elf32_xlate
, elf64_xlate
,
gelf_xlate
—
translate data between files and memory
ELF Access Library (libelf, -lelf)
#include <libelf.h>
Elf_Data *
elf32_xlatetof
(Elf_Data
*dst, Elf_Data
*src, unsigned int
file_encoding);
Elf_Data *
elf32_xlatetom
(Elf_Data
*dst, Elf_Data
*src, unsigned int
file_encoding);
Elf_Data *
elf64_xlatetof
(Elf_Data
*dst, Elf_Data
*src, unsigned int
file_encoding);
Elf_Data *
elf64_xlatetom
(Elf_Data
*dst, Elf_Data
*src, unsigned int
file_encoding);
#include
<gelf.h>
Elf_Data *
gelf_xlatetof
(Elf *elf,
Elf_Data *dst, Elf_Data *src,
unsigned int file_encoding);
Elf_Data *
gelf_xlatetom
(Elf *elf,
Elf_Data *dst, Elf_Data *src,
unsigned int file_encoding);
These functions translate between the file and memory representations of ELF
data structures. The in-memory representation of an ELF data structure would
conform to the byte ordering and data alignment restrictions dictated by the
host processor. As described in
elf(3), the
file representation of this data structure could use a different byte ordering
from that of the host, or could use a different layout within the file.
Functions elf32_xlatetom
(),
elf64_xlatetom
(), and
gelf_xlatetom
() translate data from file
representations to native, in-memory representations. Functions
elf32_xlatetof
(),
elf64_xlatetof
(), and
gelf_xlatetof
() translate data from in-memory
representations to file representations.
Argument src denotes an
Elf_Data descriptor describing the source to be
translated. The following elements of the descriptor need to be set before
invoking these functions:
- d_buf
- Set to a valid pointer value denoting the beginning of the data area to be
translated.
- d_size
- Set to the total size in bytes of the source data area to be
translated.
- d_type
- Set to the type of the source data being translated. This value is one of
the values defined in the Elf_Type enumeration. The
Elf_Type enumeration is described in
elf(3).
- d_version
- Set to the version number of the ELF data structures being translated.
Currently only version
EV_CURRENT
is
supported.
Argument dst describes the destination
buffer. The following elements of the Elf_Data
descriptor need to be set before invoking these functions:
- d_buf
- Set to a valid pointer value that denotes the start of the destination
buffer that will hold translated data. This value may be the same as that
of the source buffer, in which case an in-place conversion will be
attempted.
- d_size
- Set to the size of the destination buffer in bytes. This value will be
modified if the function call succeeds.
- d_version
- Set to the desired version number of the destination. Currently only
version
EV_CURRENT
is supported.
These translations routines allow the source and destination
buffers to coincide, in which case an in-place translation will be done if
the destination is large enough to hold the translated data. Other kinds of
overlap between the source and destination buffers are not permitted.
On successful completion of the translation request the following
fields of the dst descriptor would be modified:
- d_size
- Set to the size in bytes of the translated data.
- d_type
- Set to the d_type value of the source data
descriptor.
Argument file_encoding specifies the
encoding in which the file objects are represented. It must be one of:
ELFDATANONE
- File objects use the library's native byte ordering.
ELFDATA2LSB
- File objects use a little-endian ordering.
ELFDATA2MSB
- File objects use a big-endian ordering.
The functions gelf_xlatetof
() and
gelf_xlatetom
() select the appropriate translation
scheme based on the properties of argument elf.
These functions return argument dst if successful, or NULL
in case of an error.
To translate a GElf_Rel structure to its LSB file
representation use:
Elf_Data dst, src;
GElf_Rel rel;
Elf *e;
e = ...; /* See elf_begin(3). */
/* Set up the 'src' descriptor. */
memset(&src, 0, sizeof src);
src.d_buf = &rel;
src.d_size = sizeof(rel);
src.d_type = ELF_T_REL;
src.d_version = EV_CURRENT;
/* Set up the 'dst' descriptor. */
memset(&dst, 0, sizeof dst);
dst.d_buf = filebuf;
dst.d_size = gelf_fsize(e, ELF_T_REL, 1, EV_CURRENT);
dst.d_version = EV_CURRENT;
if (gelf_xlatetof(e, &dst, &src, ELFDATA2LSB) == NULL) {
printf("error: %s", elf_errmsg(0));
}
These functions may fail with the following errors:
- [
ELF_E_ARGUMENT
]
- One of arguments src, dst or
elf was NULL.
- [
ELF_E_ARGUMENT
]
- Arguments src and dst were
equal.
- [
ELF_E_ARGUMENT
]
- The desired encoding parameter was not one of
ELFDATANONE
, ELFDATA2LSB
or ELFDATA2MSB
.
- [
ELF_E_ARGUMENT
]
- The d_type field of argument
src specified an unsupported type.
- [
ELF_E_DATA
]
- The src argument specified a buffer size that was
not an integral multiple of its underlying type.
- [
ELF_E_DATA
]
- The dst argument specified a buffer size that was
too small.
- [
ELF_E_DATA
]
- Argument dst specified a destination buffer that
overlaps with the source buffer.
- [
ELF_E_DATA
]
- The destination buffer for a conversion to memory had an alignment
inappropriate for the underlying ELF type.
- [
ELF_E_DATA
]
- The source buffer for a conversion to file had an alignment inappropriate
for the underlying ELF type.
- [
ELF_E_UNIMPL
]
- The version numbers for arguments dst and
src were not identical.
- [
ELF_E_UNIMPL
]
- The argument src requested conversion for a type
which is not currently supported.
- [
ELF_E_VERSION
]
- Argument src specified an unsupported version
number.