| 1 | package host |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "context" |
| 6 | "os" |
| 7 | "path" |
| 8 | "strings" |
| 9 | |
| 10 | "github.com/carlosframework/platform/internal/instancectl" |
| 11 | "github.com/carlosframework/platform/internal/rootstate" |
| 12 | ) |
| 13 | |
| 14 | type claimUnitPredecessor struct { |
| 15 | Unit, Invocation, Group string |
| 16 | Boot string `json:",omitempty"` |
| 17 | GroupIdentity rootstate.FileIdentity |
| 18 | } |
| 19 | |
| 20 | type claimUnitMigration struct { |
| 21 | Definition rootstate.FileIdentity |
| 22 | Digest string |
| 23 | Predecessor claimUnitPredecessor |
| 24 | Socket claimUnitSocketIdentity `json:",omitempty"` |
| 25 | } |
| 26 | |
| 27 | type claimUnitSocketIdentity struct { |
| 28 | Boot string |
| 29 | Device, Inode uint64 |
| 30 | UID, GID, Mode uint32 |
| 31 | } |
| 32 | |
| 33 | func (p claimUnitPredecessor) valid(unit string) bool { |
| 34 | return p.Unit == unit && instancectl.ValidBoundClaimUnit(unit) && p.Invocation != "" && claimPredecessorPlacement(unit, p.Group) && p.GroupIdentity != (rootstate.FileIdentity{}) |
| 35 | } |
| 36 | |
| 37 | func (r claimUnitMigration) valid(b claimUnitBinding) bool { |
| 38 | return r.Definition != (rootstate.FileIdentity{}) && claimHexDigest(r.Digest) && r.Digest == b.Shape.PredecessorDigest && r.Predecessor.valid(b.Shape.Unit) |
| 39 | } |
| 40 | |
| 41 | // The materialization lock and root host lock cover capture through replacement. |
| 42 | // Only the root configuration's exact digest admits an operator definition. |
| 43 | func (m claimUnitMaterializer) migration(ctx context.Context, b claimUnitBinding, raw []byte, id rootstate.FileIdentity) (*claimUnitMigration, error) { |
| 44 | if !claimHexDigest(b.Shape.PredecessorDigest) || claimUnitDigest(raw) != b.Shape.PredecessorDigest || id == (rootstate.FileIdentity{}) || m.predecessor == nil || m.stopPredecessor == nil || m.replace == nil { |
| 45 | return nil, os.ErrPermission |
| 46 | } |
| 47 | p, err := m.predecessor(ctx, b) |
| 48 | if err != nil { |
| 49 | return nil, err |
| 50 | } |
| 51 | r := &claimUnitMigration{Definition: id, Digest: claimUnitDigest(raw), Predecessor: p} |
| 52 | if claimFlatSocket(b.Shape) { |
| 53 | if m.socketCapture == nil || m.socketPark == nil { |
| 54 | return nil, os.ErrPermission |
| 55 | } |
| 56 | r.Socket, err = m.socketCapture(ctx, b.Shape, p) |
| 57 | if err != nil { |
| 58 | return nil, err |
| 59 | } |
| 60 | } |
| 61 | if !r.valid(b) { |
| 62 | return nil, os.ErrPermission |
| 63 | } |
| 64 | return r, nil |
| 65 | } |
| 66 | |
| 67 | func (m claimUnitMaterializer) finishMigration(ctx context.Context, r claimUnitMaterialization, want []byte) error { |
| 68 | if r.Migration == nil || !r.Migration.valid(r.Binding) || m.stopPredecessor == nil || m.replace == nil { |
| 69 | return os.ErrPermission |
| 70 | } |
| 71 | raw, id, err := m.read(r.Binding.Shape.Unit) |
| 72 | if err != nil { |
| 73 | return err |
| 74 | } |
| 75 | if id.Same(r.Migration.Definition) && claimUnitDigest(raw) == r.Migration.Digest { |
| 76 | if err = m.stopPredecessor(ctx, r.Migration.Predecessor); err != nil { |
| 77 | return err |
| 78 | } |
| 79 | if err = m.idle(r.Binding.Shape.Host); err != nil { |
| 80 | return err |
| 81 | } |
| 82 | if err = m.finishSocketMigration(r); err != nil { |
| 83 | return err |
| 84 | } |
| 85 | if err = m.replace(r.Binding.Shape.Unit, id, want); err != nil { |
| 86 | return err |
| 87 | } |
| 88 | raw, id, err = m.read(r.Binding.Shape.Unit) |
| 89 | if err != nil { |
| 90 | return err |
| 91 | } |
| 92 | } else if !bytes.Equal(raw, want) { |
| 93 | return os.ErrPermission |
| 94 | } |
| 95 | if !bytes.Equal(raw, want) || id == (rootstate.FileIdentity{}) { |
| 96 | return os.ErrPermission |
| 97 | } |
| 98 | // A crash after rename still has to prove the predecessor gone. The durable |
| 99 | // definition refuses execution until a later root reservation opens its gate. |
| 100 | if err = m.stopPredecessor(ctx, r.Migration.Predecessor); err != nil { |
| 101 | return err |
| 102 | } |
| 103 | if err = m.idle(r.Binding.Shape.Host); err != nil { |
| 104 | return err |
| 105 | } |
| 106 | if err = m.finishSocketMigration(r); err != nil { |
| 107 | return err |
| 108 | } |
| 109 | r.Identity = id |
| 110 | return m.save(r) |
| 111 | } |
| 112 | |
| 113 | func (m claimUnitMaterializer) finishSocketMigration(r claimUnitMaterialization) error { |
| 114 | if !claimFlatSocket(r.Binding.Shape) { |
| 115 | return nil |
| 116 | } |
| 117 | if r.Migration == nil || r.Migration.Socket.Boot == "" || m.socketPark == nil { |
| 118 | return os.ErrPermission |
| 119 | } |
| 120 | return m.socketPark(r.Binding, r.Migration.Socket) |
| 121 | } |
| 122 | |
| 123 | func claimPredecessorPlacement(unit, group string) bool { |
| 124 | if !instancectl.ValidBoundClaimUnit(unit) { |
| 125 | return false |
| 126 | } |
| 127 | if group == "system.slice/"+unit { |
| 128 | return true |
| 129 | } |
| 130 | prefix, _, template := strings.Cut(unit, "@") |
| 131 | return template && prefix != "" && group == path.Join("system.slice", "system-"+instancectl.Escape(prefix)+".slice", unit) |
| 132 | } |
| 133 | |
amadan