| 1 | //go:build unix |
| 2 | |
| 3 | package hostfiles |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | |
| 9 | "golang.org/x/sys/unix" |
| 10 | ) |
| 11 | |
| 12 | // syncTree walks the tree beneath root by descriptor and calls visit for |
| 13 | // every entry that is not a directory, with the open directory that holds |
| 14 | // it, its name there, and its path relative to root. It never follows a |
| 15 | // symlink and never blocks on a FIFO: a directory is entered only through |
| 16 | // openDir. |
| 17 | // |
| 18 | // The walk is bounded (withinTreeCap): a path past MaxPathBytes refuses |
| 19 | // the whole walk with ErrTooDeep, never a |
| 20 | // silent skip, so a tree no restore could recreate is never published as |
| 21 | // complete, and a chain of directories cannot make the walk's memory grow |
| 22 | // with the square of its depth. ctx is checked on entering every |
| 23 | // directory, so a deep tree with no files still stops when cancelled. |
| 24 | func syncTree(ctx context.Context, root *dirHandle, p *Publisher, skip func(string, bool) bool, visit func(d *dirHandle, name, rel string) error) error { |
| 25 | return walkDir(ctx, root, "", skip, visit) |
| 26 | } |
| 27 | |
| 28 | func walkDir(ctx context.Context, d *dirHandle, prefix string, skip func(string, bool) bool, visit func(d *dirHandle, name, rel string) error) error { |
| 29 | if err := ctx.Err(); err != nil { |
| 30 | return err |
| 31 | } |
| 32 | names, err := d.names() |
| 33 | if err != nil { |
| 34 | return err |
| 35 | } |
| 36 | for _, name := range names { |
| 37 | rel := name |
| 38 | if prefix != "" { |
| 39 | rel = prefix + "/" + name |
| 40 | } |
| 41 | st, err := d.look(name) |
| 42 | if errors.Is(err, unix.ENOENT) { |
| 43 | continue |
| 44 | } |
| 45 | if err != nil { |
| 46 | return err |
| 47 | } |
| 48 | if !isDir(st) { |
| 49 | if skipped(skip, rel, false) { |
| 50 | continue |
| 51 | } |
| 52 | if err := withinTreeCap(rel); err != nil { |
| 53 | return err |
| 54 | } |
| 55 | if err := visit(d, name, rel); err != nil { |
| 56 | return err |
| 57 | } |
| 58 | continue |
| 59 | } |
| 60 | if skipped(skip, rel, true) { |
| 61 | continue |
| 62 | } |
| 63 | if err := withinTreeCap(rel); err != nil { |
| 64 | return err |
| 65 | } |
| 66 | betweenLookAndOpen() |
| 67 | sub, err := d.openDir(name) |
| 68 | if err != nil { |
| 69 | if errors.Is(err, unix.ENOENT) { |
| 70 | continue |
| 71 | } |
| 72 | if notADirectory(err) { |
| 73 | // It was a directory a moment ago and is something else |
| 74 | // now. Let readStable say what: it will not follow or |
| 75 | // block on it either. |
| 76 | if err := visit(d, name, rel); err != nil { |
| 77 | return err |
| 78 | } |
| 79 | continue |
| 80 | } |
| 81 | return err |
| 82 | } |
| 83 | err = walkDir(ctx, sub, rel, skip, visit) |
| 84 | sub.Close() |
| 85 | if err != nil { |
| 86 | return err |
| 87 | } |
| 88 | } |
| 89 | return nil |
| 90 | } |
| 91 | |
amadan