Branch data Line data Source code
1 : : /* Get information from auxiliary vector at the given index.
2 : : Copyright (C) 2007, 2015 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 <assert.h>
34 : : #include <gelf.h>
35 : : #include <string.h>
36 : :
37 : : #include "libelfP.h"
38 : :
39 : :
40 : : GElf_auxv_t *
41 : 168 : gelf_getauxv (Elf_Data *data, int ndx, GElf_auxv_t *dst)
42 : : {
43 : 168 : Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
44 : 168 : GElf_auxv_t *result = NULL;
45 : 168 : Elf *elf;
46 : :
47 [ + - ]: 168 : if (data_scn == NULL)
48 : : return NULL;
49 : :
50 [ - + ]: 168 : if (unlikely (data_scn->d.d_type != ELF_T_AUXV))
51 : : {
52 : 0 : __libelf_seterrno (ELF_E_INVALID_HANDLE);
53 : 0 : return NULL;
54 : : }
55 : :
56 : 168 : elf = data_scn->s->elf;
57 : :
58 : 168 : rwlock_rdlock (elf->lock);
59 : :
60 : : /* This is the one place where we have to take advantage of the fact
61 : : that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
62 : : The interface is broken so that it requires this hack. */
63 [ + + ]: 168 : if (elf->class == ELFCLASS32)
64 : : {
65 : 93 : Elf32_auxv_t *src;
66 : :
67 : : /* Here it gets a bit more complicated. The format of the vector
68 : : entries has to be converted. The user better have provided a
69 : : buffer where we can store the information. While copying the data
70 : : we convert the format. */
71 [ - + ]: 93 : if (unlikely ((ndx + 1) * sizeof (Elf32_auxv_t) > data_scn->d.d_size))
72 : : {
73 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
74 : 0 : goto out;
75 : : }
76 : :
77 : 93 : src = &((Elf32_auxv_t *) data_scn->d.d_buf)[ndx];
78 : :
79 : : /* This might look like a simple copy operation but it's
80 : : not. There are zero- and sign-extensions going on. */
81 : 93 : dst->a_type = src->a_type;
82 : 93 : dst->a_un.a_val = src->a_un.a_val;
83 : : }
84 : : else
85 : : {
86 : : /* If this is a 64 bit object it's easy. */
87 : 75 : assert (sizeof (GElf_auxv_t) == sizeof (Elf64_auxv_t));
88 : :
89 : : /* The data is already in the correct form. Just make sure the
90 : : index is OK. */
91 [ - + ]: 75 : if (unlikely ((ndx + 1) * sizeof (GElf_auxv_t) > data_scn->d.d_size))
92 : : {
93 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
94 : 0 : goto out;
95 : : }
96 : :
97 : 75 : memcpy (dst, data_scn->d.d_buf + ndx * sizeof (GElf_auxv_t),
98 : : sizeof (GElf_auxv_t));
99 : : }
100 : :
101 : : result = dst;
102 : :
103 : : out:
104 : : rwlock_unlock (elf->lock);
105 : :
106 : : return result;
107 : : }
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