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
35 static int
found_build_id(Dwfl_Module * mod,bool set,const void * bits,int len,GElf_Addr vaddr)36 found_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
59 int
60 internal_function
__libdwfl_find_build_id(Dwfl_Module * mod,bool set,Elf * elf)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
80 NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138)
81 int
dwfl_module_build_id(Dwfl_Module * mod,const unsigned char ** bits,GElf_Addr * vaddr)82 dwfl_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 }
106 NEW_INTDEF (dwfl_module_build_id)
107
108 #ifdef SYMBOL_VERSIONING
109 COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end)
110
111 int
_compat_vaddr_at_end_dwfl_module_build_id(Dwfl_Module * mod,const unsigned char ** bits,GElf_Addr * vaddr)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