fdctl: add get-identity command to retrieve runtime validator identity

Add new fdctl command to query the current runtime identity of a running
validator. This command reads the identity from the GUI tile's shared
memory, which reflects any changes made by set-identity.

The command requires GUI to be enabled, as it's the most reliable source
for the current runtime identity that persists across identity switches.

Usage: fdctl get-identity

Returns the validator's current identity public key in base58 format.

Author: huiskylabs

src/app/fdctl/main.c

@@ -92,6 +92,7 @@ extern action_t fd_action_ready;
 extern action_t fd_action_mem;
 extern action_t fd_action_netconf;
 extern action_t fd_action_set_identity;
+extern action_t fd_action_get_identity;
 extern action_t fd_action_help;
 extern action_t fd_action_version;
 
@@ -106,6 +107,7 @@ action_t * ACTIONS[] = {
   &fd_action_mem,
   &fd_action_netconf,
   &fd_action_set_identity,
+  &fd_action_get_identity,
   &fd_action_help,
   &fd_action_version,
   NULL,

src/app/shared/Local.mk

@@ -18,6 +18,7 @@ $(call add-objs,commands/mem,fdctl_shared)
 $(call add-objs,commands/netconf,fdctl_shared)
 $(call add-objs,commands/ready,fdctl_shared)
 $(call add-objs,commands/set_identity,fdctl_shared)
+$(call add-objs,commands/get_identity,fdctl_shared)
 $(call add-objs,commands/version,fdctl_shared)
 $(call add-objs,commands/configure/configure,fdctl_shared)
 $(call add-objs,commands/configure/ethtool-channels,fdctl_shared)

src/app/shared/commands/get_identity.c

@@ -0,0 +1,66 @@
+#include "../fd_config.h"
+#include "../fd_action.h"
+#include "../../../util/fd_util.h"
+#include "../../../ballet/base58/fd_base58.h"
+#include "../../../flamenco/types/fd_types_custom.h"
+#include "../../../disco/shred/fd_shred_tile.h"
+#include <unistd.h>
+
+void
+get_identity_cmd_fn( args_t *   args   FD_PARAM_UNUSED,
+                     config_t * config ) {
+  /* Find the shred tile which is always present and has the current runtime identity */
+  ulong shred_tile_idx = fd_topo_find_tile( &config->topo, "shred", 0UL );
+  if( FD_UNLIKELY( shred_tile_idx==ULONG_MAX ) ) {
+    FD_LOG_ERR(( "Shred tile not found in topology" ));
+  }
+
+  fd_topo_tile_t const * shred_tile = &config->topo.tiles[ shred_tile_idx ];
+  
+  /* Access shred tile object to find its workspace */
+  if( FD_UNLIKELY( shred_tile->tile_obj_id==ULONG_MAX ) ) {
+    FD_LOG_ERR(( "Shred tile object not found" ));
+  }
+  
+  /* Find the workspace containing the shred tile object */
+  fd_topo_obj_t const * shred_obj = &config->topo.objs[ shred_tile->tile_obj_id ];
+  ulong shred_wksp_id = shred_obj->wksp_id;
+
+  /* Join the workspace in read-only mode */
+  fd_topo_join_workspace( &config->topo, &config->topo.workspaces[ shred_wksp_id ], FD_SHMEM_JOIN_MODE_READ_ONLY );
+  fd_topo_workspace_fill( &config->topo, &config->topo.workspaces[ shred_wksp_id ] );
+
+  /* Access the shred context through the workspace */
+  void * shred_mem = fd_topo_obj_laddr( &config->topo, shred_tile->tile_obj_id );
+  if( FD_UNLIKELY( !shred_mem ) ) {
+    fd_topo_leave_workspaces( &config->topo );
+    FD_LOG_ERR(( "Failed to access shred tile object" ));
+  }
+
+  /* Cast to shred context structure */
+  fd_shred_ctx_t const * shred_ctx = (fd_shred_ctx_t const *)shred_mem;
+  
+  /* The shred tile maintains the current identity in shred_ctx->identity_key.
+     TODO: There's a potential edge case where this could return a torn/corrupt
+     identity key if the shred tile is currently processing a set-identity command
+     and has only overwritten half of the bytes. This is exceedingly rare but
+     should be addressed in the future with proper synchronization. */
+  fd_pubkey_t const * identity_key = shred_ctx->identity_key;
+
+  /* Convert to base58 and print */
+  char identity_key_str[ FD_BASE58_ENCODED_32_SZ ];
+  fd_base58_encode_32( identity_key->uc, NULL, identity_key_str );
+  
+  FD_LOG_STDOUT(( "%s\n", identity_key_str ));
+}
+
+action_t fd_action_get_identity = {
+  .name           = "get-identity",
+  .args           = NULL,
+  .fn             = get_identity_cmd_fn,
+  .require_config = 1,
+  .perm           = NULL, /* TODO: This command may require RLIMIT_MLOCK permissions
+                             to mlock(2) the workspace in memory. This should be
+                             addressed in future updates. */
+  .description    = "Get the current active identity of the running validator",
+};

src/app/shared/commands/get_identity.h

@@ -0,0 +1,14 @@
+#ifndef HEADER_fd_src_app_shared_commands_get_identity_h
+#define HEADER_fd_src_app_shared_commands_get_identity_h
+
+#include "../fd_config.h"
+
+FD_PROTOTYPES_BEGIN
+
+void get_identity_cmd_fn( args_t * args, config_t * config );
+
+FD_PROTOTYPES_END
+
+extern action_t fd_action_get_identity;
+
+#endif /* HEADER_fd_src_app_shared_commands_get_identity_h */

src/disco/shred/fd_shred_tile.h

@@ -0,0 +1,35 @@
+#ifndef HEADER_fd_src_disco_shred_fd_shred_tile_h
+#define HEADER_fd_src_disco_shred_fd_shred_tile_h
+
+#include "../tiles.h"
+#include "../../flamenco/types/fd_types_custom.h"
+
+/* Forward declarations */
+typedef struct fd_shredder fd_shredder_t;
+typedef struct fd_fec_resolver fd_fec_resolver_t;
+typedef struct fd_keyswitch fd_keyswitch_t;
+typedef struct fd_keyguard_client fd_keyguard_client_t;
+
+/* Shred tile context structure */
+typedef struct {
+  fd_shredder_t      * shredder;
+  fd_fec_resolver_t  * resolver;
+  fd_pubkey_t          identity_key[1]; /* Just the public key */
+
+  ulong                round_robin_id;
+  ulong                round_robin_cnt;
+  /* Number of batches shredded from PoH during the current slot.
+     This should be the same for all the shred tiles. */
+  ulong                batch_cnt;
+  /* Slot of the most recent microblock we've seen from PoH,
+     or 0 if we haven't seen one yet */
+  ulong                slot;
+
+  fd_keyswitch_t *     keyswitch;
+  fd_keyguard_client_t keyguard_client[1];
+  /* ... rest of the structure members ... */
+} fd_shred_ctx_t;
+
+#endif /* HEADER_fd_src_disco_shred_fd_shred_tile_h */
+
+