ELF_XLATE(3E) ELF_XLATE(3E)
elf_xlate: elf32_xlatetof, elf32_xlatetom,elf64_xlatetof, elf64_xlatetom
- class-dependent data translation
cc [flag ...] file ... -lelf [library ...]
#include <libelf.h>
Elf_Data *elf32_xlatetof(Elf_Data *dst, const Elf_Data *src,
unsigned encode);
Elf_Data *elf32_xlatetom(Elf_Data *dst, const Elf_Data *src,
unsigned encode);
Elf_Data *elf64_xlatetof(Elf_Data *dst, const Elf_Data *src,
unsigned encode);
Elf_Data *elf64_xlatetom(Elf_Data *dst, const Elf_Data *src,
unsigned encode);
elf32_xlatetom translates various data structures from their 32-bit class
file representations to their memory representations; elf32_xlatetof
provides the inverse. This conversion is particularly important for
cross development environments. src is a pointer to the source buffer
that holds the original data; dst is a pointer to a destination buffer
that will hold the translated copy. encode gives the byte encoding in
which the file objects are (to be) represented and must have one of the
encoding values defined for the ELF header's e_ident[EI_DATA] entry [see
elf_getident(3E)]. If the data can be translated, the functions return
dst. Otherwise, they return null because an error occurred, such as
incompatible types, destination buffer overflow, etc.
elf_getdata(3E) describes the Elf_Data descriptor, which the translation
routines use as follows.
d_buf Both the source and destination must have valid buffer
pointers.
d_type This member's value specifies the type of the data to which
d_buf points and the type of data to be created in the
destination. The program supplies a d_type value in the
source; the library sets the destination's d_type to the
same value. These values are summarized below.
d_size This member holds the total size, in bytes, of the memory
occupied by the source data and the size allocated for the
destination data. If the destination buffer is not large
enough, the routines do not change its original contents.
The translation routines reset the destination's d_size
member to the actual size required, after the translation
occurs. The source and destination sizes may differ.
Page 1
ELF_XLATE(3E) ELF_XLATE(3E)
d_version This member holds version number of the objects (desired)
in the buffer. The source and destination versions are
independent.
Translation routines allow the source and destination buffers to
coincide. That is, dst->d_buf may equal src->d_buf. Other cases where
the source and destination buffers overlap give undefined behavior.
Elf_Type 32-Bit Memory Type
____________|___________________
ELF_T_ADDR | Elf32_Addr
ELF_T_BYTE | unsigned char
ELF_T_DYN | Elf32_Dyn
ELF_T_EHDR | Elf32_Ehdr
ELF_T_HALF | Elf32_Half
ELT_T_OFF | Elf32_Off
ELF_T_PHDR | Elf32_Phdr
ELF_T_REL | Elf32_Rel
ELF_T_RELA | Elf32_Rela
ELF_T_SHDR | Elf32_Shdr
ELF_T_SWORD | Elf32_Sword
ELF_T_SYM | Elf32_Sym
ELF_T_WORD | Elf32_Word
____________|___________________
``Translating'' buffers of type ELF_T_BYTE does not change the byte
order.
The 64-bit class works identically, simply replacing all instances of 32
in the description and table with 64.
elf(3E), elf_fsize(3E), elf_getdata(3E), elf_getident(3E).
By default, the Elf_Data used for the 64-bit class in a 32-bit
application restricts one to building 64-bit class applications with only
32-bit fields unless the entire application is compiled with
_LIBELF_XTND_64 defined (see elf.3e).
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