github.com/comwrg/go/src@v0.0.0-20220319063731-c238d0440370/runtime/runtime_mmap_test.go (about) 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 //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris 6 // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris 7 8 package runtime_test 9 10 import ( 11 "runtime" 12 "testing" 13 "unsafe" 14 ) 15 16 // Test that the error value returned by mmap is positive, as that is 17 // what the code in mem_bsd.go, mem_darwin.go, and mem_linux.go expects. 18 // See the uses of ENOMEM in sysMap in those files. 19 func TestMmapErrorSign(t *testing.T) { 20 p, err := runtime.Mmap(nil, ^uintptr(0)&^(runtime.GetPhysPageSize()-1), 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0) 21 22 if p != nil || err != runtime.ENOMEM { 23 t.Errorf("mmap = %v, %v, want nil, %v", p, err, runtime.ENOMEM) 24 } 25 } 26 27 func TestPhysPageSize(t *testing.T) { 28 // Mmap fails if the address is not page aligned, so we can 29 // use this to test if the page size is the true page size. 30 ps := runtime.GetPhysPageSize() 31 32 // Get a region of memory to play with. This should be page-aligned. 33 b, err := runtime.Mmap(nil, 2*ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0) 34 if err != 0 { 35 t.Fatalf("Mmap: %v", err) 36 } 37 38 if runtime.GOOS == "aix" { 39 // AIX does not allow mapping a range that is already mapped. 40 runtime.Munmap(unsafe.Pointer(uintptr(b)), 2*ps) 41 } 42 43 // Mmap should fail at a half page into the buffer. 44 _, err = runtime.Mmap(unsafe.Pointer(uintptr(b)+ps/2), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0) 45 if err == 0 { 46 t.Errorf("Mmap should have failed with half-page alignment %d, but succeeded: %v", ps/2, err) 47 } 48 49 // Mmap should succeed at a full page into the buffer. 50 _, err = runtime.Mmap(unsafe.Pointer(uintptr(b)+ps), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0) 51 if err != 0 { 52 t.Errorf("Mmap at full-page alignment %d failed: %v", ps, err) 53 } 54 }