Linux POSIX paths
The direct Linux x86-64 backend implements path_dirname, resolve_path, path_relative, and current_dir. Lexical path operations do not grant filesystem or subprocess authority.
Private helpers use kelft-native/1 and object metadata pathABI: kelft-native-paths/1. String arguments are borrowed and returned strings owned. Context layout and canonical Core are unchanged. Kelft private-IR builders must emit deterministic complete objects.
Lexical operations follow POSIX paths, regardless of the compiler host. A slash separates components; backslashes are ordinary bytes. resolve_path removes empty, . and .. components, clamps parents at root, and removes trailing slashes except at root. An absolute second argument replaces the base. Relative bases resolve against the executing process's working directory. path_relative compares normalized absolute paths at component boundaries, returns an empty string for equal paths, and uses / between components. path_dirname preserves the POSIX double-slash spelling and internal redundant separators, as the existing JavaScript POSIX implementation does. Unicode and embedded NUL bytes survive lexical processing. NUL does not become permission to pass an invalid OS path.
These operations do not access path contents, follow symlinks, canonicalize filesystem objects, or grant filesystem/subprocess authority. Object generation does not read or embed the compiler host's working directory. An absolute resolve_path needs no working-directory syscall.
current_dir uses Linux x86-64 syscall 79 through k_os_getcwd, returning the actual execution-time directory. Kernel buffer growth (ERANGE) retries with doubled, heap-accounted storage. Nonpositive results, malformed lengths, missing NUL terminators and nonabsolute results trap with KRT_IO; invalid UTF-8 traps with KRT_UTF8. This is not a filesystem authorization check. The raw mechanism returns the signed kernel result in exactly four result bytes, including the terminating NUL in successful byte counts. Its register clobbers respect System V AMD64. No libc or additional production tool dependency is introduced.
Lexical workspaces, cwd buffers and returned values count toward the existing heap limit. Length growth is bounded before allocation; scratch storage is released on normal returns. Traps terminate the process. Inputs, their reference counts, call depth and caller result canaries are checked by an independent C harness. C is a test dependency only.
Validation includes eight source fixtures, deterministic object bytes, 4,370 deterministic Node POSIX oracle cases, six guard-page strings, allocation failure, real cwd, long Unicode cwd, deleted cwd, invalid UTF-8 cwd, and seven injected syscall sequences. Injection weakens only the mechanism symbol in a test copy; code and unwind sections remain byte-identical. Production objects retain their complete unwind metadata. Existing aggregate, stream, map and deep-graph ABI probes run alongside these checks.
Focused checks must retain the required runtime and ABI probes and identify their selected fixtures. Reports bind source, toolchain, and artifact hashes; a focused pass does not establish full-corpus or platform qualification.
Arguments and inserted Intent guards are implemented and tested separately. Canonical paths and reads now have separate authority checks. Write operations and artifact execution remain unsupported. Full native Intent integration, actual baseline isolation, standalone driver/closure, native self-compilation and all six release lanes remain required.
Source: public Kelft compiler, commit f567c21684362db37e0aa0a68e71e7614502c45a. Compiler 0.1.0-alpha.2; Core 0.1; Intent 0.2.