Daniel Samson
3cc1d38dd0
The manager is now a harness service on the well-known .device_manager endpoint. Every driver spawns supervised; drivers with an assignment must hello (device-manager-protocol, versioned) within a deadline enforced by a timer sweep. Exit reasons drive the restart decision: clean exits stay down, faults restart with 300/600/1200ms backoff, and three fast deaths mark a driver failed instead of respawning forever. usb-xhci-bus is the first conforming driver; the crash-test fixture claims a device, hellos, and faults on purpose — each respawn re-proving claim release on death through the manager's own path. maximum_tasks grows 16 -> 32: the initial-ramdisk sweep (15 binaries at once) was intermittently overflowing the static pool.
59 lines
2.3 KiB
Zig
59 lines
2.3 KiB
Zig
//! The device-manager protocol (docs/device-manager.md): what drivers and
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//! applications say to the device manager over its well-known endpoint. The
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//! vfs-protocol pattern — extern-struct messages, a version in the handshake,
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//! reserved fields — so both sides depend on the contract by name. Deliberately
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//! contains nothing lifecycle-shaped: stopping, liveness (the zero-length ping),
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//! and exit reasons are the universal vocabulary of
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//! docs/process-lifecycle.md, not this protocol.
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/// The protocol version a driver states in its hello. A manager that cannot
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/// serve a driver's version refuses the hello, and the mismatch is loud at
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/// startup instead of quiet corruption later.
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pub const version: u16 = 1;
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/// What kind of driver is talking (docs/driver-model.md's shapes).
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pub const Role = enum(u8) {
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/// Owns a controller and reports the devices behind it (`child_added`).
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bus = 1,
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/// Serves one device, reached through a bus's transfer protocol.
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device = 2,
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};
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/// The message kinds. `child_added`/`child_removed` land in M18.2;
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/// `enumerate`/`subscribe` in M18.3.
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pub const Operation = enum(u8) {
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hello = 1,
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};
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/// `Hello.device_id` for a driver that serves no enumerated device (a test
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/// fixture, a synthetic source).
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pub const no_device: u64 = ~@as(u64, 0);
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/// The handshake, sent once by every driver the manager spawns — the manager's
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/// one self-enforced deadline: spawned and silent past it means wrong binary,
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/// wrong version, or wedged before main, and the stop sequence follows.
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pub const Hello = extern struct {
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operation: u8 = @intFromEnum(Operation.hello),
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/// A Role value.
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role: u8,
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/// The protocol version this driver was built against (`version`).
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version: u16 = version,
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reserved: u32 = 0,
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/// The device this driver was assigned (its argv[1]), or `no_device`.
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device_id: u64,
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};
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pub const hello_size = @sizeOf(Hello);
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/// The manager's answer to a hello. Nonzero status = refused (version mismatch,
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/// unknown sender); a refused driver should exit cleanly.
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pub const HelloReply = extern struct {
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status: i32,
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reserved: u32 = 0,
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};
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pub const reply_size = @sizeOf(HelloReply);
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/// Upper bound on any message in this protocol — sizes the endpoint buffers.
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pub const message_maximum = 64;
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