Xapt Package Updates

xapt Package Updates

xapt is XAIOS's native, deliberately small package updater. It distributes complete XAIOS application ELFs rather than source packages or Linux/FreeBSD binaries. Applications can be installed, upgraded, removed, or rolled back without replacing the OS. A system update is streamed into the inactive A/B slot and takes effect only after reboot.

Operator commands

xapt update
xapt list
xapt list --upgradable
xapt search calculator
xapt show calculator
xapt install calculator
xapt upgrade calculator
xapt rollback calculator
xapt remove calculator
xapt os-upgrade

xapt update fetches and activates the catalog only after signature, architecture, and monotonic-generation validation. Install and upgrade are explicit confirmation actions; there is no dependency resolver and no automatic background update. A newly installed application is available by name immediately and is not started automatically.

Compatibility and integrity

Each application manifest binds:

• application name and semantic version;
• target architecture;
• minimum XAIOS version and ABI version;
• exact capability mask;
• payload size and SHA-256 digest;
• Ed25519 signer identity and signature.

Catalogs are signed separately, architecture-specific, and generation monotonic. XAIOS rejects incompatible, downgraded, malformed, oversized, or corrupted content before activation. Current and previous versions are stored separately so xapt rollback NAME is one-step and atomic. Failed staging does not change the active application.

System records bind version, architecture, monotonic system generation, byte size, SHA-256, signed update metadata, and image path. xapt os-upgrade rejects the current or an older version, streams the image in bounded chunks, verifies it in the inactive slot, and marks that slot pending. The boot lifecycle retains the existing verified fallback behavior.

Storage layout

/etc/xapt.conf              image default
/state/xapt/config          administrator override
/state/xapt/catalog         last verified catalog
/update/xapt/               non-authoritative staging
/apps/NAME/current.elf      active application
/apps/NAME/current.manifest active signed metadata
/apps/NAME/previous.*       one rollback version

The default development origin is 91.99.176.243:8090. Configuration is plain text:

host=91.99.176.243
port=8090
base=/

HTTP is only the transport. Authenticity and integrity come from signed catalogs/manifests and payload hashes. The current client requires HTTP/1.1 with Content-Length and does not support transfer encoding, compression, TLS, mirrors, proxies, deltas, dependencies, or unattended upgrades.

Build and publish a development repository

make xapt-repository
./scripts/publish-xapt-repository.sh

The first command creates and verifies both architecture trees under build/xapt/repository. The publisher re-verifies locally, synchronizes to /var/xaios_updater, validates the repository Caddy configuration, and reloads Caddy on port 8090. Override the destination with XAIOS_UPDATE_HOST and XAIOS_UPDATE_ROOT.

The repository shape is:

catalog-aarch64.txt
catalog-x86_64.txt
apps/ARCH/NAME/VERSION/{NAME.elf,manifest.txt,record.json}
os/ARCH/VERSION/{kernel.elf,record.json}

Use tools/xaios_xapt_repo.py for focused package, system, catalog, and verify operations. Publishing a newer catalog requires a strictly higher generation.

Security boundary

The checked-in Ed25519 key is a deterministic test fixture and its private seed is public. It exists so builds and QEMU tests are reproducible. A server using that key is a development origin, not a production trust root. Production use is blocked until maintainers define offline key custody, root rotation, revocation, signing authorization, recovery, and release audit procedures.

The app loader remains capability-based and does not add a package-manager syscall. xapt uses the existing filesystem, network, clock, and control protocol surface. Eight new administrative control operations fit inside the existing control syscall, so the XAIOS syscall count remains 50.

Evidence

make xapt-test
make qemu-xapt-gate

The dual-architecture QEMU gate proves signed catalog refresh, independent app install and argv execution, upgrade, one-step rollback, tamper rejection, streamed A/B OS delivery, reboot persistence, and removal. QEMU does not prove physical-device durability, Internet-scale availability, or production key security.

See Applications, Administration, Testing XAIOS, and Security Model.