UAPI Group Specifications#
The following specifications have been accepted by the UAPI group:
- UAPI.1 Boot Loader Specification: Defines a set of file formats and naming conventions to allow distribution independent boot loader menus supportable by multiple bootloaders. (canonical online location)
- UAPI.2 Discoverable Partitions Specification: Discusses GUID UUIDs for auto-discovery of partition semantics and mount points. (canonical online location)
- UAPI.3 Discoverable Disk Images: Describes the Discoverable Disk Image format for self-describing system images. (canonical online location)
- UAPI.4 Extension Images: Describes the use of Discoverable Disk Images to create extensions to a base image. (canonical online location)
- UAPI.5 Unified Kernel Images: Describes the use of UEFI PE binaries to provide a Unified Kernel Image containing the kernel, initrd, command line, and other components. (canonical online location)
- UAPI.6 Configuration Files Specification: Standardises default locations and environment variables for locating common files or base directories. This is derived from, and extends, the XDG Base Directory Specification, to allow for separation between vendor and admin configuration files, drop-in files, and masking. (canonical online location)
- UAPI.7 Linux TPM PCR Registry: An informative list of how TPM PCRs are used on a Linux system. (canonical online location)
- UAPI.8 Package Metadata for Executable Files: Describes the format and mechanism to include packaging metadata in ELF/PE binaries. (canonical online location)
- UAPI.9 Linux File System Hierarchy: Describes the layout of directories and files in an installation of Linux (canonical online location)
- UAPI.10 Version Format Specification: Defines semantics of version strings used in the other specifications listed here. (canonical online location)
- UAPI.11 File Hierarchy for the Verification of OS Artifacts (VOA): Describes the use of Discoverable Disk Images to create extensions to a base image. (canonical online location)
- UAPI.12 dlopen() Metadata for ELF Files: Describes the format and mechanism to include dynamically loaded libraries metadata in ELF binaries. (canonical online location)
- UAPI.13 Efficient Time Synchronisation for Virtual Machines: Describes the format and mechanism to synchronize the guest clock. (canonical online location)
- UAPI.14 Virtual Machine Generation ID: Describes the mechanism for detecting virtual machine rollback events. (canonical online location)
- UAPI.15 OSC 3008: Hierarchical Context Signalling: Defines a mechanism for terminal emulators to follow the context hierarchy of what’s on screen. (canonical online location)
Work in Progress#
See open PRs on github.
License#
All specifications are licensed under CC-BY-4.0.
Versioning#
All specifications are versioned.
The versioning format is MAJOR.MINOR.
Compatible changes increment the MINOR version.
Incompatible changes increment the MAJOR version and reset the MINOR version to 0.
Work in progress specifications have a MAJOR version of 0.
A filename/MAJOR.MINOR git tag will be created when a new version of a given spec is released.
Glossary#
This section clarifies on terms and abbreviations used in specs and other documents.
General terms and abbreviations#
- ELF – Executable and Linkable Format (Linux executable binary format)
- MOK – Machine Owner Key (shim)
- PCR – TPM Platform Configuration Registers
- PE – Portable Executable (UEFI executable binary format)
- SBAT – UEFI Secure Boot Advanced Targeting
- TPM – Trusted Platform Module (security chip)
Terms and abbreviations specific to UAPI group specifications#
- BLS - Boot Loader Specification
- confext – Configuration Extension Image
(type of DDI that is overlayed on top of
/etc/via overlayfs and can extend the underlying OS’ configuration in a composable, immutable fashion) - DDI - Discoverable Disk Image
- DPS - Discovery Partition Specification
- sysext – System Extension Image
(type of DDI that is overlayed on top of
/usr/and/opt/via overlayfs and can extend the underlying OS vendor resources in a composable, immutable fashion) - UKI – Unified Kernel Images (UEFI boot stub + kernel + initrd + more)
- VMClock – Virtual Machine Clock (efficient time synchronisation for virtual machines)
- VMGenID – Virtual Machine Generation ID (mechanism for detecting VM rollback events)
- VOA – Verification of OS Artifacts
Participate#
Please use the specifications issue tracker to engage with the project.