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#ifdef HAVE_CONFIG_H
30# include <config.h>
31#endif
32
33#include "libdwflP.h"
34
35static int
36found_build_id (Dwfl_Module *mod, bool set,
37		const void *bits, int len, GElf_Addr vaddr)
38{
39  if (!set)
40    /* When checking bits, we do not compare VADDR because the
41       address found in a debuginfo file may not match the main
42       file as modified by prelink.  */
43    return 1 + (mod->build_id_len == len
44		&& !memcmp (bits, mod->build_id_bits, len));
45
46  void *copy = malloc (len);
47  if (unlikely (copy == NULL))
48    {
49      __libdwfl_seterrno (DWFL_E_NOMEM);
50      return -1;
51    }
52
53  mod->build_id_bits = memcpy (copy, bits, len);
54  mod->build_id_vaddr = vaddr;
55  mod->build_id_len = len;
56  return len;
57}
58
59int
60internal_function
61__libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf)
62{
63  const void *build_id_bits;
64  GElf_Addr build_id_elfaddr;
65  int build_id_len;
66
67  /* For mod == NULL use dwelf_elf_gnu_build_id directly.  */
68  assert (mod != NULL);
69
70  int result = __libdwfl_find_elf_build_id (mod, elf, &build_id_bits,
71					    &build_id_elfaddr, &build_id_len);
72  if (result <= 0)
73    return result;
74
75  GElf_Addr build_id_vaddr = build_id_elfaddr + (build_id_elfaddr != 0
76						 ? mod->main_bias : 0);
77  return found_build_id (mod, set, build_id_bits, build_id_len, build_id_vaddr);
78}
79
80NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138)
81int
82dwfl_module_build_id (Dwfl_Module *mod,
83		      const unsigned char **bits, GElf_Addr *vaddr)
84{
85  if (mod == NULL)
86    return -1;
87
88  if (mod->build_id_len == 0 && mod->main.elf != NULL)
89    {
90      /* We have the file, but have not examined it yet.  */
91      int result = __libdwfl_find_build_id (mod, true, mod->main.elf);
92      if (result <= 0)
93	{
94	  mod->build_id_len = -1;	/* Cache negative result.  */
95	  return result;
96	}
97    }
98
99  if (mod->build_id_len <= 0)
100    return 0;
101
102  *bits = mod->build_id_bits;
103  *vaddr = mod->build_id_vaddr;
104  return mod->build_id_len;
105}
106NEW_INTDEF (dwfl_module_build_id)
107
108#ifdef SYMBOL_VERSIONING
109COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end)
110
111int
112_compat_vaddr_at_end_dwfl_module_build_id (Dwfl_Module *mod,
113					   const unsigned char **bits,
114					   GElf_Addr *vaddr)
115{
116  int result = INTUSE(dwfl_module_build_id) (mod, bits, vaddr);
117  if (result > 0)
118    *vaddr += (result + 3) & -4;
119  return result;
120}
121#endif
122