From fca4a8c3466c41f0dd56c1074217cfbbce6c5528 Mon Sep 17 00:00:00 2001
From: Lukasz Rymanowski <lukasz.rymanowski@tieto.com>
Date: Thu, 20 Nov 2014 16:55:14 +0100
Subject: [PATCH] shared/hfp: Improve handling AT commands

This patch improves handling AT commands in cases:

1. In ring buffer we have currupted commands like Y\rAT+X\r
2. In ring buffer for some reason we have more than AT commands and all
commands are unknown except the last one.

In bith cases parser read data until first \r and then stop to read.
This is fixed with this patch
---
 src/shared/hfp.c | 91 +++++++++++++++++++++++++++++-------------------
 1 file changed, 55 insertions(+), 36 deletions(-)

diff --git a/src/shared/hfp.c b/src/shared/hfp.c
index 41eae740b..5a91d129e 100644
--- a/src/shared/hfp.c
+++ b/src/shared/hfp.c
@@ -476,54 +476,73 @@ static void process_input(struct hfp_gw *hfp)
 	char *str, *ptr;
 	size_t len, count;
 	bool free_ptr = false;
+	bool read_again;
 
-	str = ringbuf_peek(hfp->read_buf, 0, &len);
-	if (!str)
-		return;
+	do {
+		str = ringbuf_peek(hfp->read_buf, 0, &len);
+		if (!str)
+			return;
 
-	ptr = memchr(str, '\r', len);
-	if (!ptr) {
-		char *str2;
-		size_t len2;
+		ptr = memchr(str, '\r', len);
+		if (!ptr) {
+			char *str2;
+			size_t len2;
 
-		/*
-		 * If there is no more data in ringbuffer,
-		 * it's just an incomplete command.
-		 */
-		if (len == ringbuf_len(hfp->read_buf))
-			return;
+			/*
+			 * If there is no more data in ringbuffer,
+			 * it's just an incomplete command.
+			 */
+			if (len == ringbuf_len(hfp->read_buf))
+				return;
 
-		str2 = ringbuf_peek(hfp->read_buf, len, &len2);
-		if (!str2)
-			return;
+			str2 = ringbuf_peek(hfp->read_buf, len, &len2);
+			if (!str2)
+				return;
 
-		ptr = memchr(str2, '\r', len2);
-		if (!ptr)
-			return;
+			ptr = memchr(str2, '\r', len2);
+			if (!ptr)
+				return;
 
-		*ptr = '\0';
+			*ptr = '\0';
 
-		count = len2 + len;
-		ptr = malloc(count);
-		if (!ptr)
-			return;
+			count = len2 + len;
+			ptr = malloc(count);
+			if (!ptr)
+				return;
 
-		memcpy(ptr, str, len);
-		memcpy(ptr + len, str2, len2);
+			memcpy(ptr, str, len);
+			memcpy(ptr + len, str2, len2);
 
-		free_ptr = true;
-		str = ptr;
-	} else {
-		count = ptr - str;
-		*ptr = '\0';
-	}
+			free_ptr = true;
+			str = ptr;
+		} else {
+			count = ptr - str;
+			*ptr = '\0';
+		}
+
+		if (!handle_at_command(hfp, str))
+			/*
+			 * Command is not handled that means that was some
+			 * trash. Let's skip that and keep reading from ring
+			 * buffer.
+			 */
+			read_again = true;
+		else
+			/*
+			 * Command has been handled. If we are waiting for a
+			 * result from upper layer, we can stop reading. If we
+			 * already reply i.e. ERROR on unknown command, then we
+			 * can keep reading ring buffer. Actually ring buffer
+			 * should be empty but lets just look there.
+			 */
+			read_again = !hfp->result_pending;
 
-	handle_at_command(hfp, str);
+		ringbuf_drain(hfp->read_buf, count + 1);
 
-	ringbuf_drain(hfp->read_buf, count + 1);
+		if (free_ptr)
+			free(ptr);
 
-	if (free_ptr)
-		free(ptr);
+	} while (read_again);
 }
 
 static void read_watch_destroy(void *user_data)
-- 
2.47.3