Line data Source code
1 : /* Returns the file name and crc stored in the .gnu_debuglink if found.
2 : Copyright (C) 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 "libdwelfP.h"
34 :
35 : const char *
36 129 : dwelf_elf_gnu_debuglink (Elf *elf, GElf_Word *crc)
37 : {
38 : size_t shstrndx;
39 129 : if (elf_getshdrstrndx (elf, &shstrndx) < 0)
40 : return NULL;
41 :
42 : Elf_Scn *scn = NULL;
43 3027 : while ((scn = elf_nextscn (elf, scn)) != NULL)
44 : {
45 : GElf_Shdr shdr_mem;
46 2962 : GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
47 2962 : if (shdr == NULL)
48 0 : return NULL;
49 :
50 2962 : const char *name = elf_strptr (elf, shstrndx, shdr->sh_name);
51 2962 : if (name == NULL)
52 : return NULL;
53 :
54 2962 : if (!strcmp (name, ".gnu_debuglink"))
55 : break;
56 : }
57 :
58 129 : if (scn == NULL)
59 : return NULL;
60 :
61 : /* Found the .gnu_debuglink section. Extract its contents. */
62 64 : Elf_Data *rawdata = elf_rawdata (scn, NULL);
63 64 : if (rawdata == NULL || rawdata->d_buf == NULL)
64 : return NULL;
65 :
66 : /* The CRC comes after the zero-terminated file name,
67 : (aligned up to 4 bytes) at the end of the section data. */
68 64 : if (rawdata->d_size <= sizeof *crc
69 64 : || memchr (rawdata->d_buf, '\0', rawdata->d_size - sizeof *crc) == NULL)
70 : return NULL;
71 :
72 64 : Elf_Data crcdata =
73 : {
74 : .d_type = ELF_T_WORD,
75 : .d_buf = crc,
76 : .d_size = sizeof *crc,
77 : .d_version = EV_CURRENT,
78 : };
79 128 : Elf_Data conv =
80 : {
81 : .d_type = ELF_T_WORD,
82 64 : .d_buf = rawdata->d_buf + rawdata->d_size - sizeof *crc,
83 : .d_size = sizeof *crc,
84 : .d_version = EV_CURRENT,
85 : };
86 :
87 : GElf_Ehdr ehdr_mem;
88 64 : GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
89 64 : if (ehdr == NULL)
90 : return NULL;
91 :
92 64 : Elf_Data *d = gelf_xlatetom (elf, &crcdata, &conv, ehdr->e_ident[EI_DATA]);
93 64 : if (d == NULL)
94 : return NULL;
95 64 : assert (d == &crcdata);
96 :
97 64 : return rawdata->d_buf;
98 : }
99 : INTDEF(dwelf_elf_gnu_debuglink)
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