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
|
// 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 kernfs
import (
"fmt"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/usermem"
)
// DynamicBytesFile implements kernfs.Inode and represents a read-only file
// whose contents are backed by a vfs.DynamicBytesSource. If data additionally
// implements vfs.WritableDynamicBytesSource, the file also supports dispatching
// writes to the implementer, but note that this will not update the source data.
//
// Must be instantiated with NewDynamicBytesFile or initialized with Init
// before first use.
//
// +stateify savable
type DynamicBytesFile struct {
InodeAttrs
InodeNoStatFS
InodeNoopRefCount
InodeNotDirectory
InodeNotSymlink
InodeWatches
locks vfs.FileLocks
// data can additionally implement vfs.WritableDynamicBytesSource to support
// writes. This field cannot be changed to a different bytes source after
// Init.
data vfs.DynamicBytesSource
}
var _ Inode = (*DynamicBytesFile)(nil)
// Init initializes a dynamic bytes file.
func (f *DynamicBytesFile) Init(ctx context.Context, creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, data vfs.DynamicBytesSource, perm linux.FileMode) {
if perm&^linux.PermissionsMask != 0 {
panic(fmt.Sprintf("Only permission mask must be set: %x", perm&linux.PermissionsMask))
}
f.InodeAttrs.Init(ctx, creds, devMajor, devMinor, ino, linux.ModeRegular|perm)
f.data = data
}
// Open implements Inode.Open.
func (f *DynamicBytesFile) Open(ctx context.Context, rp *vfs.ResolvingPath, d *Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
fd := &DynamicBytesFD{}
if err := fd.Init(rp.Mount(), d, f.data, &f.locks, opts.Flags); err != nil {
return nil, err
}
return &fd.vfsfd, nil
}
// SetStat implements Inode.SetStat. By default DynamicBytesFile doesn't allow
// inode attributes to be changed. Override SetStat() making it call
// f.InodeAttrs to allow it.
func (*DynamicBytesFile) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
return linuxerr.EPERM
}
// Locks returns the file locks for this file.
func (f *DynamicBytesFile) Locks() *vfs.FileLocks {
return &f.locks
}
// Data returns the underlying data source.
func (f *DynamicBytesFile) Data() vfs.DynamicBytesSource {
return f.data
}
// DynamicBytesFD implements vfs.FileDescriptionImpl for an FD backed by a
// DynamicBytesFile.
//
// Must be initialized with Init before first use.
//
// +stateify savable
type DynamicBytesFD struct {
vfs.FileDescriptionDefaultImpl
vfs.DynamicBytesFileDescriptionImpl
vfs.LockFD
vfsfd vfs.FileDescription
inode Inode
}
// Init initializes a DynamicBytesFD.
func (fd *DynamicBytesFD) Init(m *vfs.Mount, d *Dentry, data vfs.DynamicBytesSource, locks *vfs.FileLocks, flags uint32) error {
fd.LockFD.Init(locks)
if err := fd.vfsfd.Init(fd, flags, m, d.VFSDentry(), &vfs.FileDescriptionOptions{}); err != nil {
return err
}
fd.inode = d.inode
fd.DynamicBytesFileDescriptionImpl.Init(&fd.vfsfd, data)
return nil
}
// Seek implements vfs.FileDescriptionImpl.Seek.
func (fd *DynamicBytesFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
return fd.DynamicBytesFileDescriptionImpl.Seek(ctx, offset, whence)
}
// Read implements vfs.FileDescriptionImpl.Read.
func (fd *DynamicBytesFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
return fd.DynamicBytesFileDescriptionImpl.Read(ctx, dst, opts)
}
// PRead implements vfs.FileDescriptionImpl.PRead.
func (fd *DynamicBytesFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
return fd.DynamicBytesFileDescriptionImpl.PRead(ctx, dst, offset, opts)
}
// Write implements vfs.FileDescriptionImpl.Write.
func (fd *DynamicBytesFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
return fd.DynamicBytesFileDescriptionImpl.Write(ctx, src, opts)
}
// PWrite implements vfs.FileDescriptionImpl.PWrite.
func (fd *DynamicBytesFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
return fd.DynamicBytesFileDescriptionImpl.PWrite(ctx, src, offset, opts)
}
// Release implements vfs.FileDescriptionImpl.Release.
func (fd *DynamicBytesFD) Release(context.Context) {}
// Stat implements vfs.FileDescriptionImpl.Stat.
func (fd *DynamicBytesFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
fs := fd.vfsfd.VirtualDentry().Mount().Filesystem()
return fd.inode.Stat(ctx, fs, opts)
}
// SetStat implements vfs.FileDescriptionImpl.SetStat.
func (fd *DynamicBytesFD) SetStat(context.Context, vfs.SetStatOptions) error {
// DynamicBytesFiles are immutable.
return linuxerr.EPERM
}
|
