Conventions

§1.3.1 Normative keywords #

The key words MUST, MUST NOT, SHOULD, SHOULD NOT, and MAY in this specification are to be interpreted as described in RFC 2119.

§1.3.2 Pseudocode #

Pseudocode in this specification uses the following conventions, matching the KACS v0.20 specification:

• | bitwise OR, & bitwise AND, ~ bitwise NOT.
• |= and &= augmented assignment.
• -> field access on a pointer/reference.
• // single-line comments.
• → denotes return type in function signatures.

SID comparison is binary (byte-for-byte equality). Two SIDs match if and only if every field is identical.

Access mask comparison is bitwise. "Mask A includes right R" means (A & R) == R.

§1.3.3 Ioctl encoding #

Ioctl numbers are constructed using the standard Linux _IOC macro: _IOC(direction, type, number, size). The type byte, direction, and number for each ioctl are listed in the Constants appendix. The size is the total byte count of the ioctl's argument struct as defined in the Struct Layouts appendix. The final 32-bit ioctl number is derived from these four components per the Linux kernel ioctl encoding convention.

§1.3.4 Byte order #

All multi-byte integers in LCS data structures, the RSI wire protocol, and the backup format are little-endian unless explicitly stated otherwise.

§1.3.5 String encoding #

All strings in the LCS interface (key names, value names, hive names, layer names, paths) are UTF-8 encoded. Case folding for case-insensitive comparison is applied at the Unicode codepoint level after decoding from UTF-8, not on raw bytes. The case folding algorithm is defined in the data model Keys section.

§1.3.6 Registry paths #

Registry paths use the backslash (\) as the canonical separator. LCS accepts forward slash (/) on input and normalises it to backslash before processing. Paths in this specification always use the canonical backslash form.

Paths are case-preserving and case-insensitive. The comparison algorithm is defined in the data model Keys section.