Line data Source code
1 : /* Get section at specific index.
2 : Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2015 Red Hat, Inc.
3 : This file is part of elfutils.
4 : Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
5 :
6 : This file is free software; you can redistribute it and/or modify
7 : it under the terms of either
8 :
9 : * the GNU Lesser General Public License as published by the Free
10 : Software Foundation; either version 3 of the License, or (at
11 : your option) any later version
12 :
13 : or
14 :
15 : * the GNU General Public License as published by the Free
16 : Software Foundation; either version 2 of the License, or (at
17 : your option) any later version
18 :
19 : or both in parallel, as here.
20 :
21 : elfutils is distributed in the hope that it will be useful, but
22 : WITHOUT ANY WARRANTY; without even the implied warranty of
23 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 : General Public License for more details.
25 :
26 : You should have received copies of the GNU General Public License and
27 : the GNU Lesser General Public License along with this program. If
28 : not, see <http://www.gnu.org/licenses/>. */
29 :
30 : #ifdef HAVE_CONFIG_H
31 : # include <config.h>
32 : #endif
33 :
34 : #include <assert.h>
35 : #include <stddef.h>
36 : #include <stdlib.h>
37 :
38 : #include "libelfP.h"
39 :
40 :
41 : Elf_Scn *
42 1774818604 : elf_getscn (Elf *elf, size_t idx)
43 : {
44 1774818604 : if (elf == NULL)
45 : return NULL;
46 :
47 1774818604 : if (unlikely (elf->kind != ELF_K_ELF))
48 : {
49 0 : __libelf_seterrno (ELF_E_INVALID_HANDLE);
50 0 : return NULL;
51 : }
52 :
53 1774818604 : rwlock_rdlock (elf->lock);
54 :
55 1774818604 : Elf_Scn *result = NULL;
56 :
57 : /* Find the section in the list. */
58 1774818604 : Elf_ScnList *runp = (elf->class == ELFCLASS32
59 : || (offsetof (struct Elf, state.elf32.scns)
60 : == offsetof (struct Elf, state.elf64.scns))
61 : ? &elf->state.elf32.scns : &elf->state.elf64.scns);
62 :
63 : /* Section zero is special. It always exists even if there is no
64 : "first" section. And it is needed to store "overflow" values
65 : from the Elf header. */
66 1774818604 : if (idx == 0 && runp->cnt == 0 && runp->max > 0)
67 : {
68 17 : Elf_Scn *scn0 = &runp->data[0];
69 17 : if (elf->class == ELFCLASS32)
70 : {
71 9 : scn0->shdr.e32 = (Elf32_Shdr *) calloc (1, sizeof (Elf32_Shdr));
72 9 : if (scn0->shdr.e32 == NULL)
73 : {
74 0 : __libelf_seterrno (ELF_E_NOMEM);
75 0 : goto out;
76 : }
77 : }
78 : else
79 : {
80 8 : scn0->shdr.e64 = (Elf64_Shdr *) calloc (1, sizeof (Elf64_Shdr));
81 8 : if (scn0->shdr.e64 == NULL)
82 : {
83 0 : __libelf_seterrno (ELF_E_NOMEM);
84 0 : goto out;
85 : }
86 : }
87 17 : scn0->elf = elf;
88 17 : scn0->shdr_flags = ELF_F_DIRTY | ELF_F_MALLOCED;
89 17 : scn0->list = elf->state.elf.scns_last;
90 17 : scn0->data_read = 1;
91 17 : runp->cnt = 1;
92 : }
93 :
94 1776974574 : while (1)
95 : {
96 1776974574 : if (idx < runp->max)
97 : {
98 1774818557 : if (idx < runp->cnt)
99 1774818557 : result = &runp->data[idx];
100 : else
101 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
102 : break;
103 : }
104 :
105 2156017 : idx -= runp->max;
106 :
107 2156017 : runp = runp->next;
108 2156017 : if (runp == NULL)
109 : {
110 47 : __libelf_seterrno (ELF_E_INVALID_INDEX);
111 47 : break;
112 : }
113 : }
114 :
115 : out:
116 : rwlock_unlock (elf->lock);
117 :
118 : return result;
119 : }
120 : INTDEF(elf_getscn)
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