ELF_RAWFILE(3ELF) ELF Library Functions ELF_RAWFILE(3ELF)

NAME

elf_rawfile - retrieve uninterpreted file contents

SYNOPSIS

cc [ flag... ] file ... -lelf [ library ... ]
#include <libelf.h>

char *elf_rawfile(Elf *elf, size_t *ptr);

DESCRIPTION

The elf_rawfile() function returns a pointer to an uninterpreted byte
image of the file. This function should be used only to retrieve a file
being read. For example, a program might use elf_rawfile() to retrieve
the bytes for an archive member.


A program may not close or disable (see elf_cntl(3ELF)) the file
descriptor associated with elf before the initial call to elf_rawfile() ,
because elf_rawfile() might have to read the data from the file if it
does not already have the original bytes in memory. Generally, this
function is more efficient for unknown file types than for object files.
The library implicitly translates object files in memory, while it leaves
unknown files unmodified. Thus, asking for the uninterpreted image of an
object file may create a duplicate copy in memory.


elf_rawdata() is a related function, providing access to sections within
a file. See elf_getdata(3ELF).


If ptr is non-null, the library also stores the file's size, in bytes, in
the location to which ptr points. If no data are present, elf is null, or
an error occurs, the return value is a null pointer, with 0 stored
through ptr, if ptr is non-null.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Stable |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

elf(3ELF), elf32_getehdr(3ELF), elf_begin(3ELF), elf_cntl(3ELF),
elf_getdata(3ELF), elf_getident(3ELF), elf_kind(3ELF), libelf(3LIB),
attributes(7)

NOTES

A program that uses elf_rawfile() and that also interprets the same file
as an object file potentially has two copies of the bytes in memory. If
such a program requests the raw image first, before it asks for
translated information (through such functions as elf32_getehdr(),
elf_getdata(), and so on), the library ``freezes'' its original memory
copy for the raw image. It then uses this frozen copy as the source for
creating translated objects, without reading the file again.
Consequently, the application should view the raw file image returned by
elf_rawfile() as a read-only buffer, unless it wants to alter its own
view of data subsequently translated. In any case, the application may
alter the translated objects without changing bytes visible in the raw
image.


Multiple calls to elf_rawfile() with the same ELF descriptor return the
same value; the library does not create duplicate copies of the file.

July 11, 2001 ELF_RAWFILE(3ELF)