| 1 | //go:build linux |
| 2 | |
| 3 | package hostfloor |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "path/filepath" |
| 9 | |
| 10 | "golang.org/x/sys/unix" |
| 11 | |
| 12 | "github.com/carlosframework/platform/internal/safefile" |
| 13 | ) |
| 14 | |
| 15 | // EnsureControllerDir creates <dataDir>/.hostexec, the claim controllers' |
| 16 | // state directory (claim D6), and settles an existing one: a real directory |
| 17 | // owned by uid:gid, mode 2770, like /data/hostguard. The floor-armed update |
| 18 | // path refuses while the directory is missing (CheckControllersIdle), so |
| 19 | // guard-arm creates it (Opus re-review M1-2). |
| 20 | // |
| 21 | // Neither dataDir nor .hostexec may be a symlink. Ownership and mode are set |
| 22 | // through the opened descriptor, so a path swapped after the open changes |
| 23 | // nothing but the directory that was checked. Existing records are kept. |
| 24 | func EnsureControllerDir(dataDir string, uid, gid int) error { |
| 25 | if !filepath.IsAbs(dataDir) || filepath.Clean(dataDir) != dataDir { |
| 26 | return ErrFloor |
| 27 | } |
| 28 | parentDir, err := safefile.OpenDir(dataDir) |
| 29 | if err != nil { |
| 30 | return fmt.Errorf("open %s: %w", dataDir, err) |
| 31 | } |
| 32 | defer parentDir.Close() |
| 33 | parent := int(parentDir.Fd()) |
| 34 | if err = unix.Mkdirat(parent, ".hostexec", 0o700); err != nil && !errors.Is(err, unix.EEXIST) { |
| 35 | return fmt.Errorf("create %s/.hostexec: %w", dataDir, err) |
| 36 | } |
| 37 | fd, err := unix.Openat(parent, ".hostexec", unix.O_RDONLY|unix.O_DIRECTORY|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0) |
| 38 | if err != nil { |
| 39 | return fmt.Errorf("%w: %s/.hostexec is not a directory: %v", ErrFloor, dataDir, err) |
| 40 | } |
| 41 | defer unix.Close(fd) |
| 42 | var st unix.Stat_t |
| 43 | if err = unix.Fstat(fd, &st); err != nil { |
| 44 | return err |
| 45 | } |
| 46 | if st.Mode&unix.S_IFMT != unix.S_IFDIR { |
| 47 | return ErrFloor |
| 48 | } |
| 49 | if err = unix.Fchown(fd, uid, gid); err != nil { |
| 50 | return err |
| 51 | } |
| 52 | if err = unix.Fchmod(fd, 0o2770); err != nil { |
| 53 | return err |
| 54 | } |
| 55 | if err = unix.Fsync(fd); err != nil { |
| 56 | return err |
| 57 | } |
| 58 | return unix.Fsync(parent) |
| 59 | } |
| 60 | |
amadan