forked from RepoMirrors/btrfs
98 lines
2.1 KiB
Go
98 lines
2.1 KiB
Go
package btrfs
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/dennwc/btrfs/mtab"
|
|
"os"
|
|
"path/filepath"
|
|
"strings"
|
|
"syscall"
|
|
"unsafe"
|
|
)
|
|
|
|
func isBtrfs(path string) (bool, error) {
|
|
var stfs syscall.Statfs_t
|
|
if err := syscall.Statfs(path, &stfs); err != nil {
|
|
return false, &os.PathError{Op: "statfs", Path: path, Err: err}
|
|
}
|
|
return stfs.Type == SuperMagic, nil
|
|
}
|
|
|
|
func findMountRoot(path string) (string, error) {
|
|
mounts, err := mtab.Mounts()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
longest := ""
|
|
isBtrfs := false
|
|
for _, m := range mounts {
|
|
if !strings.HasPrefix(path, m.Mount) {
|
|
continue
|
|
}
|
|
if len(longest) < len(m.Mount) {
|
|
longest = m.Mount
|
|
isBtrfs = m.Type == "btrfs"
|
|
}
|
|
}
|
|
if longest == "" {
|
|
return "", os.ErrNotExist
|
|
} else if !isBtrfs {
|
|
return "", ErrNotBtrfs{Path: longest}
|
|
}
|
|
return filepath.Abs(longest)
|
|
}
|
|
|
|
// openDir does the following checks before calling Open:
|
|
// 1: path is in a btrfs filesystem
|
|
// 2: path is a directory
|
|
func openDir(path string) (*os.File, error) {
|
|
if ok, err := isBtrfs(path); err != nil {
|
|
return nil, err
|
|
} else if !ok {
|
|
return nil, ErrNotBtrfs{Path: path}
|
|
}
|
|
file, err := os.Open(path)
|
|
if err != nil {
|
|
return nil, err
|
|
} else if st, err := file.Stat(); err != nil {
|
|
file.Close()
|
|
return nil, err
|
|
} else if !st.IsDir() {
|
|
file.Close()
|
|
return nil, fmt.Errorf("not a directory: %s", path)
|
|
}
|
|
return file, nil
|
|
}
|
|
|
|
type searchResult struct {
|
|
TransID uint64
|
|
ObjectID objectID
|
|
Type treeKeyType
|
|
Offset uint64
|
|
Data []byte
|
|
}
|
|
|
|
func treeSearchRaw(mnt *os.File, key btrfs_ioctl_search_key) (out []searchResult, _ error) {
|
|
args := btrfs_ioctl_search_args{
|
|
key: key,
|
|
}
|
|
if err := iocTreeSearch(mnt, &args); err != nil {
|
|
return nil, err
|
|
}
|
|
out = make([]searchResult, 0, args.key.nr_items)
|
|
buf := args.buf[:]
|
|
for i := 0; i < int(args.key.nr_items); i++ {
|
|
h := (*btrfs_ioctl_search_header)(unsafe.Pointer(&buf[0]))
|
|
buf = buf[unsafe.Sizeof(btrfs_ioctl_search_header{}):]
|
|
out = append(out, searchResult{
|
|
TransID: h.transid,
|
|
ObjectID: h.objectid,
|
|
Offset: h.offset,
|
|
Type: h.typ,
|
|
Data: buf[:h.len:h.len], // TODO: reallocate?
|
|
})
|
|
buf = buf[h.len:]
|
|
}
|
|
return out, nil
|
|
}
|