From 3abe93f4b90cf10d3d29dcb48e90dd65353e0bc5 Mon Sep 17 00:00:00 2001
From: Olivier Matz <zer0@droids-corp.org>
Date: Thu, 6 Mar 2014 18:37:16 +0100
Subject: [PATCH] prevent log flooding

---
 cmdline.c | 57 ++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 11 deletions(-)

diff --git a/cmdline.c b/cmdline.c
index 736fa52..568dcad 100644
--- a/cmdline.c
+++ b/cmdline.c
@@ -35,9 +35,13 @@
 #include "main.h"
 #include "cmdline.h"
 
+#define FLUSH_LOGS_MS 1000 /* every second */
+#define LOG_PER_SEC_MAX 10
 
 extern const parse_ctx_t PROGMEM main_ctx[];
 
+static struct callout flush_log_timer;
+static uint8_t log_count;
 
 int cmdline_dev_send(char c, FILE* f)
 {
@@ -108,13 +112,6 @@ void cmdline_write_char(char c)
 }
 
 
-void cmdline_init(void)
-{
-	rdline_init(&xbeeboard.rdl, cmdline_write_char, cmdline_valid_buffer, complete_buffer);
-	snprintf_P(xbeeboard.prompt, sizeof(xbeeboard.prompt), PSTR("mainboard > "));
-}
-
-
 /* sending "pop" on cmdline uart resets the robot */
 void emergency(char c)
 {
@@ -132,8 +129,7 @@ void emergency(char c)
 	}
 }
 
-/* log function, add a command to configure
- * it dynamically */
+/* log function, configured dynamically */
 void mylog(struct error * e, ...)
 {
 #ifndef HOST_VERSION
@@ -142,7 +138,13 @@ void mylog(struct error * e, ...)
 	va_list ap;
 	uint8_t i, flags;
 	uint32_t ms;
+	uint8_t prio;
 
+	/* too many logs */
+	if (log_count >= LOG_PER_SEC_MAX)
+		return;
+
+	/* higher log value means lower criticity */
 	if (e->severity > ERROR_SEVERITY_ERROR) {
 		if (xbeeboard.log_level < e->severity)
 			return;
@@ -154,21 +156,42 @@ void mylog(struct error * e, ...)
 			return;
 	}
 
-	va_start(ap, e);
+	/* get time */
 	IRQ_LOCK(flags);
 	ms = global_ms;
 	IRQ_UNLOCK(flags);
 
-	printf_P(PSTR("%d.%.3d: "), (int)(ms/1000UL), (int)(ms%1000UL));
+	/* prevent flush log to occur */
+	prio = callout_mgr_set_prio(&xbeeboard.intr_cm,
+		LOW_PRIO);
 
+	/* display the log */
+	va_start(ap, e);
+	printf_P(PSTR("%d.%.3d: "), (int)(ms/1000UL), (int)(ms%1000UL));
 	vfprintf_P(stdout, e->text, ap);
 	printf_P(PSTR("\r\n"));
 	va_end(ap);
+
 #ifndef HOST_VERSION
 	stdout->flags = stream_flags;
 #endif
+	callout_mgr_restore_prio(&xbeeboard.intr_cm, prio);
+}
+
+static void flush_logs_cb(struct callout_mgr *cm, struct callout *tim,
+	void *arg)
+{
+	(void)cm;
+	(void)tim;
+	(void)arg;
+
+	if (log_count == LOG_PER_SEC_MAX)
+		printf_P("some logs were dropped\n");
+	callout_reschedule(&xbeeboard.intr_cm, &flush_log_timer,
+		FLUSH_LOGS_MS);
 }
 
+
 int cmdline_poll(void)
 {
 	const char *history, *buffer;
@@ -199,3 +222,15 @@ int cmdline_poll(void)
 	return 0;
 }
 
+void cmdline_init(void)
+{
+	/* init command line */
+	rdline_init(&xbeeboard.rdl, cmdline_write_char, cmdline_valid_buffer,
+		complete_buffer);
+	snprintf_P(xbeeboard.prompt, sizeof(xbeeboard.prompt),
+		PSTR("mainboard > "));
+
+	/* load a timer for flushing logs */
+	callout_init(&flush_log_timer, flush_logs_cb, NULL, LOW_PRIO);
+	callout_schedule(&xbeeboard.intr_cm, &flush_log_timer, FLUSH_LOGS_MS);
+}
-- 
2.20.1