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
|
// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package host
import (
"syscall"
"unsafe"
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
)
// NulByte is a single NUL byte. It is passed to readlinkat as an empty string.
var NulByte byte = '\x00'
func createLink(fd int, name string, linkName string) error {
namePtr, err := syscall.BytePtrFromString(name)
if err != nil {
return err
}
linkNamePtr, err := syscall.BytePtrFromString(linkName)
if err != nil {
return err
}
_, _, errno := syscall.Syscall(
syscall.SYS_SYMLINKAT,
uintptr(unsafe.Pointer(namePtr)),
uintptr(fd),
uintptr(unsafe.Pointer(linkNamePtr)))
if errno != 0 {
return errno
}
return nil
}
func readLink(fd int) (string, error) {
// Buffer sizing copied from os.Readlink.
for l := 128; ; l *= 2 {
b := make([]byte, l)
n, _, errno := syscall.Syscall6(
syscall.SYS_READLINKAT,
uintptr(fd),
uintptr(unsafe.Pointer(&NulByte)), // ""
uintptr(unsafe.Pointer(&b[0])),
uintptr(l),
0, 0)
if errno != 0 {
return "", errno
}
if n < uintptr(l) {
return string(b[:n]), nil
}
}
}
func unlinkAt(fd int, name string, dir bool) error {
namePtr, err := syscall.BytePtrFromString(name)
if err != nil {
return err
}
var flags uintptr
if dir {
flags = linux.AT_REMOVEDIR
}
_, _, errno := syscall.Syscall(
syscall.SYS_UNLINKAT,
uintptr(fd),
uintptr(unsafe.Pointer(namePtr)),
flags,
)
if errno != 0 {
return errno
}
return nil
}
func timespecFromTimestamp(t ktime.Time, omit, setSysTime bool) syscall.Timespec {
if omit {
return syscall.Timespec{0, linux.UTIME_OMIT}
}
if setSysTime {
return syscall.Timespec{0, linux.UTIME_NOW}
}
return syscall.NsecToTimespec(t.Nanoseconds())
}
func setTimestamps(fd int, ts fs.TimeSpec) error {
if ts.ATimeOmit && ts.MTimeOmit {
return nil
}
var sts [2]syscall.Timespec
sts[0] = timespecFromTimestamp(ts.ATime, ts.ATimeOmit, ts.ATimeSetSystemTime)
sts[1] = timespecFromTimestamp(ts.MTime, ts.MTimeOmit, ts.MTimeSetSystemTime)
_, _, errno := syscall.Syscall6(
syscall.SYS_UTIMENSAT,
uintptr(fd),
0, /* path */
uintptr(unsafe.Pointer(&sts)),
0, /* flags */
0, 0)
if errno != 0 {
return errno
}
return nil
}
func fstatat(fd int, name string, flags int) (syscall.Stat_t, error) {
var stat syscall.Stat_t
namePtr, err := syscall.BytePtrFromString(name)
if err != nil {
return stat, err
}
_, _, errno := syscall.Syscall6(
syscall.SYS_NEWFSTATAT,
uintptr(fd),
uintptr(unsafe.Pointer(namePtr)),
uintptr(unsafe.Pointer(&stat)),
uintptr(flags),
0, 0)
if errno != 0 {
return stat, errno
}
return stat, nil
}
|
