Merge pull request #2859 from lightpanda-io/crypto-random-leak

use getrandom syscall for std.crypto.random

src/log.zig

@@ -172,7 +172,11 @@ pub fn log(scope: Scope, level: Level, msg: []const u8, data: anytype) void {
 
     var buf: [4096]u8 = undefined;
     var stderr = std.fs.File.stderr();
-    var writer = stderr.writer(&buf);
+    // writerStreaming, not writer: the default positional mode starts each
+    // fresh Writer at offset 0, so when stderr is redirected to a regular file
+    // every log line overwrites the previous one. Streaming writes at the fd
+    // offset, which is what append-style logging needs.
+    var writer = stderr.writerStreaming(&buf);
 
     logTo(scope, level, msg, data, &writer.interface) catch |log_err| {
         std.debug.print("$time={d} $level=fatal $scope={s} $msg=\"log err\" err={s} log_msg=\"{s}\"\n", .{ timestamp(.clock), @errorName(log_err), @tagName(scope), msg });

src/main.zig

@@ -27,6 +27,16 @@ const Config = lp.Config;
 const SigHandler = @import("Sighandler.zig");
 pub const panic = lp.crash_handler.panic;
 
+pub const std_options: std.Options = .{
+    // std.crypto.random's default backend mmaps a thread-local 528-byte state
+    // page on first use and never unmaps it — there is no thread-exit hook.
+    // With one detached thread per CDP connection (Server.handleConnection),
+    // that leaks one resident page per connection (uuidv4 in
+    // Page.getOrCreateOrigin touches it), ~4KB/conn of unbounded RSS growth.
+    // Route every std.crypto.random call to the getrandom syscall instead.
+    .crypto_always_getrandom = true,
+};
+
 pub fn main() !void {
     // allocator
     // - in Debug mode we use the General Purpose Allocator to detect memory leaks