Should verify that the max value is not too big

ulimit_linux.go

@@ -0,0 +1,18 @@
+package units
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+// Verify that ulimit values work with current kernel
+func (u *Ulimit) Verify() error {
+	var rlimit unix.Rlimit
+	if err := unix.Getrlimit(ulimitNameMapping[u.Name], &rlimit); err == nil {
+		if u.Hard > int64(rlimit.Max) {
+			return fmt.Errorf("ulimit hard limit (%d) must be less than or equal to hard limit for the current process %d", u.Hard, rlimit.Max)
+		}
+	}
+	return nil
+}

ulimit_linux_test.go

@@ -0,0 +1,24 @@
+// +build linux
+
+package units
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+	"testing"
+)
+
+func TestParseUlimitTooBig(t *testing.T) {
+	var rlimit unix.Rlimit
+	if err := unix.Getrlimit(rlimitNofile, &rlimit); err != nil {
+		t.Fatalf("Failed to get rlimit of current process %q", err)
+	}
+	u, err := ParseUlimit(fmt.Sprintf("nofile=512:%d", rlimit.Max+1))
+	if err != nil {
+		t.Fatalf("expected valid value got %q", err)
+	}
+	if err := u.Verify(); err == nil {
+		t.Fatalf("expected invalid hard limit")
+	}
+}

ulimit_unsupported.go

@@ -0,0 +1,8 @@
+// +build !linux
+
+package units
+
+// Verify that ulimit values work with current kernel
+func (u *Ulimit) Verify() error {
+	return nil
+}