main/libgo/go/syscall/passfd_test.go

   1 // Copyright 2012 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 // +build linux darwin freebsd netbsd openbsd
   6
   7 package syscall_test
   8
   9 import (
  10         "flag"
  11         "fmt"
  12         "io/ioutil"
  13         "net"
  14         "os"
  15         "os/exec"
  16         "syscall"
  17         "testing"
  18         "time"
  19 )
  20
  21 // TestPassFD tests passing a file descriptor over a Unix socket.
  22 //
  23 // This test involved both a parent and child process. The parent
  24 // process is invoked as a normal test, with "go test", which then
  25 // runs the child process by running the current test binary with args
  26 // "-test.run=^TestPassFD$" and an environment variable used to signal
  27 // that the test should become the child process instead.
  28 func TestPassFD(t *testing.T) {
  29         if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
  30                 passFDChild()
  31                 return
  32         }
  33
  34         tempDir, err := ioutil.TempDir("", "TestPassFD")
  35         if err != nil {
  36                 t.Fatal(err)
  37         }
  38         defer os.RemoveAll(tempDir)
  39
  40         fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
  41         if err != nil {
  42                 t.Fatalf("Socketpair: %v", err)
  43         }
  44         defer syscall.Close(fds[0])
  45         defer syscall.Close(fds[1])
  46         writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
  47         readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
  48         defer writeFile.Close()
  49         defer readFile.Close()
  50
  51         cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
  52         cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
  53         path := os.Getenv("LD_LIBRARY_PATH")
  54         if path != "" {
  55                 cmd.Env = append(cmd.Env, "LD_LIBRARY_PATH="+path)
  56         }
  57         cmd.ExtraFiles = []*os.File{writeFile}
  58
  59         out, err := cmd.CombinedOutput()
  60         if len(out) > 0 || err != nil {
  61                 t.Fatalf("child process: %q, %v", out, err)
  62         }
  63
  64         c, err := net.FileConn(readFile)
  65         if err != nil {
  66                 t.Fatalf("FileConn: %v", err)
  67         }
  68         defer c.Close()
  69
  70         uc, ok := c.(*net.UnixConn)
  71         if !ok {
  72                 t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
  73         }
  74
  75         buf := make([]byte, 32) // expect 1 byte
  76         oob := make([]byte, 32) // expect 24 bytes
  77         closeUnix := time.AfterFunc(5*time.Second, func() {
  78                 t.Logf("timeout reading from unix socket")
  79                 uc.Close()
  80         })
  81         _, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
  82         closeUnix.Stop()
  83
  84         scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
  85         if err != nil {
  86                 t.Fatalf("ParseSocketControlMessage: %v", err)
  87         }
  88         if len(scms) != 1 {
  89                 t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
  90         }
  91         scm := scms[0]
  92         gotFds, err := syscall.ParseUnixRights(&scm)
  93         if err != nil {
  94                 t.Fatalf("syscall.ParseUnixRights: %v", err)
  95         }
  96         if len(gotFds) != 1 {
  97                 t.Fatalf("wanted 1 fd; got %#v", gotFds)
  98         }
  99
 100         f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
 101         defer f.Close()
 102
 103         got, err := ioutil.ReadAll(f)
 104         want := "Hello from child process!\n"
 105         if string(got) != want {
 106                 t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
 107         }
 108 }
 109
 110 // passFDChild is the child process used by TestPassFD.
 111 func passFDChild() {
 112         defer os.Exit(0)
 113
 114         // Look for our fd. It should be fd 3, but we work around an fd leak
 115         // bug here (http://golang.org/issue/2603) to let it be elsewhere.
 116         var uc *net.UnixConn
 117         for fd := uintptr(3); fd <= 10; fd++ {
 118                 f := os.NewFile(fd, "unix-conn")
 119                 var ok bool
 120                 netc, _ := net.FileConn(f)
 121                 uc, ok = netc.(*net.UnixConn)
 122                 if ok {
 123                         break
 124                 }
 125         }
 126         if uc == nil {
 127                 fmt.Println("failed to find unix fd")
 128                 return
 129         }
 130
 131         // Make a file f to send to our parent process on uc.
 132         // We make it in tempDir, which our parent will clean up.
 133         flag.Parse()
 134         tempDir := flag.Arg(0)
 135         f, err := ioutil.TempFile(tempDir, "")
 136         if err != nil {
 137                 fmt.Printf("TempFile: %v", err)
 138                 return
 139         }
 140
 141         f.Write([]byte("Hello from child process!\n"))
 142         f.Seek(0, 0)
 143
 144         rights := syscall.UnixRights(int(f.Fd()))
 145         dummyByte := []byte("x")
 146         n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
 147         if err != nil {
 148                 fmt.Printf("WriteMsgUnix: %v", err)
 149                 return
 150         }
 151         if n != 1 || oobn != len(rights) {
 152                 fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
 153                 return
 154         }
 155 }
 156
 157 // TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
 158 // and ParseUnixRights are able to successfully round-trip lists of file descriptors.
 159 func TestUnixRightsRoundtrip(t *testing.T) {
 160         testCases := [...][][]int{
 161                 {{42}},
 162                 {{1, 2}},
 163                 {{3, 4, 5}},
 164                 {{}},
 165                 {{1, 2}, {3, 4, 5}, {}, {7}},
 166         }
 167         for _, testCase := range testCases {
 168                 b := []byte{}
 169                 var n int
 170                 for _, fds := range testCase {
 171                         // Last assignment to n wins
 172                         n = len(b) + syscall.CmsgLen(4*len(fds))
 173                         b = append(b, syscall.UnixRights(fds...)...)
 174                 }
 175                 // Truncate b
 176                 b = b[:n]
 177
 178                 scms, err := syscall.ParseSocketControlMessage(b)
 179                 if err != nil {
 180                         t.Fatalf("ParseSocketControlMessage: %v", err)
 181                 }
 182                 if len(scms) != len(testCase) {
 183                         t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
 184                 }
 185                 for i, scm := range scms {
 186                         gotFds, err := syscall.ParseUnixRights(&scm)
 187                         if err != nil {
 188                                 t.Fatalf("ParseUnixRights: %v", err)
 189                         }
 190                         wantFds := testCase[i]
 191                         if len(gotFds) != len(wantFds) {
 192                                 t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
 193                         }
 194                         for j, fd := range gotFds {
 195                                 if fd != wantFds[j] {
 196                                         t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
 197                                 }
 198                         }
 199                 }
 200         }
 201 }