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>
@@ -565,41 +565,58 @@ void logv(struct logger *log, enum log_level level,
 {
 	int save_errno = errno;
 	struct log_entry *l = new_log_entry(log, level, node_id);
+	char *log_msg = NULL;
 
 	/* 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]);
+	const char *unescaped_log =
+	    json_escape_unescape(log, (struct json_escape *)log_msg);
+	if (!strchr(log_msg, '\\') || !unescaped_log) {
+		l->log = log_msg;
+		size_t log_len = strlen(l->log);
 
 		/* 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] = '?';
+		for (size_t i = 0; i < log_len; i++)
+			if (l->log[i] < ' ' || l->log[i] >= 0x7f)
+				l->log[i] = '?';
 
-		maybe_print(log, line_entry);
-		maybe_notify_log(log, line_entry);
+		maybe_print(log, l);
+		maybe_notify_log(log, l);
 
-		add_entry(log, &line_entry);
+		add_entry(log, &l);
+	} else {
+		char **lines =
+		    tal_strsplit(log, unescaped_log, "\n", STR_NO_EMPTY);
+
+		/* Split to lines and log them separately. */
+		for (size_t j = 0; lines[j]; j++) {
+			l->log = strdup(lines[j]);
+
+			/* Sanitize any non-printable characters, and replace
+			 * with '?'
+			 */
+			size_t line_len = strlen(l->log);
+			for (size_t i = 0; i < line_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);
+			free(l->log);
+		}
+		tal_free(lines);
 	}
 
 	if (call_notifier)
 		notify_warning(log->log_book->ld, l);
 
-	tal_free(ctx);
+	tal_free(unescaped_log);
 	errno = save_errno;
 }