gopkg.in/hugelgupf/u-root.v9@v9.0.0-20180831063832-3f6f1057f09b/cmds/mknod/mknod_linux_test.go (about)

     1  // Copyright 2018 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 main
     6  
     7  import (
     8  	"io/ioutil"
     9  	"os"
    10  	"os/user"
    11  	"path/filepath"
    12  	"testing"
    13  
    14  	"github.com/u-root/u-root/pkg/testutil"
    15  	"golang.org/x/sys/unix"
    16  )
    17  
    18  // Test major and minor numbers greater then 255.
    19  //
    20  // This is supported since Linux 2.6. The major/minor numbers used for this
    21  // test are (1110, 74616). According to "kdev_t.h":
    22  //
    23  //       mkdev(1110, 74616)
    24  //     = mkdev(0x456, 0x12378)
    25  //     = (0x12378 & 0xff) | (0x456 << 8) | ((0x12378 & ~0xff) << 12)
    26  //     = 0x12345678
    27  func TestLargeDevNumber(t *testing.T) {
    28  	if user, err := user.Current(); err != nil || user.Uid != "0" {
    29  		t.Skip("test requires root.")
    30  	}
    31  
    32  	// Make a temporary directory.
    33  	tmpDir, err := ioutil.TempDir("", "ls")
    34  	if err != nil {
    35  		t.Fatal(err)
    36  	}
    37  	defer os.RemoveAll(tmpDir)
    38  	file := filepath.Join(tmpDir, "large_node")
    39  
    40  	// Run "mknod large_node b 1110 74616".
    41  	err = testutil.Command(t, file, "b", "1110", "74616").Run()
    42  	if err != nil {
    43  		t.Fatal(err)
    44  	}
    45  
    46  	// Check the device number.
    47  	var s unix.Stat_t
    48  	err = unix.Stat(file, &s)
    49  	if err != nil {
    50  		t.Fatal(err)
    51  	}
    52  	if s.Rdev != 0x12345678 {
    53  		t.Fatalf("expected the device number to be 0x12345678, got %#x", s.Rdev)
    54  	}
    55  }