bitcoind: explicit flag to bitcoin-cli for testnet/regtest.

Three days of on and off debugging, before I realized my server was talking
to a non-testnet bitcoind.  There was a bitcoind on that machine running
on testnet, but it uses the same dir and config, so the --bitcoin-datadir
option couldn't help.

This is more certain: specify whether we're testnet on every single query.
Now we can skip the attempt to parse bitcoin.conf, too.

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

daemon/bitcoind.c

@@ -24,13 +24,17 @@
 
 char *bitcoin_datadir;
 
-static char **gather_args(const tal_t *ctx, const char *cmd, va_list ap)
+static char **gather_args(struct lightningd_state *dstate,
+			  const tal_t *ctx, const char *cmd, va_list ap)
 {
 	size_t n = 0;
-	char **args = tal_arr(ctx, char *, 1);
+	char **args = tal_arr(ctx, char *, 3);
 
 	args[n++] = BITCOIN_CLI;
-	tal_resize(&args, n + 1);
+	if (dstate->config.regtest)
+		args[n++] = "-regtest=1";
+	else
+		args[n++] = tal_fmt(args, "-testnet=%u", dstate->config.testnet);
 	if (bitcoin_datadir) {
 		args[n++] = tal_fmt(args, "-datadir=%s", bitcoin_datadir);
 		tal_resize(&args, n + 1);
@@ -169,7 +173,7 @@ start_bitcoin_cli(struct lightningd_state *dstate,
 	else
 		bcli->exitstatus = NULL;
 	va_start(ap, cmd);
-	bcli->args = gather_args(bcli, cmd, ap);
+	bcli->args = gather_args(dstate, bcli, cmd, ap);
 	va_end(ap);
 
 	list_add_tail(&dstate->bitcoin_req, &bcli->list);
@@ -430,45 +434,3 @@ void bitcoind_getblockhash_(struct lightningd_state *dstate,
 	start_bitcoin_cli(dstate, process_getblockhash, false, cb, arg,
 			  "getblockhash", str, NULL);
 }
-
-/* Make testnet/regtest status matches us. */
-void check_bitcoind_config(struct lightningd_state *dstate)
-{
-	void *ctx = tal(dstate, char);
-	char *path, *config, **lines;
-	size_t i;
-	int testnet = -1, regtest = -1;
-
-	path = path_simplify(ctx, path_join(ctx, path_cwd(ctx),
-					    "../.bitcoin/bitcoin.conf"));
-	config = grab_file(ctx, path);
-	if (!config) {
-		log_unusual(dstate->base_log, "Could not open %s to check it",
-			    path);
-		goto out;
-	}
-
-	lines = tal_strsplit(ctx, config, "\n", STR_NO_EMPTY);
-	for (i = 0; lines[i]; i++) {
-		char *str;
-		if (tal_strreg(ctx, lines[i],
-				    "^[ \t]*testnet[ \t]*=[ \t]*([01])", &str))
-			testnet = atoi(str);
-		else if (tal_strreg(ctx, lines[i],
-				    "^[ \t]*regtest[ \t]*=[ \t]*([01])", &str))
-			regtest = atoi(str);
-	}
-
-	if (dstate->config.testnet) {
-		if (testnet != 1 && regtest != 1)
-			log_unusual(dstate->base_log,
-				    "%s does not set testnet/regtest,"
-				    " but we are on testnet.",
-				    path);
-	} else if (testnet == 1 || regtest == 1)
-		log_unusual(dstate->base_log,
-			    "%s sets %s, but we are not on testnet",
-			    path, testnet == 1 ? "testnet" : "regtest");
-out:
-	tal_free(ctx);
-}

daemon/bitcoind.h

@@ -97,6 +97,4 @@ void bitcoind_getrawblock_(struct lightningd_state *dstate,
 						  struct lightningd_state *, \
 						  struct bitcoin_block *), \
 			      (arg))
-
-void check_bitcoind_config(struct lightningd_state *dstate);
 #endif /* LIGHTNING_DAEMON_BITCOIND_H */

daemon/lightningd.c

@@ -94,6 +94,9 @@ static void opt_show_s32(char buf[OPT_SHOW_LEN], const s32 *u)
 
 static void config_register_opts(struct lightningd_state *dstate)
 {
+	opt_register_noarg("--bitcoind-regtest", opt_set_bool,
+			   &dstate->config.regtest,
+			   "Bitcoind is in regtest mode");
 	opt_register_arg("--locktime-blocks", opt_set_u32, opt_show_u32,
 			 &dstate->config.locktime_blocks,
 			 "Blocks before peer can unilaterally spend funds");
@@ -162,6 +165,7 @@ static void default_config(struct config *config)
 {
 	/* aka. "Dude, where's my coins?" */
 	config->testnet = true;
+	config->regtest = false;
 
 	/* ~one day to catch cheating attempts. */
 	config->locktime_blocks = 6 * 24;
@@ -353,8 +357,6 @@ int main(int argc, char *argv[])
 
 	check_config(dstate);
 	
-	check_bitcoind_config(dstate);
-
 	/* Set up node ID and private key. */
 	secrets_init(dstate);
 	new_node(dstate, &dstate->id);

daemon/lightningd.h

@@ -11,8 +11,8 @@
 
 /* Various adjustable things. */
 struct config {
-	/* Are we on testnet? */
+	/* Are we on testnet? regtest?*/
-	bool testnet;
+	bool testnet, regtest;
 
 	/* How long do we want them to lock up their funds? (blocks) */
 	u32 locktime_blocks;

daemon/test/test.sh

@@ -366,6 +366,7 @@ fi
 cat > $DIR1/config <<EOF
 disable-irc
 log-level=debug
+bitcoind-regtest
 bitcoind-poll=1s
 deadline-blocks=5
 min-htlc-expiry=6
@@ -376,6 +377,7 @@ EOF
 
 cat > $DIR2/config <<EOF
 disable-irc
+bitcoind-regtest
 log-level=debug
 bitcoind-poll=1s
 deadline-blocks=5