add --conf parameter

doc/lightningd-config.5

@@ -2,12 +2,12 @@
 .\"     Title: lightningd-config
 .\"    Author: [see the "AUTHOR" section]
 .\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
-.\"      Date: 06/23/2018
+.\"      Date: 07/12/2018
 .\"    Manual: \ \&
 .\"    Source: \ \&
 .\"  Language: English
 .\"
-.TH "LIGHTNINGD\-CONFIG" "5" "06/23/2018" "\ \&" "\ \&"
+.TH "LIGHTNINGD\-CONFIG" "5" "07/12/2018" "\ \&" "\ \&"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -168,6 +168,11 @@ Set JSON\-RPC socket (or /dev/tty), such as for lightning\-cli(1)\&.
 .RS 4
 Run in the background, suppress stdout and stderr\&.
 .RE
+.PP
+\fBconf\fR=\fIPATH\fR
+.RS 4
+Sets configuration file\&. Relative paths will be prefixed by lightning\-dir location\&. (default: config)
+.RE
 .sp
 Lightning node customization options:
 .PP

doc/lightningd-config.5.txt

@@ -91,7 +91,7 @@ Bitcoin control options:
 
 *rescan*='BLOCKS'::
     Number of blocks to rescan from the current head, or absolute blockheight
-    if negative.  This is only needed if something goes badly wrong.
+    if negative. This is only needed if something goes badly wrong.
 
 Lightning daemon options:
 
@@ -117,6 +117,9 @@ Lightning daemon options:
 *daemon*::
     Run in the background, suppress stdout and stderr.
 
+*conf*='PATH'::
+    Sets configuration file. Relative paths will be prefixed by lightning-dir location. (default: config)
+
 Lightning node customization options:
 
 *rgb*='RRGGBB'::

lightningd/lightningd.c

@@ -80,6 +80,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	timers_init(&ld->timers, time_mono());
 	ld->topology = new_topology(ld, ld->log);
 	ld->daemon = false;
+	ld->config_filename = NULL;
 	ld->pidfile = NULL;
 	ld->ini_autocleaninvoice_cycle = 0;
 	ld->ini_autocleaninvoice_expiredby = 86400;

lightningd/lightningd.h

@@ -80,6 +80,8 @@ struct lightningd {
 	char *config_dir;
 	char *rpc_filename;
 
+	/* Configuration file name */
+	char *config_filename;
 	/* Configuration settings. */
 	struct config config;
 

lightningd/options.c

@@ -339,6 +339,9 @@ static char *opt_set_locktime(const char *arg, u32 *u)
 
 static void config_register_opts(struct lightningd *ld)
 {
+	opt_register_early_arg("--conf=<file>", opt_set_talstr, NULL,
+		&ld->config_filename,
+		"Specify configuration file. Relative paths will be prefixed by lightning-dir location. (default: config)");
 	opt_register_noarg("--daemon", opt_set_bool, &ld->daemon,
 			 "Run in the background, suppress stdout/stderr");
 	opt_register_arg("--ignore-fee-limits", opt_set_bool_arg, opt_show_bool,
@@ -697,10 +700,14 @@ static void opt_parse_from_config(struct lightningd *ld)
 	char *argv[3];
 	int i, argc;
 
-	contents = grab_file(ld, "config");
-	/* Doesn't have to exist. */
+	if (ld->config_filename != NULL) {
+		contents = grab_file(ld, ld->config_filename);
+	} else
+		contents = grab_file(ld, "config");
+	/* The default config doesn't have to exist, but if the config was
+	 * specified on the command line it has to exist. */
 	if (!contents) {
-		if (errno != ENOENT)
+		if ((errno != ENOENT) || (ld->config_filename != NULL))
 			fatal("Opening and reading config: %s",
 			      strerror(errno));
 		/* Now we can set up defaults, since no config file. */