Source file src/syscall/syscall_unix_test.go

Documentation: syscall

     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 aix 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  	"strconv"
    21  	"syscall"
    22  	"testing"
    23  	"time"
    24  )
    25  
    26  // Tests that below functions, structures and constants are consistent
    27  // on all Unix-like systems.
    28  func _() {
    29  	// program scheduling priority functions and constants
    30  	var (
    31  		_ func(int, int, int) error   = syscall.Setpriority
    32  		_ func(int, int) (int, error) = syscall.Getpriority
    33  	)
    34  	const (
    35  		_ int = syscall.PRIO_USER
    36  		_ int = syscall.PRIO_PROCESS
    37  		_ int = syscall.PRIO_PGRP
    38  	)
    39  
    40  	// termios constants
    41  	const (
    42  		_ int = syscall.TCIFLUSH
    43  		_ int = syscall.TCIOFLUSH
    44  		_ int = syscall.TCOFLUSH
    45  	)
    46  
    47  	// fcntl file locking structure and constants
    48  	var (
    49  		_ = syscall.Flock_t{
    50  			Type:   int16(0),
    51  			Whence: int16(0),
    52  			Start:  int64(0),
    53  			Len:    int64(0),
    54  			Pid:    int32(0),
    55  		}
    56  	)
    57  	const (
    58  		_ = syscall.F_GETLK
    59  		_ = syscall.F_SETLK
    60  		_ = syscall.F_SETLKW
    61  	)
    62  }
    63  
    64  // TestFcntlFlock tests whether the file locking structure matches
    65  // the calling convention of each kernel.
    66  // On some Linux systems, glibc uses another set of values for the
    67  // commands and translates them to the correct value that the kernel
    68  // expects just before the actual fcntl syscall. As Go uses raw
    69  // syscalls directly, it must use the real value, not the glibc value.
    70  // Thus this test also verifies that the Flock_t structure can be
    71  // roundtripped with F_SETLK and F_GETLK.
    72  func TestFcntlFlock(t *testing.T) {
    73  	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
    74  		t.Skip("skipping; no child processes allowed on iOS")
    75  	}
    76  	flock := syscall.Flock_t{
    77  		Type:  syscall.F_WRLCK,
    78  		Start: 31415, Len: 271828, Whence: 1,
    79  	}
    80  	if os.Getenv("GO_WANT_HELPER_PROCESS") == "" {
    81  		// parent
    82  		tempDir, err := ioutil.TempDir("", "TestFcntlFlock")
    83  		if err != nil {
    84  			t.Fatalf("Failed to create temp dir: %v", err)
    85  		}
    86  		name := filepath.Join(tempDir, "TestFcntlFlock")
    87  		fd, err := syscall.Open(name, syscall.O_CREAT|syscall.O_RDWR|syscall.O_CLOEXEC, 0)
    88  		if err != nil {
    89  			t.Fatalf("Open failed: %v", err)
    90  		}
    91  		defer os.RemoveAll(tempDir)
    92  		defer syscall.Close(fd)
    93  		if err := syscall.Ftruncate(fd, 1<<20); err != nil {
    94  			t.Fatalf("Ftruncate(1<<20) failed: %v", err)
    95  		}
    96  		if err := syscall.FcntlFlock(uintptr(fd), syscall.F_SETLK, &flock); err != nil {
    97  			t.Fatalf("FcntlFlock(F_SETLK) failed: %v", err)
    98  		}
    99  		cmd := exec.Command(os.Args[0], "-test.run=^TestFcntlFlock$")
   100  		cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
   101  		cmd.ExtraFiles = []*os.File{os.NewFile(uintptr(fd), name)}
   102  		out, err := cmd.CombinedOutput()
   103  		if len(out) > 0 || err != nil {
   104  			t.Fatalf("child process: %q, %v", out, err)
   105  		}
   106  	} else {
   107  		// child
   108  		got := flock
   109  		// make sure the child lock is conflicting with the parent lock
   110  		got.Start--
   111  		got.Len++
   112  		if err := syscall.FcntlFlock(3, syscall.F_GETLK, &got); err != nil {
   113  			t.Fatalf("FcntlFlock(F_GETLK) failed: %v", err)
   114  		}
   115  		flock.Pid = int32(syscall.Getppid())
   116  		// Linux kernel always set Whence to 0
   117  		flock.Whence = 0
   118  		if got.Type == flock.Type && got.Start == flock.Start && got.Len == flock.Len && got.Pid == flock.Pid && got.Whence == flock.Whence {
   119  			os.Exit(0)
   120  		}
   121  		t.Fatalf("FcntlFlock got %v, want %v", got, flock)
   122  	}
   123  }
   124  
   125  // TestPassFD tests passing a file descriptor over a Unix socket.
   126  //
   127  // This test involved both a parent and child process. The parent
   128  // process is invoked as a normal test, with "go test", which then
   129  // runs the child process by running the current test binary with args
   130  // "-test.run=^TestPassFD$" and an environment variable used to signal
   131  // that the test should become the child process instead.
   132  func TestPassFD(t *testing.T) {
   133  	testenv.MustHaveExec(t)
   134  
   135  	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
   136  		passFDChild()
   137  		return
   138  	}
   139  
   140  	if runtime.GOOS == "aix" {
   141  		// Unix network isn't properly working on AIX 7.2 with Technical Level < 2
   142  		out, err := exec.Command("oslevel", "-s").Output()
   143  		if err != nil {
   144  			t.Skipf("skipping on AIX because oslevel -s failed: %v", err)
   145  		}
   146  		if len(out) < len("7200-XX-ZZ-YYMM") { // AIX 7.2, Tech Level XX, Service Pack ZZ, date YYMM
   147  			t.Skip("skipping on AIX because oslevel -s hasn't the right length")
   148  		}
   149  		aixVer := string(out[:4])
   150  		tl, err := strconv.Atoi(string(out[5:7]))
   151  		if err != nil {
   152  			t.Skipf("skipping on AIX because oslevel -s output cannot be parsed: %v", err)
   153  		}
   154  		if aixVer < "7200" || (aixVer == "7200" && tl < 2) {
   155  			t.Skip("skipped on AIX versions previous to 7.2 TL 2")
   156  		}
   157  
   158  	}
   159  
   160  	tempDir, err := ioutil.TempDir("", "TestPassFD")
   161  	if err != nil {
   162  		t.Fatal(err)
   163  	}
   164  	defer os.RemoveAll(tempDir)
   165  
   166  	fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
   167  	if err != nil {
   168  		t.Fatalf("Socketpair: %v", err)
   169  	}
   170  	defer syscall.Close(fds[0])
   171  	defer syscall.Close(fds[1])
   172  	writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
   173  	readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
   174  	defer writeFile.Close()
   175  	defer readFile.Close()
   176  
   177  	cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
   178  	cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
   179  	cmd.ExtraFiles = []*os.File{writeFile}
   180  
   181  	out, err := cmd.CombinedOutput()
   182  	if len(out) > 0 || err != nil {
   183  		t.Fatalf("child process: %q, %v", out, err)
   184  	}
   185  
   186  	c, err := net.FileConn(readFile)
   187  	if err != nil {
   188  		t.Fatalf("FileConn: %v", err)
   189  	}
   190  	defer c.Close()
   191  
   192  	uc, ok := c.(*net.UnixConn)
   193  	if !ok {
   194  		t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
   195  	}
   196  
   197  	buf := make([]byte, 32) // expect 1 byte
   198  	oob := make([]byte, 32) // expect 24 bytes
   199  	closeUnix := time.AfterFunc(5*time.Second, func() {
   200  		t.Logf("timeout reading from unix socket")
   201  		uc.Close()
   202  	})
   203  	_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
   204  	if err != nil {
   205  		t.Fatalf("ReadMsgUnix: %v", err)
   206  	}
   207  	closeUnix.Stop()
   208  
   209  	scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
   210  	if err != nil {
   211  		t.Fatalf("ParseSocketControlMessage: %v", err)
   212  	}
   213  	if len(scms) != 1 {
   214  		t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
   215  	}
   216  	scm := scms[0]
   217  	gotFds, err := syscall.ParseUnixRights(&scm)
   218  	if err != nil {
   219  		t.Fatalf("syscall.ParseUnixRights: %v", err)
   220  	}
   221  	if len(gotFds) != 1 {
   222  		t.Fatalf("wanted 1 fd; got %#v", gotFds)
   223  	}
   224  
   225  	f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
   226  	defer f.Close()
   227  
   228  	got, err := ioutil.ReadAll(f)
   229  	want := "Hello from child process!\n"
   230  	if string(got) != want {
   231  		t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
   232  	}
   233  }
   234  
   235  // passFDChild is the child process used by TestPassFD.
   236  func passFDChild() {
   237  	defer os.Exit(0)
   238  
   239  	// Look for our fd. It should be fd 3, but we work around an fd leak
   240  	// bug here (https://golang.org/issue/2603) to let it be elsewhere.
   241  	var uc *net.UnixConn
   242  	for fd := uintptr(3); fd <= 10; fd++ {
   243  		f := os.NewFile(fd, "unix-conn")
   244  		var ok bool
   245  		netc, _ := net.FileConn(f)
   246  		uc, ok = netc.(*net.UnixConn)
   247  		if ok {
   248  			break
   249  		}
   250  	}
   251  	if uc == nil {
   252  		fmt.Println("failed to find unix fd")
   253  		return
   254  	}
   255  
   256  	// Make a file f to send to our parent process on uc.
   257  	// We make it in tempDir, which our parent will clean up.
   258  	flag.Parse()
   259  	tempDir := flag.Arg(0)
   260  	f, err := ioutil.TempFile(tempDir, "")
   261  	if err != nil {
   262  		fmt.Printf("TempFile: %v", err)
   263  		return
   264  	}
   265  
   266  	f.Write([]byte("Hello from child process!\n"))
   267  	f.Seek(0, io.SeekStart)
   268  
   269  	rights := syscall.UnixRights(int(f.Fd()))
   270  	dummyByte := []byte("x")
   271  	n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
   272  	if err != nil {
   273  		fmt.Printf("WriteMsgUnix: %v", err)
   274  		return
   275  	}
   276  	if n != 1 || oobn != len(rights) {
   277  		fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
   278  		return
   279  	}
   280  }
   281  
   282  // TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
   283  // and ParseUnixRights are able to successfully round-trip lists of file descriptors.
   284  func TestUnixRightsRoundtrip(t *testing.T) {
   285  	testCases := [...][][]int{
   286  		{{42}},
   287  		{{1, 2}},
   288  		{{3, 4, 5}},
   289  		{{}},
   290  		{{1, 2}, {3, 4, 5}, {}, {7}},
   291  	}
   292  	for _, testCase := range testCases {
   293  		b := []byte{}
   294  		var n int
   295  		for _, fds := range testCase {
   296  			// Last assignment to n wins
   297  			n = len(b) + syscall.CmsgLen(4*len(fds))
   298  			b = append(b, syscall.UnixRights(fds...)...)
   299  		}
   300  		// Truncate b
   301  		b = b[:n]
   302  
   303  		scms, err := syscall.ParseSocketControlMessage(b)
   304  		if err != nil {
   305  			t.Fatalf("ParseSocketControlMessage: %v", err)
   306  		}
   307  		if len(scms) != len(testCase) {
   308  			t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
   309  		}
   310  		for i, scm := range scms {
   311  			gotFds, err := syscall.ParseUnixRights(&scm)
   312  			if err != nil {
   313  				t.Fatalf("ParseUnixRights: %v", err)
   314  			}
   315  			wantFds := testCase[i]
   316  			if len(gotFds) != len(wantFds) {
   317  				t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
   318  			}
   319  			for j, fd := range gotFds {
   320  				if fd != wantFds[j] {
   321  					t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
   322  				}
   323  			}
   324  		}
   325  	}
   326  }
   327  
   328  func TestRlimit(t *testing.T) {
   329  	var rlimit, zero syscall.Rlimit
   330  	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlimit)
   331  	if err != nil {
   332  		t.Fatalf("Getrlimit: save failed: %v", err)
   333  	}
   334  	if zero == rlimit {
   335  		t.Fatalf("Getrlimit: save failed: got zero value %#v", rlimit)
   336  	}
   337  	set := rlimit
   338  	set.Cur = set.Max - 1
   339  	if runtime.GOOS == "darwin" && set.Cur > 10240 {
   340  		// The max file limit is 10240, even though
   341  		// the max returned by Getrlimit is 1<<63-1.
   342  		// This is OPEN_MAX in sys/syslimits.h.
   343  		set.Cur = 10240
   344  	}
   345  	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &set)
   346  	if err != nil {
   347  		t.Fatalf("Setrlimit: set failed: %#v %v", set, err)
   348  	}
   349  	var get syscall.Rlimit
   350  	err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &get)
   351  	if err != nil {
   352  		t.Fatalf("Getrlimit: get failed: %v", err)
   353  	}
   354  	set = rlimit
   355  	set.Cur = set.Max - 1
   356  	if runtime.GOOS == "darwin" && set.Cur > 10240 {
   357  		set.Cur = 10240
   358  	}
   359  	if set != get {
   360  		t.Fatalf("Rlimit: change failed: wanted %#v got %#v", set, get)
   361  	}
   362  	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlimit)
   363  	if err != nil {
   364  		t.Fatalf("Setrlimit: restore failed: %#v %v", rlimit, err)
   365  	}
   366  }
   367  
   368  func TestSeekFailure(t *testing.T) {
   369  	_, err := syscall.Seek(-1, 0, io.SeekStart)
   370  	if err == nil {
   371  		t.Fatalf("Seek(-1, 0, 0) did not fail")
   372  	}
   373  	str := err.Error() // used to crash on Linux
   374  	t.Logf("Seek: %v", str)
   375  	if str == "" {
   376  		t.Fatalf("Seek(-1, 0, 0) return error with empty message")
   377  	}
   378  }
   379  
   380  func TestSetsockoptString(t *testing.T) {
   381  	// should not panic on empty string, see issue #31277
   382  	err := syscall.SetsockoptString(-1, 0, 0, "")
   383  	if err == nil {
   384  		t.Fatalf("SetsockoptString: did not fail")
   385  	}
   386  }
   387  
   388  func TestENFILETemporary(t *testing.T) {
   389  	if !syscall.ENFILE.Temporary() {
   390  		t.Error("ENFILE is not treated as a temporary error")
   391  	}
   392  }
   393  

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