Crate crate_metadata_serde

Standalone crate containing (de)serializable types for crate and section metadata.

The primary reason this exists is because LoadedCrate and LoadedSection make copious usage of Arc and Weak reference-counted pointer types, which cannot be properly (de)serialized by serde. The types in this module remove those refcount types so that they can be reconstructed individually at runtime after deserialization by the crate_metadata crate.

This is currently only used to parse and serialize the nano_core binary at compile time. The nano_core’s SerializedCrate is then included as a boot module so it can be deserialized into a LoadedCrate at runtime by mod_mgmt.

Some other types have been moved from crate_metadata into this crate because they are required for (de)serialization, e.g., SectionType.

Goal: minimal dependencies

This crate’s dependencies should be kept to a bare minimum in order to minimize the dependencies of the tools/serialize_nano_core executable, allowing it to build and run quickly.

Thus, instead of using Theseus-specific types here in this crate, we prefer using types from this crate in other Theseus kernel crates. For example, instead of implementing the routines to convert a SerializedCrate into a LoadedCrate here, we implement the routine to create a LoadedCrate from a SerializedCrate in the mod_mgmt crate itself. In other words, other larger/complex Theseus crates should depend on this crate instead of this crate depending on other Theseus crates.

Structs

• SerializedCrate
  A (de)serializable representation of a loaded crate that is serde-compatible.
• SerializedSection
  A (de)serializable representation of a loaded section that is serde-compatible.

Enums

• SectionType
  The possible types of sections that can be loaded from a crate object file.

Constants

• BSS_SECTION_NAME
• CLS_SECTION_FLAG
  The flag identifying CLS sections.
• CLS_SECTION_NAME
• CLS_SYMBOL_TYPE
  The type identifying CLS symbols.
• DATA_SECTION_NAME
• EH_FRAME_SECTION_NAME
• GCC_EXCEPT_TABLE_SECTION_NAME
• RODATA_SECTION_NAME
• TEXT_SECTION_NAME
• TLS_BSS_SECTION_NAME
• TLS_DATA_SECTION_NAME

Type Aliases

• Shndx
  A Section Header iNDeX (SHNDX), as specified by the ELF format. Even though this is typically encoded as a u16, its decoded form can exceed the max size of u16.