52 lines
2.0 KiB
Zig
52 lines
2.0 KiB
Zig
//! The per-process logger: std.log wired to the tagged kernel log ring.
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//!
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//! A program just calls `std.log.info("mounted {s}", .{path})` (or a scoped
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//! logger); this backend formats the line into a fixed buffer and emits ONE
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//! `debug_write` record carrying the level. The kernel stamps the record with
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//! the sender's pid and task name (its binary path) — the process does NOT put
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//! its own name in the payload; attribution is the kernel's, structural and
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//! unforgeable. Serial shows the kernel-rendered `<path>: message` line, and
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//! the logger service demultiplexes the ring into one file per process.
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//!
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//! Installed for every user binary by the root shim (library/runtime/root.zig)
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//! via `std_options`; a program can override by declaring its own
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//! `pub const std_options`.
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const std = @import("std");
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const system = @import("system.zig");
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fn levelOf(comptime level: std.log.Level) system.KlogLevel {
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return switch (level) {
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.err => .err,
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.warn => .warn,
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.info => .info,
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.debug => .debug,
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};
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}
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pub fn logFn(
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comptime level: std.log.Level,
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comptime scope: @EnumLiteral(),
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comptime format: []const u8,
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args: anytype,
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) void {
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// One record = one line = at most klog_maximum_message bytes of payload.
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// On overflow keep what fits and end with "~" so the record is still a
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// whole line (the kernel would split an embedded rest anyway).
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var buffer: [256]u8 = undefined;
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const prefix = if (scope == .default) "" else "(" ++ @tagName(scope) ++ ") ";
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const line = std.fmt.bufPrint(&buffer, prefix ++ format, args) catch truncated: {
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buffer[buffer.len - 1] = '~';
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break :truncated buffer[0..];
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};
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_ = system.writeRecord(levelOf(level), line);
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}
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/// The std.Options the root shim installs unless the program overrides it.
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/// Debug level: filtering is the log *reader's* job here — the ring is cheap,
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/// serial is a dev convenience, and the logger service keeps everything.
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pub const default_options: std.Options = .{
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.log_level = .debug,
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.logFn = logFn,
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};
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