bits of BPROP
         aren't empty to indicate that BPROP should be added
         to ABFD.  */
      updated = bprop->u.number != 0;
    }
      }
    return updated;
  }
      else if (pr_type >= GNU_PROPERTY_UINT32_AND_LO
         && pr_type <= GNU_PROPERTY_UINT32_AND_HI)
  {
    /* Only one of APROP and BPROP can be NULL:
       1. APROP & BPROP when both APROP and BPROP aren't NULL.
       2. If APROP is NULL, remove x86 feature.
       3. Otherwise, do nothing.
       */
    if (aprop != NULL && bprop != NULL)
      {
        number = aprop->u.number;
        aprop->u.number = number & bprop->u.number;
        updated = number != (unsigned int) aprop->u.number;
        /* Remove the property if all feature bits are cleared.  */
        if (aprop->u.number == 0)
    aprop->pr_kind = property_remove;
      }
    else
      {
        /* There should be no AND properties since some input
           doesn't have them.   */
        if (aprop != NULL)
    {
      aprop->pr_kind = property_remove;
      updated = true;
    }
      }
    return updated;
  }

      /* Never should happen.  */
      abort ();
    }

  return false;
}

/* Return the property of TYPE on *LISTP and remove it from *LISTP if RM is
   true.  Return NULL if not found.  */

static elf_property *
elf_find_and_remove_property (elf_property_list **listp,
            unsigned int type, bool rm)
{
  elf_property_list *prev;
  elf_property_list *p = _bfd_elf_find_property (*listp, type, &prev);
  if (p == NULL)
    return NULL;

  if (rm)
    *listp = _bfd_elf_remove_property (*listp, p, prev);

  /* FIXME: we leak memory with this approach.  */
  return &p->property;
}

/* Merge GNU property list *LISTP in ABFD with FIRST_PBFD.  */

static void
elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
           bfd *abfd, elf_property_list **listp)
{
  elf_property_list *p, **lastp;
  elf_property *pr;
  bool number_p;
  bfd_vma number = 0;

  /* Merge each GNU property in FIRST_PBFD with the one on *LISTP.  */
  lastp = &elf_properties (first_pbfd);
  for (p = *lastp; p; p = p->next)
    if (p->property.pr_kind != property_remove)
      {
  if (p->property.pr_kind == property_number)
    {
      number_p = true;
      number = p->property.u.number;
    }
  else
    number_p = false;
  pr = elf_find_and_remove_property (listp, p->property.pr_type,
             true);
  /* Pass NULL to elf_merge_gnu_properties for the property which
     isn't on *LISTP.  */
  elf_merge_gnu_properties (info, first_pbfd, abfd, &p->property, pr);
  if (p->property.pr_kind == property_remove)
    {
      if (info->has_map_file)
        {
    if (number_p)
      {
        if (pr != NULL)
          info->callbacks->minfo
      (_("Removed property %W to merge %pB (0x%v) "
         "and %pB (0x%v)\n"),
       (bfd_vma) p->property.pr_type, first_pbfd,
       number, abfd, pr->u.number);
        else
          info->callbacks->minfo
      (_("Removed property %W to merge %pB (0x%v) "
         "and %pB (not found)\n"),
       (bfd_vma) p->property.pr_type, first_pbfd,
       number, abfd);
      }
    else
      {
        if (pr != NULL)
          info->callbacks->minfo
      (_("Removed property %W to merge %pB and %pB\n"),
       (bfd_vma) p->property.pr_type, first_pbfd, abfd);
        else
          info->callbacks->minfo
      (_("Removed property %W to merge %pB and %pB "
         "(not found)\n"),
       (bfd_vma) p->property.pr_type, first_pbfd, abfd);
      }
        }

      /* Remove this property.  */
      *lastp = p->next;
      continue;
    }
  else if (number_p)
    {
      if (pr != NULL)
        {
    if (p->property.u.number != number
        || p->property.u.number != pr->u.number)
      info->callbacks->minfo
        (_("Updated property %W (0x%v) to merge %pB (0x%v) "
           "and %pB (0x%v)\n"),
         (bfd_vma) p->property.pr_type, p->property.u.number,
         first_pbfd, number, abfd, pr->u.number);
        }
      else
        {
    if (p->property.u.number != number)
      info->callbacks->minfo
        (_("Updated property %W (%v) to merge %pB (0x%v) "
           "and %pB (not found)\n"),
         (bfd_vma) p->property.pr_type, p->property.u.number,
         first_pbfd, number, abfd);
        }
    }
  lastp = &p->next;
      }

  /* Merge the remaining properties on *LISTP with FIRST_PBFD.  */
  for (p = *listp; p != NULL; p = p->next)
    {
      if (p->property.pr_kind == property_number)
  {
    number_p = true;
    number = p->property.u.number;
  }
      else
  number_p = false;

      if (elf_merge_gnu_properties (info, first_pbfd, abfd, NULL, &p->property))
  {
    if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
      elf_has_no_copy_on_protected (first_pbfd) = true;

    pr = _bfd_elf_get_property (first_pbfd, p->property.pr_type,
              p->property.pr_datasz);
    /* It must be a new property.  */
    if (pr->pr_kind != property_unknown)
      abort ();
    /* Add a new property.  */
    *pr = p->property;
  }
      else
  {
    pr = elf_find_and_remove_property (&elf_properties (first_pbfd),
               p->property.pr_type,
               false);
    if (pr == NULL)
      {
        if (number_p)
    info->callbacks->minfo
      (_("Removed property %W to merge %pB (not found) and "
         "%pB (0x%v)\n"),
       (bfd_vma) p->property.pr_type, first_pbfd, abfd,
       number);
        else
    info->callbacks->minfo
      (_("Removed property %W to merge %pB and %pB\n"),
       (bfd_vma) p->property.pr_type, first_pbfd, abfd);
      }
    else if (pr->pr_kind != property_remove)
      abort ();
  }
    }
}

/* Get GNU property section size.  */

static bfd_size_type
elf_get_gnu_property_section_size (elf_property_list *list,
           unsigned int align_size)
{
  bfd_size_type size;
  unsigned int descsz;

  /* Compute the output section size.  */
  descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
  descsz = (descsz + 3) & -(unsigned int) 4;
  size = descsz;
  for (; list != NULL; list = list->next)
    {
      unsigned int datasz;
      /* Check if this property should be skipped.  */
      if (list->property.pr_kind == property_remove)
  continue;
      /* There are 4 byte type + 4 byte datasz for each property.  */
      if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
  datasz = align_size;
      else
  datasz = list->property.pr_datasz;
      size += 4 + 4 + datasz;
      /* Align each property.  */
      size = (size + (align_size - 1)) & ~(align_size - 1);
    }

  return size;
}

/* Write GNU properties.  */

static void
elf_write_gnu_properties (struct bfd_link_info *info,
        bfd *abfd, bfd_byte *contents,
        elf_property_list *list, unsigned int size,
        unsigned int align_size)
{
  unsigned int descsz;
  unsigned int datasz;
  Elf_External_Note *e_note;

  e_note = (Elf_External_Note *) contents;
  descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
  descsz = (descsz + 3) & -(unsigned int) 4;
  bfd_h_put_32 (abfd, sizeof "GNU", &e_note->namesz);
  bfd_h_put_32 (abfd, size - descsz, &e_note->descsz);
  bfd_h_put_32 (abfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type);
  memcpy (e_note->name, "GNU", sizeof "GNU");

  size = descsz;
  for (; list != NULL; list = list->next)
    {
      /* Check if this property should be skipped.  */
      if (list->property.pr_kind == property_remove)
  continue;
      /* There are 4 byte type + 4 byte datasz for each property.  */
      if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
  datasz = align_size;
      else
  datasz = list->property.pr_datasz;
      bfd_h_put_32 (abfd, list->property.pr_type, contents + size);
      bfd_h_put_32 (abfd, datasz, contents + size + 4);
      size += 4 + 4;

      /* Write out property value.  */
      switch (list->property.pr_kind)
  {
  case property_number:
    switch (datasz)
      {
      default:
        /* Never should happen.  */
        abort ();

      case 0:
        break;

      case 4:
        /* Save the pointer to GNU_PROPERTY_1_NEEDED so that it
     can be updated later if needed.  */
        if (info != NULL
      && list->property.pr_type == GNU_PROPERTY_1_NEEDED)
    info->needed_1_p = contents + size;
        bfd_h_put_32 (abfd, list->property.u.number,
          contents + size);
        break;

      case 8:
        bfd_h_put_64 (abfd, list->property.u.number,
          contents + size);
        break;
      }
    break;

  default:
    /* Never should happen.  */
    abort ();
  }
      size += datasz;

      /* Align each property.  */
      datasz = -size & (align_size - 1);
      if (datasz)
  {
    memset (contents + size, 0, datasz);
    size += datasz;
  }
    }
}

static asection *
_bfd_elf_link_create_gnu_property_sec (struct bfd_link_info *info, bfd *elf_bfd,
               unsigned int elfclass)
{
  asection *sec;

  sec = bfd_make_section_with_flags (elf_bfd,
             NOTE_GNU_PROPERTY_SECTION_NAME,
             (SEC_ALLOC
              | SEC_LOAD
              | SEC_IN_MEMORY
              | SEC_READONLY
              | SEC_HAS_CONTENTS
              | SEC_DATA));
  if (sec == NULL
      || !bfd_set_section_alignment (sec, elfclass == ELFCLASS64 ? 3 : 2))
    info->callbacks->fatal (_("%P: failed to create %s\n"),
          NOTE_GNU_PROPERTY_SECTION_NAME);

  elf_section_type (sec) = SHT_NOTE;
  return sec;
}

/* Prune empty generic properties.  */

static void
elf_prune_empty_properties (elf_property_list **pp)
{
  elf_property_list *p;

  while ((p = *pp) != NULL)
    if ((p->property.pr_type < GNU_PROPERTY_LOPROC
   || p->property.pr_type >= GNU_PROPERTY_LOUSER)
  && p->property.pr_datasz != 0
  && p->property.pr_kind == property_number
  && p->property.u.number == 0)
      *pp = p->next;
    else
      pp = &p->next;
}

/* Set up GNU properties.  Return the first relocatable ELF input with
   GNU properties if found.  Otherwise, return NULL.  */

bfd *
_bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info)
{
  bfd *abfd, *first_pbfd = NULL, *elf_bfd = NULL;
  elf_property_list *list;
  asection *sec;
  bool has_properties = false;
  elf_backend_data *bed = get_elf_backend_data (info->output_bfd);
  unsigned int elfclass = bed->s->elfclass;
  int elf_machine_code = bed->elf_machine_code;
  elf_property *p;

  /* Find the first relocatable ELF input with GNU properties.  */
  for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
    if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
  && (abfd->flags & DYNAMIC) == 0
  && (elf_machine_code
      == get_elf_backend_data (abfd)->elf_machine_code)
  && (elfclass == get_elf_backend_data (abfd)->s->elfclass))
      {
  /* Ignore GNU properties from ELF objects with different machine
     code or class.  Also skip objects without a GNU_PROPERTY note
     section.  */
  elf_bfd = abfd;

  if (elf_properties (abfd) != NULL)
    {
      has_properties = true;

      if (bfd_get_section_by_name (abfd,
           NOTE_GNU_PROPERTY_SECTION_NAME)
    != NULL)
        {
    /* Keep .note.gnu.property section in FIRST_PBFD.  */
    first_pbfd = abfd;
    break;
        }
    }
      }

  if (info->indirect_extern_access > 0 && elf_bfd != NULL)
    {
      /* Support -z indirect-extern-access.  */
      if (first_pbfd == NULL)
  {
    sec = _bfd_elf_link_create_gnu_property_sec (info, elf_bfd, elfclass);
    first_pbfd = elf_bfd;
    has_properties = true;
  }

      p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_1_NEEDED, 4);
      if (p->pr_kind == property_unknown)
  {
    /* Create GNU_PROPERTY_1_NEEDED.  */
    p->u.number
      = GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
    p->pr_kind = property_number;
  }
      else
  p->u.number
    |= GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
    }

  if (elf_bfd != NULL)
    {
      if (info->memory_seal)
  {
    /* Support -z no-memory-seal.  */
    if (first_pbfd == NULL)
      {
        sec = _bfd_elf_link_create_gnu_property_sec (info, elf_bfd, elfclass);
        first_pbfd = elf_bfd;
        has_properties = true;
      }

    p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_MEMORY_SEAL, 0);
    if (p->pr_kind == property_unknown)
      {
        /* Create GNU_PROPERTY_NO_MEMORY_SEAL.  */
        p->u.number = GNU_PROPERTY_MEMORY_SEAL;
        p->pr_kind = property_number;
      }
  }
      else
  elf_find_and_remove_property (&elf_properties (elf_bfd),
              GNU_PROPERTY_MEMORY_SEAL, true);
    }

  /* Do nothing if there is no .note.gnu.property section.  */
  if (!has_properties)
    return NULL;

  /* Merge .note.gnu.property sections.  */
  info->callbacks->minfo (_("\n"));
  info->callbacks->minfo (_("Merging program properties\n"));
  info->callbacks->minfo (_("\n"));

  for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
    if (abfd != first_pbfd
  && (abfd->flags & (DYNAMIC | BFD_PLUGIN | BFD_LINKER_CREATED)) == 0)
      {
  elf_property_list *null_ptr = NULL;
  elf_property_list **listp = &null_ptr;

  /* Merge .note.gnu.property section in relocatable ELF input.  */
  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
    {
      list = elf_properties (abfd);

      /* Ignore GNU properties from ELF objects with different
         machine code.  */
      if (list != NULL
    && (elf_machine_code
        == get_elf_backend_data (abfd)->elf_machine_code))
        listp = &elf_properties (abfd);
    }
  else
    list = NULL;

  /* Merge properties with FIRST_PBFD.  FIRST_PBFD can be NULL
     when all properties are from ELF objects with different
     machine code or class.  */
  if (first_pbfd != NULL)
    elf_merge_gnu_property_list (info, first_pbfd, abfd, listp);

  if (list != NULL)
    {
      /* Discard the .note.gnu.property section in this bfd.  */
      sec = bfd_get_section_by_name (abfd,
             NOTE_GNU_PROPERTY_SECTION_NAME);
      if (sec != NULL)
        sec->output_section = bfd_abs_section_ptr;
    }
      }

  /* Rewrite .note.gnu.property section so that GNU properties are
     always sorted by type even if input GNU properties aren't sorted.  */
  if (first_pbfd != NULL)
    {
      bfd_size_type size;
      bfd_byte *contents;
      unsigned int align_size = elfclass == ELFCLASS64 ? 8 : 4;

      sec = bfd_get_section_by_name (first_pbfd,
             NOTE_GNU_PROPERTY_SECTION_NAME);
      BFD_ASSERT (sec != NULL);

      /* Update stack size in .note.gnu.property with -z stack-size=N
   if N > 0.  */
      if (info->stacksize > 0)
  {
    bfd_vma stacksize = info->stacksize;

    p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE,
             align_size);
    if (p->pr_kind == property_unknown)
      {
        /* Create GNU_PROPERTY_STACK_SIZE.  */
        p->u.number = stacksize;
        p->pr_kind = property_number;
      }
    else if (stacksize > p->u.number)
      p->u.number = stacksize;
  }
      else if (elf_properties (first_pbfd) == NULL)
  {
    /* Discard .note.gnu.property section if all properties have
       been removed.  */
    sec->output_section = bfd_abs_section_ptr;
    return NULL;
  }

      /* Fix up GNU properties.  */
      if (bed->fixup_gnu_properties)
  bed->fixup_gnu_properties (info, &elf_properties (first_pbfd));

      if (info->indirect_extern_access <= 0)
  {
    /* Get GNU_PROPERTY_1_NEEDED properties.  */
    p = elf_find_and_remove_property (&elf_properties (first_pbfd),
              GNU_PROPERTY_1_NEEDED, false);
    if (p != NULL)
      {
        if (info->indirect_extern_access < 0)
    {
      /* Set indirect_extern_access to 1 to indicate that
         it is turned on by input properties.  */
      if ((p->u.number
           & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
          != 0)
        info->indirect_extern_access = 1;
    }
        else
    /* Turn off indirect external access.  */
    p->u.number
      &= ~GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
      }
  }

      elf_prune_empty_properties (&elf_properties (first_pbfd));

      if (elf_properties (first_pbfd) == NULL)
  {
    /* Discard .note.gnu.property section if all properties have
       been removed.  */
    sec->output_section = bfd_abs_section_ptr;
    return NULL;
  }

      /* Compute the section size.  */
      list = elf_properties (first_pbfd);
      size = elf_get_gnu_property_section_size (list, align_size);

      /* Update .note.gnu.property section now.  */
      sec->size = size;
      contents = bfd_alloc (first_pbfd, size);

      elf_write_gnu_properties (info, first_pbfd, contents, list, size,
        align_size);

      /* Cache the section contents for elf_link_input_bfd.  */
      sec->alloced = 1;
      elf_section_data (sec)->this_hdr.contents = contents;

      /* If GNU_PROPERTY_NO_COPY_ON_PROTECTED is set, protected data
   symbol is defined in the shared object.  */
      if (elf_has_no_copy_on_protected (first_pbfd))
  info->extern_protected_data = false;

      if (info->indirect_extern_access > 0)
  {
    /* For indirect external access, don't generate copy
       relocations.  NB: Set to nocopyreloc to 2 to indicate
       that it is implied by indirect_extern_access.  */
    info->nocopyreloc = 2;
    info->extern_protected_data = false;
  }
    }

  return first_pbfd;
}

/* Convert GNU property size.  */

bfd_size_type
_bfd_elf_convert_gnu_property_size (bfd *ibfd, bfd *obfd)
{
  unsigned int align_size;
  elf_backend_data *bed;
  elf_property_list *list = elf_properties (ibfd);

  bed = get_elf_backend_data (obfd);
  align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;

  /* Get the output .note.gnu.property section size.  */
  return elf_get_gnu_property_section_size (list, align_size);
}

/* Convert GNU properties.  */

bool
_bfd_elf_convert_gnu_properties (bfd *ibfd, asection *isec,
         bfd *obfd, bfd_byte **ptr,
         bfd_size_type *ptr_size)
{
  unsigned int size;
  bfd_byte *contents;
  unsigned int align_shift;
  elf_backend_data *bed;
  elf_property_list *list = elf_properties (ibfd);

  bed = get_elf_backend_data (obfd);
  align_shift = bed->s->elfclass == ELFCLASS64 ? 3 : 2;

  /* Get the output .note.gnu.property section size.  */
  size = bfd_section_size (isec->output_section);

  /* Update the output .note.gnu.property section alignment.  */
  bfd_set_section_alignment (isec->output_section, align_shift);

  if (size > bfd_section_size (isec))
    {
      contents = (bfd_byte *) bfd_malloc (size);
      if (contents == NULL)
  return false;
      free (*ptr);
      *ptr = contents;
    }
  else
    contents = *ptr;

  *ptr_size = size;

  /* Generate the output .note.gnu.property section.  */
  elf_write_gnu_properties (NULL, ibfd, contents, list, size,
          1 << align_shift);

  return true;
}

Coverage Report

Created: 2026-05-11 07:54