lightningd: remember --log-file arg.

And fclose old ones if we get handed it multiple times.

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

lightningd/lightningd.c

@@ -56,6 +56,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx,
 	htlc_out_map_init(&ld->htlcs_out);
 	ld->log_book = log_book;
 	ld->log = new_log(log_book, log_book, "lightningd(%u):", (int)getpid());
+	ld->logfile = NULL;
 	ld->alias = NULL;
 	ld->rgb = NULL;
 	list_head_init(&ld->connects);

lightningd/lightningd.h

@@ -90,6 +90,7 @@ struct lightningd {
 	/* Log for general stuff. */
 	struct log_book *log_book;
 	struct log *log;
+	const char *logfile;
 
 	/* This is us. */
 	struct pubkey id;

lightningd/log.c

@@ -376,12 +376,30 @@ static char *arg_log_level(const char *arg, struct log *log)
 	return tal_fmt(NULL, "unknown log level");
 }
 
+static void show_log_level(char buf[OPT_SHOW_LEN], const struct log *log)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(log_levels); i++) {
+		if (log->lr->print_level == log_levels[i].level) {
+			strncpy(buf, log_levels[i].name, OPT_SHOW_LEN-1);
+			return;
+		}
+	}
+	abort();
+}
+
 static char *arg_log_prefix(const char *arg, struct log *log)
 {
 	set_log_prefix(log, arg);
 	return NULL;
 }
 
+static void show_log_prefix(char buf[OPT_SHOW_LEN], const struct log *log)
+{
+	strncpy(buf, log->prefix, OPT_SHOW_LEN);
+}
+
 static void log_to_file(const char *prefix,
 			enum log_level level,
 			bool continued,
@@ -396,22 +414,30 @@ static void log_to_file(const char *prefix,
 	fflush(logf);
 }
 
-static char *arg_log_to_file(const char *arg, struct log *log)
+static char *arg_log_to_file(const char *arg, struct lightningd *ld)
 {
-	FILE *logf = fopen(arg, "a");
+	FILE *logf;
+
+	if (ld->logfile) {
+		fclose(ld->log->lr->print_arg);
+		ld->logfile = tal_free(ld->logfile);
+	}
+	ld->logfile = tal_strdup(ld, arg);
+	logf = fopen(arg, "a");
 	if (!logf)
 		return tal_fmt(NULL, "Failed to open: %s", strerror(errno));
-	set_log_outfn(log->lr, log_to_file, logf);
+	set_log_outfn(ld->log->lr, log_to_file, logf);
 	return NULL;
 }
 
-void opt_register_logging(struct log *log)
+void opt_register_logging(struct lightningd *ld)
 {
-	opt_register_arg("--log-level", arg_log_level, NULL, log,
+	opt_register_arg("--log-level", arg_log_level, show_log_level, ld->log,
 			 "log level (debug, info, unusual, broken)");
-	opt_register_arg("--log-prefix", arg_log_prefix, NULL, log,
+	opt_register_arg("--log-prefix", arg_log_prefix, show_log_prefix,
+			 ld->log,
 			 "log prefix");
-	opt_register_arg("--log-file=<file>", arg_log_to_file, NULL, log,
+	opt_register_arg("--log-file=<file>", arg_log_to_file, NULL, ld,
 			 "log to file instead of stdout");
 }
 

lightningd/log.h

@@ -6,6 +6,7 @@
 #include <common/type_to_string.h>
 #include <stdarg.h>
 
+struct lightningd;
 struct timerel;
 
 enum log_level {
@@ -85,7 +86,7 @@ void log_each_line_(const struct log_book *lr,
 
 
 void log_dump_to_file(int fd, const struct log_book *lr);
-void opt_register_logging(struct log *log);
+void opt_register_logging(struct lightningd *ld);
 void crashlog_activate(const char *argv0, struct log *log);
 
 /* Convenience parent for temporary allocations (eg. type_to_string)

lightningd/options.c

@@ -563,7 +563,7 @@ void register_opts(struct lightningd *ld)
 	    &ld->config.channel_update_interval,
 	    "Time in seconds between channel updates for our own channels.");
 
-	opt_register_logging(ld->log);
+	opt_register_logging(ld);
 	opt_register_version();
 
 	configdir_register_opts(ld, &ld->config_dir, &ld->rpc_filename);