bfd/elf-properties.c

   1 /* ELF program property support.
   2    Copyright (C) 2017-2024 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 /* GNU program property draft is at:
  22
  23    https://github.com/hjl-tools/linux-abi/wiki/property-draft.pdf
  24  */
  25
  26 #include "sysdep.h"
  27 #include "bfd.h"
  28 #include "libbfd.h"
  29 #include "elf-bfd.h"
  30
  31 /* Get a property, allocate a new one if needed.  */
  32
  33 elf_property *
  34 _bfd_elf_get_property (bfd *abfd, unsigned int type, unsigned int datasz)
  35 {
  36   elf_property_list *p, **lastp;
  37
  38   if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
  39     {
  40       /* Never should happen.  */
  41       abort ();
  42     }
  43
  44   /* Keep the property list in order of type.  */
  45   lastp = &elf_properties (abfd);
  46   for (p = *lastp; p; p = p->next)
  47     {
  48       /* Reuse the existing entry.  */
  49       if (type == p->property.pr_type)
  50         {
  51           if (datasz > p->property.pr_datasz)
  52             {
  53               /* This can happen when mixing 32-bit and 64-bit objects.  */
  54               p->property.pr_datasz = datasz;
  55             }
  56           return &p->property;
  57         }
  58       else if (type < p->property.pr_type)
  59         break;
  60       lastp = &p->next;
  61     }
  62   p = (elf_property_list *) bfd_alloc (abfd, sizeof (*p));
  63   if (p == NULL)
  64     {
  65       _bfd_error_handler (_("%pB: out of memory in _bfd_elf_get_property"),
  66                           abfd);
  67       _exit (EXIT_FAILURE);
  68     }
  69   memset (p, 0, sizeof (*p));
  70   p->property.pr_type = type;
  71   p->property.pr_datasz = datasz;
  72   p->next = *lastp;
  73   *lastp = p;
  74   return &p->property;
  75 }
  76
  77 /* Parse GNU properties.  */
  78
  79 bool
  80 _bfd_elf_parse_gnu_properties (bfd *abfd, Elf_Internal_Note *note)
  81 {
  82   const struct elf_backend_data *bed = get_elf_backend_data (abfd);
  83   unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;
  84   bfd_byte *ptr = (bfd_byte *) note->descdata;
  85   bfd_byte *ptr_end = ptr + note->descsz;
  86
  87   if (note->descsz < 8 || (note->descsz % align_size) != 0)
  88     {
  89     bad_size:
  90       _bfd_error_handler
  91         (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx"),
  92          abfd, note->type, note->descsz);
  93       return false;
  94     }
  95
  96   while (ptr != ptr_end)
  97     {
  98       unsigned int type;
  99       unsigned int datasz;
 100       elf_property *prop;
 101
 102       if ((size_t) (ptr_end - ptr) < 8)
 103         goto bad_size;
 104
 105       type = bfd_h_get_32 (abfd, ptr);
 106       datasz = bfd_h_get_32 (abfd, ptr + 4);
 107       ptr += 8;
 108
 109       if (datasz > (size_t) (ptr_end - ptr))
 110         {
 111           _bfd_error_handler
 112             (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x"),
 113              abfd, note->type, type, datasz);
 114           /* Clear all properties.  */
 115           elf_properties (abfd) = NULL;
 116           return false;
 117         }
 118
 119       if (type >= GNU_PROPERTY_LOPROC)
 120         {
 121           if (bed->elf_machine_code == EM_NONE)
 122             {
 123               /* Ignore processor-specific properties with generic ELF
 124                  target vector.  They should be handled by the matching
 125                  ELF target vector.  */
 126               goto next;
 127             }
 128           else if (type < GNU_PROPERTY_LOUSER
 129                    && bed->parse_gnu_properties)
 130             {
 131               enum elf_property_kind kind
 132                 = bed->parse_gnu_properties (abfd, type, ptr, datasz);
 133               if (kind == property_corrupt)
 134                 {
 135                   /* Clear all properties.  */
 136                   elf_properties (abfd) = NULL;
 137                   return false;
 138                 }
 139               else if (kind != property_ignored)
 140                 goto next;
 141             }
 142         }
 143       else
 144         {
 145           switch (type)
 146             {
 147             case GNU_PROPERTY_STACK_SIZE:
 148               if (datasz != align_size)
 149                 {
 150                   _bfd_error_handler
 151                     (_("warning: %pB: corrupt stack size: 0x%x"),
 152                      abfd, datasz);
 153                   /* Clear all properties.  */
 154                   elf_properties (abfd) = NULL;
 155                   return false;
 156                 }
 157               prop = _bfd_elf_get_property (abfd, type, datasz);
 158               if (datasz == 8)
 159                 prop->u.number = bfd_h_get_64 (abfd, ptr);
 160               else
 161                 prop->u.number = bfd_h_get_32 (abfd, ptr);
 162               prop->pr_kind = property_number;
 163               goto next;
 164
 165             case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
 166               if (datasz != 0)
 167                 {
 168                   _bfd_error_handler
 169                     (_("warning: %pB: corrupt no copy on protected size: 0x%x"),
 170                      abfd, datasz);
 171                   /* Clear all properties.  */
 172                   elf_properties (abfd) = NULL;
 173                   return false;
 174                 }
 175               prop = _bfd_elf_get_property (abfd, type, datasz);
 176               elf_has_no_copy_on_protected (abfd) = true;
 177               prop->pr_kind = property_number;
 178               goto next;
 179
 180             default:
 181               if ((type >= GNU_PROPERTY_UINT32_AND_LO
 182                    && type <= GNU_PROPERTY_UINT32_AND_HI)
 183                   || (type >= GNU_PROPERTY_UINT32_OR_LO
 184                       && type <= GNU_PROPERTY_UINT32_OR_HI))
 185                 {
 186                   if (datasz != 4)
 187                     {
 188                       _bfd_error_handler
 189                         (_("error: %pB: <corrupt property (0x%x) size: 0x%x>"),
 190                          abfd, type, datasz);
 191                       /* Clear all properties.  */
 192                       elf_properties (abfd) = NULL;
 193                       return false;
 194                     }
 195                   prop = _bfd_elf_get_property (abfd, type, datasz);
 196                   prop->u.number |= bfd_h_get_32 (abfd, ptr);
 197                   prop->pr_kind = property_number;
 198                   if (type == GNU_PROPERTY_1_NEEDED
 199                       && ((prop->u.number
 200                            & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
 201                           != 0))
 202                     {
 203                       elf_has_indirect_extern_access (abfd) = true;
 204                       /* GNU_PROPERTY_NO_COPY_ON_PROTECTED is implied.  */
 205                       elf_has_no_copy_on_protected (abfd) = true;
 206                     }
 207                   goto next;
 208                 }
 209               break;
 210             }
 211         }
 212
 213       _bfd_error_handler
 214         (_("warning: %pB: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x"),
 215          abfd, note->type, type);
 216
 217     next:
 218       ptr += (datasz + (align_size - 1)) & ~ (align_size - 1);
 219     }
 220
 221   return true;
 222 }
 223
 224 /* Merge GNU property BPROP with APROP.  If APROP isn't NULL, return TRUE
 225    if APROP is updated.  Otherwise, return TRUE if BPROP should be merged
 226    with ABFD.  */
 227
 228 static bool
 229 elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd, bfd *bbfd,
 230                           elf_property *aprop, elf_property *bprop)
 231 {
 232   const struct elf_backend_data *bed = get_elf_backend_data (abfd);
 233   unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type;
 234   unsigned int number;
 235   bool updated;
 236
 237   if (bed->merge_gnu_properties != NULL
 238       && pr_type >= GNU_PROPERTY_LOPROC
 239       && pr_type < GNU_PROPERTY_LOUSER)
 240     return bed->merge_gnu_properties (info, abfd, bbfd, aprop, bprop);
 241
 242   switch (pr_type)
 243     {
 244     case GNU_PROPERTY_STACK_SIZE:
 245       if (aprop != NULL && bprop != NULL)
 246         {
 247           if (bprop->u.number > aprop->u.number)
 248             {
 249               aprop->u.number = bprop->u.number;
 250               return true;
 251             }
 252           break;
 253         }
 254       /* FALLTHROUGH */
 255
 256     case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
 257       /* Return TRUE if APROP is NULL to indicate that BPROP should
 258          be added to ABFD.  */
 259       return aprop == NULL;
 260
 261     default:
 262       updated = false;
 263       if (pr_type >= GNU_PROPERTY_UINT32_OR_LO
 264           && pr_type <= GNU_PROPERTY_UINT32_OR_HI)
 265         {
 266           if (aprop != NULL && bprop != NULL)
 267             {
 268               number = aprop->u.number;
 269               aprop->u.number = number | bprop->u.number;
 270               /* Remove the property if all bits are empty.  */
 271               if (aprop->u.number == 0)
 272                 {
 273                   aprop->pr_kind = property_remove;
 274                   updated = true;
 275                 }
 276               else
 277                 updated = number != (unsigned int) aprop->u.number;
 278             }
 279           else
 280             {
 281               /* Only one of APROP and BPROP can be NULL.  */
 282               if (aprop != NULL)
 283                 {
 284                   if (aprop->u.number == 0)
 285                     {
 286                       /* Remove APROP if all bits are empty.  */
 287                       aprop->pr_kind = property_remove;
 288                       updated = true;
 289                     }
 290                 }
 291               else
 292                 {
 293                   /* Return TRUE if APROP is NULL and all bits of BPROP
 294                      aren't empty to indicate that BPROP should be added
 295                      to ABFD.  */
 296                   updated = bprop->u.number != 0;
 297                 }
 298             }
 299           return updated;
 300         }
 301       else if (pr_type >= GNU_PROPERTY_UINT32_AND_LO
 302                && pr_type <= GNU_PROPERTY_UINT32_AND_HI)
 303         {
 304           /* Only one of APROP and BPROP can be NULL:
 305              1. APROP & BPROP when both APROP and BPROP aren't NULL.
 306              2. If APROP is NULL, remove x86 feature.
 307              3. Otherwise, do nothing.
 308              */
 309           if (aprop != NULL && bprop != NULL)
 310             {
 311               number = aprop->u.number;
 312               aprop->u.number = number & bprop->u.number;
 313               updated = number != (unsigned int) aprop->u.number;
 314               /* Remove the property if all feature bits are cleared.  */
 315               if (aprop->u.number == 0)
 316                 aprop->pr_kind = property_remove;
 317             }
 318           else
 319             {
 320               /* There should be no AND properties since some input
 321                  doesn't have them.   */
 322               if (aprop != NULL)
 323                 {
 324                   aprop->pr_kind = property_remove;
 325                   updated = true;
 326                 }
 327             }
 328           return updated;
 329         }
 330
 331       /* Never should happen.  */
 332       abort ();
 333     }
 334
 335   return false;
 336 }
 337
 338 /* Return the property of TYPE on *LISTP and remove it from *LISTP if RM is
 339    true.  Return NULL if not found.  */
 340
 341 static elf_property *
 342 elf_find_and_remove_property (elf_property_list **listp,
 343                               unsigned int type, bool rm)
 344 {
 345   elf_property_list *list;
 346
 347   for (list = *listp; list; list = list->next)
 348     {
 349       if (type == list->property.pr_type)
 350         {
 351           /* Remove this property.  */
 352           if (rm)
 353             *listp = list->next;
 354           return &list->property;
 355         }
 356       else if (type < list->property.pr_type)
 357         break;
 358       listp = &list->next;
 359     }
 360
 361   return NULL;
 362 }
 363
 364 /* Merge GNU property list *LISTP in ABFD with FIRST_PBFD.  */
 365
 366 static void
 367 elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
 368                              bfd *abfd, elf_property_list **listp)
 369 {
 370   elf_property_list *p, **lastp;
 371   elf_property *pr;
 372   bool number_p;
 373   bfd_vma number = 0;
 374
 375   /* Merge each GNU property in FIRST_PBFD with the one on *LISTP.  */
 376   lastp = &elf_properties (first_pbfd);
 377   for (p = *lastp; p; p = p->next)
 378     if (p->property.pr_kind != property_remove)
 379       {
 380         if (p->property.pr_kind == property_number)
 381           {
 382             number_p = true;
 383             number = p->property.u.number;
 384           }
 385         else
 386           number_p = false;
 387         pr = elf_find_and_remove_property (listp, p->property.pr_type,
 388                                            true);
 389         /* Pass NULL to elf_merge_gnu_properties for the property which
 390            isn't on *LISTP.  */
 391         elf_merge_gnu_properties (info, first_pbfd, abfd, &p->property, pr);
 392         if (p->property.pr_kind == property_remove)
 393           {
 394             if (info->has_map_file)
 395               {
 396                 if (number_p)
 397                   {
 398                     if (pr != NULL)
 399                       info->callbacks->minfo
 400                         (_("Removed property %W to merge %pB (0x%v) "
 401                            "and %pB (0x%v)\n"),
 402                          (bfd_vma) p->property.pr_type, first_pbfd,
 403                          number, abfd, pr->u.number);
 404                     else
 405                       info->callbacks->minfo
 406                         (_("Removed property %W to merge %pB (0x%v) "
 407                            "and %pB (not found)\n"),
 408                          (bfd_vma) p->property.pr_type, first_pbfd,
 409                          number, abfd);
 410                   }
 411                 else
 412                   {
 413                     if (pr != NULL)
 414                       info->callbacks->minfo
 415                         (_("Removed property %W to merge %pB and %pB\n"),
 416                          (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 417                     else
 418                       info->callbacks->minfo
 419                         (_("Removed property %W to merge %pB and %pB "
 420                            "(not found)\n"),
 421                          (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 422                   }
 423               }
 424
 425             /* Remove this property.  */
 426             *lastp = p->next;
 427             continue;
 428           }
 429         else if (number_p)
 430           {
 431             if (pr != NULL)
 432               {
 433                 if (p->property.u.number != number
 434                     || p->property.u.number != pr->u.number)
 435                   info->callbacks->minfo
 436                     (_("Updated property %W (0x%v) to merge %pB (0x%v) "
 437                        "and %pB (0x%v)\n"),
 438                      (bfd_vma) p->property.pr_type, p->property.u.number,
 439                      first_pbfd, number, abfd, pr->u.number);
 440               }
 441             else
 442               {
 443                 if (p->property.u.number != number)
 444                   info->callbacks->minfo
 445                     (_("Updated property %W (%v) to merge %pB (0x%v) "
 446                        "and %pB (not found)\n"),
 447                      (bfd_vma) p->property.pr_type, p->property.u.number,
 448                      first_pbfd, number, abfd);
 449               }
 450           }
 451         lastp = &p->next;
 452       }
 453
 454   /* Merge the remaining properties on *LISTP with FIRST_PBFD.  */
 455   for (p = *listp; p != NULL; p = p->next)
 456     {
 457       if (p->property.pr_kind == property_number)
 458         {
 459           number_p = true;
 460           number = p->property.u.number;
 461         }
 462       else
 463         number_p = false;
 464
 465       if (elf_merge_gnu_properties (info, first_pbfd, abfd, NULL, &p->property))
 466         {
 467           if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
 468             elf_has_no_copy_on_protected (first_pbfd) = true;
 469
 470           pr = _bfd_elf_get_property (first_pbfd, p->property.pr_type,
 471                                       p->property.pr_datasz);
 472           /* It must be a new property.  */
 473           if (pr->pr_kind != property_unknown)
 474             abort ();
 475           /* Add a new property.  */
 476           *pr = p->property;
 477         }
 478       else
 479         {
 480           pr = elf_find_and_remove_property (&elf_properties (first_pbfd),
 481                                              p->property.pr_type,
 482                                              false);
 483           if (pr == NULL)
 484             {
 485               if (number_p)
 486                 info->callbacks->minfo
 487                   (_("Removed property %W to merge %pB (not found) and "
 488                      "%pB (0x%v)\n"),
 489                    (bfd_vma) p->property.pr_type, first_pbfd, abfd,
 490                    number);
 491               else
 492                 info->callbacks->minfo
 493                   (_("Removed property %W to merge %pB and %pB\n"),
 494                    (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 495             }
 496           else if (pr->pr_kind != property_remove)
 497             abort ();
 498         }
 499     }
 500 }
 501
 502 /* Get GNU property section size.  */
 503
 504 static bfd_size_type
 505 elf_get_gnu_property_section_size (elf_property_list *list,
 506                                    unsigned int align_size)
 507 {
 508   bfd_size_type size;
 509   unsigned int descsz;
 510
 511   /* Compute the output section size.  */
 512   descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
 513   descsz = (descsz + 3) & -(unsigned int) 4;
 514   size = descsz;
 515   for (; list != NULL; list = list->next)
 516     {
 517       unsigned int datasz;
 518       /* Check if this property should be skipped.  */
 519       if (list->property.pr_kind == property_remove)
 520         continue;
 521       /* There are 4 byte type + 4 byte datasz for each property.  */
 522       if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
 523         datasz = align_size;
 524       else
 525         datasz = list->property.pr_datasz;
 526       size += 4 + 4 + datasz;
 527       /* Align each property.  */
 528       size = (size + (align_size - 1)) & ~(align_size - 1);
 529     }
 530
 531   return size;
 532 }
 533
 534 /* Write GNU properties.  */
 535
 536 static void
 537 elf_write_gnu_properties (struct bfd_link_info *info,
 538                           bfd *abfd, bfd_byte *contents,
 539                           elf_property_list *list, unsigned int size,
 540                           unsigned int align_size)
 541 {
 542   unsigned int descsz;
 543   unsigned int datasz;
 544   Elf_External_Note *e_note;
 545
 546   e_note = (Elf_External_Note *) contents;
 547   descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
 548   descsz = (descsz + 3) & -(unsigned int) 4;
 549   bfd_h_put_32 (abfd, sizeof "GNU", &e_note->namesz);
 550   bfd_h_put_32 (abfd, size - descsz, &e_note->descsz);
 551   bfd_h_put_32 (abfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type);
 552   memcpy (e_note->name, "GNU", sizeof "GNU");
 553
 554   size = descsz;
 555   for (; list != NULL; list = list->next)
 556     {
 557       /* Check if this property should be skipped.  */
 558       if (list->property.pr_kind == property_remove)
 559         continue;
 560       /* There are 4 byte type + 4 byte datasz for each property.  */
 561       if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
 562         datasz = align_size;
 563       else
 564         datasz = list->property.pr_datasz;
 565       bfd_h_put_32 (abfd, list->property.pr_type, contents + size);
 566       bfd_h_put_32 (abfd, datasz, contents + size + 4);
 567       size += 4 + 4;
 568
 569       /* Write out property value.  */
 570       switch (list->property.pr_kind)
 571         {
 572         case property_number:
 573           switch (datasz)
 574             {
 575             default:
 576               /* Never should happen.  */
 577               abort ();
 578
 579             case 0:
 580               break;
 581
 582             case 4:
 583               /* Save the pointer to GNU_PROPERTY_1_NEEDED so that it
 584                  can be updated later if needed.  */
 585               if (info != NULL
 586                   && list->property.pr_type == GNU_PROPERTY_1_NEEDED)
 587                 info->needed_1_p = contents + size;
 588               bfd_h_put_32 (abfd, list->property.u.number,
 589                             contents + size);
 590               break;
 591
 592             case 8:
 593               bfd_h_put_64 (abfd, list->property.u.number,
 594                             contents + size);
 595               break;
 596             }
 597           break;
 598
 599         default:
 600           /* Never should happen.  */
 601           abort ();
 602         }
 603       size += datasz;
 604
 605       /* Align each property.  */
 606       size = (size + (align_size - 1)) & ~ (align_size - 1);
 607     }
 608 }
 609
 610 /* Set up GNU properties.  Return the first relocatable ELF input with
 611    GNU properties if found.  Otherwise, return NULL.  */
 612
 613 bfd *
 614 _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info)
 615 {
 616   bfd *abfd, *first_pbfd = NULL, *elf_bfd = NULL;
 617   elf_property_list *list;
 618   asection *sec;
 619   bool has_properties = false;
 620   const struct elf_backend_data *bed
 621     = get_elf_backend_data (info->output_bfd);
 622   unsigned int elfclass = bed->s->elfclass;
 623   int elf_machine_code = bed->elf_machine_code;
 624   elf_property *p;
 625
 626   /* Find the first relocatable ELF input with GNU properties.  */
 627   for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
 628     if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
 629         && (abfd->flags & DYNAMIC) == 0
 630         && (elf_machine_code
 631             == get_elf_backend_data (abfd)->elf_machine_code)
 632         && (elfclass == get_elf_backend_data (abfd)->s->elfclass))
 633       {
 634         /* Ignore GNU properties from ELF objects with different machine
 635            code or class.  Also skip objects without a GNU_PROPERTY note
 636            section.  */
 637         elf_bfd = abfd;
 638
 639         if (elf_properties (abfd) != NULL)
 640           {
 641             has_properties = true;
 642
 643             if (bfd_get_section_by_name (abfd,
 644                                          NOTE_GNU_PROPERTY_SECTION_NAME)
 645                 != NULL)
 646               {
 647                 /* Keep .note.gnu.property section in FIRST_PBFD.  */
 648                 first_pbfd = abfd;
 649                 break;
 650               }
 651           }
 652       }
 653
 654   if (info->indirect_extern_access > 0 && elf_bfd != NULL)
 655     {
 656       /* Support -z indirect-extern-access.  */
 657       if (first_pbfd == NULL)
 658         {
 659           sec = bfd_make_section_with_flags (elf_bfd,
 660                                              NOTE_GNU_PROPERTY_SECTION_NAME,
 661                                              (SEC_ALLOC
 662                                               | SEC_LOAD
 663                                               | SEC_IN_MEMORY
 664                                               | SEC_READONLY
 665                                               | SEC_HAS_CONTENTS
 666                                               | SEC_DATA));
 667           if (sec == NULL)
 668             info->callbacks->einfo (_("%F%P: failed to create GNU property section\n"));
 669
 670           if (!bfd_set_section_alignment (sec,
 671                                           elfclass == ELFCLASS64 ? 3 : 2))
 672             info->callbacks->einfo (_("%F%pA: failed to align section\n"),
 673                                     sec);
 674
 675           elf_section_type (sec) = SHT_NOTE;
 676           first_pbfd = elf_bfd;
 677           has_properties = true;
 678         }
 679
 680       p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_1_NEEDED, 4);
 681       if (p->pr_kind == property_unknown)
 682         {
 683           /* Create GNU_PROPERTY_1_NEEDED.  */
 684           p->u.number
 685             = GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 686           p->pr_kind = property_number;
 687         }
 688       else
 689         p->u.number
 690           |= GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 691     }
 692
 693   /* Do nothing if there is no .note.gnu.property section.  */
 694   if (!has_properties)
 695     return NULL;
 696
 697   /* Merge .note.gnu.property sections.  */
 698   info->callbacks->minfo (_("\n"));
 699   info->callbacks->minfo (_("Merging program properties\n"));
 700   info->callbacks->minfo (_("\n"));
 701
 702   for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
 703     if (abfd != first_pbfd
 704         && (abfd->flags & (DYNAMIC | BFD_PLUGIN | BFD_LINKER_CREATED)) == 0)
 705       {
 706         elf_property_list *null_ptr = NULL;
 707         elf_property_list **listp = &null_ptr;
 708
 709         /* Merge .note.gnu.property section in relocatable ELF input.  */
 710         if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 711           {
 712             list = elf_properties (abfd);
 713
 714             /* Ignore GNU properties from ELF objects with different
 715                machine code.  */
 716             if (list != NULL
 717                 && (elf_machine_code
 718                     == get_elf_backend_data (abfd)->elf_machine_code))
 719               listp = &elf_properties (abfd);
 720           }
 721         else
 722           list = NULL;
 723
 724         /* Merge properties with FIRST_PBFD.  FIRST_PBFD can be NULL
 725            when all properties are from ELF objects with different
 726            machine code or class.  */
 727         if (first_pbfd != NULL)
 728           elf_merge_gnu_property_list (info, first_pbfd, abfd, listp);
 729
 730         if (list != NULL)
 731           {
 732             /* Discard the .note.gnu.property section in this bfd.  */
 733             sec = bfd_get_section_by_name (abfd,
 734                                            NOTE_GNU_PROPERTY_SECTION_NAME);
 735             if (sec != NULL)
 736               sec->output_section = bfd_abs_section_ptr;
 737           }
 738       }
 739
 740   /* Rewrite .note.gnu.property section so that GNU properties are
 741      always sorted by type even if input GNU properties aren't sorted.  */
 742   if (first_pbfd != NULL)
 743     {
 744       bfd_size_type size;
 745       bfd_byte *contents;
 746       unsigned int align_size = elfclass == ELFCLASS64 ? 8 : 4;
 747
 748       sec = bfd_get_section_by_name (first_pbfd,
 749                                      NOTE_GNU_PROPERTY_SECTION_NAME);
 750       BFD_ASSERT (sec != NULL);
 751
 752       /* Update stack size in .note.gnu.property with -z stack-size=N
 753          if N > 0.  */
 754       if (info->stacksize > 0)
 755         {
 756           bfd_vma stacksize = info->stacksize;
 757
 758           p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE,
 759                                      align_size);
 760           if (p->pr_kind == property_unknown)
 761             {
 762               /* Create GNU_PROPERTY_STACK_SIZE.  */
 763               p->u.number = stacksize;
 764               p->pr_kind = property_number;
 765             }
 766           else if (stacksize > p->u.number)
 767             p->u.number = stacksize;
 768         }
 769       else if (elf_properties (first_pbfd) == NULL)
 770         {
 771           /* Discard .note.gnu.property section if all properties have
 772              been removed.  */
 773           sec->output_section = bfd_abs_section_ptr;
 774           return NULL;
 775         }
 776
 777       /* Fix up GNU properties.  */
 778       if (bed->fixup_gnu_properties)
 779         bed->fixup_gnu_properties (info, &elf_properties (first_pbfd));
 780
 781       if (elf_properties (first_pbfd) == NULL)
 782         {
 783           /* Discard .note.gnu.property section if all properties have
 784              been removed.  */
 785           sec->output_section = bfd_abs_section_ptr;
 786           return NULL;
 787         }
 788
 789       /* Compute the section size.  */
 790       list = elf_properties (first_pbfd);
 791       size = elf_get_gnu_property_section_size (list, align_size);
 792
 793       /* Update .note.gnu.property section now.  */
 794       sec->size = size;
 795       contents = (bfd_byte *) bfd_zalloc (first_pbfd, size);
 796
 797       if (info->indirect_extern_access <= 0)
 798         {
 799           /* Get GNU_PROPERTY_1_NEEDED properties.  */
 800           p = elf_find_and_remove_property (&elf_properties (first_pbfd),
 801                                             GNU_PROPERTY_1_NEEDED, false);
 802           if (p != NULL)
 803             {
 804               if (info->indirect_extern_access < 0)
 805                 {
 806                   /* Set indirect_extern_access to 1 to indicate that
 807                      it is turned on by input properties.  */
 808                   if ((p->u.number
 809                        & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
 810                       != 0)
 811                     info->indirect_extern_access = 1;
 812                 }
 813               else
 814                 /* Turn off indirect external access.  */
 815                 p->u.number
 816                   &= ~GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 817             }
 818         }
 819
 820       elf_write_gnu_properties (info, first_pbfd, contents, list, size,
 821                                 align_size);
 822
 823       /* Cache the section contents for elf_link_input_bfd.  */
 824       elf_section_data (sec)->this_hdr.contents = contents;
 825
 826       /* If GNU_PROPERTY_NO_COPY_ON_PROTECTED is set, protected data
 827          symbol is defined in the shared object.  */
 828       if (elf_has_no_copy_on_protected (first_pbfd))
 829         info->extern_protected_data = false;
 830
 831       if (info->indirect_extern_access > 0)
 832         {
 833           /* For indirect external access, don't generate copy
 834              relocations.  NB: Set to nocopyreloc to 2 to indicate
 835              that it is implied by indirect_extern_access.  */
 836           info->nocopyreloc = 2;
 837           info->extern_protected_data = false;
 838         }
 839     }
 840
 841   return first_pbfd;
 842 }
 843
 844 /* Convert GNU property size.  */
 845
 846 bfd_size_type
 847 _bfd_elf_convert_gnu_property_size (bfd *ibfd, bfd *obfd)
 848 {
 849   unsigned int align_size;
 850   const struct elf_backend_data *bed;
 851   elf_property_list *list = elf_properties (ibfd);
 852
 853   bed = get_elf_backend_data (obfd);
 854   align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;
 855
 856   /* Get the output .note.gnu.property section size.  */
 857   return elf_get_gnu_property_section_size (list, align_size);
 858 }
 859
 860 /* Convert GNU properties.  */
 861
 862 bool
 863 _bfd_elf_convert_gnu_properties (bfd *ibfd, asection *isec,
 864                                  bfd *obfd, bfd_byte **ptr,
 865                                  bfd_size_type *ptr_size)
 866 {
 867   unsigned int size;
 868   bfd_byte *contents;
 869   unsigned int align_shift;
 870   const struct elf_backend_data *bed;
 871   elf_property_list *list = elf_properties (ibfd);
 872
 873   bed = get_elf_backend_data (obfd);
 874   align_shift = bed->s->elfclass == ELFCLASS64 ? 3 : 2;
 875
 876   /* Get the output .note.gnu.property section size.  */
 877   size = bfd_section_size (isec->output_section);
 878
 879   /* Update the output .note.gnu.property section alignment.  */
 880   bfd_set_section_alignment (isec->output_section, align_shift);
 881
 882   if (size > bfd_section_size (isec))
 883     {
 884       contents = (bfd_byte *) bfd_malloc (size);
 885       if (contents == NULL)
 886         return false;
 887       free (*ptr);
 888       *ptr = contents;
 889     }
 890   else
 891     contents = *ptr;
 892
 893   *ptr_size = size;
 894
 895   /* Generate the output .note.gnu.property section.  */
 896   elf_write_gnu_properties (NULL, ibfd, contents, list, size,
 897                             1 << align_shift);
 898
 899   return true;
 900 }