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
|
package syscallcompat
import (
"os"
"path/filepath"
"sync"
"syscall"
)
// Sorry, fallocate is not available on OSX at all and
// fcntl F_PREALLOCATE is not accessible from Go.
// See https://github.com/rfjakob/gocryptfs/issues/18 if you want to help.
func EnospcPrealloc(fd int, off int64, len int64) (err error) {
return nil
}
// See above.
func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
return syscall.EOPNOTSUPP
}
var chdirMutex sync.Mutex
// Poor man's Openat
func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
if !filepath.IsAbs(path) {
// Save the old working directory
oldWd, err := os.Getwd()
if err != nil {
return -1, err
}
// Chdir to target directory
err = syscall.Fchdir(dirfd)
if err != nil {
return -1, err
}
// Chdir back at the end
defer os.Chdir(oldWd)
}
return syscall.Open(path, flags, mode)
}
// Poor man's Renameat
func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
// Unless both paths are absolute we have to save the old working dir and
// Chdir(oldWd) back to it in the end. If we error out before the first
// chdir, Chdir(oldWd) is unneccassary but does no harm.
if !filepath.IsAbs(oldpath) || !filepath.IsAbs(newpath) {
oldWd, err := os.Getwd()
if err != nil {
return err
}
defer os.Chdir(oldWd)
}
// Make oldpath absolute
oldpath, err = dirfdAbs(olddirfd, oldpath)
if err != nil {
return err
}
// Make newpath absolute
newpath, err = dirfdAbs(newdirfd, newpath)
if err != nil {
return err
}
return syscall.Rename(oldpath, newpath)
}
// Poor man's Unlinkat
func Unlinkat(dirfd int, path string) (err error) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
if !filepath.IsAbs(path) {
oldWd, err := os.Getwd()
if err != nil {
return err
}
defer os.Chdir(oldWd)
}
path, err = dirfdAbs(dirfd, path)
if err != nil {
return err
}
return syscall.Unlink(path)
}
// dirfdAbs transforms the dirfd-relative "path" to an absolute one. If the
// path is not already absolute, this function will change the working
// directory. The caller has to chdir back.
func dirfdAbs(dirfd int, path string) (absPath string, err error) {
if filepath.IsAbs(path) {
return path, nil
}
err = syscall.Fchdir(dirfd)
if err != nil {
return "", err
}
wd, err := os.Getwd()
if err != nil {
return "", err
}
return filepath.Join(wd, path), nil
}
|
