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
|
//go:build aix || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris
package dirent
import (
"encoding/binary"
"os"
"runtime"
"syscall"
"unsafe"
)
const InvalidMode = os.FileMode(1<<32 - 1)
// readInt returns the size-bytes unsigned integer in native byte order at offset off.
func readInt(b []byte, off, size uintptr) (uint64, bool) {
if len(b) < int(off+size) {
return 0, false
}
b = b[off:]
switch size {
case 1:
return uint64(b[0]), true
case 2:
return uint64(binary.NativeEndian.Uint16(b)), true
case 4:
return uint64(binary.NativeEndian.Uint32(b)), true
case 8:
return uint64(binary.NativeEndian.Uint64(b)), true
default:
// This case is impossible if the tests pass. Previously, we panicked
// here but for performance reasons (escape analysis) it's better to
// trigger a panic via an out-of-bounds reference.
_ = b[len(b)]
return 0, false
}
}
func Parse(buf []byte) (consumed int, name string, typ os.FileMode) {
reclen, ok := direntReclen(buf)
if !ok || reclen > uint64(len(buf)) {
// WARN: this is a hard error because we consumed 0 bytes
// and not stopping here could lead to an infinite loop.
return 0, "", InvalidMode
}
consumed = int(reclen)
rec := buf[:reclen]
ino, ok := direntIno(rec)
if !ok {
return consumed, "", InvalidMode
}
// When building to wasip1, the host runtime might be running on Windows
// or might expose a remote file system which does not have the concept
// of inodes. Therefore, we cannot make the assumption that it is safe
// to skip entries with zero inodes.
if ino == 0 && runtime.GOOS != "wasip1" {
return consumed, "", InvalidMode
}
typ = direntType(buf)
const namoff = uint64(unsafe.Offsetof(syscall.Dirent{}.Name))
namlen, ok := direntNamlen(rec)
if !ok || namoff+namlen > uint64(len(rec)) {
return consumed, "", InvalidMode
}
namebuf := rec[namoff : namoff+namlen]
for i, c := range namebuf {
if c == 0 {
namebuf = namebuf[:i]
break
}
}
// Check for useless names before allocating a string.
if string(namebuf) == "." {
name = "."
} else if string(namebuf) == ".." {
name = ".."
} else {
name = string(namebuf)
}
return consumed, name, typ
}
|
