Daniel Samson
1b1c587c14
Three services had each written the same thing and got it three different ways: input polled the process list to notice a dead subscriber, and only when someone else subscribed; the power service never noticed at all; the device manager noticed drivers but not subscribers. The harness owns the table now, driven by the events a protocol declares — it registers on the reserved verb, frames each event once, posts to everyone interested without waiting on any of them, and reclaims a slot when the kernel says its owner died. Interest masks moved to the envelope, so a subscriber that wants only mice asks the same way everywhere. Two consequences the plan had not foreseen. The device manager now hears a supervised child's death twice, once as its supervisor and once as a subscriber, so restart backoff counted every crash twice and gave up after half as many; it retires the id before counting. And the kernel's published exit table had eight slots for what is now six subscriptions in a plain boot, so it holds sixteen. The other half is a hole the design named early and left standing: a backend handed out a small integer and then honoured it from anyone. A process that guessed a file's node id read another client's file; a display layer had no owner at all, so any client could reconfigure or destroy any layer; a USB device token was never checked against the client that opened it. Each is now bound to the task that opened it, and a wrong owner gets exactly what an unknown id gets — the refusal must not become the oracle the identical answers elsewhere were designed to remove. Closing a file changed with it: it used to succeed unconditionally, which would have told a caller which ids existed. Suite 111/111, with a new case in which one process holds a file and a layer, hands both ids to a second process, and finds them untouched after that process has tried everything with them.
35 lines
1.4 KiB
Zig
35 lines
1.4 KiB
Zig
//! The display service as a binary package (docs/build-packages-plan.md):
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//! this file names the binary and EXACTLY the modules its source imports —
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//! build-support resolves each name from the domains this zon declares.
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const std = @import("std");
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const build_support = @import("build-support");
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pub fn build(b: *std.Build) void {
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const exe = build_support.userBinary(b, .{
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.name = "display",
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.root_source_file = b.path("display.zig"),
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.imports = &.{
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"channel", "display-client", "display-protocol", "driver", "envelope", "input-client",
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"ipc", "logging", "memory", "process", "scanout-protocol",
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"service", "thread", "time",
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},
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.threaded = true, // real atomics/TLS (docs/threading.md)
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});
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b.installArtifact(exe);
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// Standalone `zig build test`; the root aggregate depends on this step.
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const test_step = b.step("test", "Run the display unit tests");
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for ([_][]const u8{
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"compositor.zig", // Rect math + fill/composite/blit-tile
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}) |test_root| {
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const unit_tests = b.addTest(.{
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.root_module = b.createModule(.{
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.root_source_file = b.path(test_root),
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.target = b.resolveTargetQuery(.{}),
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}),
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});
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test_step.dependOn(&b.addRunArtifact(unit_tests).step);
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}
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}
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