1 /* Return build ID information for a module.
2 Copyright (C) 2007-2010 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4
5 Red Hat elfutils is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by the
7 Free Software Foundation; version 2 of the License.
8
9 Red Hat elfutils is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
13
14 You should have received a copy of the GNU General Public License along
15 with Red Hat elfutils; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
17
18 In addition, as a special exception, Red Hat, Inc. gives You the
19 additional right to link the code of Red Hat elfutils with code licensed
20 under any Open Source Initiative certified open source license
21 (http://www.opensource.org/licenses/index.php) which requires the
22 distribution of source code with any binary distribution and to
23 distribute linked combinations of the two. Non-GPL Code permitted under
24 this exception must only link to the code of Red Hat elfutils through
25 those well defined interfaces identified in the file named EXCEPTION
26 found in the source code files (the "Approved Interfaces"). The files
27 of Non-GPL Code may instantiate templates or use macros or inline
28 functions from the Approved Interfaces without causing the resulting
29 work to be covered by the GNU General Public License. Only Red Hat,
30 Inc. may make changes or additions to the list of Approved Interfaces.
31 Red Hat's grant of this exception is conditioned upon your not adding
32 any new exceptions. If you wish to add a new Approved Interface or
33 exception, please contact Red Hat. You must obey the GNU General Public
34 License in all respects for all of the Red Hat elfutils code and other
35 code used in conjunction with Red Hat elfutils except the Non-GPL Code
36 covered by this exception. If you modify this file, you may extend this
37 exception to your version of the file, but you are not obligated to do
38 so. If you do not wish to provide this exception without modification,
39 you must delete this exception statement from your version and license
40 this file solely under the GPL without exception.
41
42 Red Hat elfutils is an included package of the Open Invention Network.
43 An included package of the Open Invention Network is a package for which
44 Open Invention Network licensees cross-license their patents. No patent
45 license is granted, either expressly or impliedly, by designation as an
46 included package. Should you wish to participate in the Open Invention
47 Network licensing program, please visit www.openinventionnetwork.com
48 <http://www.openinventionnetwork.com>. */
49
50 #include "libdwflP.h"
51
52 static int
found_build_id(Dwfl_Module * mod,bool set,const void * bits,int len,GElf_Addr vaddr)53 found_build_id (Dwfl_Module *mod, bool set,
54 const void *bits, int len, GElf_Addr vaddr)
55 {
56 if (!set)
57 /* When checking bits, we do not compare VADDR because the
58 address found in a debuginfo file may not match the main
59 file as modified by prelink. */
60 return 1 + (mod->build_id_len == len
61 && !memcmp (bits, mod->build_id_bits, len));
62
63 void *copy = malloc (len);
64 if (unlikely (copy == NULL))
65 {
66 __libdwfl_seterrno (DWFL_E_NOMEM);
67 return -1;
68 }
69
70 mod->build_id_bits = memcpy (copy, bits, len);
71 mod->build_id_vaddr = vaddr;
72 mod->build_id_len = len;
73 return len;
74 }
75
76 #define NO_VADDR ((GElf_Addr) -1l)
77
78 static int
check_notes(Dwfl_Module * mod,bool set,Elf_Data * data,GElf_Addr data_vaddr)79 check_notes (Dwfl_Module *mod, bool set, Elf_Data *data, GElf_Addr data_vaddr)
80 {
81 size_t pos = 0;
82 GElf_Nhdr nhdr;
83 size_t name_pos;
84 size_t desc_pos;
85 while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos, &desc_pos)) > 0)
86 if (nhdr.n_type == NT_GNU_BUILD_ID
87 && nhdr.n_namesz == sizeof "GNU" && !memcmp (data->d_buf + name_pos,
88 "GNU", sizeof "GNU"))
89 return found_build_id (mod, set,
90 data->d_buf + desc_pos, nhdr.n_descsz,
91 data_vaddr == NO_VADDR ? 0
92 : data_vaddr + desc_pos);
93 return 0;
94 }
95
96 int
97 internal_function
__libdwfl_find_build_id(Dwfl_Module * mod,bool set,Elf * elf)98 __libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf)
99 {
100 size_t shstrndx = SHN_UNDEF;
101 int result = 0;
102
103 Elf_Scn *scn = elf_nextscn (elf, NULL);
104
105 if (scn == NULL)
106 {
107 /* No sections, have to look for phdrs. */
108 GElf_Ehdr ehdr_mem;
109 GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
110 size_t phnum;
111 if (unlikely (ehdr == NULL)
112 || unlikely (elf_getphdrnum (elf, &phnum) != 0))
113 {
114 __libdwfl_seterrno (DWFL_E_LIBELF);
115 return -1;
116 }
117 for (size_t i = 0; result == 0 && i < phnum; ++i)
118 {
119 GElf_Phdr phdr_mem;
120 GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
121 if (likely (phdr != NULL) && phdr->p_type == PT_NOTE)
122 result = check_notes (mod, set,
123 elf_getdata_rawchunk (elf,
124 phdr->p_offset,
125 phdr->p_filesz,
126 ELF_T_NHDR),
127 dwfl_adjusted_address (mod, phdr->p_vaddr));
128 }
129 }
130 else
131 do
132 {
133 GElf_Shdr shdr_mem;
134 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
135 if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE)
136 {
137 /* Determine the right sh_addr in this module. */
138 GElf_Addr vaddr = 0;
139 if (!(shdr->sh_flags & SHF_ALLOC))
140 vaddr = NO_VADDR;
141 else if (mod->e_type != ET_REL)
142 vaddr = dwfl_adjusted_address (mod, shdr->sh_addr);
143 else if (__libdwfl_relocate_value (mod, elf, &shstrndx,
144 elf_ndxscn (scn), &vaddr))
145 vaddr = NO_VADDR;
146 result = check_notes (mod, set, elf_getdata (scn, NULL), vaddr);
147 }
148 }
149 while (result == 0 && (scn = elf_nextscn (elf, scn)) != NULL);
150
151 return result;
152 }
153
154 int
dwfl_module_build_id(Dwfl_Module * mod,const unsigned char ** bits,GElf_Addr * vaddr)155 dwfl_module_build_id (Dwfl_Module *mod,
156 const unsigned char **bits, GElf_Addr *vaddr)
157 {
158 if (mod == NULL)
159 return -1;
160
161 if (mod->build_id_len == 0 && mod->main.elf != NULL)
162 {
163 /* We have the file, but have not examined it yet. */
164 int result = __libdwfl_find_build_id (mod, true, mod->main.elf);
165 if (result <= 0)
166 {
167 mod->build_id_len = -1; /* Cache negative result. */
168 return result;
169 }
170 }
171
172 if (mod->build_id_len <= 0)
173 return 0;
174
175 *bits = mod->build_id_bits;
176 *vaddr = mod->build_id_vaddr;
177 return mod->build_id_len;
178 }
179 INTDEF (dwfl_module_build_id)
180 NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138)
181
182 #ifdef SHARED
183 COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end)
184
185 int
_compat_vaddr_at_end_dwfl_module_build_id(Dwfl_Module * mod,const unsigned char ** bits,GElf_Addr * vaddr)186 _compat_vaddr_at_end_dwfl_module_build_id (Dwfl_Module *mod,
187 const unsigned char **bits,
188 GElf_Addr *vaddr)
189 {
190 int result = INTUSE(dwfl_module_build_id) (mod, bits, vaddr);
191 if (result > 0)
192 *vaddr += (result + 3) & -4;
193 return result;
194 }
195 #endif
196