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
|
// Copyright 2018 The gVisor Authors.
//
// 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 linux
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/anon"
"gvisor.dev/gvisor/pkg/sentry/kernel"
)
const allFlags = int(linux.IN_NONBLOCK | linux.IN_CLOEXEC)
// InotifyInit1 implements the inotify_init1() syscalls.
func InotifyInit1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
flags := int(args[0].Int())
if flags&^allFlags != 0 {
return 0, nil, linuxerr.EINVAL
}
dirent := fs.NewDirent(t, anon.NewInode(t), "inotify")
fileFlags := fs.FileFlags{
Read: true,
Write: true,
NonBlocking: flags&linux.IN_NONBLOCK != 0,
}
n := fs.NewFile(t, dirent, fileFlags, fs.NewInotify(t))
defer n.DecRef(t)
fd, err := t.NewFDFrom(0, n, kernel.FDFlags{
CloseOnExec: flags&linux.IN_CLOEXEC != 0,
})
if err != nil {
return 0, nil, err
}
return uintptr(fd), nil, nil
}
// InotifyInit implements the inotify_init() syscalls.
func InotifyInit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
args[0].Value = 0
return InotifyInit1(t, args)
}
// fdToInotify resolves an fd to an inotify object. If successful, the file will
// have an extra ref and the caller is responsible for releasing the ref.
func fdToInotify(t *kernel.Task, fd int32) (*fs.Inotify, *fs.File, error) {
file := t.GetFile(fd)
if file == nil {
// Invalid fd.
return nil, nil, linuxerr.EBADF
}
ino, ok := file.FileOperations.(*fs.Inotify)
if !ok {
// Not an inotify fd.
file.DecRef(t)
return nil, nil, linuxerr.EINVAL
}
return ino, file, nil
}
// InotifyAddWatch implements the inotify_add_watch() syscall.
func InotifyAddWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
addr := args[1].Pointer()
mask := args[2].Uint()
// "IN_DONT_FOLLOW: Don't dereference pathname if it is a symbolic link."
// -- inotify(7)
resolve := mask&linux.IN_DONT_FOLLOW == 0
// "EINVAL: The given event mask contains no valid events."
// -- inotify_add_watch(2)
if validBits := mask & linux.ALL_INOTIFY_BITS; validBits == 0 {
return 0, nil, linuxerr.EINVAL
}
ino, file, err := fdToInotify(t, fd)
if err != nil {
return 0, nil, err
}
defer file.DecRef(t)
path, _, err := copyInPath(t, addr, false /* allowEmpty */)
if err != nil {
return 0, nil, err
}
err = fileOpOn(t, linux.AT_FDCWD, path, resolve, func(root *fs.Dirent, dirent *fs.Dirent, _ uint) error {
// "IN_ONLYDIR: Only watch pathname if it is a directory." -- inotify(7)
if onlyDir := mask&linux.IN_ONLYDIR != 0; onlyDir && !fs.IsDir(dirent.Inode.StableAttr) {
return linuxerr.ENOTDIR
}
// Copy out to the return frame.
fd = ino.AddWatch(dirent, mask)
return nil
})
return uintptr(fd), nil, err // Return from the existing value.
}
// InotifyRmWatch implements the inotify_rm_watch() syscall.
func InotifyRmWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
wd := args[1].Int()
ino, file, err := fdToInotify(t, fd)
if err != nil {
return 0, nil, err
}
defer file.DecRef(t)
return 0, nil, ino.RmWatch(t, wd)
}
|
