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
199
200
201
202
203
204
205
206
|
// Copyright 2019 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 sys implements sysfs.
package sys
import (
"bytes"
"fmt"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/coverage"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
)
// Name is the default filesystem name.
const Name = "sysfs"
const defaultSysDirMode = linux.FileMode(0755)
// FilesystemType implements vfs.FilesystemType.
//
// +stateify savable
type FilesystemType struct{}
// filesystem implements vfs.FilesystemImpl.
//
// +stateify savable
type filesystem struct {
kernfs.Filesystem
devMinor uint32
}
// Name implements vfs.FilesystemType.Name.
func (FilesystemType) Name() string {
return Name
}
// Release implements vfs.FilesystemType.Release.
func (FilesystemType) Release(ctx context.Context) {}
// GetFilesystem implements vfs.FilesystemType.GetFilesystem.
func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
devMinor, err := vfsObj.GetAnonBlockDevMinor()
if err != nil {
return nil, nil, err
}
fs := &filesystem{
devMinor: devMinor,
}
fs.VFSFilesystem().Init(vfsObj, &fsType, fs)
root := fs.newDir(ctx, creds, defaultSysDirMode, map[string]kernfs.Inode{
"block": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"bus": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"class": fs.newDir(ctx, creds, defaultSysDirMode, map[string]kernfs.Inode{
"power_supply": fs.newDir(ctx, creds, defaultSysDirMode, nil),
}),
"dev": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"devices": fs.newDir(ctx, creds, defaultSysDirMode, map[string]kernfs.Inode{
"system": fs.newDir(ctx, creds, defaultSysDirMode, map[string]kernfs.Inode{
"cpu": cpuDir(ctx, fs, creds),
}),
}),
"firmware": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"fs": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"kernel": kernelDir(ctx, fs, creds),
"module": fs.newDir(ctx, creds, defaultSysDirMode, nil),
"power": fs.newDir(ctx, creds, defaultSysDirMode, nil),
})
var rootD kernfs.Dentry
rootD.Init(&fs.Filesystem, root)
return fs.VFSFilesystem(), rootD.VFSDentry(), nil
}
func cpuDir(ctx context.Context, fs *filesystem, creds *auth.Credentials) kernfs.Inode {
k := kernel.KernelFromContext(ctx)
maxCPUCores := k.ApplicationCores()
children := map[string]kernfs.Inode{
"online": fs.newCPUFile(ctx, creds, maxCPUCores, linux.FileMode(0444)),
"possible": fs.newCPUFile(ctx, creds, maxCPUCores, linux.FileMode(0444)),
"present": fs.newCPUFile(ctx, creds, maxCPUCores, linux.FileMode(0444)),
}
for i := uint(0); i < maxCPUCores; i++ {
children[fmt.Sprintf("cpu%d", i)] = fs.newDir(ctx, creds, linux.FileMode(0555), nil)
}
return fs.newDir(ctx, creds, defaultSysDirMode, children)
}
func kernelDir(ctx context.Context, fs *filesystem, creds *auth.Credentials) kernfs.Inode {
// If kcov is available, set up /sys/kernel/debug/kcov. Technically, debugfs
// should be mounted at debug/, but for our purposes, it is sufficient to
// keep it in sys.
var children map[string]kernfs.Inode
if coverage.KcovAvailable() {
children = map[string]kernfs.Inode{
"debug": fs.newDir(ctx, creds, linux.FileMode(0700), map[string]kernfs.Inode{
"kcov": fs.newKcovFile(ctx, creds),
}),
}
}
return fs.newDir(ctx, creds, defaultSysDirMode, children)
}
// Release implements vfs.FilesystemImpl.Release.
func (fs *filesystem) Release(ctx context.Context) {
fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
fs.Filesystem.Release(ctx)
}
// dir implements kernfs.Inode.
//
// +stateify savable
type dir struct {
dirRefs
kernfs.InodeAlwaysValid
kernfs.InodeAttrs
kernfs.InodeNotSymlink
kernfs.InodeDirectoryNoNewChildren
kernfs.InodeTemporary
kernfs.OrderedChildren
locks vfs.FileLocks
}
func (fs *filesystem) newDir(ctx context.Context, creds *auth.Credentials, mode linux.FileMode, contents map[string]kernfs.Inode) kernfs.Inode {
d := &dir{}
d.InodeAttrs.Init(ctx, creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0755)
d.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
d.EnableLeakCheck()
d.IncLinks(d.OrderedChildren.Populate(contents))
return d
}
// SetStat implements kernfs.Inode.SetStat not allowing inode attributes to be changed.
func (*dir) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
return syserror.EPERM
}
// Open implements kernfs.Inode.Open.
func (d *dir) Open(ctx context.Context, rp *vfs.ResolvingPath, kd *kernfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), kd, &d.OrderedChildren, &d.locks, &opts, kernfs.GenericDirectoryFDOptions{
SeekEnd: kernfs.SeekEndStaticEntries,
})
if err != nil {
return nil, err
}
return fd.VFSFileDescription(), nil
}
// DecRef implements kernfs.Inode.DecRef.
func (d *dir) DecRef(ctx context.Context) {
d.dirRefs.DecRef(func() { d.Destroy(ctx) })
}
// StatFS implements kernfs.Inode.StatFS.
func (d *dir) StatFS(ctx context.Context, fs *vfs.Filesystem) (linux.Statfs, error) {
return vfs.GenericStatFS(linux.SYSFS_MAGIC), nil
}
// cpuFile implements kernfs.Inode.
//
// +stateify savable
type cpuFile struct {
implStatFS
kernfs.DynamicBytesFile
maxCores uint
}
// Generate implements vfs.DynamicBytesSource.Generate.
func (c *cpuFile) Generate(ctx context.Context, buf *bytes.Buffer) error {
fmt.Fprintf(buf, "0-%d\n", c.maxCores-1)
return nil
}
func (fs *filesystem) newCPUFile(ctx context.Context, creds *auth.Credentials, maxCores uint, mode linux.FileMode) kernfs.Inode {
c := &cpuFile{maxCores: maxCores}
c.DynamicBytesFile.Init(ctx, creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), c, mode)
return c
}
// +stateify savable
type implStatFS struct{}
// StatFS implements kernfs.Inode.StatFS.
func (*implStatFS) StatFS(context.Context, *vfs.Filesystem) (linux.Statfs, error) {
return vfs.GenericStatFS(linux.SYSFS_MAGIC), nil
}
|
