Add get genesis api endpoint

api/api.go

@@ -60,6 +60,7 @@ type FullNode interface {
 	ChainGetTipSetByHeight(context.Context, uint64, *types.TipSet) (*types.TipSet, error)
 	ChainReadObj(context.Context, cid.Cid) ([]byte, error)
 	ChainSetHead(context.Context, *types.TipSet) error
+	ChainGetGenesis(context.Context) (*types.TipSet, error)
 
 	// syncer
 	SyncState(context.Context) (*SyncState, error)

api/struct.go

@@ -48,6 +48,7 @@ type FullNodeStruct struct {
 		ChainGetTipSetByHeight func(context.Context, uint64, *types.TipSet) (*types.TipSet, error)        `perm:"read"`
 		ChainReadObj           func(context.Context, cid.Cid) ([]byte, error)                             `perm:"read"`
 		ChainSetHead           func(context.Context, *types.TipSet) error                                 `perm:"admin"`
+		ChainGetGenesis        func(context.Context) (*types.TipSet, error)                               `perm:"read"`
 
 		SyncState func(context.Context) (*SyncState, error) `perm:"read"`
 
@@ -308,6 +309,10 @@ func (c *FullNodeStruct) ChainSetHead(ctx context.Context, ts *types.TipSet) err
 	return c.Internal.ChainSetHead(ctx, ts)
 }
 
+func (c *FullNodeStruct) ChainGetGenesis(ctx context.Context) (*types.TipSet, error) {
+	return c.Internal.ChainGetGenesis(ctx)
+}
+
 func (c *FullNodeStruct) SyncState(ctx context.Context) (*SyncState, error) {
 	return c.Internal.SyncState(ctx)
 }

cli/chain.go

@@ -210,6 +210,12 @@ var chainGetMsgCmd = &cli.Command{
 var chainSetHeadCmd = &cli.Command{
 	Name:  "sethead",
 	Usage: "manually set the local nodes head tipset (Caution: normally only used for recovery)",
+	Flags: []cli.Flag{
+		&cli.BoolFlag{
+			Name:  "genesis",
+			Usage: "reset head to genesis",
+		},
+	},
 	Action: func(cctx *cli.Context) error {
 		api, closer, err := GetFullNodeAPI(cctx)
 		if err != nil {
@@ -218,13 +224,25 @@ var chainSetHeadCmd = &cli.Command{
 		defer closer()
 		ctx := ReqContext(cctx)
 
-		if !cctx.Args().Present() {
+		gen := cctx.Bool("genesis")
+
+		if !cctx.Args().Present() && !gen {
 			return fmt.Errorf("must pass cids for tipset to set as head")
 		}
 
-		ts, err := parseTipSet(api, ctx, cctx.Args().Slice())
-		if err != nil {
-			return err
+		var ts *types.TipSet
+		if gen {
+			gents, err := api.ChainGetGenesis(ctx)
+			if err != nil {
+				return err
+			}
+			ts = gents
+		} else {
+			parsedts, err := parseTipSet(api, ctx, cctx.Args().Slice())
+			if err != nil {
+				return err
+			}
+			ts = parsedts
 		}
 
 		if err := api.ChainSetHead(ctx, ts); err != nil {

node/impl/full/chain.go

@@ -161,3 +161,12 @@ func (a *ChainAPI) ChainReadObj(ctx context.Context, obj cid.Cid) ([]byte, error
 func (a *ChainAPI) ChainSetHead(ctx context.Context, ts *types.TipSet) error {
 	return a.Chain.SetHead(ts)
 }
+
+func (a *ChainAPI) ChainGetGenesis(ctx context.Context) (*types.TipSet, error) {
+	genb, err := a.Chain.GetGenesis()
+	if err != nil {
+		return nil, err
+	}
+
+	return types.NewTipSet([]*types.BlockHeader{genb})
+}