diff --git a/src/debug.c b/src/debug.c
index c071df0..735fce3 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -127,12 +127,22 @@
 	fflush(outfd);
 }
 
-void hexdump(unsigned char *buf, int len)
+static char hexd_buff[4096];
+
+char *hexdump(unsigned char *buf, int len)
 {
 	int i;
+	char *cur = hexd_buff;
+
+	hexd_buff[0] = 0;
 	for (i = 0; i < len; i++) {
-		fprintf(stdout, "%02x ", buf[i]);
+		int len_remain = sizeof(hexd_buff) - (cur - hexd_buff);
+		int rc = snprintf(cur, len_remain, "%02x ", buf[i]);
+		if (rc <= 0)
+			break;
+		cur += rc;
 	}
-	fprintf(stdout, "\n");
+	hexd_buff[sizeof(hexd_buff)-1] = 0;
+	return hexd_buff;
 }