Daniel Samson
d2dfbcabf8
The folded header stops being a rule in a document and becomes the layout on the wire. Verbs number from sixteen, leaving describe, enumerate, subscribe and unsubscribe reserved and answered the same way by every provider — none of them writes a line to do it. What each protocol used to carry in a field of its own now travels in the header: a vfs node and a display layer are the packet's target, and a reply opens with a status the envelope stamps rather than one each protocol spelled for itself. Display gains the most. One forty-byte request had served eleven verbs, so attach_scanout smuggled stride through x, refresh through y and format through colour, and every coordinate crossed as a bitcast. Per-operation structs end all three: the fields have their own names and their own signs, and the tile payload grows to 224 bytes because the prefix shrank. Scanout loses a message maximum of 64 it had no business declaring — it answers calls, and the floor for a call is 256 — and virtio-gpu stops hard-coding that number at its harness. Two changes are semantic rather than notational. A directory now ends at an entry with no name, because the fixed part of a reply always travels and a zero-length reply no longer exists to mean anything. And input joins the service harness, the last loop in the tree that answered no ping and heard no terminate; its subscriber table, its pruning and its fan-out are the same code, and a shutdown now asks it to stop instead of killing it. A new conformance case reads the registry's own listing and asks every protocol it finds for its name, its version and its verb count, then offers a verb nobody defines and requires -ENOSYS — the envelope's promise, checked against providers rather than against itself. What it cannot reach in that boot it names on the serial line instead of passing quietly. Suite 110/110.
51 lines
2.2 KiB
Zig
51 lines
2.2 KiB
Zig
//! The "client" library domain (library/client): userspace-service clients —
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//! they talk to services over IPC, not to the kernel. Client modules end in
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//! `-client` the way wire protocols end in `-protocol`, so a service, its
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//! protocol, and its client never share a name (`display` the service,
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//! `display-protocol` the wire contract, `display-client` a program's view).
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const std = @import("std");
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pub fn build(b: *std.Build) void {
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const kernel = b.dependency("kernel", .{});
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const protocol = b.dependency("protocol", .{});
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const ipc = kernel.module("ipc");
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const time = kernel.module("time");
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// Every client reaches its service by name now: resolve `/protocol/<name>`,
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// open it, and take the provider's endpoint out of the reply
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// (docs/os-development/protocol-namespace.md).
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const channel = kernel.module("channel");
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// A client frames its own packets, so it needs the envelope alongside the
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// protocol whose verbs it speaks.
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const envelope = protocol.module("envelope");
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_ = b.addModule("display-client", .{
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.root_source_file = b.path("display/display-client.zig"),
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.imports = &.{
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.{ .name = "channel", .module = channel },
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.{ .name = "envelope", .module = envelope },
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.{ .name = "ipc", .module = ipc },
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.{ .name = "time", .module = time },
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.{ .name = "display-protocol", .module = protocol.module("display-protocol") },
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},
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});
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_ = b.addModule("input-client", .{
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.root_source_file = b.path("input/input-client.zig"),
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.imports = &.{
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.{ .name = "channel", .module = channel },
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.{ .name = "envelope", .module = envelope },
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.{ .name = "ipc", .module = ipc },
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.{ .name = "time", .module = time },
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.{ .name = "input-protocol", .module = protocol.module("input-protocol") },
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},
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});
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// Standalone `zig build test`, kept for uniformity across the domains (the
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// root aggregate depends on every domain's test step). The clients have no
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// host-runnable unit tests yet — they are thin IPC conversation wrappers —
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// so the step is empty until one grows some.
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_ = b.step("test", "Run the client unit tests (none yet)");
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}
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