| 1 | //go:build plan9 |
| 2 | |
| 3 | package fileutil |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "os" |
| 8 | "path/filepath" |
| 9 | "strings" |
| 10 | ) |
| 11 | |
| 12 | func OpenFileBeneath(root, rel string) (*os.File, error) { |
| 13 | root = filepath.Clean(strings.TrimSpace(root)) |
| 14 | if root == "" || root == "." { |
| 15 | return nil, fmt.Errorf("workspace root is empty") |
| 16 | } |
| 17 | rel, err := confinedRelativePath(rel) |
| 18 | if err != nil { |
| 19 | return nil, err |
| 20 | } |
| 21 | target, err := filepath.EvalSymlinks(filepath.Join(root, rel)) |
| 22 | if err != nil { |
| 23 | return nil, err |
| 24 | } |
| 25 | resolvedRoot, err := filepath.EvalSymlinks(root) |
| 26 | if err != nil { |
| 27 | return nil, err |
| 28 | } |
| 29 | resolvedRel, err := filepath.Rel(resolvedRoot, target) |
| 30 | if err != nil || resolvedRel == ".." || strings.HasPrefix(resolvedRel, ".."+string(filepath.Separator)) { |
| 31 | return nil, fmt.Errorf("file resolves outside workspace root") |
| 32 | } |
| 33 | return os.Open(target) |
| 34 | } |
| 35 |