144 lines
3.7 KiB
Go
144 lines
3.7 KiB
Go
// +build linux darwin dragonfly freebsd netbsd openbsd
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/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package cmd
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import (
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"os"
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"path"
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"runtime"
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"strings"
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"syscall"
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"unsafe"
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)
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const (
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// readDirentBufSize for syscall.ReadDirent() to hold multiple
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// directory entries in one buffer. golang source uses 4096 as
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// buffer size whereas we want 25 times larger to save lots of
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// entries to avoid multiple syscall.ReadDirent() call.
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readDirentBufSize = 4096 * 25
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)
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// actual length of the byte array from the c - world.
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func clen(n []byte) int {
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for i := 0; i < len(n); i++ {
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if n[i] == 0 {
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return i
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}
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}
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return len(n)
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}
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// parseDirents - inspired from
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// https://golang.org/src/syscall/syscall_<os>.go
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func parseDirents(dirPath string, buf []byte) (entries []string, err error) {
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bufidx := 0
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for bufidx < len(buf) {
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dirent := (*syscall.Dirent)(unsafe.Pointer(&buf[bufidx]))
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// On non-Linux operating systems for rec length of zero means
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// we have reached EOF break out.
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if runtime.GOOS != "linux" && dirent.Reclen == 0 {
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break
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}
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bufidx += int(dirent.Reclen)
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// Skip if they are absent in directory.
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if isEmptyDirent(dirent) {
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continue
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}
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bytes := (*[10000]byte)(unsafe.Pointer(&dirent.Name[0]))
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var name = string(bytes[0:clen(bytes[:])])
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// Reserved names skip them.
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if name == "." || name == ".." {
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continue
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}
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// Skip special files.
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if hasPosixReservedPrefix(name) {
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continue
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}
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switch dirent.Type {
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case syscall.DT_DIR:
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entries = append(entries, name+slashSeparator)
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case syscall.DT_REG:
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entries = append(entries, name)
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case syscall.DT_LNK, syscall.DT_UNKNOWN:
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// If its symbolic link, follow the link using os.Stat()
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// On Linux XFS does not implement d_type for on disk
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// format << v5. Fall back to Stat().
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var fi os.FileInfo
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fi, err = os.Stat(path.Join(dirPath, name))
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if err != nil {
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// If file does not exist, we continue and skip it.
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// Could happen if it was deleted in the middle while
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// this list was being performed.
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if os.IsNotExist(err) {
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continue
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}
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return nil, err
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}
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if fi.IsDir() {
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entries = append(entries, fi.Name()+slashSeparator)
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} else if fi.Mode().IsRegular() {
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entries = append(entries, fi.Name())
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}
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default:
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// Skip entries which are not file or directory.
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continue
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}
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}
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return entries, nil
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}
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// Return all the entries at the directory dirPath.
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func readDir(dirPath string) (entries []string, err error) {
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buf := make([]byte, readDirentBufSize)
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d, err := os.Open(dirPath)
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if err != nil {
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// File is really not found.
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if os.IsNotExist(err) {
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return nil, errFileNotFound
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}
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// File path cannot be verified since one of the parents is a file.
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if strings.Contains(err.Error(), "not a directory") {
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return nil, errFileNotFound
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}
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return nil, err
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}
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defer d.Close()
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fd := int(d.Fd())
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for {
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nbuf, err := syscall.ReadDirent(fd, buf)
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if err != nil {
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return nil, err
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}
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if nbuf <= 0 {
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break
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}
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var tmpEntries []string
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if tmpEntries, err = parseDirents(dirPath, buf[:nbuf]); err != nil {
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return nil, err
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}
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entries = append(entries, tmpEntries...)
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}
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return
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}
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