rpm-codec

Encode/decode rpm lead/header(s)

== Which version of RPM is supported?

According to <> there are, well, three versions of rpm:

1. 'THE' rpm
2. rpm.org, a public effort starting around 2007 producing versions 4.8 to 4.10
3. rpm v5 creating version 5

The first rpm i got my hand on was 4.4, so for now the one and only implementation is 4.4. Do not expect any newer features such as compression other than gzip (lzma, xz, ...).

RPM file format specification

RPM files are persisted in network byte order and consist of four parts.

Lead

Our lead looks like this:

magic (0-3):: Magic value for both 'file' and rpm utilities ('ED AB EE DB')

major (4):: RPM Major version ('03')

minor (5):: RPM minor version ('00')

type (6-9):: Type binary ('00 00 00 00'). Type source ('00 00 00 01') not supported yet.

deprecated (10-95):: The rest is not used any more because its format is inflexible. Content is superseded by the header. It's only use is to support non-rpm utilities such as 'file' that can identify rpms based on a magic value. (85 times '00')

Signature

Signature format is equal to header format. This lib does not support checksums because the order of the checksum field would require the complete rpm structure to be processed before streaming could continue.

Header

Supported index types:

• NULL = 0
• CHAR = 1
• INT8 = 2
• INT16 = 3
• INT32 = 4
• INT64 = 5
• STRING = 6
• BIN = 7
• STRING_ARRAY = 8

Payload

A gzip,xz compressed cpio structure carries the rpm payload. Other compressions algorithms exist, and are supported by newer versions of 'rpm', but for now it's gzip.

API

Table of Contents

• RPMHeader
  • Properties
• RPMDecoder
  • Parameters
• defaultEntryHandler
  • Parameters
• contentDecoder
  • Parameters
• TYPE_NULL
• TYPE_STRING
• TYPE_STRING_ARRAY
• TYPE_I18NSTRING

RPMHeader

decoded rpm header

Type: Object

Properties

• lead Object
• signature Object
• header Object

RPMDecoder

Decodes the rpm header.

Parameters

• stream Stream

Returns RPMHeader

defaultEntryHandler

null handler simply skips content

Parameters

• header Object file header
• stream ReadStream
• callback Function

contentDecoder

Decode the body part of an rpm stream

Parameters

• result RPMHeader
• entryHandler EntryHandler (optional, default defaultEntryHandler)

TYPE_NULL

Not Implemented

Type: number

TYPE_STRING

variable, NUL terminated

Type: number

TYPE_STRING_ARRAY

Variable, sequence of NUL terminated strings

Type: number

TYPE_I18NSTRING

Variable, sequence of NUL terminated strings

Type: number

Bibliography

[bibliography]

• wikipedia RPM Package Manager
• maxrpm Edward C. Bailey. Maximum rpm. Red Hat Software, Inc. 1997.
• LSB Linux Base RPM File Format
• cpio FreeBSD cpio (odc and newc) file format spec
• kernel Al Viro, H. Peter Anvin. initramfs buffer format. Linux Kernel. 2002