1/* Return build ID information for a module.
2   Copyright (C) 2007-2010, 2014 Red Hat, Inc.
3   This file is part of elfutils.
4
5   This file is free software; you can redistribute it and/or modify
6   it under the terms of either
7
8     * the GNU Lesser General Public License as published by the Free
9       Software Foundation; either version 3 of the License, or (at
10       your option) any later version
11
12   or
13
14     * the GNU General Public License as published by the Free
15       Software Foundation; either version 2 of the License, or (at
16       your option) any later version
17
18   or both in parallel, as here.
19
20   elfutils is distributed in the hope that it will be useful, but
21   WITHOUT ANY WARRANTY; without even the implied warranty of
22   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23   General Public License for more details.
24
25   You should have received copies of the GNU General Public License and
26   the GNU Lesser General Public License along with this program.  If
27   not, see <http://www.gnu.org/licenses/>.  */
28
29#include "libdwflP.h"
30
31static int
32found_build_id (Dwfl_Module *mod, bool set,
33		const void *bits, int len, GElf_Addr vaddr)
34{
35  if (!set)
36    /* When checking bits, we do not compare VADDR because the
37       address found in a debuginfo file may not match the main
38       file as modified by prelink.  */
39    return 1 + (mod->build_id_len == len
40		&& !memcmp (bits, mod->build_id_bits, len));
41
42  void *copy = malloc (len);
43  if (unlikely (copy == NULL))
44    {
45      __libdwfl_seterrno (DWFL_E_NOMEM);
46      return -1;
47    }
48
49  mod->build_id_bits = memcpy (copy, bits, len);
50  mod->build_id_vaddr = vaddr;
51  mod->build_id_len = len;
52  return len;
53}
54
55int
56internal_function
57__libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf)
58{
59  const void *build_id_bits;
60  GElf_Addr build_id_elfaddr;
61  int build_id_len;
62
63  /* For mod == NULL use dwelf_elf_gnu_build_id directly.  */
64  assert (mod != NULL);
65
66  int result = __libdwfl_find_elf_build_id (mod, elf, &build_id_bits,
67					    &build_id_elfaddr, &build_id_len);
68  if (result <= 0)
69    return result;
70
71  GElf_Addr build_id_vaddr = build_id_elfaddr + (build_id_elfaddr != 0
72						 ? mod->main_bias : 0);
73  return found_build_id (mod, set, build_id_bits, build_id_len, build_id_vaddr);
74}
75
76int
77dwfl_module_build_id (Dwfl_Module *mod,
78		      const unsigned char **bits, GElf_Addr *vaddr)
79{
80  if (mod == NULL)
81    return -1;
82
83  if (mod->build_id_len == 0 && mod->main.elf != NULL)
84    {
85      /* We have the file, but have not examined it yet.  */
86      int result = __libdwfl_find_build_id (mod, true, mod->main.elf);
87      if (result <= 0)
88	{
89	  mod->build_id_len = -1;	/* Cache negative result.  */
90	  return result;
91	}
92    }
93
94  if (mod->build_id_len <= 0)
95    return 0;
96
97  *bits = mod->build_id_bits;
98  *vaddr = mod->build_id_vaddr;
99  return mod->build_id_len;
100}
101INTDEF (dwfl_module_build_id)
102NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138)
103
104#ifdef SYMBOL_VERSIONING
105COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end)
106
107int
108_compat_vaddr_at_end_dwfl_module_build_id (Dwfl_Module *mod,
109					   const unsigned char **bits,
110					   GElf_Addr *vaddr)
111{
112  int result = INTUSE(dwfl_module_build_id) (mod, bits, vaddr);
113  if (result > 0)
114    *vaddr += (result + 3) & -4;
115  return result;
116}
117#endif
118