202 lines
5.1 KiB
Go
202 lines
5.1 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build linux darwin freebsd netbsd openbsd
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package syscall_test
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import (
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"flag"
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"fmt"
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"io/ioutil"
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"net"
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"os"
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"os/exec"
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"syscall"
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"testing"
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"time"
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)
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// TestPassFD tests passing a file descriptor over a Unix socket.
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//
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// This test involved both a parent and child process. The parent
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// process is invoked as a normal test, with "go test", which then
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// runs the child process by running the current test binary with args
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// "-test.run=^TestPassFD$" and an environment variable used to signal
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// that the test should become the child process instead.
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func TestPassFD(t *testing.T) {
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if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
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passFDChild()
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return
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}
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tempDir, err := ioutil.TempDir("", "TestPassFD")
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if err != nil {
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t.Fatal(err)
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}
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defer os.RemoveAll(tempDir)
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fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
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if err != nil {
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t.Fatalf("Socketpair: %v", err)
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}
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defer syscall.Close(fds[0])
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defer syscall.Close(fds[1])
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writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
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readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
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defer writeFile.Close()
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defer readFile.Close()
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cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
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cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
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path := os.Getenv("LD_LIBRARY_PATH")
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if path != "" {
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cmd.Env = append(cmd.Env, "LD_LIBRARY_PATH="+path)
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}
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cmd.ExtraFiles = []*os.File{writeFile}
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out, err := cmd.CombinedOutput()
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if len(out) > 0 || err != nil {
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t.Fatalf("child process: %q, %v", out, err)
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}
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c, err := net.FileConn(readFile)
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if err != nil {
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t.Fatalf("FileConn: %v", err)
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}
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defer c.Close()
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uc, ok := c.(*net.UnixConn)
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if !ok {
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t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
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}
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buf := make([]byte, 32) // expect 1 byte
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oob := make([]byte, 32) // expect 24 bytes
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closeUnix := time.AfterFunc(5*time.Second, func() {
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t.Logf("timeout reading from unix socket")
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uc.Close()
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})
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_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
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closeUnix.Stop()
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scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
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if err != nil {
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t.Fatalf("ParseSocketControlMessage: %v", err)
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}
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if len(scms) != 1 {
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t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
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}
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scm := scms[0]
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gotFds, err := syscall.ParseUnixRights(&scm)
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if err != nil {
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t.Fatalf("syscall.ParseUnixRights: %v", err)
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}
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if len(gotFds) != 1 {
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t.Fatalf("wanted 1 fd; got %#v", gotFds)
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}
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f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
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defer f.Close()
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got, err := ioutil.ReadAll(f)
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want := "Hello from child process!\n"
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if string(got) != want {
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t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
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}
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}
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// passFDChild is the child process used by TestPassFD.
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func passFDChild() {
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defer os.Exit(0)
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// Look for our fd. It should be fd 3, but we work around an fd leak
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// bug here (http://golang.org/issue/2603) to let it be elsewhere.
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var uc *net.UnixConn
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for fd := uintptr(3); fd <= 10; fd++ {
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f := os.NewFile(fd, "unix-conn")
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var ok bool
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netc, _ := net.FileConn(f)
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uc, ok = netc.(*net.UnixConn)
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if ok {
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break
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}
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}
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if uc == nil {
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fmt.Println("failed to find unix fd")
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return
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}
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// Make a file f to send to our parent process on uc.
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// We make it in tempDir, which our parent will clean up.
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flag.Parse()
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tempDir := flag.Arg(0)
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f, err := ioutil.TempFile(tempDir, "")
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if err != nil {
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fmt.Printf("TempFile: %v", err)
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return
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}
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f.Write([]byte("Hello from child process!\n"))
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f.Seek(0, 0)
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rights := syscall.UnixRights(int(f.Fd()))
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dummyByte := []byte("x")
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n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
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if err != nil {
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fmt.Printf("WriteMsgUnix: %v", err)
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return
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}
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if n != 1 || oobn != len(rights) {
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fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
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return
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}
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}
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// TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
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// and ParseUnixRights are able to successfully round-trip lists of file descriptors.
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func TestUnixRightsRoundtrip(t *testing.T) {
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testCases := [...][][]int{
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{{42}},
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{{1, 2}},
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{{3, 4, 5}},
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{{}},
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{{1, 2}, {3, 4, 5}, {}, {7}},
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}
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for _, testCase := range testCases {
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b := []byte{}
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var n int
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for _, fds := range testCase {
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// Last assignment to n wins
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n = len(b) + syscall.CmsgLen(4*len(fds))
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b = append(b, syscall.UnixRights(fds...)...)
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}
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// Truncate b
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b = b[:n]
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scms, err := syscall.ParseSocketControlMessage(b)
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if err != nil {
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t.Fatalf("ParseSocketControlMessage: %v", err)
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}
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if len(scms) != len(testCase) {
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t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
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}
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for i, scm := range scms {
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gotFds, err := syscall.ParseUnixRights(&scm)
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if err != nil {
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t.Fatalf("ParseUnixRights: %v", err)
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}
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wantFds := testCase[i]
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if len(gotFds) != len(wantFds) {
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t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
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}
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for j, fd := range gotFds {
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if fd != wantFds[j] {
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t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
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}
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}
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}
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}
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}
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