| 1 | package cgroup |
| 2 | |
| 3 | import ( |
| 4 | "errors" |
| 5 | "os" |
| 6 | "os/exec" |
| 7 | "path/filepath" |
| 8 | "strconv" |
| 9 | "testing" |
| 10 | ) |
| 11 | |
| 12 | // writeProcs makes dir a fixture cgroup listing pids. |
| 13 | func writeProcs(t *testing.T, dir string, pids ...int) { |
| 14 | t.Helper() |
| 15 | if err := os.MkdirAll(dir, 0o755); err != nil { |
| 16 | t.Fatal(err) |
| 17 | } |
| 18 | body := "" |
| 19 | for _, p := range pids { |
| 20 | body += strconv.Itoa(p) + "\n" |
| 21 | } |
| 22 | if err := os.WriteFile(filepath.Join(dir, "cgroup.procs"), []byte(body), 0o644); err != nil { |
| 23 | t.Fatal(err) |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | // HostProcs over a fixture cgroupfs: the exec group and every group below |
| 28 | // it count, and so does the unit's group; absent groups count 0; another |
| 29 | // host's group never counts. |
| 30 | func TestHostProcsCountsTheHostsGroupsOnly(t *testing.T) { |
| 31 | root := t.TempDir() |
| 32 | const host = "shop.example.com" |
| 33 | if n, err := HostProcs(root, host, ""); err != nil || n != 0 { |
| 34 | t.Fatalf("no group: (%d, %v), want (0, nil)", n, err) |
| 35 | } |
| 36 | writeProcs(t, filepath.Join(root, ExecName(host))) |
| 37 | if n, err := HostProcs(root, host, ""); err != nil || n != 0 { |
| 38 | t.Fatalf("an empty group: (%d, %v), want (0, nil)", n, err) |
| 39 | } |
| 40 | writeProcs(t, filepath.Join(root, ExecName(host)), 101) |
| 41 | writeProcs(t, filepath.Join(root, ExecName(host), "sidecar"), 102, 103) |
| 42 | writeProcs(t, filepath.Join(root, ExecName("other.example.com")), 201, 202, 203) |
| 43 | if n, err := HostProcs(root, host, ""); err != nil || n != 3 { |
| 44 | t.Fatalf("exec group and child: (%d, %v), want (3, nil)", n, err) |
| 45 | } |
| 46 | slice := filepath.Join(t.TempDir(), "carlos.slice", "carlos-instances.slice", "carlos-instances-shop.slice") |
| 47 | if n, err := HostProcs(root, host, slice); err != nil || n != 3 { |
| 48 | t.Fatalf("an absent unit group: (%d, %v), want (3, nil)", n, err) |
| 49 | } |
| 50 | writeProcs(t, filepath.Join(slice, "carlos-instance@shop.service"), 301) |
| 51 | if n, err := HostProcs(root, host, slice); err != nil || n != 4 { |
| 52 | t.Fatalf("with the unit's group: (%d, %v), want (4, nil)", n, err) |
| 53 | } |
| 54 | if _, err := HostProcs(root, host, "relative/slice"); err == nil { |
| 55 | t.Fatal("a relative unit path was read") |
| 56 | } |
| 57 | for _, bad := range []string{"", "..", "a/b"} { |
| 58 | if _, err := HostProcs(root, bad, ""); err == nil { |
| 59 | t.Fatalf("host %q was read", bad) |
| 60 | } |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | // Without a delegated subtree the exec children cannot be told apart from |
| 65 | // the agent's own processes: unknown, never 0. |
| 66 | func TestHostProcsWithoutDelegationIsUnknown(t *testing.T) { |
| 67 | if _, err := HostProcs("", "shop.example.com", ""); !errors.Is(err, ErrUnknown) { |
| 68 | t.Fatalf("no root: %v, want ErrUnknown", err) |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | // A real process in a real cgroup, where the kernel lets this test make one: |
| 73 | // a child group of the test's own cgroup, with a sleep moved into it. Where |
| 74 | // the cgroup is not writable (the usual case outside a delegated unit) the |
| 75 | // fixture test above is the witness. |
| 76 | func TestHostProcsSeesARealProcess(t *testing.T) { |
| 77 | b, err := os.ReadFile("/proc/self/cgroup") |
| 78 | if err != nil { |
| 79 | t.Skipf("no /proc/self/cgroup: %v", err) |
| 80 | } |
| 81 | rel, ok := ParseSelfCgroup(string(b)) |
| 82 | if !ok { |
| 83 | t.Skip("no cgroup v2 path") |
| 84 | } |
| 85 | parent := filepath.Join("/sys/fs/cgroup", rel) |
| 86 | root := filepath.Join(parent, "hostprocs-test-"+strconv.Itoa(os.Getpid())) |
| 87 | const host = "shop.example.com" |
| 88 | group := filepath.Join(root, ExecName(host)) |
| 89 | if err := os.MkdirAll(group, 0o755); err != nil { |
| 90 | t.Skipf("this cgroup is not writable: %v", err) |
| 91 | } |
| 92 | t.Cleanup(func() { |
| 93 | _ = os.Remove(group) |
| 94 | _ = os.Remove(root) |
| 95 | }) |
| 96 | cmd := exec.Command("sleep", "30") |
| 97 | if err := cmd.Start(); err != nil { |
| 98 | t.Skipf("no sleep: %v", err) |
| 99 | } |
| 100 | t.Cleanup(func() { |
| 101 | _ = cmd.Process.Kill() |
| 102 | _ = cmd.Wait() |
| 103 | }) |
| 104 | if err := os.WriteFile(filepath.Join(group, "cgroup.procs"), []byte(strconv.Itoa(cmd.Process.Pid)), 0o644); err != nil { |
| 105 | t.Skipf("the kernel refused the move: %v", err) |
| 106 | } |
| 107 | if n, err := HostProcs(root, host, ""); err != nil || n != 1 { |
| 108 | t.Fatalf("a sleep in the host's group: (%d, %v), want (1, nil)", n, err) |
| 109 | } |
| 110 | _ = cmd.Process.Kill() |
| 111 | _ = cmd.Wait() |
| 112 | if n, err := HostProcs(root, host, ""); err != nil || n != 0 { |
| 113 | t.Fatalf("after the sleep exited: (%d, %v), want (0, nil)", n, err) |
| 114 | } |
| 115 | } |
| 116 | |
amadan