Line data Source code
1 : /* Get section at specific index.
2 : Copyright (C) 2005, 2008, 2015 Red Hat, Inc.
3 : This file is part of elfutils.
4 : Contributed by Ulrich Drepper <drepper@redhat.com>, 2005.
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 : #ifndef LIBELFBITS
41 : # define LIBELFBITS 32
42 : #endif
43 :
44 :
45 : Elf_Scn *
46 290 : elfw2(LIBELFBITS,offscn) (Elf *elf, ElfW2(LIBELFBITS,Off) offset)
47 : {
48 290 : if (elf == NULL)
49 : return NULL;
50 :
51 290 : if (unlikely (elf->kind != ELF_K_ELF))
52 : {
53 0 : __libelf_seterrno (ELF_E_INVALID_HANDLE);
54 0 : return NULL;
55 : }
56 :
57 290 : Elf_ScnList *runp = &elf->state.ELFW(elf,LIBELFBITS).scns;
58 :
59 : /* If we have not looked at section headers before,
60 : we might need to read them in first. */
61 290 : if (runp->cnt > 0
62 290 : && unlikely (runp->data[0].shdr.ELFW(e,LIBELFBITS) == NULL)
63 1 : && unlikely (elfw2(LIBELFBITS,getshdr) (&runp->data[0]) == NULL))
64 : return NULL;
65 :
66 : rwlock_rdlock (elf->lock);
67 :
68 290 : Elf_Scn *result = NULL;
69 :
70 : /* Find the section in the list. */
71 : while (1)
72 : {
73 6379 : for (unsigned int i = 0; i < runp->cnt; ++i)
74 6379 : if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_offset == offset)
75 : {
76 295 : result = &runp->data[i];
77 :
78 : /* If this section is empty, the following one has the same
79 : sh_offset. We presume the caller is looking for a nonempty
80 : section, so keep looking if this one is empty. */
81 295 : if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_size != 0
82 295 : && runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_type != SHT_NOBITS)
83 : goto out;
84 : }
85 :
86 0 : runp = runp->next;
87 0 : if (runp == NULL)
88 : {
89 0 : __libelf_seterrno (ELF_E_INVALID_OFFSET);
90 0 : break;
91 : }
92 : }
93 :
94 : out:
95 : rwlock_unlock (elf->lock);
96 :
97 : return result;
98 : }
99 : INTDEF(elfw2(LIBELFBITS,offscn))
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