outpost-package-metadata

Append outpost metadata to an application at link time using the Elf Package Metadata standard

Metadata

ELF package metadata is a JSon file with the following entry in the case of an outpost application.

generic metadata

The following metadata are fetched from meson introspect command, those are string typed.

• type: outpost application
• os: outpost
• name: Application Name, based on the meson project name
• version: Application version, based on the meson project version
• libshield_version: Version of the C runtime used (a.k.a. libshield) Task configuration is a json node filled with Task config in the task .config used (see https://git.orange.ledgerlabs.net/outpost/sentry-kernel/blob/main/uapi/task.Kconfig)
• task: outpost task configuration (json object)

task configuration metadata

• priority: task priority
• quantum: task jiffies quantum allowed
• auto_start: task start policy (auto or manually)
• exit_policy: policy on task exit (panic, restart, norestart)
• stack_size: task stack size in Bytes
• heap_size: task heap size in Bytes (it is up to the task to implements its own allocator)
• capabilities: Array of outpost system capabilities
• devs: Array of owned device ids

Example

Here an example of metadata added to the .note.package ELF section.

$ /opt/arm-none-eabi/bin/arm-none-eabi-readelf --notes app-sample.elf

Displaying notes found in: .note.package
 Owner                Data size        Description
 FDO                  0x000001f4       FDO_PACKAGING_METADATA
   Packaging Metadata: {"type": "outpost application", "os": "outpost", "name": "app-sample", "version": "0.0.0-post.14+c6ed142.dirty", "libshield_version": "0.0.0-post.8+ccf3a11.dirty", "task": {"priority": "42", "quantum": "4", "auto_start": "true", "exit_norestart": "true", "stack_size": "0x200", "heap_size": "0x400", "magic_value": "0xdeadcafe", "capabilities": ["dev_buses", "dev_io", "dev_timer", "dev_storage", "dev_crypto", "dev_power", "sys_power", "sys_procstart", "mem_shm_own", "mem_shm_use", "cry_krng"], "devs": [0, 1]}}

Meson

Pre requisites

• Python 3.10+
• The Meson Build System (>= 1.4.0)
• Dunamai

How To

While used as meson subproject this package automatically adds a custom target that use project introspection and Kconfig json output and preprocessed dts in order to generates outpost application relative metadata in a text file to be used as linker option.

In order to add the .note.* section(s) to the generated elf file, one must add the meson internal dependency to the dependencies list of its executable.

Usage example

project('outpost-app', [...])

[...]

app_metadata_proj = subproject('meson-app-metadata')
app_metadata_dep = app_metadata_proj.get_variable('package_metadata_dep')
outpost_app_deps += [ app_metadata_dep ]


executable(meson.project_name(),
    [...]
    dependencies: [ outpost_app_deps ],
    [...]
)

Cargo

Pre requisites

• Rust >= 1.82

Usage example

Add outpost-package-metadata as build dependencies.

[build-dependencies]
outpost_metadata = "x.y.z"

Generate metadata from a build script (build.rs)

use std::env;

fn main() {
    let metadata = outpost_metadata::cargo_package_introspect(
        env::var("CARGO_MANIFEST_PATH").ok().as_deref()
    );
    let _ = outpost_metadata::gen_package_metadata(
        env::var("CARGO_PKG_NAME").unwrap().as_str(),
        metadata, env::var("config").ok().as_deref(),
        None);
}

License

Licensed under Apache-2.0

see LICENSE file