libgo/go/runtime/runtime_mmap_test.go

   1 // Copyright 2016 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package runtime_test
   6
   7 import (
   8         "runtime"
   9         "testing"
  10         "unsafe"
  11 )
  12
  13 // Test that the error value returned by mmap is positive, as that is
  14 // what the code in mem_bsd.go, mem_darwin.go, and mem_linux.go expects.
  15 // See the uses of ENOMEM in sysMap in those files.
  16 func TestMmapErrorSign(t *testing.T) {
  17         p, err := runtime.Mmap(nil, ^uintptr(0)&^(runtime.GetPhysPageSize()-1), 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0)
  18
  19         if p != nil || err != runtime.ENOMEM {
  20                 t.Errorf("mmap = %v, %v, want nil, %v", p, err, runtime.ENOMEM)
  21         }
  22 }
  23
  24 func TestPhysPageSize(t *testing.T) {
  25         // Mmap fails if the address is not page aligned, so we can
  26         // use this to test if the page size is the true page size.
  27         ps := runtime.GetPhysPageSize()
  28
  29         // Get a region of memory to play with. This should be page-aligned.
  30         b, err := runtime.Mmap(nil, 2*ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0)
  31         if err != 0 {
  32                 t.Fatalf("Mmap: %v", err)
  33         }
  34
  35         // Mmap should fail at a half page into the buffer.
  36         _, err = runtime.Mmap(unsafe.Pointer(uintptr(b)+ps/2), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0)
  37         if err == 0 {
  38                 t.Errorf("Mmap should have failed with half-page alignment %d, but succeeded: %v", ps/2, err)
  39         }
  40
  41         // Mmap should succeed at a full page into the buffer.
  42         _, err = runtime.Mmap(unsafe.Pointer(uintptr(b)+ps), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0)
  43         if err != 0 {
  44                 t.Errorf("Mmap at full-page alignment %d failed: %v", ps, err)
  45         }
  46 }