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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build unix
package syscall_test
import (
"bytes"
"fmt"
"os"
"path/filepath"
"runtime"
"sort"
"strconv"
"strings"
"syscall"
"testing"
"unsafe"
)
func TestDirent(t *testing.T) {
const (
direntBufSize = 2048 // arbitrary? See https://go.dev/issue/37323.
filenameMinSize = 11
)
d := t.TempDir()
t.Logf("tmpdir: %s", d)
for i, c := range []byte("0123456789") {
name := string(bytes.Repeat([]byte{c}, filenameMinSize+i))
err := os.WriteFile(filepath.Join(d, name), nil, 0644)
if err != nil {
t.Fatalf("writefile: %v", err)
}
}
names := make([]string, 0, 10)
fd, err := syscall.Open(d, syscall.O_RDONLY, 0)
if err != nil {
t.Fatalf("syscall.open: %v", err)
}
defer syscall.Close(fd)
buf := bytes.Repeat([]byte{0xCD}, direntBufSize)
for {
n, err := syscall.ReadDirent(fd, buf)
if err == syscall.EINVAL {
// On linux, 'man getdents64' says that EINVAL indicates “result buffer is too small”.
// Try a bigger buffer.
t.Logf("ReadDirent: %v; retrying with larger buffer", err)
buf = bytes.Repeat([]byte{0xCD}, len(buf)*2)
continue
}
if err != nil {
t.Fatalf("syscall.readdir: %v", err)
}
t.Logf("ReadDirent: read %d bytes", n)
if n == 0 {
break
}
var consumed, count int
consumed, count, names = syscall.ParseDirent(buf[:n], -1, names)
t.Logf("ParseDirent: %d new name(s)", count)
if consumed != n {
t.Fatalf("ParseDirent: consumed %d bytes; expected %d", consumed, n)
}
}
sort.Strings(names)
t.Logf("names: %q", names)
if len(names) != 10 {
t.Errorf("got %d names; expected 10", len(names))
}
for i, name := range names {
ord, err := strconv.Atoi(name[:1])
if err != nil {
t.Fatalf("names[%d] is non-integer %q: %v", i, names[i], err)
}
if expected := strings.Repeat(name[:1], filenameMinSize+ord); name != expected {
t.Errorf("names[%d] is %q (len %d); expected %q (len %d)", i, name, len(name), expected, len(expected))
}
}
}
func TestDirentRepeat(t *testing.T) {
const N = 100
// Note: the size of the buffer is small enough that the loop
// below will need to execute multiple times. See issue #31368.
size := N * unsafe.Offsetof(syscall.Dirent{}.Name) / 4
if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
if size < 1024 {
size = 1024 // DIRBLKSIZ, see issue 31403.
}
}
// Make a directory containing N files
d := t.TempDir()
var files []string
for i := 0; i < N; i++ {
files = append(files, fmt.Sprintf("file%d", i))
}
for _, file := range files {
err := os.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
if err != nil {
t.Fatalf("writefile: %v", err)
}
}
// Read the directory entries using ReadDirent.
fd, err := syscall.Open(d, syscall.O_RDONLY, 0)
if err != nil {
t.Fatalf("syscall.open: %v", err)
}
defer syscall.Close(fd)
var files2 []string
for {
buf := make([]byte, size)
n, err := syscall.ReadDirent(fd, buf)
if err != nil {
t.Fatalf("syscall.readdir: %v", err)
}
if n == 0 {
break
}
buf = buf[:n]
for len(buf) > 0 {
var consumed int
consumed, _, files2 = syscall.ParseDirent(buf, -1, files2)
buf = buf[consumed:]
}
}
// Check results
sort.Strings(files)
sort.Strings(files2)
if strings.Join(files, "|") != strings.Join(files2, "|") {
t.Errorf("bad file list: want\n%q\ngot\n%q", files, files2)
}
}
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