issue18146.go

Documentation: cmd/cgo/internal/test

     1  // Copyright 2016 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 cgo && !windows
     6  
     7  // Issue 18146: pthread_create failure during syscall.Exec.
     8  
     9  package cgotest
    10  
    11  import (
    12  	"bytes"
    13  	"crypto/md5"
    14  	"os"
    15  	"os/exec"
    16  	"runtime"
    17  	"syscall"
    18  	"testing"
    19  	"time"
    20  )
    21  
    22  func test18146(t *testing.T) {
    23  	if testing.Short() {
    24  		t.Skip("skipping in short mode")
    25  	}
    26  
    27  	if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
    28  		t.Skipf("skipping flaky test on %s; see golang.org/issue/18202", runtime.GOOS)
    29  	}
    30  
    31  	if runtime.GOARCH == "mips" || runtime.GOARCH == "mips64" {
    32  		t.Skipf("skipping on %s", runtime.GOARCH)
    33  	}
    34  
    35  	attempts := 1000
    36  	threads := 4
    37  
    38  	// Restrict the number of attempts based on RLIMIT_NPROC.
    39  	// Tediously, RLIMIT_NPROC was left out of the syscall package,
    40  	// probably because it is not in POSIX.1, so we define it here.
    41  	// It is not defined on Solaris.
    42  	var nproc int
    43  	setNproc := true
    44  	switch runtime.GOOS {
    45  	default:
    46  		setNproc = false
    47  	case "aix":
    48  		nproc = 9
    49  	case "linux":
    50  		nproc = 6
    51  	case "darwin", "dragonfly", "freebsd", "netbsd", "openbsd":
    52  		nproc = 7
    53  	}
    54  	if setNproc {
    55  		var rlim syscall.Rlimit
    56  		if syscall.Getrlimit(nproc, &rlim) == nil {
    57  			max := int(rlim.Cur) / (threads + 5)
    58  			if attempts > max {
    59  				t.Logf("lowering attempts from %d to %d for RLIMIT_NPROC", attempts, max)
    60  				attempts = max
    61  			}
    62  		}
    63  	}
    64  
    65  	if os.Getenv("test18146") == "exec" {
    66  		runtime.GOMAXPROCS(1)
    67  		for n := threads; n > 0; n-- {
    68  			go func() {
    69  				for {
    70  					_ = md5.Sum([]byte("Hello, !"))
    71  				}
    72  			}()
    73  		}
    74  		runtime.GOMAXPROCS(threads)
    75  		argv := append(os.Args, "-test.run=^$")
    76  		if err := syscall.Exec(os.Args[0], argv, os.Environ()); err != nil {
    77  			t.Fatal(err)
    78  		}
    79  	}
    80  
    81  	var cmds []*exec.Cmd
    82  	defer func() {
    83  		for _, cmd := range cmds {
    84  			cmd.Process.Kill()
    85  		}
    86  	}()
    87  
    88  	args := append(append([]string(nil), os.Args[1:]...), "-test.run=^Test18146$")
    89  	for n := attempts; n > 0; n-- {
    90  		cmd := exec.Command(os.Args[0], args...)
    91  		cmd.Env = append(os.Environ(), "test18146=exec")
    92  		buf := bytes.NewBuffer(nil)
    93  		cmd.Stdout = buf
    94  		cmd.Stderr = buf
    95  		if err := cmd.Start(); err != nil {
    96  			// We are starting so many processes that on
    97  			// some systems (problem seen on Darwin,
    98  			// Dragonfly, OpenBSD) the fork call will fail
    99  			// with EAGAIN.
   100  			if pe, ok := err.(*os.PathError); ok {
   101  				err = pe.Err
   102  			}
   103  			if se, ok := err.(syscall.Errno); ok && (se == syscall.EAGAIN || se == syscall.EMFILE) {
   104  				time.Sleep(time.Millisecond)
   105  				continue
   106  			}
   107  
   108  			t.Error(err)
   109  			return
   110  		}
   111  		cmds = append(cmds, cmd)
   112  	}
   113  
   114  	failures := 0
   115  	for _, cmd := range cmds {
   116  		err := cmd.Wait()
   117  		if err == nil {
   118  			continue
   119  		}
   120  
   121  		t.Errorf("syscall.Exec failed: %v\n%s", err, cmd.Stdout)
   122  		failures++
   123  	}
   124  
   125  	if failures > 0 {
   126  		t.Logf("Failed %v of %v attempts.", failures, len(cmds))
   127  	}
   128  }
   129
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