nexoniarz/SchOS
nexoniarz/SchOS
Watch
1
0
Fork
You've already forked SchOS
 0
Code Issues Pull requests Projects Releases 1 Packages Wiki Activity Actions

debugger: D5, the network transport -- and the plan closes

Browse source 
schdbgd bridges TCP to the debugger, which is the one way in that does not
need you to be sitting at the machine. It is a bridge and nothing else: a line
in becomes a line written to /dev/dbgro and the answer comes back, so `nc` is a
complete client and there is no clever client to be broken on the day you need
this.

    # schdbgd &
    schdbgd: debugger on port 4444, loopback only
    $ nc 127.0.0.1 4444
    dma
    arena  0xffff80003da41000-0xffff80003ea41000  16384 KB total, ...

A kernel debugger plus a TCP socket is a remote root hole, so three things were
decided rather than discovered:

  - It does not start by itself. schdbgd.job ships Disabled. SchOS has no
    kernel command line, so the boot flag the plan asked for is the job
    manifest, which is the same thing in this system's own idiom.
  - It binds loopback; -a names an address and says so in a paragraph.
  - It cannot reach a view that changes state, enforced in the kernel.

That last one is /dev/dbgro: /dev/dbg on minor 1. The minor is the one piece of
per-open state a character device already sees, so which node you opened is the
permission -- nothing to latch, nothing to remember between the write and the
read, no way across. Which views are refused comes from dbg_register_rw() on
the registration itself, because a central list of dangerous views goes stale
in the direction where a new view is quietly treated as safe. Today that is
`watch <addr>`; `watch` with no argument is still the listing and still
answered.

Also: socket() now accepts IPPROTO_TCP with SOCK_STREAM and IPPROTO_UDP with
SOCK_DGRAM. They name the default rather than departing from it, and toybox's
nc writes them out -- so TCP was "Protocol not supported" on a system whose
whole network is TCP.

docs/plan/debugger.md retires into docs/architecture/debugging.md; 16 files
repointed. Every plan in docs/plan/ that was open is now closed, so the next
thing is Gate 0 itself: the survey, with the instrument built.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2
This commit is contained in:
Nexoniarz 2026-09-14 15:33:53 +02:00
commit bc39b73969
23 changed files with 491 additions and 293 deletions
Download patch file Download diff file Expand all files Collapse all files

19
docs/plan/1.0.md
View file

@ -95,9 +95,9 @@ The galling ones. The work exists, is tested, and nothing uses it.
|---|---|
| **`foundations.md`** | Item 1 built. Items 2 (a shareable memory object), 3 (`AF_UNIX` in the filesystem namespace), 4 and 5 open. **Wayland stops at item 2.** |
| ~~**`hybrid.md`**~~ | **Closed.** All four mechanisms built; H1, H2 and H3 done. H4 — the USB eviction — is *withdrawn* rather than outstanding: USB is the bus peripherals arrive on, not a peripheral, and an eviction that has to leave an identical driver behind has moved nothing. See [hybrid.md](hybrid.md), "Decided: USB stays in the kernel". |
| ~~**`ldls.md`**~~ | **Closed.** L0 through L4 built: the loader handles 2,440 stock modules, `8139too` runs in a SchOS process driving QEMU's rtl8139 through `/dev/pci`, `ping` works over it, and killing the host releases the device and DMA so a replacement takes over. Described in [../architecture/ldls.md](../architecture/ldls.md). One driver, one kernel version, tried once. |
| ~~**`ldls.md`**~~ | **Closed.** L0 through L4 built: the loader handles 2,440 stock modules, and both `8139too` and Linux's `e1000` run in a SchOS process through `/dev/pci` with `ping` working over each. The e1000 run is a handover — the kernel was driving that NIC and gave it up. Described in [../architecture/ldls.md](../architecture/ldls.md). Two drivers, one kernel version, one machine. |
| **Schcom v0** | 715 lines that composite, over a wire format that is superseded. Frozen: it runs, nothing more is added, and it is kept only because it is the one thing in the tree that has ever put a client's pixels on screen. |
| **`debugger.md`** | D0 through D4 built and described in [../architecture/debugging.md](../architecture/debugging.md). Only the network transport is open — a userspace daemon bridging TCP to `/dev/dbg`, which is deliberately last. |
| ~~**`debugger.md`**~~ | **Closed.** D0 through D5 built, including the network transport: `schdbgd` bridges TCP to `/dev/dbgro`, ships disabled, binds loopback, and cannot reach a view that changes state. Described in [../architecture/debugging.md](../architecture/debugging.md). |
**The row LDLS spent, and gave back.** `hybrid.md` closed — H3 built, H4
withdrawn — and `ldls.md` took the slot it freed. It has since closed too, so
@ -107,13 +107,16 @@ part of 1.0**: nothing in the acceptance test needs a foreign driver. It was
taken on because the mechanisms it uses were finished and idle, and because
the alternative to it is writing a driver for every device that exists.
**The row the debugger spent.** Adding one requires closing one, and *A released
PCI device* closed when H2 landed. It is worth saying plainly that the debugger
is not a capability of the OS the way every other row here is: nothing in it
ships to a user or appears in the acceptance test. The case for it is that
**Gate 0 is a list of bugs to find in a kernel that could not be asked
**The row the debugger spent, and gave back.** Adding one requires closing one,
and *A released PCI device* closed when H2 landed. It is worth saying plainly
that the debugger is not a capability of the OS the way every other row here is:
nothing in it ships to a user or appears in the acceptance test. The case for it
is that **Gate 0 is a list of bugs to find in a kernel that could not be asked
anything** — so it is the instrument the rest of this register is surveyed with,
and it earns its slot by making every other row cheaper to close.
and it earned its slot by making every other row cheaper to close.
It has closed. **Every plan in `docs/plan/` that was open is now closed**, which
means the next thing is Gate 0 itself: the survey, with the instrument built.
**Closed since this register was written.** *A released PCI device* — release is
now symmetric with claim (bus mastering cleared before the DMA is freed, a