c/os: Setrlimit/Getrlimit

internal/lib/syscall/rlimit_darwin.go

@@ -0,0 +1,20 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin
+
+package syscall
+
+// adjustFileLimit adds per-OS limitations on the Rlimit used for RLIMIT_NOFILE. See rlimit.go.
+func adjustFileLimit(lim *Rlimit) {
+	// On older macOS, setrlimit(RLIMIT_NOFILE, lim) with lim.Cur = infinity fails.
+	// Set to the value of kern.maxfilesperproc instead.
+	n, err := SysctlUint32("kern.maxfilesperproc")
+	if err != nil {
+		return
+	}
+	if lim.Cur > uint64(n) {
+		lim.Cur = uint64(n)
+	}
+}