source: rtems-tools/rtemstoolkit/elftoolchain/libelf/elf_strptr.c @ 6f48c91

5
Last change on this file since 6f48c91 was 6f48c91, checked in by Chris Johns <chrisj@…>, on 04/30/18 at 03:39:09

Revert "rtemstoolkit: Update elftoolchain to the latest code."

This reverts commit 0c5db2dd13b8270bb80c497d5f53ae2471f8a819.

  • Property mode set to 100644
File size: 3.6 KB
Line 
1/*-
2 * Copyright (c) 2006,2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <assert.h>
28#include <gelf.h>
29
30#include "_libelf.h"
31
32LIBELF_VCSID("$Id: elf_strptr.c 189 2008-07-20 10:38:08Z jkoshy $");
33
34/*
35 * Convert an ELF section#,offset pair to a string pointer.
36 */
37
38char *
39elf_strptr(Elf *e, size_t scndx, size_t offset)
40{
41        Elf_Scn *s;
42        Elf_Data *d;
43        size_t alignment, count;
44        GElf_Shdr shdr;
45
46        if (e == NULL || e->e_kind != ELF_K_ELF) {
47                LIBELF_SET_ERROR(ARGUMENT, 0);
48                return (NULL);
49        }
50
51        if ((s = elf_getscn(e, scndx)) == NULL ||
52            gelf_getshdr(s, &shdr) == NULL)
53                return (NULL);
54
55        if (shdr.sh_type != SHT_STRTAB ||
56            offset >= shdr.sh_size) {
57                LIBELF_SET_ERROR(ARGUMENT, 0);
58                return (NULL);
59        }
60
61        d = NULL;
62        if (e->e_flags & ELF_F_LAYOUT) {
63
64                /*
65                 * The application is taking responsibility for the
66                 * ELF object's layout, so we can directly translate
67                 * an offset to a `char *' address using the `d_off'
68                 * members of Elf_Data descriptors.
69                 */
70                while ((d = elf_getdata(s, d)) != NULL) {
71
72                        if (d->d_buf == 0 || d->d_size == 0)
73                                continue;
74
75                        if (d->d_type != ELF_T_BYTE) {
76                                LIBELF_SET_ERROR(DATA, 0);
77                                return (NULL);
78                        }
79
80                        if (offset >= d->d_off &&
81                            offset < d->d_off + d->d_size)
82                                return ((char *) d->d_buf + offset - d->d_off);
83                }
84        } else {
85                /*
86                 * Otherwise, the `d_off' members are not useable and
87                 * we need to compute offsets ourselves, taking into
88                 * account 'holes' in coverage of the section introduced
89                 * by alignment requirements.
90                 */
91                count = (size_t) 0;     /* cumulative count of bytes seen */
92                while ((d = elf_getdata(s, d)) != NULL && count <= offset) {
93
94                        if (d->d_buf == NULL || d->d_size == 0)
95                                continue;
96
97                        if (d->d_type != ELF_T_BYTE) {
98                                LIBELF_SET_ERROR(DATA, 0);
99                                return (NULL);
100                        }
101
102                        if ((alignment = d->d_align) > 1) {
103                                if ((alignment & (alignment - 1)) != 0) {
104                                        LIBELF_SET_ERROR(DATA, 0);
105                                        return (NULL);
106                                }
107                                count = roundup2(count, alignment);
108                        }
109
110                        if (offset < count) {
111                                /* offset starts in the 'hole' */
112                                LIBELF_SET_ERROR(ARGUMENT, 0);
113                                return (NULL);
114                        }
115
116                        if (offset < count + d->d_size) {
117                                if (d->d_buf != NULL)
118                                        return ((char *) d->d_buf +
119                                            offset - count);
120                                LIBELF_SET_ERROR(DATA, 0);
121                                return (NULL);
122                        }
123
124                        count += d->d_size;
125                }
126        }
127
128        LIBELF_SET_ERROR(ARGUMENT, 0);
129        return (NULL);
130}
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