| 1 | //go:build linux |
| 2 | |
| 3 | package instancefs |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "os" |
| 8 | "path/filepath" |
| 9 | "syscall" |
| 10 | "testing" |
| 11 | "time" |
| 12 | ) |
| 13 | |
| 14 | // OpenBeneathOrAbsent is the one place absence is decided: absent only |
| 15 | // when the name is not found beneath the descriptor dir was opened as. |
| 16 | func TestOpenBeneathOrAbsentDecidesAbsenceBeneathOneDescriptor(t *testing.T) { |
| 17 | setup := func(t *testing.T) (dir string) { |
| 18 | t.Helper() |
| 19 | dir = filepath.Join(t.TempDir(), "inst") |
| 20 | if err := os.Mkdir(dir, 0o700); err != nil { |
| 21 | t.Fatal(err) |
| 22 | } |
| 23 | if err := os.WriteFile(filepath.Join(dir, "f"), []byte("bytes"), 0o600); err != nil { |
| 24 | t.Fatal(err) |
| 25 | } |
| 26 | return dir |
| 27 | } |
| 28 | open := func(t *testing.T, dir, name string) (string, bool, error) { |
| 29 | t.Helper() |
| 30 | type res struct { |
| 31 | b string |
| 32 | absent bool |
| 33 | err error |
| 34 | } |
| 35 | done := make(chan res, 1) |
| 36 | go func() { |
| 37 | f, absent, err := OpenBeneathOrAbsent(dir, name) |
| 38 | var b []byte |
| 39 | if f != nil { |
| 40 | b, _ = readLimit(f, name, 1<<10) |
| 41 | f.Close() |
| 42 | } |
| 43 | done <- res{string(b), absent, err} |
| 44 | }() |
| 45 | select { |
| 46 | case r := <-done: |
| 47 | return r.b, r.absent, r.err |
| 48 | case <-time.After(20 * time.Second): |
| 49 | t.Fatal("OpenBeneathOrAbsent blocked") |
| 50 | return "", false, nil |
| 51 | } |
| 52 | } |
| 53 | t.Run("present", func(t *testing.T) { |
| 54 | if b, absent, err := open(t, setup(t), "f"); err != nil || absent || b != "bytes" { |
| 55 | t.Fatalf("got %q absent=%v %v", b, absent, err) |
| 56 | } |
| 57 | }) |
| 58 | t.Run("absent beneath a directory that opened", func(t *testing.T) { |
| 59 | if _, absent, err := open(t, setup(t), "g"); err != nil || !absent { |
| 60 | t.Fatalf("absent=%v %v", absent, err) |
| 61 | } |
| 62 | }) |
| 63 | t.Run("a missing directory is an error", func(t *testing.T) { |
| 64 | _, absent, err := open(t, filepath.Join(t.TempDir(), "gone"), "f") |
| 65 | if absent || !errors.Is(err, ErrDirUnopened) || !errors.Is(err, os.ErrNotExist) { |
| 66 | t.Fatalf("absent=%v %v", absent, err) |
| 67 | } |
| 68 | }) |
| 69 | t.Run("a symlinked directory is an error", func(t *testing.T) { |
| 70 | dir := setup(t) |
| 71 | if err := os.Symlink(dir, dir+".link"); err != nil { |
| 72 | t.Fatal(err) |
| 73 | } |
| 74 | _, absent, err := open(t, dir+".link", "f") |
| 75 | if absent || !errors.Is(err, ErrDirUnopened) || !errors.Is(err, ErrSymlink) { |
| 76 | t.Fatalf("absent=%v %v", absent, err) |
| 77 | } |
| 78 | }) |
| 79 | t.Run("a symlink at the name is the name's, not the directory's", func(t *testing.T) { |
| 80 | dir := setup(t) |
| 81 | if err := os.Symlink(filepath.Join(dir, "f"), filepath.Join(dir, "l")); err != nil { |
| 82 | t.Fatal(err) |
| 83 | } |
| 84 | _, absent, err := open(t, dir, "l") |
| 85 | if absent || !errors.Is(err, ErrSymlink) || errors.Is(err, ErrDirUnopened) { |
| 86 | t.Fatalf("absent=%v %v", absent, err) |
| 87 | } |
| 88 | }) |
| 89 | t.Run("a FIFO", func(t *testing.T) { |
| 90 | dir := setup(t) |
| 91 | if err := syscall.Mkfifo(filepath.Join(dir, "p"), 0o600); err != nil { |
| 92 | t.Fatal(err) |
| 93 | } |
| 94 | if _, absent, err := open(t, dir, "p"); absent || !errors.Is(err, ErrNotRegular) { |
| 95 | t.Fatalf("absent=%v %v", absent, err) |
| 96 | } |
| 97 | }) |
| 98 | // Astra P2: the directory renamed away after it was opened, and an |
| 99 | // empty one put at its path, is still the directory looked in. A |
| 100 | // lookup that reopened the path would read the file as absent. |
| 101 | t.Run("a directory renamed away after the open", func(t *testing.T) { |
| 102 | dir := setup(t) |
| 103 | prev := betweenDirAndLookup |
| 104 | betweenDirAndLookup = func() { |
| 105 | if err := os.Rename(dir, dir+".away"); err != nil { |
| 106 | t.Error(err) |
| 107 | } |
| 108 | if err := os.Mkdir(dir, 0o700); err != nil { |
| 109 | t.Error(err) |
| 110 | } |
| 111 | } |
| 112 | t.Cleanup(func() { betweenDirAndLookup = prev }) |
| 113 | if b, absent, err := open(t, dir, "f"); err != nil || absent || b != "bytes" { |
| 114 | t.Fatalf("got %q absent=%v %v; want the file the opened directory holds", b, absent, err) |
| 115 | } |
| 116 | }) |
| 117 | } |
| 118 | |
| 119 | // Opus M3: without /proc, OpenRootBeneath is an error, never a fallback to |
| 120 | // opening the path. |
| 121 | func TestOpenRootBeneathWithoutProcIsAnError(t *testing.T) { |
| 122 | parent := t.TempDir() |
| 123 | if err := os.Mkdir(filepath.Join(parent, "d"), 0o700); err != nil { |
| 124 | t.Fatal(err) |
| 125 | } |
| 126 | prev := procSelfFD |
| 127 | procSelfFD = filepath.Join(t.TempDir(), "no-proc") + "/" |
| 128 | t.Cleanup(func() { procSelfFD = prev }) |
| 129 | r, err := OpenRootBeneath(parent, "d") |
| 130 | if err == nil || r != nil { |
| 131 | if r != nil { |
| 132 | r.Close() |
| 133 | } |
| 134 | t.Fatalf("OpenRootBeneath without /proc: root %v, %v; want an error", r != nil, err) |
| 135 | } |
| 136 | } |
| 137 | |
amadan