atproto relay implementation in zig
zlay.waow.tech
fix pingLoop use-after-free: respect cancellation, check isClosed
pingLoop swallowed error.Canceled from io.sleep(), preventing
ping_future.cancel() from stopping the task before client.deinit()
freed the stream/TLS buffers. next writeFrame hit freed memory → GPF.
two changes:
- io.sleep() catch {} → catch return (cancellation-cooperative)
- check client.isClosed() before writeFrame (defense-in-depth)
also bumps zat to v0.3.0-alpha.11 and websocket.zig to 104608b.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+10
-7
+4
-4
build.zig.zon
+4
-4
build.zig.zon
···
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5
.minimum_zig_version = "0.16.0",
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.dependencies = .{
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.zat = .{
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.url = "https://tangled.org/zat.dev/zat/archive/v0.3.0-alpha.10.tar.gz",
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.hash = "zat-0.3.0-alpha.10-5PuC7nVhBQBinQH3IMZnhsHpL0OJcYhF4p3Wfo7OYAdX",
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+
.url = "https://tangled.org/zat.dev/zat/archive/v0.3.0-alpha.11.tar.gz",
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+
.hash = "zat-0.3.0-alpha.11-5PuC7nVhBQCNUnJEi_YUqQK6V8bbZacA-QN54nUunu4K",
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},
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.websocket = .{
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.url = "https://github.com/zzstoatzz/websocket.zig/archive/4222f98.tar.gz",
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.hash = "websocket-0.1.0-ZPISdQTUAwDJt7jFEbYJhdqRBztn8mHIFh-dNK5dOlxL",
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+
.url = "https://github.com/zzstoatzz/websocket.zig/archive/104608b.tar.gz",
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.hash = "websocket-0.1.0-ZPISdXjUAwC3rN7rT5NMG8HQJRug1NOboVWeX09SvSGv",
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},
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.pg = .{
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.url = "git+https://github.com/zzstoatzz/pg.zig?ref=dev#5ce2355b1d851075523709c7d3068dcdb0224322",
+6
-3
src/subscriber.zig
+6
-3
src/subscriber.zig
···
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fn pingLoop(client: *websocket.Client, self: *Subscriber) void {
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var fail_count: u32 = 0;
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while (!self.shouldStop()) {
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// sleep in 1s increments so we can check shutdown
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// sleep in 1s increments so we can check shutdown.
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// return on any sleep error — critically, error.Canceled from
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// ping_future.cancel() must not be swallowed, otherwise deinit
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// frees the client while we're still running.
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var elapsed: u32 = 0;
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while (elapsed < ping_interval_sec and !self.shouldStop()) {
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self.io.sleep(Io.Duration.fromSeconds(1), .awake) catch {};
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self.io.sleep(Io.Duration.fromSeconds(1), .awake) catch return;
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elapsed += 1;
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}
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if (self.shouldStop()) return;
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if (self.shouldStop() or client.isClosed()) return;
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client.writeFrame(.ping, &.{}) catch {
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fail_count += 1;