filesys: mount host directories as AmigaDOS volumes by codewiz · Pull Request #159 · LinuxJedi/Copperline

codewiz · 2026-07-11T04:45:02Z

Host-filesystem support: [[filesys]] config entries export host directories to the guest as AmigaDOS volumes:

# Define HOSTFS0:
[[filesys]]
path = "/home/bernie/emu/amiga/hd/WB"
volume = "WB"   # Optional, defaults to the directory name
bootpri = 5     # Optional boot priority; default -128 = never boot

# Multiple filesystems supported
[[filesys]]
path = "/home/bernie/emu/amiga/hd/Work"

Design

A new Copperline services board (manufacturer 0x1448, product 5, 64K Zorro II, RAM-backed) carries everything guest-side, with room for future services (RTG, clipboard, ...) on the same board:

guest/services/ -- a tiny handler in C plus an asm entry table, built with the dockerized m68k-amigaos GCC 16 (stefanreinauer/amiga-gcc:gcc-v16.1), compiled -mpcrel so the ROM is relocation-free and runs at whatever base autoconfig assigns (the Makefile fails the build if relocations or data/bss sneak in). The built ROM is committed as assets/services/services_rom.bin (~600 bytes), so a plain cargo build needs no cross-toolchain. The DiagArea is embedded in the ROM at +0x40, like real autoboot board ROMs.
Boot: Kickstart copies the DiagArea; its DiagPoint stub jsr's back into the ROM, which traps to the emulator and mounts one DeviceNode per config entry via AddBootNode (ADNF_STARTPROC), so DOS mounts and starts the handlers at boot. Each mount's boot priority comes from a per-unit DosEnvec the emulator writes into the board window; when a HOSTFS node wins the boot vote, the DiagArea's BootPoint runs the standard autoboot sequence (FindResident("dos.library"), jsr rt_Init) and DOS mounts it as SYS:.
Packets: the handler process is a pure pump -- WaitPort/GetMsg, one reserved A-line trap per DosPacket (D1 = packet, A1 = port), PutMsg the reply. All ACTION_* semantics live host-side in src/filesys.rs (FilesysHle, the CPU's high-level-emulation hook), which reads/writes guest memory directly.
Volumes: at handler startup the emulator builds a DLT_VOLUME DosList node in the board window and the guest AddDosEntrys it (a dedicated trap return code -- only guest code may take the DosList semaphore). id_VolumeNode/fl_Volume point at it, which is what makes Workbench icons and C:Info work.
DOS ABI layer: src/amigaos/dos.rs mirrors the NDK dos.h/dosextens.h constants and structures as repr(C) structs of big-endian fields (zerocopy), so the Rust definition is the guest layout and one write serializes it -- no magic offsets at call sites. Guest-visible objects (FileLocks, volume nodes) are allocated from board-window pools, so the host never calls guest AllocMem.

Path resolution follows FFS semantics, verified against the real FFS handler (a single trailing slash is the directory itself: "Prefs/" lists Prefs, "Prefs//" its parent; names are case-insensitive; an Assign: prefix in a packet name resolves relative to the supplied lock, like UAE's get_aino).

Status

Area	Feature
Mounting	Autoconfig board, DiagArea boot, `AddBootNode` mounts, handler autostart	✅
Mounting	Volume DosList node (Workbench icon, C:Info row)	✅
Mounting	Guest warm-reboot state reset (stale ports/locks in the emulator)	✅
Mounting	Real `FileSysStartupMsg`/`DosEnvec`, so Early Startup shows `CLFS hostfs-N`	✅
Mounting	`bootpri` config option; BootPoint boots DOS off a HOSTFS volume	✅
Mounting	`ACTION_DIE` dismount: volume off the DosList, handler process exits; refused with `ERROR_OBJECT_IN_USE` while locks or files are open (protects the boot volume). `dn_Task` is cleared, so the next access to the device restarts the handler and remounts the volume	✅
Info	`DISK_INFO` / `INFO` with real statvfs sizes, UAE-style block scaling	✅
Info	`IS_FILESYSTEM`	✅
Locks	`LOCATE_OBJECT`, `FREE_LOCK`, `COPY_DIR` (DupLock), `PARENT`, `SAME_LOCK`	✅
Locks	Access-mode enforcement (exclusive vs shared)	❌
Examine	`EXAMINE_OBJECT`, `EXAMINE_NEXT` (dir, list), `EXAMINE_FH`	✅
Examine	`EXAMINE_ALL` (DOS falls back to `EXAMINE_NEXT`)	❌
Read I/O	`FINDINPUT`, `READ`, `SEEK`, `END`, `FH_FROM_LOCK`, `PARENT_FH`, `FLUSH` (type, copy-from)	✅
Write I/O	`FINDOUTPUT` / `FINDUPDATE`, `WRITE`, `SET_FILE_SIZE` (all write actions refused with `ERROR_DISK_WRITE_PROTECTED`, and `id_DiskState` reports Read Only)	❌
Metadata	Protection bits, comments, and exact datestamps from UAE `.uaem` sidecars (`+s`/`+p`/`+a`; sidecars hidden from listings); host read-only maps to `w`-denied	✅
Metadata	`SET_PROTECT` (accepted and ignored; persist to `.uaem` once writes land)	✅
Metadata	`CREATE_DIR`, `DELETE`, `RENAME`, `SET_DATE`, `SET_COMMENT`	❌
Misc	Notifications, `RENAME_DISK`, Latin-1 filename mapping	❌

Testing

Unit tests lock the board-window layout, the DOS struct sizes/serialization, path resolution (assign-lock prefixes), block-count scaling, and DateStamp conversion.
Multiple HostFS volumes mount on emulated config (A1200/040 OS3.x).
info / dir / list / type / copy all behave.
Workbench can browse volumes and copy files to RAM:.
Boots a production Workbench (OS 3.2, SetPatch, ENVARC: copy, WBStartup, DOpus5) directly off a host directory with bootpri = 5, and survives warm reboots.
Dismount cycle: ACTION_DIE removes the volume and ends the handler task (watched in Scout), a later dir remounts it, and dismounting the boot volume is refused with error 202.

🤖 Generated with Claude Code - hand edited afterwards

A Copperline services board (0x1448 product 5, 64K Zorro II) carries a tiny guest handler (guest/filesys/, C, built reloc-free with dockerized m68k-amigaos GCC 16) that mounts each [[filesys]] config entry via the DiagArea and pumps every DosPacket to the emulator through an A-line trap; src/filesys.rs implements the ACTION_* semantics on the host side. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ACTION_COPY_DIR/PARENT/SET_PROTECT plus read-only file I/O (FINDINPUT/READ/SEEK/END), enough for list, type, and copy-from. A single trailing slash means the directory itself, not its parent (verified against FFS: "Prefs/" lists Prefs, "Prefs//" its parent). The NDK dos.h/dosextens.h constants and structures move to amigaos::dos as repr(C) structs of big-endian fields (zerocopy), so the definition is the guest layout and one write_bytes serializes it. All hand-assembled bytes leave board_image(): the DiagArea now lives inside the handler ROM (entry.s), like real autoboot board ROMs. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

codewiz · 2026-07-11T08:53:06Z

I ran out of Fable credits while testing the .uaem metadata parser.

My next goals are:

Complete read-only functionality
Get Workbench to boot
Performance (ExAll, caching .uaem files...)
Finally, write support.

Read the UAE .uaem metadata sidecars (same grammar as the Amiberry fsdb: hsparwed presence flags with the rwed group flipped to the FIB deny convention, centisecond timestamp, optional comment) for protection bits, exact datestamps, and file comments; hide the sidecars from listings. Without a sidecar, a read-only host file denies w, and e stays allowed, both matching the UAE fsdb. Sidecar timestamps convert civil-date-direct, with no timezone round trip. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Flush all per-boot handler state (ports, volumes, locks, open files, lock pool) at expansion init, so a warm reboot starts clean instead of misrouting packets to stale MsgPort addresses. Point dn_Startup at a per-unit FileSysStartupMsg (plus shared DosEnvec and device BSTR) written into the board window, so Early Startup shows 'CLFS hostfs-N' instead of dereferencing a raw integer as a BPTR. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

[[filesys]] entries take bootpri (-128..127, default -128 = never a boot candidate), carried in a per-unit DosEnvec whose de_BootPri the guest handler passes to AddBootNode. The DiagArea's BootPoint is now the standard autoboot code (FindResident dos.library, jsr rt_Init), and DiagPoint returns success so Kickstart keeps the diag copy strap boots through. Booting a real Workbench off a host directory flushed out packet-level gaps, all fixed: names with an "Assign:" prefix must resolve relative to the supplied lock, not the root (broke SetPatch's LIBS: opens); ACTION_FH_FROM_LOCK (broke the ENVARC: copy), ACTION_SAME_LOCK, ACTION_EXAMINE_FH, ACTION_PARENT_FH, and ACTION_FLUSH. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Copilot

Pull request overview

This PR adds experimental host-filesystem support by introducing a new Copperline “services” Zorro II board and a guest-side handler ROM that forwards AmigaDOS packets to a host-side Rust HLE implementation, enabling [[filesys]] config entries to mount host directories as HOSTFS<n>: volumes.

Changes:

Introduces a new services autoconfig board type and plumbing to pre-seed its RAM window with the handler ROM + mount/diag data.
Adds src/filesys.rs (host-side HLE) plus an AmigaDOS ABI mirror (src/amigaos/dos.rs) and configuration parsing/validation for [[filesys]].
Adds guest-side handler sources/build instructions and commits the built ROM artifact for normal cargo build workflows.

Reviewed changes

Copilot reviewed 14 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/zorro.rs	Adds a services board product ID/spec and a helper to add RAM-backed boards pre-seeded with an image.
src/lib.rs	Exposes the new `filesys` module.
src/filesys.rs	Implements host-side AmigaDOS packet semantics for mounted host directories, plus board-window layout helpers and unit tests.
src/emulator.rs	Wires config-provided `filesys` mounts into the machine at build time.
src/cpu.rs	Replaces the no-op HLE handler with `FilesysHle` and adds a mounts setter.
src/config.rs	Adds `[[filesys]]` parsing, defaulting, validation, and services-board insertion into the Zorro chain.
src/amigaos/dos.rs	Adds a zerocopy-backed big-endian ABI mirror for DOS constants and structures.
src/amigaos.rs	Exposes the new `amigaos::dos` module.
guest/services/README.md	Documents the guest-side handler ROM purpose and rebuild process.
guest/services/Makefile	Adds dockerized m68k build pipeline and checks for relocations/data/bss.
guest/services/handler.c	Implements the guest packet-pump handler and expansion-init mounting logic.
guest/services/entry.s	Defines the entry table and embedded DiagArea used for expansion init / autoboot.
guest/services/copperline_board.h	Shares board layout/trap opcode constants between guest and host.
Cargo.toml	Adds `zerocopy` dependency for ABI structs.
Cargo.lock	Locks `zerocopy` dependency.
.gitignore	Ensures the committed services ROM artifact is not ignored; ignores guest build intermediates.

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Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

A guest could Lock("HOSTFS:..") and walk out of the mounted directory onto the host filesystem: AmigaDOS gives dots no special meaning, but match_component passed them to the host, which does. Found by Copilot review on PR LinuxJedi#159. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Deleting a file popped "unknown packet" (209); a write-protected FFS disk answers every write-family action with error 214 instead, so do the same until write support lands. id_DiskState now reports ID_WRITE_PROTECTED, so C:Info shows the volumes as Read Only. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

A dismount tool sends ACTION_DIE to shut a handler down; stock Assign DISMOUNT only unlinks the DeviceNode silently. Refused with ERROR_OBJECT_IN_USE while locks or files are open (protects the boot volume). On success the host frees the unit state and clears dn_Task, and the guest RemDosEntry-s the volume and exits the process, so the next reference to the device simply restarts the handler and remounts. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The packet pump needs well under 200 bytes; 8K per handler process was just wasted guest RAM. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

codewiz · 2026-07-12T04:14:29Z

@codex review

Copilot

Pull request overview

Copilot reviewed 16 out of 19 changed files in this pull request and generated 4 comments.

codewiz · 2026-07-12T11:55:20Z

+            for m in &self.filesys {
+                if !m.path.is_dir() {
+                    anyhow::bail!("[[filesys]] path {} is not a directory", m.path.display());
+                }
+            }


Fixed in 4540ff1: the [[filesys]] config loop now validates the resolved volume name with three separate checks and messages -- empty, over 30 bytes, and containing a colon, slash, or NUL -- failing fast instead of silently truncating or building a broken volume node. Added a rejection test.

codewiz · 2026-07-12T10:02:03Z

Config GUI proposal (I could push it as a separate branch and open a PR if you want to review it):

So multi-mount debug logs say which HOSTFS unit a packet belongs to. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The read length comes straight from the guest packet, so allocating it up front let a bogus multi-GB read force an unbounded host allocation. Read in 64 KiB chunks instead; DOS callers see identical results. Reported by Copilot on PR LinuxJedi#159. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

handle_aline claimed the whole 0xA400-0xA4FF range and returned true for any opcode, swallowing the CPU A-line exception. We only emit 0xA400 and 0xA402; return false for the rest so guest software using its own A-line traps takes the exception as on hardware. Reported by Copilot on PR LinuxJedi#159. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The volume name becomes an AmigaDOS DosList BSTR, so reject up front rather than silently truncating or building a broken volume node. Three separate checks with their own errors: empty, over 30 bytes, and containing ":" "/" or NUL. Adds a rejection test. Reported by Copilot on PR LinuxJedi#159. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

TRAP_DIAG_ENTRY reset the per-boot maps field by field and missed next_file_key, which could (in theory) wrap and alias an open file. Reassign *self from a default, preserving only the configured mounts, so a newly added per-boot field can never be forgotten. Reported by Copilot on PR LinuxJedi#159. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

codewiz force-pushed the feat/filesys branch from 006a3fd to ea5801a Compare July 11, 2026 04:57

codewiz force-pushed the feat/filesys branch from ea5801a to def5dfd Compare July 11, 2026 06:54

codewiz changed the title ~~filesys: mount host directories as HOSTFS volumes~~ filesys: mount host directories as AmigaDOS volumes Jul 11, 2026

codewiz and others added 3 commits July 11, 2026 20:51

codewiz marked this pull request as ready for review July 11, 2026 13:58

LinuxJedi requested a review from Copilot July 11, 2026 17:54

Copilot started reviewing on behalf of LinuxJedi July 11, 2026 17:55 View session

Copilot AI reviewed Jul 11, 2026

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Comment thread src/filesys.rs

Comment thread src/cpu.rs Outdated

codewiz and others added 7 commits July 12, 2026 02:52

[[filesys.mount]] -> [[filesys]]

f68e4a7

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

filesys: rustfmt

feb11c3

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs: document [[filesys]] mounts in the example config and guide

a519b8d

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

filesys: shrink the handler stack to 2K

b1cb792

The packet pump needs well under 200 bytes; 8K per handler process was just wasted guest RAM. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

codewiz force-pushed the feat/filesys branch from 4cfa216 to b1cb792 Compare July 12, 2026 03:22

LinuxJedi requested a review from Copilot July 12, 2026 05:16

Copilot started reviewing on behalf of LinuxJedi July 12, 2026 05:17 View session

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codewiz and others added 4 commits July 12, 2026 19:17

filesys: prefix packet traces with the device name

0aa0c2f

So multi-mount debug logs say which HOSTFS unit a packet belongs to. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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filesys: mount host directories as AmigaDOS volumes#159

filesys: mount host directories as AmigaDOS volumes#159
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