Document the deltarpm format

[DemiMarie]

What is the format of a deltarpm package?

[mlschroe]

I guess "drpm" is compatible to "deltarpm". The format is somewhat documented here:

https://github.com/rpm-software-management/deltarpm/blob/master/README

[DemiMarie]

I guess "drpm" is compatible to "deltarpm". The format is somewhat documented here:

https://github.com/rpm-software-management/deltarpm/blob/master/README

What is the format of the delta instructions? This is the part that confuses me.

[DemiMarie]

To elaborate: I want to audit the drpm implementation for security, and doing that requires knowing what the format of the input is.

[mlschroe]

IIRC there are just two types of instructions:

1. copy n bytes from the "literal" data
2. copy n bytes from the reconstructed old cpio archive at position p, modifying the bytes by adding n bytes from the "addblock" data

It's the same as in the "bsdiff" tool.

[DemiMarie]

IIRC there are just two types of instructions:

1. copy n bytes from the "literal" data
2. copy n bytes from the reconstructed old cpio archive at position p, modifying the bytes by adding n bytes from the "addblock" data

It's the same as in the "bsdiff" tool.

Can those instructions, and their encoding, be documented in detail? The documentation should be sufficient should for someone to reimplement the format from scratch.