lightningd/log: Improve logging to handle multi-line messages

Changelog-Added: Improved logging format in `lightningd/log` to handle multi-line messages by unescaping '\n' and logging each line separately.

Signed-off-by: Nishant Bansal <[email protected]>

Author: NishantBansal2003

lightningd/log.c

@@ -1,13 +1,13 @@
 #include "config.h"
 #include <ccan/err/err.h>
 #include <ccan/io/io.h>
+#include <ccan/json_escape/json_escape.h>
 #include <ccan/read_write_all/read_write_all.h>
 #include <ccan/str/hex/hex.h>
 #include <ccan/tal/link/link.h>
 #include <ccan/tal/str/str.h>
 #include <common/configvar.h>
 #include <common/json_command.h>
-#include <ccan/json_escape/json_escape.h>
 #include <common/json_param.h>
 #include <common/memleak.h>
 #include <errno.h>
@@ -558,48 +558,62 @@ static void maybe_notify_log(struct logger *log,
 		notify_log(log->log_book->ld, l);
 }
 
+static void add_one_log_entry(struct logger *log, enum log_level level,
+			      const struct node_id *node_id, bool call_notifier,
+			      char *log_msg)
+{
+	struct log_entry *l = new_log_entry(log, level, node_id);
+
+	l->log = strdup(log_msg);
+	size_t log_len = strlen(l->log);
+
+	/* Sanitize any non-printable characters, and replace with '?'
+	 */
+	for (size_t i = 0; i < log_len; i++)
+		if (l->log[i] < ' ' || l->log[i] >= 0x7f)
+			l->log[i] = '?';
+
+	maybe_print(log, l);
+	maybe_notify_log(log, l);
+
+	add_entry(log, &l);
+
+	if (call_notifier)
+		notify_warning(log->log_book->ld, l);
+}
+
 void logv(struct logger *log, enum log_level level,
 	  const struct node_id *node_id,
 	  bool call_notifier,
 	  const char *fmt, va_list ap)
 {
 	int save_errno = errno;
-	struct log_entry *l = new_log_entry(log, level, node_id);
+	char *log_msg = NULL;
+	const char *unescaped_log;
 
 	/* This is WARN_UNUSED_RESULT, because everyone should somehow deal
 	 * with OOM, even though nobody does. */
-	if (vasprintf(&l->log, fmt, ap) == -1)
+	if (vasprintf(&log_msg, fmt, ap) == -1)
 		abort();
 
-	tal_t *ctx = tal(NULL, char);
-	const char *log_line = tal_strdup(
-	    ctx, json_escape_unescape(ctx, (struct json_escape *)l->log));
-	char **lines = tal_strsplit(ctx, log_line, "\n", STR_NO_EMPTY);
-
-	/* Split to lines and log them separately. */
-	for (size_t i = 0; i < tal_count(lines) - 1; i++) {
-		struct log_entry *line_entry =
-		    new_log_entry(log, level, node_id);
-		line_entry->log = tal_strdup(ctx, lines[i]);
-
-		/* Sanitize any non-printable characters, and replace with '?'
-		 */
-		size_t line_len = strlen(line_entry->log);
-		for (size_t i = 0; i < line_len; i++)
-			if (line_entry->log[i] < ' ' ||
-			    line_entry->log[i] >= 0x7f)
-				line_entry->log[i] = '?';
-
-		maybe_print(log, line_entry);
-		maybe_notify_log(log, line_entry);
-
-		add_entry(log, &line_entry);
+	/* Nothing to escape: simple copy */
+	if (!strchr(log_msg, '\\'))
+		add_one_log_entry(log, level, node_id, call_notifier, log_msg);
+	/* If it's weird, unescaping can fail */
+	else if ((unescaped_log = json_escape_unescape(
+		      tmpctx, (struct json_escape *)log_msg)) == NULL)
+		add_one_log_entry(log, level, node_id, call_notifier, log_msg);
+	else {
+		char **lines = tal_strsplit(unescaped_log, unescaped_log, "\n",
+					    STR_EMPTY_OK);
+		/* Split to lines and log them separately. */
+		for (size_t i = 0; lines[i]; i++)
+			add_one_log_entry(log, level, node_id, call_notifier,
+					  lines[i]);
 	}
 
-	if (call_notifier)
-		notify_warning(log->log_book->ld, l);
+	free(log_msg);
 
-	tal_free(ctx);
 	errno = save_errno;
 }