1 /* ELF program property support.
2 Copyright (C) 2017 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
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.
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.
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. */
21 /* GNU program property draft is at:
23 https://github.com/hjl-tools/linux-abi/wiki/property-draft.pdf
31 /* Get a property, allocate a new one if needed. */
34 _bfd_elf_get_property (bfd *abfd, unsigned int type, unsigned int datasz)
36 elf_property_list *p, **lastp;
38 if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
40 /* Never should happen. */
44 /* Keep the property list in order of type. */
45 lastp = &elf_properties (abfd);
46 for (p = *lastp; p; p = p->next)
48 /* Reuse the existing entry. */
49 if (type == p->property.pr_type)
51 if (datasz > p->property.pr_datasz)
53 /* This can happen when mixing 32-bit and 64-bit objects. */
54 p->property.pr_datasz = datasz;
58 else if (type < p->property.pr_type)
62 p = (elf_property_list *) bfd_alloc (abfd, sizeof (*p));
65 _bfd_error_handler (_("%B: out of memory in _bfd_elf_get_property"),
69 memset (p, 0, sizeof (*p));
70 p->property.pr_type = type;
71 p->property.pr_datasz = datasz;
77 /* Parse GNU properties. */
80 _bfd_elf_parse_gnu_properties (bfd *abfd, Elf_Internal_Note *note)
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;
87 if (note->descsz < 8 || (note->descsz % align_size) != 0)
91 (_("warning: %B: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx\n"),
92 abfd, note->type, note->descsz);
98 unsigned int type = bfd_h_get_32 (abfd, ptr);
99 unsigned int datasz = bfd_h_get_32 (abfd, ptr + 4);
104 if ((ptr + datasz) > ptr_end)
107 (_("warning: %B: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x\n"),
108 abfd, note->type, type, datasz);
109 /* Clear all properties. */
110 elf_properties (abfd) = NULL;
114 if (type >= GNU_PROPERTY_LOPROC)
116 if (type < GNU_PROPERTY_LOUSER && bed->parse_gnu_properties)
118 enum elf_property_kind kind
119 = bed->parse_gnu_properties (abfd, type, ptr, datasz);
120 if (kind == property_corrupt)
122 /* Clear all properties. */
123 elf_properties (abfd) = NULL;
126 else if (kind != property_ignored)
134 case GNU_PROPERTY_STACK_SIZE:
135 if (datasz != align_size)
138 (_("warning: %B: corrupt stack size: 0x%x\n"),
140 /* Clear all properties. */
141 elf_properties (abfd) = NULL;
144 prop = _bfd_elf_get_property (abfd, type, datasz);
146 prop->u.number = bfd_h_get_64 (abfd, ptr);
148 prop->u.number = bfd_h_get_32 (abfd, ptr);
149 prop->pr_kind = property_number;
152 case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
156 (_("warning: %B: corrupt no copy on protected size: 0x%x\n"),
158 /* Clear all properties. */
159 elf_properties (abfd) = NULL;
162 prop = _bfd_elf_get_property (abfd, type, datasz);
163 prop->pr_kind = property_number;
172 (_("warning: %B: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x\n"),
173 abfd, note->type, type);
176 ptr += (datasz + (align_size - 1)) & ~ (align_size - 1);
180 if (ptr > (ptr_end - 8))
187 /* Merge GNU property BPROP with APROP. If APROP isn't NULL, return TRUE
188 if APROP is updated. Otherwise, return TRUE if BPROP should be merged
192 elf_merge_gnu_properties (bfd *abfd, elf_property *aprop,
195 const struct elf_backend_data *bed = get_elf_backend_data (abfd);
196 unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type;
198 if (bed->merge_gnu_properties != NULL
199 && pr_type >= GNU_PROPERTY_LOPROC
200 && pr_type < GNU_PROPERTY_LOUSER)
201 return bed->merge_gnu_properties (abfd, aprop, bprop);
205 case GNU_PROPERTY_STACK_SIZE:
206 if (aprop != NULL && bprop != NULL)
208 if (bprop->u.number > aprop->u.number)
210 aprop->u.number = bprop->u.number;
217 case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
218 /* Return TRUE if APROP is NULL to indicate that BPROP should
220 return aprop == NULL;
223 /* Never should happen. */
230 /* Return the property of TYPE on *LISTP and remove it from *LISTP.
231 Return NULL if not found. */
233 static elf_property *
234 elf_find_and_remove_property (elf_property_list **listp,
237 elf_property_list *list;
239 for (list = *listp; list; list = list->next)
241 if (type == list->property.pr_type)
243 /* Remove this property. */
245 return &list->property;
247 else if (type < list->property.pr_type)
255 /* Merge GNU property list *LISTP with ABFD. */
258 elf_merge_gnu_property_list (bfd *abfd, elf_property_list **listp)
260 elf_property_list *p, **lastp;
263 /* Merge each GNU property in ABFD with the one on *LISTP. */
264 lastp = &elf_properties (abfd);
265 for (p = *lastp; p; p = p->next)
267 pr = elf_find_and_remove_property (listp, p->property.pr_type);
268 /* Pass NULL to elf_merge_gnu_properties for the property which
270 elf_merge_gnu_properties (abfd, &p->property, pr);
271 if (p->property.pr_kind == property_remove)
273 /* Remove this property. */
280 /* Merge the remaining properties on *LISTP with ABFD. */
281 for (p = *listp; p != NULL; p = p->next)
282 if (elf_merge_gnu_properties (abfd, NULL, &p->property))
284 pr = _bfd_elf_get_property (abfd, p->property.pr_type,
285 p->property.pr_datasz);
286 /* It must be a new property. */
287 if (pr->pr_kind != property_unknown)
289 /* Add a new property. */
294 /* Set up GNU properties. */
297 _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info)
299 bfd *abfd, *first_pbfd = NULL;
300 elf_property_list *list;
302 bfd_boolean has_properties = FALSE;
303 const struct elf_backend_data *bed
304 = get_elf_backend_data (info->output_bfd);
305 unsigned int elfclass = bed->s->elfclass;
306 int elf_machine_code = bed->elf_machine_code;
308 /* Find the first relocatable ELF input with GNU properties. */
309 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
310 if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
311 && bfd_count_sections (abfd) != 0
312 && elf_properties (abfd) != NULL)
314 has_properties = TRUE;
316 /* Ignore GNU properties from ELF objects with different machine
318 if ((elf_machine_code
319 == get_elf_backend_data (abfd)->elf_machine_code)
321 == get_elf_backend_data (abfd)->s->elfclass))
323 /* Keep .note.gnu.property section in FIRST_PBFD. */
329 /* Do nothing if there is no .note.gnu.property section. */
333 /* Merge .note.gnu.property sections. */
334 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
335 if (abfd != first_pbfd && bfd_count_sections (abfd) != 0)
337 elf_property_list *null_ptr = NULL;
338 elf_property_list **listp = &null_ptr;
340 /* Merge .note.gnu.property section in relocatable ELF input. */
341 if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
343 list = elf_properties (abfd);
345 /* Ignore GNU properties from ELF objects with different
349 == get_elf_backend_data (abfd)->elf_machine_code))
350 listp = &elf_properties (abfd);
355 /* Merge properties with FIRST_PBFD. FIRST_PBFD can be NULL
356 when all properties are from ELF objects with different
357 machine code or class. */
358 if (first_pbfd != NULL)
359 elf_merge_gnu_property_list (first_pbfd, listp);
363 /* Discard .note.gnu.property section in the rest inputs. */
364 sec = bfd_get_section_by_name (abfd,
365 NOTE_GNU_PROPERTY_SECTION_NAME);
366 sec->output_section = bfd_abs_section_ptr;
370 /* Rewrite .note.gnu.property section so that GNU properties are
371 always sorted by type even if input GNU properties aren't sorted. */
372 if (first_pbfd != NULL)
377 Elf_External_Note *e_note;
378 unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;
380 sec = bfd_get_section_by_name (first_pbfd,
381 NOTE_GNU_PROPERTY_SECTION_NAME);
383 /* Update stack size in .note.gnu.property with -z stack-size=N
385 if (info->stacksize > 0)
388 bfd_vma stacksize = info->stacksize;
390 p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE,
392 if (p->pr_kind == property_unknown)
394 /* Create GNU_PROPERTY_STACK_SIZE. */
395 p->u.number = stacksize;
396 p->pr_kind = property_number;
398 else if (stacksize > p->u.number)
399 p->u.number = stacksize;
401 else if (elf_properties (first_pbfd) == NULL)
403 /* Discard .note.gnu.property section if all properties have
405 sec->output_section = bfd_abs_section_ptr;
409 /* Compute the section size. */
410 descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
411 descsz = (descsz + 3) & -(unsigned int) 4;
413 for (list = elf_properties (first_pbfd);
417 /* There are 4 byte type + 4 byte datasz for each property. */
418 size += 4 + 4 + list->property.pr_datasz;
419 /* Align each property. */
420 size = (size + (align_size - 1)) & ~(align_size - 1);
423 /* Update .note.gnu.property section now. */
425 contents = (bfd_byte *) bfd_zalloc (first_pbfd, size);
427 e_note = (Elf_External_Note *) contents;
428 bfd_h_put_32 (first_pbfd, sizeof "GNU", &e_note->namesz);
429 bfd_h_put_32 (first_pbfd, size - descsz, &e_note->descsz);
430 bfd_h_put_32 (first_pbfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type);
431 memcpy (e_note->name, "GNU", sizeof "GNU");
434 for (list = elf_properties (first_pbfd);
438 /* There are 4 byte type + 4 byte datasz for each property. */
439 bfd_h_put_32 (first_pbfd, list->property.pr_type,
441 bfd_h_put_32 (first_pbfd, list->property.pr_datasz,
442 contents + size + 4);
445 /* Write out property value. */
446 switch (list->property.pr_kind)
448 case property_number:
449 switch (list->property.pr_datasz)
452 /* Never should happen. */
459 bfd_h_put_32 (first_pbfd, list->property.u.number,
464 bfd_h_put_64 (first_pbfd, list->property.u.number,
471 /* Never should happen. */
474 size += list->property.pr_datasz;
476 /* Align each property. */
477 size = (size + (align_size - 1)) & ~ (align_size - 1);
480 /* Cache the section contents for elf_link_input_bfd. */
481 elf_section_data (sec)->this_hdr.contents = contents;