libgo/go/syscall/syscall_unix_test.go

   1 // Copyright 2013 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 darwin dragonfly freebsd linux netbsd openbsd solaris
   6
   7 package syscall_test
   8
   9 import (
  10         "flag"
  11         "fmt"
  12         "internal/testenv"
  13         "io"
  14         "io/ioutil"
  15         "net"
  16         "os"
  17         "os/exec"
  18         "path/filepath"
  19         "runtime"
  20         "syscall"
  21         "testing"
  22         "time"
  23 )
  24
  25 // Tests that below functions, structures and constants are consistent
  26 // on all Unix-like systems.
  27 func _() {
  28         // program scheduling priority functions and constants
  29         var (
  30                 _ func(int, int, int) error   = syscall.Setpriority
  31                 _ func(int, int) (int, error) = syscall.Getpriority
  32         )
  33         const (
  34                 _ int = syscall.PRIO_USER
  35                 _ int = syscall.PRIO_PROCESS
  36                 _ int = syscall.PRIO_PGRP
  37         )
  38
  39         // termios constants
  40         const (
  41                 _ int = syscall.TCIFLUSH
  42                 _ int = syscall.TCIOFLUSH
  43                 _ int = syscall.TCOFLUSH
  44         )
  45
  46         // fcntl file locking structure and constants
  47         var (
  48                 _ = syscall.Flock_t{
  49                         Type:   int16(0),
  50                         Whence: int16(0),
  51                         Start:  int64(0),
  52                         Len:    int64(0),
  53                         Pid:    int32(0),
  54                 }
  55         )
  56         const (
  57                 _ = syscall.F_GETLK
  58                 _ = syscall.F_SETLK
  59                 _ = syscall.F_SETLKW
  60         )
  61 }
  62
  63 // TestFcntlFlock tests whether the file locking structure matches
  64 // the calling convention of each kernel.
  65 // On some Linux systems, glibc uses another set of values for the
  66 // commands and translates them to the correct value that the kernel
  67 // expects just before the actual fcntl syscall. As Go uses raw
  68 // syscalls directly, it must use the real value, not the glibc value.
  69 // Thus this test also verifies that the Flock_t structure can be
  70 // roundtripped with F_SETLK and F_GETLK.
  71 func TestFcntlFlock(t *testing.T) {
  72         if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
  73                 t.Skip("skipping; no child processes allowed on iOS")
  74         }
  75         flock := syscall.Flock_t{
  76                 Type:  syscall.F_WRLCK,
  77                 Start: 31415, Len: 271828, Whence: 1,
  78         }
  79         if os.Getenv("GO_WANT_HELPER_PROCESS") == "" {
  80                 // parent
  81                 tempDir, err := ioutil.TempDir("", "TestFcntlFlock")
  82                 if err != nil {
  83                         t.Fatalf("Failed to create temp dir: %v", err)
  84                 }
  85                 name := filepath.Join(tempDir, "TestFcntlFlock")
  86                 fd, err := syscall.Open(name, syscall.O_CREAT|syscall.O_RDWR|syscall.O_CLOEXEC, 0)
  87                 if err != nil {
  88                         t.Fatalf("Open failed: %v", err)
  89                 }
  90                 defer os.RemoveAll(tempDir)
  91                 defer syscall.Close(fd)
  92                 if err := syscall.Ftruncate(fd, 1<<20); err != nil {
  93                         t.Fatalf("Ftruncate(1<<20) failed: %v", err)
  94                 }
  95                 if err := syscall.FcntlFlock(uintptr(fd), syscall.F_SETLK, &flock); err != nil {
  96                         t.Fatalf("FcntlFlock(F_SETLK) failed: %v", err)
  97                 }
  98                 cmd := exec.Command(os.Args[0], "-test.run=^TestFcntlFlock$")
  99                 cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
 100                 cmd.ExtraFiles = []*os.File{os.NewFile(uintptr(fd), name)}
 101                 out, err := cmd.CombinedOutput()
 102                 if len(out) > 0 || err != nil {
 103                         t.Fatalf("child process: %q, %v", out, err)
 104                 }
 105         } else {
 106                 // child
 107                 got := flock
 108                 // make sure the child lock is conflicting with the parent lock
 109                 got.Start--
 110                 got.Len++
 111                 if err := syscall.FcntlFlock(3, syscall.F_GETLK, &got); err != nil {
 112                         t.Fatalf("FcntlFlock(F_GETLK) failed: %v", err)
 113                 }
 114                 flock.Pid = int32(syscall.Getppid())
 115                 // Linux kernel always set Whence to 0
 116                 flock.Whence = 0
 117                 if got.Type == flock.Type && got.Start == flock.Start && got.Len == flock.Len && got.Pid == flock.Pid && got.Whence == flock.Whence {
 118                         os.Exit(0)
 119                 }
 120                 t.Fatalf("FcntlFlock got %v, want %v", got, flock)
 121         }
 122 }
 123
 124 // TestPassFD tests passing a file descriptor over a Unix socket.
 125 //
 126 // This test involved both a parent and child process. The parent
 127 // process is invoked as a normal test, with "go test", which then
 128 // runs the child process by running the current test binary with args
 129 // "-test.run=^TestPassFD$" and an environment variable used to signal
 130 // that the test should become the child process instead.
 131 func TestPassFD(t *testing.T) {
 132         testenv.MustHaveExec(t)
 133
 134         if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
 135                 passFDChild()
 136                 return
 137         }
 138
 139         tempDir, err := ioutil.TempDir("", "TestPassFD")
 140         if err != nil {
 141                 t.Fatal(err)
 142         }
 143         defer os.RemoveAll(tempDir)
 144
 145         fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
 146         if err != nil {
 147                 t.Fatalf("Socketpair: %v", err)
 148         }
 149         defer syscall.Close(fds[0])
 150         defer syscall.Close(fds[1])
 151         writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
 152         readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
 153         defer writeFile.Close()
 154         defer readFile.Close()
 155
 156         cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
 157         cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
 158         cmd.ExtraFiles = []*os.File{writeFile}
 159
 160         out, err := cmd.CombinedOutput()
 161         if len(out) > 0 || err != nil {
 162                 t.Fatalf("child process: %q, %v", out, err)
 163         }
 164
 165         c, err := net.FileConn(readFile)
 166         if err != nil {
 167                 t.Fatalf("FileConn: %v", err)
 168         }
 169         defer c.Close()
 170
 171         uc, ok := c.(*net.UnixConn)
 172         if !ok {
 173                 t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
 174         }
 175
 176         buf := make([]byte, 32) // expect 1 byte
 177         oob := make([]byte, 32) // expect 24 bytes
 178         closeUnix := time.AfterFunc(5*time.Second, func() {
 179                 t.Logf("timeout reading from unix socket")
 180                 uc.Close()
 181         })
 182         _, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
 183         if err != nil {
 184                 t.Fatalf("ReadMsgUnix: %v", err)
 185         }
 186         closeUnix.Stop()
 187
 188         scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
 189         if err != nil {
 190                 t.Fatalf("ParseSocketControlMessage: %v", err)
 191         }
 192         if len(scms) != 1 {
 193                 t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
 194         }
 195         scm := scms[0]
 196         gotFds, err := syscall.ParseUnixRights(&scm)
 197         if err != nil {
 198                 t.Fatalf("syscall.ParseUnixRights: %v", err)
 199         }
 200         if len(gotFds) != 1 {
 201                 t.Fatalf("wanted 1 fd; got %#v", gotFds)
 202         }
 203
 204         f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
 205         defer f.Close()
 206
 207         got, err := ioutil.ReadAll(f)
 208         want := "Hello from child process!\n"
 209         if string(got) != want {
 210                 t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
 211         }
 212 }
 213
 214 // passFDChild is the child process used by TestPassFD.
 215 func passFDChild() {
 216         defer os.Exit(0)
 217
 218         // Look for our fd. It should be fd 3, but we work around an fd leak
 219         // bug here (https://golang.org/issue/2603) to let it be elsewhere.
 220         var uc *net.UnixConn
 221         for fd := uintptr(3); fd <= 10; fd++ {
 222                 f := os.NewFile(fd, "unix-conn")
 223                 var ok bool
 224                 netc, _ := net.FileConn(f)
 225                 uc, ok = netc.(*net.UnixConn)
 226                 if ok {
 227                         break
 228                 }
 229         }
 230         if uc == nil {
 231                 fmt.Println("failed to find unix fd")
 232                 return
 233         }
 234
 235         // Make a file f to send to our parent process on uc.
 236         // We make it in tempDir, which our parent will clean up.
 237         flag.Parse()
 238         tempDir := flag.Arg(0)
 239         f, err := ioutil.TempFile(tempDir, "")
 240         if err != nil {
 241                 fmt.Printf("TempFile: %v", err)
 242                 return
 243         }
 244
 245         f.Write([]byte("Hello from child process!\n"))
 246         f.Seek(0, io.SeekStart)
 247
 248         rights := syscall.UnixRights(int(f.Fd()))
 249         dummyByte := []byte("x")
 250         n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
 251         if err != nil {
 252                 fmt.Printf("WriteMsgUnix: %v", err)
 253                 return
 254         }
 255         if n != 1 || oobn != len(rights) {
 256                 fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
 257                 return
 258         }
 259 }
 260
 261 // TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
 262 // and ParseUnixRights are able to successfully round-trip lists of file descriptors.
 263 func TestUnixRightsRoundtrip(t *testing.T) {
 264         testCases := [...][][]int{
 265                 {{42}},
 266                 {{1, 2}},
 267                 {{3, 4, 5}},
 268                 {{}},
 269                 {{1, 2}, {3, 4, 5}, {}, {7}},
 270         }
 271         for _, testCase := range testCases {
 272                 b := []byte{}
 273                 var n int
 274                 for _, fds := range testCase {
 275                         // Last assignment to n wins
 276                         n = len(b) + syscall.CmsgLen(4*len(fds))
 277                         b = append(b, syscall.UnixRights(fds...)...)
 278                 }
 279                 // Truncate b
 280                 b = b[:n]
 281
 282                 scms, err := syscall.ParseSocketControlMessage(b)
 283                 if err != nil {
 284                         t.Fatalf("ParseSocketControlMessage: %v", err)
 285                 }
 286                 if len(scms) != len(testCase) {
 287                         t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
 288                 }
 289                 for i, scm := range scms {
 290                         gotFds, err := syscall.ParseUnixRights(&scm)
 291                         if err != nil {
 292                                 t.Fatalf("ParseUnixRights: %v", err)
 293                         }
 294                         wantFds := testCase[i]
 295                         if len(gotFds) != len(wantFds) {
 296                                 t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
 297                         }
 298                         for j, fd := range gotFds {
 299                                 if fd != wantFds[j] {
 300                                         t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
 301                                 }
 302                         }
 303                 }
 304         }
 305 }
 306
 307 func TestRlimit(t *testing.T) {
 308         var rlimit, zero syscall.Rlimit
 309         err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlimit)
 310         if err != nil {
 311                 t.Fatalf("Getrlimit: save failed: %v", err)
 312         }
 313         if zero == rlimit {
 314                 t.Fatalf("Getrlimit: save failed: got zero value %#v", rlimit)
 315         }
 316         set := rlimit
 317         set.Cur = set.Max - 1
 318         err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &set)
 319         if err != nil {
 320                 t.Fatalf("Setrlimit: set failed: %#v %v", set, err)
 321         }
 322         var get syscall.Rlimit
 323         err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &get)
 324         if err != nil {
 325                 t.Fatalf("Getrlimit: get failed: %v", err)
 326         }
 327         set = rlimit
 328         set.Cur = set.Max - 1
 329         if set != get {
 330                 // Seems like Darwin requires some privilege to
 331                 // increase the soft limit of rlimit sandbox, though
 332                 // Setrlimit never reports an error.
 333                 switch runtime.GOOS {
 334                 case "darwin":
 335                 default:
 336                         t.Fatalf("Rlimit: change failed: wanted %#v got %#v", set, get)
 337                 }
 338         }
 339         err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlimit)
 340         if err != nil {
 341                 t.Fatalf("Setrlimit: restore failed: %#v %v", rlimit, err)
 342         }
 343 }
 344
 345 func TestSeekFailure(t *testing.T) {
 346         _, err := syscall.Seek(-1, 0, io.SeekStart)
 347         if err == nil {
 348                 t.Fatalf("Seek(-1, 0, 0) did not fail")
 349         }
 350         str := err.Error() // used to crash on Linux
 351         t.Logf("Seek: %v", str)
 352         if str == "" {
 353                 t.Fatalf("Seek(-1, 0, 0) return error with empty message")
 354         }
 355 }