signal_cgo_test.go

     1  // Copyright 2017 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  //go:build (darwin || dragonfly || freebsd || (linux && !android) || netbsd || openbsd) && cgo
     6  
     7  // Note that this test does not work on Solaris: issue #22849.
     8  // Don't run the test on Android because at least some versions of the
     9  // C library do not define the posix_openpt function.
    10  
    11  package signal_test
    12  
    13  import (
    14  	"bufio"
    15  	"bytes"
    16  	"context"
    17  	"fmt"
    18  	"io"
    19  	"io/fs"
    20  	"os"
    21  	"os/exec"
    22  	ptypkg "os/signal/internal/pty"
    23  	"strconv"
    24  	"strings"
    25  	"sync"
    26  	"syscall"
    27  	"testing"
    28  	"time"
    29  )
    30  
    31  func TestTerminalSignal(t *testing.T) {
    32  	const enteringRead = "test program entering read"
    33  	if os.Getenv("GO_TEST_TERMINAL_SIGNALS") != "" {
    34  		var b [1]byte
    35  		fmt.Println(enteringRead)
    36  		n, err := os.Stdin.Read(b[:])
    37  		if n == 1 {
    38  			if b[0] == '\n' {
    39  				// This is what we expect
    40  				fmt.Println("read newline")
    41  			} else {
    42  				fmt.Printf("read 1 byte: %q\n", b)
    43  			}
    44  		} else {
    45  			fmt.Printf("read %d bytes\n", n)
    46  		}
    47  		if err != nil {
    48  			fmt.Println(err)
    49  			os.Exit(1)
    50  		}
    51  		os.Exit(0)
    52  	}
    53  
    54  	t.Parallel()
    55  
    56  	// The test requires a shell that uses job control.
    57  	bash, err := exec.LookPath("bash")
    58  	if err != nil {
    59  		t.Skipf("could not find bash: %v", err)
    60  	}
    61  
    62  	scale := 1
    63  	if s := os.Getenv("GO_TEST_TIMEOUT_SCALE"); s != "" {
    64  		if sc, err := strconv.Atoi(s); err == nil {
    65  			scale = sc
    66  		}
    67  	}
    68  	pause := time.Duration(scale) * 10 * time.Millisecond
    69  	wait := time.Duration(scale) * 5 * time.Second
    70  
    71  	// The test only fails when using a "slow device," in this
    72  	// case a pseudo-terminal.
    73  
    74  	pty, procTTYName, err := ptypkg.Open()
    75  	if err != nil {
    76  		ptyErr := err.(*ptypkg.PtyError)
    77  		if ptyErr.FuncName == "posix_openpt" && ptyErr.Errno == syscall.EACCES {
    78  			t.Skip("posix_openpt failed with EACCES, assuming chroot and skipping")
    79  		}
    80  		t.Fatal(err)
    81  	}
    82  	defer pty.Close()
    83  	procTTY, err := os.OpenFile(procTTYName, os.O_RDWR, 0)
    84  	if err != nil {
    85  		t.Fatal(err)
    86  	}
    87  	defer procTTY.Close()
    88  
    89  	// Start an interactive shell.
    90  	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    91  	defer cancel()
    92  	cmd := exec.CommandContext(ctx, bash, "--norc", "--noprofile", "-i")
    93  	// Clear HISTFILE so that we don't read or clobber the user's bash history.
    94  	cmd.Env = append(os.Environ(), "HISTFILE=")
    95  	cmd.Stdin = procTTY
    96  	cmd.Stdout = procTTY
    97  	cmd.Stderr = procTTY
    98  	cmd.SysProcAttr = &syscall.SysProcAttr{
    99  		Setsid:  true,
   100  		Setctty: true,
   101  		Ctty:    0,
   102  	}
   103  
   104  	if err := cmd.Start(); err != nil {
   105  		t.Fatal(err)
   106  	}
   107  
   108  	if err := procTTY.Close(); err != nil {
   109  		t.Errorf("closing procTTY: %v", err)
   110  	}
   111  
   112  	progReady := make(chan bool)
   113  	sawPrompt := make(chan bool, 10)
   114  	const prompt = "prompt> "
   115  
   116  	// Read data from pty in the background.
   117  	var wg sync.WaitGroup
   118  	wg.Add(1)
   119  	defer wg.Wait()
   120  	go func() {
   121  		defer wg.Done()
   122  		input := bufio.NewReader(pty)
   123  		var line, handled []byte
   124  		for {
   125  			b, err := input.ReadByte()
   126  			if err != nil {
   127  				if len(line) > 0 || len(handled) > 0 {
   128  					t.Logf("%q", append(handled, line...))
   129  				}
   130  				if perr, ok := err.(*fs.PathError); ok {
   131  					err = perr.Err
   132  				}
   133  				// EOF means pty is closed.
   134  				// EIO means child process is done.
   135  				// "file already closed" means deferred close of pty has happened.
   136  				if err != io.EOF && err != syscall.EIO && !strings.Contains(err.Error(), "file already closed") {
   137  					t.Logf("error reading from pty: %v", err)
   138  				}
   139  				return
   140  			}
   141  
   142  			line = append(line, b)
   143  
   144  			if b == '\n' {
   145  				t.Logf("%q", append(handled, line...))
   146  				line = nil
   147  				handled = nil
   148  				continue
   149  			}
   150  
   151  			if bytes.Contains(line, []byte(enteringRead)) {
   152  				close(progReady)
   153  				handled = append(handled, line...)
   154  				line = nil
   155  			} else if bytes.Contains(line, []byte(prompt)) && !bytes.Contains(line, []byte("PS1=")) {
   156  				sawPrompt <- true
   157  				handled = append(handled, line...)
   158  				line = nil
   159  			}
   160  		}
   161  	}()
   162  
   163  	// Set the bash prompt so that we can see it.
   164  	if _, err := pty.Write([]byte("PS1='" + prompt + "'\n")); err != nil {
   165  		t.Fatalf("setting prompt: %v", err)
   166  	}
   167  	select {
   168  	case <-sawPrompt:
   169  	case <-time.After(wait):
   170  		t.Fatal("timed out waiting for shell prompt")
   171  	}
   172  
   173  	// Start a small program that reads from stdin
   174  	// (namely the code at the top of this function).
   175  	if _, err := pty.Write([]byte("GO_TEST_TERMINAL_SIGNALS=1 " + os.Args[0] + " -test.run=TestTerminalSignal\n")); err != nil {
   176  		t.Fatal(err)
   177  	}
   178  
   179  	// Wait for the program to print that it is starting.
   180  	select {
   181  	case <-progReady:
   182  	case <-time.After(wait):
   183  		t.Fatal("timed out waiting for program to start")
   184  	}
   185  
   186  	// Give the program time to enter the read call.
   187  	// It doesn't matter much if we occasionally don't wait long enough;
   188  	// we won't be testing what we want to test, but the overall test
   189  	// will pass.
   190  	time.Sleep(pause)
   191  
   192  	// Send a ^Z to stop the program.
   193  	if _, err := pty.Write([]byte{26}); err != nil {
   194  		t.Fatalf("writing ^Z to pty: %v", err)
   195  	}
   196  
   197  	// Wait for the program to stop and return to the shell.
   198  	select {
   199  	case <-sawPrompt:
   200  	case <-time.After(wait):
   201  		t.Fatal("timed out waiting for shell prompt")
   202  	}
   203  
   204  	// Restart the stopped program.
   205  	if _, err := pty.Write([]byte("fg\n")); err != nil {
   206  		t.Fatalf("writing %q to pty: %v", "fg", err)
   207  	}
   208  
   209  	// Give the process time to restart.
   210  	// This is potentially racy: if the process does not restart
   211  	// quickly enough then the byte we send will go to bash rather
   212  	// than the program. Unfortunately there isn't anything we can
   213  	// look for to know that the program is running again.
   214  	// bash will print the program name, but that happens before it
   215  	// restarts the program.
   216  	time.Sleep(10 * pause)
   217  
   218  	// Write some data for the program to read,
   219  	// which should cause it to exit.
   220  	if _, err := pty.Write([]byte{'\n'}); err != nil {
   221  		t.Fatalf("writing %q to pty: %v", "\n", err)
   222  	}
   223  
   224  	// Wait for the program to exit.
   225  	select {
   226  	case <-sawPrompt:
   227  	case <-time.After(wait):
   228  		t.Fatal("timed out waiting for shell prompt")
   229  	}
   230  
   231  	// Exit the shell with the program's exit status.
   232  	if _, err := pty.Write([]byte("exit $?\n")); err != nil {
   233  		t.Fatalf("writing %q to pty: %v", "exit", err)
   234  	}
   235  
   236  	if err = cmd.Wait(); err != nil {
   237  		t.Errorf("subprogram failed: %v", err)
   238  	}
   239  }
   240
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