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.
elf(3),
elf_getdata(3),
gelf(3)