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
207
208
209
210
211
212
213
214
215
216
217
218
|
package fusefrontend_reverse
import (
"context"
"fmt"
"os"
"path/filepath"
"syscall"
"golang.org/x/sys/unix"
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
"github.com/rfjakob/gocryptfs/v2/internal/contentenc"
"github.com/rfjakob/gocryptfs/v2/internal/pathiv"
"github.com/rfjakob/gocryptfs/v2/internal/syscallcompat"
"github.com/rfjakob/gocryptfs/v2/internal/tlog"
)
// Node is a file or directory in the filesystem tree
// in a `gocryptfs -reverse` mount.
type Node struct {
fs.Inode
// isOtherFilesystem is used for --one-filesystem.
// It is set when the device number of this file or directory
// is different from n.rootNode().rootDev.
isOtherFilesystem bool
}
// Lookup - FUSE call for discovering a file.
func (n *Node) Lookup(ctx context.Context, cName string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
var d *dirfdPlus
t := n.lookupFileType(cName)
if t == typeDiriv {
// gocryptfs.diriv
return n.lookupDiriv(ctx, out)
}
rn := n.rootNode()
if rn.args.OneFileSystem && n.isOtherFilesystem {
// With --one-file-system, we present mountpoints as empty. That is,
// it contains only a gocryptfs.diriv file (allowed above).
return nil, syscall.ENOENT
}
if t == typeName {
// gocryptfs.longname.*.name
return n.lookupLongnameName(ctx, cName, out)
} else if t == typeConfig {
// gocryptfs.conf
return n.lookupConf(ctx, out)
} else if t == typeReal {
// real file
d, errno = n.prepareAtSyscall(cName)
//fmt.Printf("Lookup: prepareAtSyscall -> d=%#v, errno=%d\n", d, errno)
if errno != 0 {
return
}
defer syscall.Close(d.dirfd)
}
// Get device number and inode number into `st`
st, err := syscallcompat.Fstatat2(d.dirfd, d.pName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return nil, fs.ToErrno(err)
}
// Create new inode and fill `out`
ch = n.newChild(ctx, st, out)
// Translate ciphertext size in `out.Attr.Size` to plaintext size
if t == typeReal {
n.translateSize(d.dirfd, cName, d.pName, &out.Attr)
}
// Usually we always create a new Node ID by always incrementing the generation
// number.
//
// If we already have a child node that matches what we found on disk*
// (as reflected in `ch`), return it here.
//
// This keeps the Node ID for each directory entry stable
// (until forgotten), preventing extra FORGETs from the kernel.
//
// *We compare `cName`, `Ino`, `Mode` (but not `Gen`!)
old := n.Inode.GetChild(cName)
if old != nil &&
old.StableAttr().Ino == ch.StableAttr().Ino &&
// `Mode` has already been masked with syscall.S_IFMT by n.newChild()
old.StableAttr().Mode == ch.StableAttr().Mode {
return old, 0
}
return ch, 0
}
// GetAttr - FUSE call for stat()ing a file.
//
// GetAttr is symlink-safe through use of openBackingDir() and Fstatat().
func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut) (errno syscall.Errno) {
d, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(d.dirfd)
st, err := syscallcompat.Fstatat2(d.dirfd, d.pName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return fs.ToErrno(err)
}
// Fix inode number
rn := n.rootNode()
rn.inoMap.TranslateStat(st)
out.Attr.FromStat(st)
// Translate ciphertext size in `out.Attr.Size` to plaintext size
cName := filepath.Base(n.Path())
n.translateSize(d.dirfd, cName, d.pName, &out.Attr)
if rn.args.ForceOwner != nil {
out.Owner = *rn.args.ForceOwner
}
return 0
}
// Readlink - FUSE call.
//
// Symlink-safe through openBackingDir() + Readlinkat().
func (n *Node) Readlink(ctx context.Context) (out []byte, errno syscall.Errno) {
d, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(d.dirfd)
return n.readlink(d.dirfd, d.cName, d.pName)
}
// Open - FUSE call. Open already-existing file.
//
// Symlink-safe through Openat().
func (n *Node) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
d, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(d.dirfd)
fd, err := syscallcompat.Openat(d.dirfd, d.pName, syscall.O_RDONLY|syscall.O_NOFOLLOW, 0)
if err != nil {
errno = fs.ToErrno(err)
return
}
// Reject access if the file descriptor does not refer to a regular file.
var st syscall.Stat_t
err = syscall.Fstat(fd, &st)
if err != nil {
tlog.Warn.Printf("Open: Fstat error: %v", err)
syscall.Close(fd)
errno = fs.ToErrno(err)
return
}
var a fuse.Attr
a.FromStat(&st)
if !a.IsRegular() {
tlog.Warn.Printf("ino%d: newFile: not a regular file", st.Ino)
syscall.Close(fd)
errno = syscall.EACCES
return
}
// See if we have that inode number already in the table
// (even if Nlink has dropped to 1)
var derivedIVs pathiv.FileIVs
v, found := inodeTable.Load(st.Ino)
if found {
tlog.Debug.Printf("ino%d: newFile: found in the inode table", st.Ino)
derivedIVs = v.(pathiv.FileIVs)
} else {
p := n.Path()
derivedIVs = pathiv.DeriveFile(p)
// Nlink > 1 means there is more than one path to this file.
// Store the derived values so we always return the same data,
// regardless of the path that is used to access the file.
// This means that the first path wins.
if st.Nlink > 1 {
v, found = inodeTable.LoadOrStore(st.Ino, derivedIVs)
if found {
// Another thread has stored a different value before we could.
derivedIVs = v.(pathiv.FileIVs)
} else {
tlog.Debug.Printf("ino%d: newFile: Nlink=%d, stored in the inode table", st.Ino, st.Nlink)
}
}
}
header := contentenc.FileHeader{
Version: contentenc.CurrentVersion,
ID: derivedIVs.ID,
}
fh = &File{
fd: os.NewFile(uintptr(fd), fmt.Sprintf("fd%d", fd)),
header: header,
block0IV: derivedIVs.Block0IV,
contentEnc: n.rootNode().contentEnc,
}
return
}
// StatFs - FUSE call. Returns information about the filesystem.
//
// Symlink-safe because the path is ignored.
func (n *Node) Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.Errno {
p := n.rootNode().args.Cipherdir
var st syscall.Statfs_t
err := syscall.Statfs(p, &st)
if err != nil {
return fs.ToErrno(err)
}
out.FromStatfsT(&st)
return 0
}
|
