lightningd: implement more show commands to reduce listconfigs special casing.

Note that this actually changes listconfigs output for three msat
fields, which were not changed with the great msat merge.  Since
listconfigs isn't actually used by grpc, and the values are always a
little vague, I simply changed this.

Changelog-Fixed: JSON-RPC: `listconfigs` `htlc-minimum-msat`, `htlc-maximum-msat` and `max-dust-htlc-exposure-msat` fields are now numbers, not strings.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/configdir.c

@@ -239,11 +239,6 @@ bool is_restricted_ignored(const void *fn)
 		|| fn == opt_restricted_forceconf_only;
 }
 
-bool is_restricted_print_if_nonnull(const void *fn)
-{
-	return fn == opt_restricted_cmdline;
-}
-
 void setup_option_allocators(void)
 {
 	/*~ These functions make ccan/opt use tal for allocations */
@@ -324,7 +319,9 @@ void initial_config_opts(const tal_t *ctx,
 
 	/* This is only ever valid on cmdline */
 	opt_register_early_arg("--conf=<file>",
-			       opt_restricted_cmdline, NULL,
+			       opt_restricted_cmdline,
+			       /* This doesn't show if NULL! */
+			       opt_show_charp,
 			       config_filename,
 			       "Specify configuration file");
 

lightningd/lightningd.h

@@ -262,7 +262,7 @@ struct lightningd {
 
 #if DEVELOPER
 	/* If we want to debug a subdaemon/plugin. */
-	const char *dev_debug_subprocess;
+	char *dev_debug_subprocess;
 
 	/* If we have --dev-no-plugin-checksum */
 	bool dev_no_plugin_checksum;

lightningd/options.c

@@ -464,6 +464,16 @@ static bool opt_show_mode(char *buf, size_t len, const mode_t *m)
 	return true;
 }
 
+static bool opt_show_rgb(char *buf, size_t len, const struct lightningd *ld)
+{
+	/* Can happen with -h! */
+	if (!ld->rgb)
+		return false;
+	/* This is always set; if not by arg, then by default */
+	hex_encode(ld->rgb, 3, buf, len);
+	return true;
+}
+
 static char *opt_set_rgb(const char *arg, struct lightningd *ld)
 {
 	assert(arg != NULL);
@@ -480,6 +490,16 @@ static char *opt_set_rgb(const char *arg, struct lightningd *ld)
 	return NULL;
 }
 
+static bool opt_show_alias(char *buf, size_t len, const struct lightningd *ld)
+{
+	/* Can happen with -h! */
+	if (!ld->alias)
+		return false;
+
+	strncpy(buf, cast_signed(const char *, ld->alias), len);
+	return true;
+}
+
 static char *opt_set_alias(const char *arg, struct lightningd *ld)
 {
 	assert(arg != NULL);
@@ -633,12 +653,6 @@ static char *opt_set_hsm_password(struct lightningd *ld)
 }
 
 #if DEVELOPER
-static char *opt_subprocess_debug(const char *optarg, struct lightningd *ld)
-{
-	ld->dev_debug_subprocess = optarg;
-	return NULL;
-}
-
 static char *opt_force_privkey(const char *optarg, struct lightningd *ld)
 {
 	tal_free(ld->dev_force_privkey);
@@ -753,8 +767,10 @@ static void dev_register_opts(struct lightningd *ld)
 {
 	/* We might want to debug plugins, which are started before normal
 	 * option parsing */
-	opt_register_early_arg("--dev-debugger=<subprocess>", opt_subprocess_debug, NULL,
+	opt_register_early_arg("--dev-debugger=<subprocess>",
-			 ld, "Invoke gdb at start of <subprocess>");
+			       opt_set_charp, NULL,
+			       &ld->dev_debug_subprocess,
+			       "Invoke gdb at start of <subprocess>");
 
 	opt_register_early_noarg("--dev-no-plugin-checksum", opt_set_bool,
 				 &ld->dev_no_plugin_checksum,
@@ -1065,6 +1081,12 @@ static char *opt_start_daemon(struct lightningd *ld)
 	errx(1, "Died with signal %u", WTERMSIG(exitcode));
 }
 
+static bool opt_show_msat(char *buf, size_t len, const struct amount_msat *msat)
+{
+	opt_show_u64(buf, len, &msat->millisatoshis /* Raw: option output */);
+	return true;
+}
+
 static char *opt_set_msat(const char *arg, struct amount_msat *amt)
 {
 	if (!parse_amount_msat(amt, arg, strlen(arg)))
@@ -1244,9 +1266,9 @@ static void register_opts(struct lightningd *ld)
 
 	opt_register_noarg("--help|-h", opt_lightningd_usage, ld,
 				 "Print this message.");
-	opt_register_arg("--rgb", opt_set_rgb, NULL, ld,
+	opt_register_arg("--rgb", opt_set_rgb, opt_show_rgb, ld,
 			 "RRGGBB hex color for node");
-	opt_register_arg("--alias", opt_set_alias, NULL, ld,
+	opt_register_arg("--alias", opt_set_alias, opt_show_alias, ld,
 			 "Up to 32-byte alias for node");
 
 	opt_register_arg("--pid-file=<file>", opt_set_talstr, opt_show_charp,
@@ -1288,17 +1310,17 @@ static void register_opts(struct lightningd *ld)
 	opt_register_arg("--fee-per-satoshi", opt_set_u32, opt_show_u32,
 			 &ld->config.fee_per_satoshi,
 			 "Microsatoshi fee for every satoshi in HTLC");
-	opt_register_arg("--htlc-minimum-msat", opt_set_msat, NULL,
+	opt_register_arg("--htlc-minimum-msat", opt_set_msat, opt_show_msat,
 			 &ld->config.htlc_minimum_msat,
 			 "The default minimal value an HTLC must carry in order to be forwardable for new channels");
-	opt_register_arg("--htlc-maximum-msat", opt_set_msat, NULL,
+	opt_register_arg("--htlc-maximum-msat", opt_set_msat, opt_show_msat,
 			 &ld->config.htlc_maximum_msat,
 			 "The default maximal value an HTLC must carry in order to be forwardable for new channel");
 	opt_register_arg("--max-concurrent-htlcs", opt_set_u32, opt_show_u32,
 			 &ld->config.max_concurrent_htlcs,
 			 "Number of HTLCs one channel can handle concurrently. Should be between 1 and 483");
 	opt_register_arg("--max-dust-htlc-exposure-msat", opt_set_msat,
-			 NULL, &ld->config.max_dust_htlc_exposure_msat,
+			 opt_show_msat, &ld->config.max_dust_htlc_exposure_msat,
 			 "Max HTLC amount that can be trimmed");
 	opt_register_arg("--min-capacity-sat", opt_set_u64, opt_show_u64,
 			 &ld->config.min_capacity_sat,
@@ -1747,8 +1769,10 @@ static void add_config(struct lightningd *ld,
 		if (opt->desc == opt_hidden) {
 			/* Ignore hidden options (deprecated) */
 		} else if (opt->show == (void *)opt_show_charp) {
-			/* Don't truncate or quote! */
+			if (*(char **)opt->u.carg)
-			answer = tal_strdup(tmpctx, *(char **)opt->u.carg);
+				/* Don't truncate or quote! */
+				answer = tal_strdup(tmpctx,
+						    *(char **)opt->u.carg);
 		} else if (opt->show) {
 			strcpy(buf + sizeof(buf) - sizeof("..."), "...");
 			if (!opt->show(buf, sizeof(buf) - sizeof("..."), opt->u.carg))
@@ -1763,16 +1787,10 @@ static void add_config(struct lightningd *ld,
 			}
 			answer = buf;
 		} else if (opt->cb_arg == (void *)opt_set_talstr
-			   || opt->cb_arg == (void *)opt_set_charp
+			   || opt->cb_arg == (void *)opt_set_charp) {
-			   || is_restricted_print_if_nonnull(opt->cb_arg)) {
 			const char *arg = *(char **)opt->u.carg;
 			if (arg)
 				answer = tal_fmt(name0, "%s", arg);
-		} else if (opt->cb_arg == (void *)opt_set_rgb) {
-			if (ld->rgb)
-				answer = tal_hexstr(name0, ld->rgb, 3);
-		} else if (opt->cb_arg == (void *)opt_set_alias) {
-			answer = (char *)ld->alias;
 		} else if (opt->cb_arg == (void *)arg_log_to_file) {
 			if (ld->logfiles)
 				json_add_opt_log_to_files(response, name0, ld->logfiles);
@@ -1830,14 +1848,6 @@ static void add_config(struct lightningd *ld,
 			   || opt->cb_arg == (void *)plugin_opt_flag_set) {
 			/* FIXME: We actually treat it as if they specified
 			 * --plugin for each one, so ignore these */
-		} else if (opt->cb_arg == (void *)opt_set_msat) {
-			/* We allow -msat not _msat here, unlike
-			 * json_add_amount_msat */
-			assert(strends(name0, "-msat"));
-			json_add_string(response, name0,
-					fmt_amount_msat(tmpctx,
-							*(struct amount_msat *)
-							opt->u.carg));
 		} else if (opt->cb_arg == (void *)opt_set_accept_extra_tlv_types) {
 			for (size_t i = 0;
 			     i < tal_count(ld->accept_extra_tlv_types);