moby/utils/fs.go

92 lines
1.8 KiB
Go

package utils
import (
"fmt"
"os"
"path/filepath"
"strings"
"syscall"
)
// TreeSize walks a directory tree and returns its total size in bytes.
func TreeSize(dir string) (size int64, err error) {
data := make(map[uint64]bool)
err = filepath.Walk(dir, func(d string, fileInfo os.FileInfo, e error) error {
// Ignore directory sizes
if fileInfo == nil {
return nil
}
s := fileInfo.Size()
if fileInfo.IsDir() || s == 0 {
return nil
}
// Check inode to handle hard links correctly
inode := fileInfo.Sys().(*syscall.Stat_t).Ino
if _, exists := data[inode]; exists {
return nil
}
data[inode] = false
size += s
return nil
})
return
}
// FollowSymlink will follow an existing link and scope it to the root
// path provided.
func FollowSymlinkInScope(link, root string) (string, error) {
prev := "/"
root, err := filepath.Abs(root)
if err != nil {
return "", err
}
link, err = filepath.Abs(link)
if err != nil {
return "", err
}
if !strings.HasPrefix(filepath.Dir(link), root) {
return "", fmt.Errorf("%s is not within %s", link, root)
}
for _, p := range strings.Split(link, "/") {
prev = filepath.Join(prev, p)
prev = filepath.Clean(prev)
for {
stat, err := os.Lstat(prev)
if err != nil {
if os.IsNotExist(err) {
break
}
return "", err
}
if stat.Mode()&os.ModeSymlink == os.ModeSymlink {
dest, err := os.Readlink(prev)
if err != nil {
return "", err
}
switch dest[0] {
case '/':
prev = filepath.Join(root, dest)
case '.':
prev, _ = filepath.Abs(prev)
if prev = filepath.Clean(filepath.Join(filepath.Dir(prev), dest)); len(prev) < len(root) {
prev = filepath.Join(root, filepath.Base(dest))
}
}
} else {
break
}
}
}
return prev, nil
}