dirent_test.go

Documentation: syscall

		 1  // Copyright 2018 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 aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
		 6  // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
		 7  
		 8  package syscall_test
		 9  
		10  import (
		11  	"bytes"
		12  	"fmt"
		13  	"os"
		14  	"path/filepath"
		15  	"runtime"
		16  	"sort"
		17  	"strconv"
		18  	"strings"
		19  	"syscall"
		20  	"testing"
		21  	"unsafe"
		22  )
		23  
		24  func TestDirent(t *testing.T) {
		25  	const (
		26  		direntBufSize	 = 2048
		27  		filenameMinSize = 11
		28  	)
		29  
		30  	d := t.TempDir()
		31  	t.Logf("tmpdir: %s", d)
		32  
		33  	for i, c := range []byte("0123456789") {
		34  		name := string(bytes.Repeat([]byte{c}, filenameMinSize+i))
		35  		err := os.WriteFile(filepath.Join(d, name), nil, 0644)
		36  		if err != nil {
		37  			t.Fatalf("writefile: %v", err)
		38  		}
		39  	}
		40  
		41  	buf := bytes.Repeat([]byte("DEADBEAF"), direntBufSize/8)
		42  	fd, err := syscall.Open(d, syscall.O_RDONLY, 0)
		43  	if err != nil {
		44  		t.Fatalf("syscall.open: %v", err)
		45  	}
		46  	defer syscall.Close(fd)
		47  	n, err := syscall.ReadDirent(fd, buf)
		48  	if err != nil {
		49  		t.Fatalf("syscall.readdir: %v", err)
		50  	}
		51  	buf = buf[:n]
		52  
		53  	names := make([]string, 0, 10)
		54  	for len(buf) > 0 {
		55  		var bc int
		56  		bc, _, names = syscall.ParseDirent(buf, -1, names)
		57  		buf = buf[bc:]
		58  	}
		59  
		60  	sort.Strings(names)
		61  	t.Logf("names: %q", names)
		62  
		63  	if len(names) != 10 {
		64  		t.Errorf("got %d names; expected 10", len(names))
		65  	}
		66  	for i, name := range names {
		67  		ord, err := strconv.Atoi(name[:1])
		68  		if err != nil {
		69  			t.Fatalf("names[%d] is non-integer %q: %v", i, names[i], err)
		70  		}
		71  		if expected := string(strings.Repeat(name[:1], filenameMinSize+ord)); name != expected {
		72  			t.Errorf("names[%d] is %q (len %d); expected %q (len %d)", i, name, len(name), expected, len(expected))
		73  		}
		74  	}
		75  }
		76  
		77  func TestDirentRepeat(t *testing.T) {
		78  	const N = 100
		79  	// Note: the size of the buffer is small enough that the loop
		80  	// below will need to execute multiple times. See issue #31368.
		81  	size := N * unsafe.Offsetof(syscall.Dirent{}.Name) / 4
		82  	if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
		83  		if size < 1024 {
		84  			size = 1024 // DIRBLKSIZ, see issue 31403.
		85  		}
		86  		if runtime.GOOS == "freebsd" {
		87  			t.Skip("need to fix issue 31416 first")
		88  		}
		89  	}
		90  
		91  	// Make a directory containing N files
		92  	d := t.TempDir()
		93  
		94  	var files []string
		95  	for i := 0; i < N; i++ {
		96  		files = append(files, fmt.Sprintf("file%d", i))
		97  	}
		98  	for _, file := range files {
		99  		err := os.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
	 100  		if err != nil {
	 101  			t.Fatalf("writefile: %v", err)
	 102  		}
	 103  	}
	 104  
	 105  	// Read the directory entries using ReadDirent.
	 106  	fd, err := syscall.Open(d, syscall.O_RDONLY, 0)
	 107  	if err != nil {
	 108  		t.Fatalf("syscall.open: %v", err)
	 109  	}
	 110  	defer syscall.Close(fd)
	 111  	var files2 []string
	 112  	for {
	 113  		buf := make([]byte, size)
	 114  		n, err := syscall.ReadDirent(fd, buf)
	 115  		if err != nil {
	 116  			t.Fatalf("syscall.readdir: %v", err)
	 117  		}
	 118  		if n == 0 {
	 119  			break
	 120  		}
	 121  		buf = buf[:n]
	 122  		for len(buf) > 0 {
	 123  			var consumed int
	 124  			consumed, _, files2 = syscall.ParseDirent(buf, -1, files2)
	 125  			buf = buf[consumed:]
	 126  		}
	 127  	}
	 128  
	 129  	// Check results
	 130  	sort.Strings(files)
	 131  	sort.Strings(files2)
	 132  	if strings.Join(files, "|") != strings.Join(files2, "|") {
	 133  		t.Errorf("bad file list: want\n%q\ngot\n%q", files, files2)
	 134  	}
	 135  }
	 136
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