ELF Library

7.7

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ELF Library

(require elf)

package: elf

1 Introduction

2 Reference

3 Copyright and contact

1 Introduction

This library can read and write files in the exectuable and linking format common among unix like systems.

Due to the nature of overlapping binary data in ELF files, the library is strict in terms of write offsets and lengths. It is therefor the users responsibility to ensure that the length and offset fields in the headers are adjusted properly should the length of binary data be changed.

See the ELF man page elf(5) for more general information on the executable and linking format.

2 Reference

struct
(struct elf-header ( class
data
version
abi
abiver
type
machine
entry
prog-headers
section-headers
flags
header-size
prog-header-size
prog-header-count
sec-header-size
sec-header-count
sec-index))
  class : integer?
  data : integer?
  version : integer?
  abi : integer?
  abiver : integer?
  type : integer?
  machine : integer?
  entry : integer?
  prog-headers : integer?
  section-headers : integer?
  flags : integer?
  header-size : integer?
  prog-header-size : integer?
  prog-header-count : integer?
  sec-header-size : integer?
  sec-header-count : integer?
  sec-index : integer?

The ELF header.

struct
(struct program-header ( type
offset
v-addr
p-addr
file-size
mem-size
flags
align
data))
  type : integer?
  offset : integer?
  v-addr : integer?
  p-addr : integer?
  file-size : integer?
  mem-size : integer?
  flags : integer?
  align : integer?
  data : bytes?

An ELF program header.

The data field is unused currently.

struct
(struct section-header ( name
type
flags
addr
offset
size
link
info
addralign
entsize
data))
  name : integer?
  type : integer?
  flags : integer?
  addr : integer?
  offset : integer?
  size : integer?
  link : integer?
  info : integer?
  addralign : integer?
  entsize : integer?
  data : bytes?

An ELF section header.

The data field is unused currently.

procedure
(read-elf stream) → list?
stream : (file-stream-port?)

Reads an ELF from a file-stream, file stream must be seekable.

Returns a list consisting of an ELF header datastructure, a list of program-header, a list of section-header and 3 remaining elements of byte-string. One for data following the ELF header, another for data after the program headers and finally one for everything after the section headers.

procedure
(write-elf elf stream) → void?
elf : (list?)
stream : (output-port?)

Write an object representing ELF data to a file stream as binary.

Endianess and data (32 or 64 bit) should be set in the respective header fields, if someone needs to change them explictly.

procedure
(read-elf-header stream) → elf-header?
stream : (file-stream-port?)

Read an ELF header from stream at current seek position.

procedure
(write-elf-header header stream) → void?
header : (elf-header?)
stream : (output-port?)

Writes an ELF header to stream at current seek position.

procedure
(elf-magic? bstring) → boolean?
bstring : (bytes?)

Checks if byte-string has valid elf header magic string, each ELF file must have this string at first 4 bytes from its start.

procedure
(elf-info header) → string?
header : (elf-header?)

Returns a string with some general human readable information about an ELF header.

procedure
(read-elf-program-header stream
[ size
endianess]) → program-header?
  stream : (file-stream-port?)
  size : (boolean?) = false
  endianess : (boolean?) = false

Reads a program header from current seek position.

procedure
(write-elf-program-header prog-header
stream
[ data-size
endianess]) → void?
  prog-header : (program-header?)
  stream : (output-port?)
  data-size : (boolean?) = false
  endianess : (boolean?) = false

Writes a program header to stream at current seek position.

procedure
(read-section stream [size endianess]) → section-header?
  stream : (file-stream-port?)
  size : (boolean?) = false
  endianess : (boolean?) = false

Reads a section header from current seek position.

procedure
(write-section-header section-header
stream
[ data-size
endianess]) → void?
  section-header : (section-header?)
  stream : (output-port?)
  data-size : (boolean?) = false
  endianess : (boolean?) = false

Writes a section header to stream at current seek position.

value
elf-class-32 : (integer?)

Define a 32bit ELF file in the class field of the ELF header.

value
elf-class-64 : (integer?)

Define a 64bit ELF file in the class field of the ELF header.

value
elf-2cmpl-msb : (integer?)

Define a most significant bit ELF file data field of the ELF header.

value
elf-2cmpl-lsb : (integer?)

Define a least significant bit ELF file data field of the ELF header.

3 Copyright and contact

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