1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
// Copyright 2024 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 aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || wasip1
package os
import (
"errors"
"internal/syscall/unix"
"runtime"
"syscall"
)
type sysfdType = int
// openRootNolog is OpenRoot.
func openRootNolog(name string) (*Root, error) {
var fd int
err := ignoringEINTR(func() error {
var err error
fd, _, err = open(name, syscall.O_CLOEXEC, 0)
return err
})
if err != nil {
return nil, &PathError{Op: "open", Path: name, Err: err}
}
return newRoot(fd, name)
}
// newRoot returns a new Root.
// If fd is not a directory, it closes it and returns an error.
func newRoot(fd int, name string) (*Root, error) {
var fs fileStat
err := ignoringEINTR(func() error {
return syscall.Fstat(fd, &fs.sys)
})
fillFileStatFromSys(&fs, name)
if err == nil && !fs.IsDir() {
syscall.Close(fd)
return nil, &PathError{Op: "open", Path: name, Err: errors.New("not a directory")}
}
// There's a race here with fork/exec, which we are
// content to live with. See ../syscall/exec_unix.go.
if !supportsCloseOnExec {
syscall.CloseOnExec(fd)
}
r := &Root{&root{
fd: fd,
name: name,
}}
runtime.SetFinalizer(r.root, (*root).Close)
return r, nil
}
// openRootInRoot is Root.OpenRoot.
func openRootInRoot(r *Root, name string) (*Root, error) {
fd, err := doInRoot(r, name, func(parent int, name string) (fd int, err error) {
ignoringEINTR(func() error {
fd, err = unix.Openat(parent, name, syscall.O_NOFOLLOW|syscall.O_CLOEXEC, 0)
if isNoFollowErr(err) {
err = checkSymlink(parent, name, err)
}
return err
})
return fd, err
})
if err != nil {
return nil, &PathError{Op: "openat", Path: name, Err: err}
}
return newRoot(fd, name)
}
// rootOpenFileNolog is Root.OpenFile.
func rootOpenFileNolog(root *Root, name string, flag int, perm FileMode) (*File, error) {
fd, err := doInRoot(root, name, func(parent int, name string) (fd int, err error) {
ignoringEINTR(func() error {
fd, err = unix.Openat(parent, name, syscall.O_NOFOLLOW|syscall.O_CLOEXEC|flag, uint32(perm))
if isNoFollowErr(err) || err == syscall.ENOTDIR {
err = checkSymlink(parent, name, err)
}
return err
})
return fd, err
})
if err != nil {
return nil, &PathError{Op: "openat", Path: name, Err: err}
}
f := newFile(fd, joinPath(root.Name(), name), kindOpenFile, unix.HasNonblockFlag(flag))
return f, nil
}
func rootOpenDir(parent int, name string) (int, error) {
var (
fd int
err error
)
ignoringEINTR(func() error {
fd, err = unix.Openat(parent, name, syscall.O_NOFOLLOW|syscall.O_CLOEXEC|syscall.O_DIRECTORY, 0)
if isNoFollowErr(err) || err == syscall.ENOTDIR {
err = checkSymlink(parent, name, err)
} else if err == syscall.ENOTSUP || err == syscall.EOPNOTSUPP {
// ENOTSUP and EOPNOTSUPP are often, but not always, the same errno.
// Translate both to ENOTDIR, since this indicates a non-terminal
// path component was not a directory.
err = syscall.ENOTDIR
}
return err
})
return fd, err
}
func rootStat(r *Root, name string, lstat bool) (FileInfo, error) {
fi, err := doInRoot(r, name, func(parent sysfdType, n string) (FileInfo, error) {
var fs fileStat
if err := unix.Fstatat(parent, n, &fs.sys, unix.AT_SYMLINK_NOFOLLOW); err != nil {
return nil, err
}
fillFileStatFromSys(&fs, name)
if !lstat && fs.Mode()&ModeSymlink != 0 {
return nil, checkSymlink(parent, n, syscall.ELOOP)
}
return &fs, nil
})
if err != nil {
return nil, &PathError{Op: "statat", Path: name, Err: err}
}
return fi, nil
}
func mkdirat(fd int, name string, perm FileMode) error {
return ignoringEINTR(func() error {
return unix.Mkdirat(fd, name, syscallMode(perm))
})
}
func removeat(fd int, name string) error {
// The system call interface forces us to know whether
// we are removing a file or directory. Try both.
e := ignoringEINTR(func() error {
return unix.Unlinkat(fd, name, 0)
})
if e == nil {
return nil
}
e1 := ignoringEINTR(func() error {
return unix.Unlinkat(fd, name, unix.AT_REMOVEDIR)
})
if e1 == nil {
return nil
}
// Both failed. See comment in Remove for how we decide which error to return.
if e1 != syscall.ENOTDIR {
return e1
}
return e
}
// checkSymlink resolves the symlink name in parent,
// and returns errSymlink with the link contents.
//
// If name is not a symlink, return origError.
func checkSymlink(parent int, name string, origError error) error {
link, err := readlinkat(parent, name)
if err != nil {
return origError
}
return errSymlink(link)
}
func readlinkat(fd int, name string) (string, error) {
for len := 128; ; len *= 2 {
b := make([]byte, len)
var (
n int
e error
)
ignoringEINTR(func() error {
n, e = unix.Readlinkat(fd, name, b)
return e
})
if e == syscall.ERANGE {
continue
}
if e != nil {
return "", e
}
if n < 0 {
n = 0
}
if n < len {
return string(b[0:n]), nil
}
}
}
|
