hsmd: fix missing status messages.

I crashed the HSMD, and it gave no output at all.  That's because we
were only reading the status fd when we were waiting for a reply.

Fix this by using a separate request fd and status fd, which also means
that hsm_sync_read() is no longer required.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

hsmd/hsm.c

@@ -41,6 +41,8 @@
 #include <wire/gen_peer_wire.h>
 #include <wire/wire_io.h>
 
+#define REQ_FD 3
+
 /* Nobody will ever find it here! */
 static struct {
 	struct secret hsm_secret;
@@ -856,15 +858,14 @@ int main(int argc, char *argv[])
 	struct client *client;
 
 	subdaemon_setup(argc, argv);
+	status_setup_sync(STDIN_FILENO);
 
-	client = new_client(NULL, NULL, 0, HSM_CAP_MASTER | HSM_CAP_SIGN_GOSSIP, handle_client, STDIN_FILENO);
+	client = new_client(NULL, NULL, 0, HSM_CAP_MASTER | HSM_CAP_SIGN_GOSSIP, handle_client, REQ_FD);
 
 	/* We're our own master! */
 	client->master = &client->dc;
 	io_set_finish(client->dc.conn, master_gone, &client->dc);
 
-	status_setup_async(&client->dc);
-
 	/* When conn closes, everything is freed. */
 	tal_steal(client->dc.conn, client);
 	io_loop(NULL, NULL);

lightningd/gossip_control.c

@@ -215,7 +215,7 @@ void gossip_init(struct lightningd *ld)
 	if (!wire_sync_write(ld->hsm_fd, msg))
 		fatal("Could not write to HSM: %s", strerror(errno));
 
-	msg = hsm_sync_read(tmpctx, ld);
+	msg = wire_sync_read(tmpctx, ld->hsm_fd);
 	if (!fromwire_hsm_client_hsmfd_reply(msg))
 		fatal("Malformed hsmfd response: %s", tal_hex(msg, msg));
 

lightningd/hsm_control.c

@@ -14,23 +14,11 @@
 #include <lightningd/log.h>
 #include <lightningd/log_status.h>
 #include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
 #include <wally_bip32.h>
 #include <wire/wire_sync.h>
 
-u8 *hsm_sync_read(const tal_t *ctx, struct lightningd *ld)
-{
-	for (;;) {
-		u8 *msg = wire_sync_read(ctx, ld->hsm_fd);
-
-		if (!msg)
-			fatal("Could not read from HSM: %s", strerror(errno));
-		if (log_status_msg(ld->log, msg))
-			tal_free(msg);
-		else
-			return msg;
-	}
-}
-
 int hsm_get_client_fd(struct lightningd *ld,
 		      const struct pubkey *id,
 		      u64 dbid,
@@ -44,7 +32,7 @@ int hsm_get_client_fd(struct lightningd *ld,
 	if (!wire_sync_write(ld->hsm_fd, take(msg)))
 		fatal("Could not write to HSM: %s", strerror(errno));
 
-	msg = hsm_sync_read(tmpctx, ld);
+	msg = wire_sync_read(tmpctx, ld->hsm_fd);
 	if (!fromwire_hsm_client_hsmfd_reply(msg))
 		fatal("Bad reply from HSM: %s", tal_hex(tmpctx, msg));
 
@@ -57,17 +45,23 @@ int hsm_get_client_fd(struct lightningd *ld,
 void hsm_init(struct lightningd *ld)
 {
 	u8 *msg;
+	int fds[2];
 
-	ld->hsm_fd = subd_raw(ld, "lightning_hsmd");
-	if (ld->hsm_fd < 0)
+	/* We actually send requests synchronously: only status is async. */
+	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, fds) != 0)
+		err(1, "Could not create hsm socketpair");
+
+	ld->hsm = new_global_subd(ld, "lightning_hsmd", NULL, NULL,
+				  take(&fds[1]), NULL);
+	if (!ld->hsm)
 		err(1, "Could not subd hsm");
 
-	ld->hsm_log = new_log(ld, ld->log_book, "hsmd:");
+	ld->hsm_fd = fds[0];
 	if (!wire_sync_write(ld->hsm_fd, towire_hsm_init(tmpctx)))
 		err(1, "Writing init msg to hsm");
 
 	ld->wallet->bip32_base = tal(ld->wallet, struct ext_key);
-	msg = hsm_sync_read(tmpctx, ld);
+	msg = wire_sync_read(tmpctx, ld->hsm_fd);
 	if (!fromwire_hsm_init_reply(msg,
 					&ld->id,
 					&ld->peer_seed,

lightningd/hsm_control.h

@@ -15,6 +15,5 @@ int hsm_get_client_fd(struct lightningd *ld,
 		      u64 dbid,
 		      int capabilities);
 
-u8 *hsm_sync_read(const tal_t *ctx, struct lightningd *ld);
 void hsm_init(struct lightningd *ld);
 #endif /* LIGHTNING_LIGHTNINGD_HSM_CONTROL_H */

lightningd/invoice.c

@@ -93,17 +93,16 @@ static bool hsm_sign_b11(const u5 *u5bytes,
 			 secp256k1_ecdsa_recoverable_signature *rsig,
 			 struct lightningd *ld)
 {
-	u8 *msg = towire_hsm_sign_invoice(ld, u5bytes, hrpu8);
+	u8 *msg = towire_hsm_sign_invoice(NULL, u5bytes, hrpu8);
 
 	if (!wire_sync_write(ld->hsm_fd, take(msg)))
 		fatal("Could not write to HSM: %s", strerror(errno));
 
-	msg = hsm_sync_read(ld, ld);
+	msg = wire_sync_read(tmpctx, ld->hsm_fd);
         if (!fromwire_hsm_sign_invoice_reply(msg, rsig))
 		fatal("HSM gave bad sign_invoice_reply %s",
 		      tal_hex(msg, msg));
 
-	tal_free(msg);
 	return true;
 }
 

lightningd/lightningd.c

@@ -207,6 +207,7 @@ static void shutdown_subdaemons(struct lightningd *ld)
 	/* Let everyone shutdown cleanly. */
 	close(ld->hsm_fd);
 	subd_shutdown(ld->gossip, 10);
+	subd_shutdown(ld->hsm, 10);
 
 	free_htlcs(ld, NULL);
 

lightningd/lightningd.h

@@ -124,7 +124,7 @@ struct lightningd {
 
 	/* Bearer of all my secrets. */
 	int hsm_fd;
-	struct log *hsm_log;
+	struct subd *hsm;
 
 	/* Daemon looking after peers during init / before channel. */
 	struct subd *gossip;

lightningd/opening_control.c

@@ -398,7 +398,7 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 	if (!wire_sync_write(ld->hsm_fd, take(msg)))
 		fatal("Could not write to HSM: %s", strerror(errno));
 
-	msg = hsm_sync_read(fc, ld);
+	msg = wire_sync_read(fc, ld->hsm_fd);
 	if (!fromwire_hsm_sign_funding_reply(tmpctx, msg, &fundingtx))
 		fatal("HSM gave bad sign_funding_reply %s",
 		      tal_hex(msg, resp));

lightningd/subd.c

@@ -180,7 +180,6 @@ static int subd(const char *dir, const char *name,
 		}
 
 		/* Dup any extra fds up first. */
-		if (ap) {
 		while ((fd = va_arg(*ap, int *)) != NULL) {
 			int actual_fd = *fd;
 			/* If this were stdin, we moved it above! */
@@ -190,7 +189,6 @@ static int subd(const char *dir, const char *name,
 				goto child_errno_fail;
 			fdnum++;
 		}
-		}
 
 		/* Make (fairly!) sure all other fds are closed. */
 		max = sysconf(_SC_OPEN_MAX);
@@ -246,30 +244,6 @@ fail:
 	return -1;
 }
 
-int subd_raw(struct lightningd *ld, const char *name)
-{
-	pid_t pid;
-	int msg_fd;
-	const char *debug_subd = NULL;
-	int disconnect_fd = -1;
-
-#if DEVELOPER
-	debug_subd = ld->dev_debug_subdaemon;
-	disconnect_fd = ld->dev_disconnect_fd;
-#endif /* DEVELOPER */
-
-	pid = subd(ld->daemon_dir, name, debug_subd,
-		   &msg_fd, disconnect_fd,
-		   NULL);
-	if (pid == (pid_t)-1) {
-		log_unusual(ld->log, "subd %s failed: %s",
-			    name, strerror(errno));
-		return -1;
-	}
-
-	return msg_fd;
-}
-
 static struct io_plan *sd_msg_read(struct io_conn *conn, struct subd *sd);
 
 static void mark_freed(struct subd *unused UNUSED, bool *freed)

lightningd/subd.h

@@ -139,12 +139,6 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 					       (channel), bool,		\
 					       const char *),		\
 			  __VA_ARGS__)
-/**
- * subd_raw - raw interface to get a subdaemon on an fd (for HSM)
- * @ld: global state
- * @name: basename of daemon
- */
-int subd_raw(struct lightningd *ld, const char *name);
 
 /**
  * subd_send_msg - queue a message to the subdaemon.

wallet/walletrpc.c

@@ -138,7 +138,7 @@ static void json_withdraw(struct command *cmd,
 		fatal("Could not write sign_withdrawal to HSM: %s",
 		      strerror(errno));
 
-	msg = hsm_sync_read(cmd, cmd->ld);
+	msg = wire_sync_read(cmd, cmd->ld->hsm_fd);
 
 	if (!fromwire_hsm_sign_withdrawal_reply(msg, msg, &tx))
 		fatal("HSM gave bad sign_withdrawal_reply %s",