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
5package os
6
7import (
8	"syscall"
9	"time"
10)
11
12const bitSize16 = 2
13
14func 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.
46func dirstat(arg any) (*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			if err := a.incref("fstat"); err != nil {
60				return nil, err
61			}
62			n, err = syscall.Fstat(a.fd, buf)
63			a.decref()
64		case string:
65			name = a
66			n, err = syscall.Stat(a, buf)
67		default:
68			panic("phase error in dirstat")
69		}
70
71		if n < bitSize16 {
72			return nil, &PathError{Op: "stat", Path: name, Err: err}
73		}
74
75		// Pull the real size out of the stat message.
76		size = int(uint16(buf[0]) | uint16(buf[1])<<8)
77
78		// If the stat message is larger than our buffer we will
79		// go around the loop and allocate one that is big enough.
80		if size <= n {
81			d, err := syscall.UnmarshalDir(buf[:n])
82			if err != nil {
83				return nil, &PathError{Op: "stat", Path: name, Err: err}
84			}
85			return d, nil
86		}
87
88	}
89
90	if err == nil {
91		err = syscall.ErrBadStat
92	}
93
94	return nil, &PathError{Op: "stat", Path: name, Err: err}
95}
96
97// statNolog implements Stat for Plan 9.
98func statNolog(name string) (FileInfo, error) {
99	d, err := dirstat(name)
100	if err != nil {
101		return nil, err
102	}
103	return fileInfoFromStat(d), nil
104}
105
106// lstatNolog implements Lstat for Plan 9.
107func lstatNolog(name string) (FileInfo, error) {
108	return statNolog(name)
109}
110
111// For testing.
112func atime(fi FileInfo) time.Time {
113	return time.Unix(int64(fi.Sys().(*syscall.Dir).Atime), 0)
114}
115