github.com/code-reading/golang@v0.0.0-20220303082512-ba5bc0e589a3/go/src/os/stat_plan9.go (about) 1 // Copyright 2011 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 package os 6 7 import ( 8 "syscall" 9 "time" 10 ) 11 12 const bitSize16 = 2 13 14 func fileInfoFromStat(d *syscall.Dir) *fileStat { 15 fs := &fileStat{ 16 name: d.Name, 17 size: d.Length, 18 modTime: time.Unix(int64(d.Mtime), 0), 19 sys: d, 20 } 21 fs.mode = FileMode(d.Mode & 0777) 22 if d.Mode&syscall.DMDIR != 0 { 23 fs.mode |= ModeDir 24 } 25 if d.Mode&syscall.DMAPPEND != 0 { 26 fs.mode |= ModeAppend 27 } 28 if d.Mode&syscall.DMEXCL != 0 { 29 fs.mode |= ModeExclusive 30 } 31 if d.Mode&syscall.DMTMP != 0 { 32 fs.mode |= ModeTemporary 33 } 34 // Consider all files not served by #M as device files. 35 if d.Type != 'M' { 36 fs.mode |= ModeDevice 37 } 38 // Consider all files served by #c as character device files. 39 if d.Type == 'c' { 40 fs.mode |= ModeCharDevice 41 } 42 return fs 43 } 44 45 // arg is an open *File or a path string. 46 func dirstat(arg interface{}) (*syscall.Dir, error) { 47 var name string 48 var err error 49 50 size := syscall.STATFIXLEN + 16*4 51 52 for i := 0; i < 2; i++ { 53 buf := make([]byte, bitSize16+size) 54 55 var n int 56 switch a := arg.(type) { 57 case *File: 58 name = a.name 59 n, err = syscall.Fstat(a.fd, buf) 60 case string: 61 name = a 62 n, err = syscall.Stat(a, buf) 63 default: 64 panic("phase error in dirstat") 65 } 66 67 if n < bitSize16 { 68 return nil, &PathError{Op: "stat", Path: name, Err: err} 69 } 70 71 // Pull the real size out of the stat message. 72 size = int(uint16(buf[0]) | uint16(buf[1])<<8) 73 74 // If the stat message is larger than our buffer we will 75 // go around the loop and allocate one that is big enough. 76 if size <= n { 77 d, err := syscall.UnmarshalDir(buf[:n]) 78 if err != nil { 79 return nil, &PathError{Op: "stat", Path: name, Err: err} 80 } 81 return d, nil 82 } 83 84 } 85 86 if err == nil { 87 err = syscall.ErrBadStat 88 } 89 90 return nil, &PathError{Op: "stat", Path: name, Err: err} 91 } 92 93 // statNolog implements Stat for Plan 9. 94 func statNolog(name string) (FileInfo, error) { 95 d, err := dirstat(name) 96 if err != nil { 97 return nil, err 98 } 99 return fileInfoFromStat(d), nil 100 } 101 102 // lstatNolog implements Lstat for Plan 9. 103 func lstatNolog(name string) (FileInfo, error) { 104 return statNolog(name) 105 } 106 107 // For testing. 108 func atime(fi FileInfo) time.Time { 109 return time.Unix(int64(fi.Sys().(*syscall.Dir).Atime), 0) 110 }