Directory scanning support — sys_getdents64 (libc-free)

• Type: feature
• Status: done
• Owner: — (lock released; last worked by Codex)
• Opened: 2026-06-21
• Relation: Stresses low-level syscall wrappers, pointer arithmetic, and type casting in RTL. Blocker for feature-demo-file-browser.

Goal

Provide a statically-linked, libc-free directory scanning mechanism in the RTL using raw Linux system calls (sys_getdents64).

Surface (sketch)

In lib/rtl/platform.pas (or per-platform files):

• Define standard constants and records (linux_dirent64).
• Wrap the raw system call sys_getdents64 (Syscall 217 on x86-64).

In lib/rtl/sysutils.pas:

• type TFileInfo = record Name: AnsiString; IsDir: Boolean; Size: Int64; end;
• type TFileInfoArray = array of TFileInfo;
• function GetDirectoryContents(const path: AnsiString; var list: TFileInfoArray): Boolean;

Implementation Steps

1. Expose sys_getdents64 in lib/rtl/platform.pas for the different target architectures (x86_64, i386, aarch64, arm32).
2. Open directory file descriptor using sys_open with O_RDONLY | O_DIRECTORY.
3. Loop over sys_getdents64 with a local buffer (e.g. 4096 bytes) and decode the variable-length linux_dirent64 structures using pointer offsets.
4. Filter out . and .. directory links.
5. Close the descriptor and return the parsed TFileInfo records.

Log

• 2026-06-21 — Opened.

• 2026-06-21 — First Track B slice in progress: added PAL PalGetDents64, POSIX syscall numbers, ESP unsupported stub, and SysUtils.GetDirectoryContents. Regression test/lib_directory.pas covers one file plus one child directory on the POSIX backend. File size/metadata is still missing and split to feature-pal-file-stat-metadata.

• 2026-06-21 — HALTED → unfinished/. working/ lock released (no active agent). In-flight code committed as 9f22df5 (sys_getdents64 + GetDirectoryContents + test); resume from there. Follow-up: feature-pal-file-stat-metadata.

• 2026-06-22 — DONE in this commit. Re-audited current state after feature-pal-file-stat-metadata: POSIX PAL exposes PalGetDents64 and PalStatAt, SysUtils.GetDirectoryContents filters ./.. and fills directory/file metadata, and test/lib_directory.pas covers entries, type, size, and stat. Verified with make lib-test.