ADR 0328 supersedes ADR 0325: shared data is a library with one home, kept usable by
its group rather than by ACL entries. The engine now makes each library's group and
each module's user in its libraries' groups; keeps a library's root and requested
sub-paths in its group with group write and setgid on its home, making missing
sub-paths as the root is; waits for the operator's word before touching a root that
holds data, and on the take act walks it by descriptor (no link, same filesystem,
bounded and resumed, files with other names left); holds the containers of a library
whose disk or mount is not there; and puts the tool runner's account in the group.
The ACL keeping, mask repair and watch are gone; an access is again as before ADR 0325.
The controller cannot know the operator's account's uid, names an access by its
declared id (which holds a slash), and should not parse words. A tool runner's
account may now come by name alone and is read here (refused when absent or root's,
its uid said in the access's listing); the take act matches the declared id exactly;
an access wait says its reason (keep or disk) and, for a filesystem that refuses
ACLs, whether the take act can enable them.
A module's containers ran as whatever their image chose and shared folders were
made writable by putting accounts in the folder's group (ADR 0312), which ADR 0325
supersedes. The engine now makes each declared module identity as a system account
with the controller's numbers, runs a container declaring `identity` as it, and keeps
each placed shared folder usable through one POSIX ACL entry per user, set through
the kernel's xattrs on descriptors it opened itself. A folder holding data is kept
only after the operator's warrant (the take act); a missing folder is made where its
data lives and waits where its disk is not; root's data is never kept. A watch and a
bounded sweep put back what an app narrows. The group grant is removed, and what it
put an account in is taken back.
Reuses the descriptor walks, the create act, the missing-path wait and the warrant-
backed act message from the paused issue 567 branch.
mesh/merge-gate pass: builds mesh-host → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
Once a mesh directory's mode and owner go only through a walk that follows no
link another account could make, a directory behind such a link is refused
and its module gated: on the control-node that could stop the controller.
The operator is to be told which directories that walk would refuse on every
node before it lands. So the engine judges the declaration it keeps with the
same walk, making and changing nothing: on a signed ask from the controller
(mesh.node.<node>.ask.judge-directories, held to the hand-over's checks) and
as `nox-mesh-host judge-directories` at the machine.
mesh/merge-gate pass: builds mesh-host → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
The walk kept its progress every minute and nobody could read it: root-free said only that a search ran.
The account verdict now carries the progress (counts, times, mount points; never a path) as fields and in
its reason, outside what makes a verdict changed. A signed ask from the controller's terminal throws the last
search away and starts a full one, after the operator removed by hand what it found.
mesh/merge-gate pass: builds mesh-host → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
Two holes the review proved. The ask's subject proved nothing — a responder can reach it through a reply — so the engine now verifies the mesh's signature over a fixed context with the key it verifies declarations with, before reading anything, and refuses an ask for another node, expired, good too long, without a nonce, or replayed. And the apply followed a link the hand-over had refused: a component swapped for a link after the record carried root's chmod and chown to its target. A handed-over directory must now still resolve to itself, and is changed only through one descriptor opened from / with no link followed (fchmod, fchown). Tests for the reply guard, the run loop's hook, the fallback renewal on proof and a non-regular fallback; 27 checks each removed in turn, each failing a test.
mesh/merge-gate pass: builds mesh-host → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
The file on PATH was the engine a person copied at installation, and every delivered engine ran from the versions directory: the operator typed hand-over and a build from before it answered "unexpected argument". A proved engine now copies itself over that file when the bytes differ (never a link). And the hand-over of a directory used as found (issue 339) gets its channel: the controller's terminal asks this node's engine on mesh.node.<node>.ask.hand-over; the engine judges every value — the ask's size and shape, who asked, the path as it states it, a directory and no link, through no link — and records it or refuses and records nothing. Every text the engine addresses to the operator names the nox line (ADR 0272); the engine's own subcommands are install-time and rescue, and its usage says so.
jschoubben
jochen