github.com/mvdan/u-root-coreutils@v0.0.0-20230122170626-c2eef2898555/pkg/mount/loop/losetup_linux_test.go (about)

     1  // Copyright 2019 the u-root 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 loop
     6  
     7  import (
     8  	"os"
     9  	"path/filepath"
    10  	"syscall"
    11  	"testing"
    12  
    13  	"github.com/mvdan/u-root-coreutils/pkg/cp"
    14  	"golang.org/x/sys/unix"
    15  )
    16  
    17  const (
    18  	_LOOP_MAJOR = 7
    19  )
    20  
    21  func skipIfNotRoot(t *testing.T) {
    22  	if os.Getuid() != 0 {
    23  		t.Skipf("Skipping test since we are not root")
    24  	}
    25  }
    26  
    27  func TestFindDevice(t *testing.T) {
    28  	skipIfNotRoot(t)
    29  
    30  	loopdev, err := FindDevice()
    31  	if err != nil {
    32  		t.Fatalf("Failed to find loop device: %v", err)
    33  	}
    34  
    35  	s, err := os.Stat(loopdev)
    36  	if err != nil {
    37  		t.Fatalf("Could not stat loop device: %v", err)
    38  	}
    39  
    40  	st := s.Sys().(*syscall.Stat_t)
    41  	if m := unix.Major(st.Rdev); m != _LOOP_MAJOR {
    42  		t.Fatalf("Device %s is not a loop device: got major no %d, want %d", loopdev, m, _LOOP_MAJOR)
    43  	}
    44  }
    45  
    46  func TestSetFile(t *testing.T) {
    47  	skipIfNotRoot(t)
    48  
    49  	tmpDir := t.TempDir()
    50  	testdisk := filepath.Join(tmpDir, "testdisk")
    51  	if err := cp.Copy("./testdata/pristine-vfat-disk", testdisk); err != nil {
    52  		t.Fatal(err)
    53  	}
    54  
    55  	loopdev, err := New(testdisk, "vfat", "")
    56  	if err != nil {
    57  		t.Fatal(err)
    58  	}
    59  
    60  	if err := os.MkdirAll("/tmp/disk", 0o755); err != nil && !os.IsExist(err) {
    61  		t.Fatalf("Could not create /tmp/disk: %v", err)
    62  	}
    63  
    64  	mp, err := loopdev.Mount("/tmp/disk", 0)
    65  	if err != nil {
    66  		t.Fatalf("Failed to mount /tmp/disk: %v", err)
    67  	}
    68  	defer mp.Unmount(0) //nolint:errcheck
    69  
    70  	if err := os.WriteFile("/tmp/disk/foobar", []byte("Are you feeling it now Mr Krabs"), 0o755); err != nil {
    71  		t.Fatal(err)
    72  	}
    73  }