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
|
package fusefrontend_reverse
import (
"syscall"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
const (
// virtualFileMode is the mode to use for virtual files (gocryptfs.diriv and
// *.name). They are always readable, as stated in func Access
virtualFileMode = syscall.S_IFREG | 0444
// virtualInoBase is the start of the inode number range that is used
// for virtual files.
// The value 10^19 is just below 2^60. A power of 10 has been chosen so the
// "ls -li" output (which is base-10) is easy to read.
// 10^19 is the largest power of 10 that is smaller than UINT64_MAX/2.
virtualInoBase = uint64(1000000000000000000)
)
func (rfs *ReverseFS) newDirIVFile(cRelPath string) (nodefs.File, fuse.Status) {
cDir := saneDir(cRelPath)
absDir, err := rfs.abs(rfs.decryptPath(cDir))
if err != nil {
return nil, fuse.ToStatus(err)
}
return rfs.newVirtualFile(derivePathIV(cDir, ivPurposeDirIV), absDir)
}
type virtualFile struct {
// Embed nodefs.defaultFile for a ENOSYS implementation of all methods
nodefs.File
// file content
content []byte
// absolute path to a parent file
parentFile string
}
// newVirtualFile creates a new in-memory file that does not have a representation
// on disk. "content" is the file content. Timestamps and file owner are copied
// from "parentFile" (absolute plaintext path). For a "gocryptfs.diriv" file, you
// would use the parent directory as "parentFile".
func (rfs *ReverseFS) newVirtualFile(content []byte, parentFile string) (nodefs.File, fuse.Status) {
return &virtualFile{
File: nodefs.NewDefaultFile(),
content: content,
parentFile: parentFile,
}, fuse.OK
}
// Read - FUSE call
func (f *virtualFile) Read(buf []byte, off int64) (resultData fuse.ReadResult, status fuse.Status) {
if off >= int64(len(f.content)) {
return nil, fuse.OK
}
end := int(off) + len(buf)
if end > len(f.content) {
end = len(f.content)
}
return fuse.ReadResultData(f.content[off:end]), fuse.OK
}
// GetAttr - FUSE call
func (f *virtualFile) GetAttr(a *fuse.Attr) fuse.Status {
var st syscall.Stat_t
err := syscall.Lstat(f.parentFile, &st)
if err != nil {
tlog.Debug.Printf("GetAttr: Lstat %q: %v\n", f.parentFile, err)
return fuse.ToStatus(err)
}
if st.Ino > virtualInoBase {
tlog.Warn.Printf("virtualFile.GetAttr: parent file inode number %d crosses reserved space, max=%d. Returning EOVERFLOW.",
st.Ino, virtualInoBase)
return fuse.ToStatus(syscall.EOVERFLOW)
}
st.Ino = st.Ino + virtualInoBase
st.Size = int64(len(f.content))
st.Mode = virtualFileMode
st.Nlink = 1
a.FromStat(&st)
return fuse.OK
}
|
