2 * Copyright (c) 2006 Joseph Koshy
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
28 #include <sys/param.h>
30 #include <sys/sysmacros.h>
39 * Convert an ELF section#,offset pair to a string pointer.
43 elf_strptr(Elf
*e
, size_t scndx
, size_t offset
)
47 size_t alignment
, count
;
50 if (e
== NULL
|| e
->e_kind
!= ELF_K_ELF
) {
51 LIBELF_SET_ERROR(ARGUMENT
, 0);
55 if ((s
= elf_getscn(e
, scndx
)) == NULL
||
56 gelf_getshdr(s
, &shdr
) == NULL
)
59 if (shdr
.sh_type
!= SHT_STRTAB
||
60 offset
>= shdr
.sh_size
) {
61 LIBELF_SET_ERROR(ARGUMENT
, 0);
66 if (e
->e_flags
& ELF_F_LAYOUT
) {
69 * The application is taking responsibility for the
70 * ELF object's layout, so we can directly translate
71 * an offset to a `char *' address using the `d_off'
72 * members of Elf_Data descriptors.
74 while ((d
= elf_getdata(s
, d
)) != NULL
) {
76 if (d
->d_buf
== 0 || d
->d_size
== 0)
79 if (d
->d_type
!= ELF_T_BYTE
) {
80 LIBELF_SET_ERROR(DATA
, 0);
84 if (offset
>= d
->d_off
&&
85 offset
< d
->d_off
+ d
->d_size
)
86 return ((char *) d
->d_buf
+ offset
- d
->d_off
);
90 * Otherwise, the `d_off' members are not useable and
91 * we need to compute offsets ourselves, taking into
92 * account 'holes' in coverage of the section introduced
93 * by alignment requirements.
95 count
= (size_t) 0; /* cumulative count of bytes seen */
96 while ((d
= elf_getdata(s
, d
)) != NULL
&& count
<= offset
) {
98 if (d
->d_buf
== NULL
|| d
->d_size
== 0)
101 if (d
->d_type
!= ELF_T_BYTE
) {
102 LIBELF_SET_ERROR(DATA
, 0);
106 if ((alignment
= d
->d_align
) > 1) {
107 if ((alignment
& (alignment
- 1)) != 0) {
108 LIBELF_SET_ERROR(DATA
, 0);
111 count
= roundup(count
, alignment
);
114 if (offset
< count
) {
115 /* offset starts in the 'hole' */
116 LIBELF_SET_ERROR(ARGUMENT
, 0);
120 if (offset
< count
+ d
->d_size
) {
121 if (d
->d_buf
!= NULL
)
122 return ((char *) d
->d_buf
+
124 LIBELF_SET_ERROR(DATA
, 0);
132 LIBELF_SET_ERROR(ARGUMENT
, 0);