From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Wed, 21 Sep 2016 10:26:30 +0000 (+0300)
Subject: lib: Fixed istream-chain when it has multiple "previous streams".
X-Git-Tag: 2.2.26~239
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=946de454a6e2594717bdc4450164dd0db1e96b60;p=thirdparty%2Fdovecot%2Fcore.git

lib: Fixed istream-chain when it has multiple "previous streams".

Fixes assert:
Panic: file istream-chain.c: line 223 (i_stream_chain_read): assertion failed: (cur_data_pos == data_size)

Unit test for it by Stephan Bosch.
---

diff --git a/src/lib/istream-chain.c b/src/lib/istream-chain.c
index 6880f8d00e..026c1dd584 100644
--- a/src/lib/istream-chain.c
+++ b/src/lib/istream-chain.c
@@ -23,7 +23,11 @@ struct istream_chain {
 struct chain_istream {
 	struct istream_private istream;
 
-	size_t prev_stream_left, prev_skip;
+	/* how much of the previous link's stream still exists at the
+	   beginning of our buffer. skipping through this should point to
+	   the beginning of the current link's stream. */
+	size_t prev_stream_left;
+	size_t prev_skip;
 	bool have_explicit_max_buffer_size;
 	
 	struct istream_chain chain;
@@ -131,12 +135,16 @@ static void i_stream_chain_read_next(struct chain_istream *cstream)
 
 	if (cstream->prev_stream_left > 0) {
 		/* we've already buffered some of the prev_input. continue
-		   appending the rest to it. */
+		   appending the rest to it. if it's already at EOF, there's
+		   nothing more to append. */
 		cur_data_pos = cstream->istream.pos -
 			(cstream->istream.skip + cstream->prev_stream_left);
 		i_assert(cur_data_pos <= data_size);
 		data += cur_data_pos;
 		data_size -= cur_data_pos;
+		/* the stream has now become "previous", so its contents in
+		   buffer are now part of prev_stream_left. */
+		cstream->prev_stream_left += cur_data_pos;
 	} else {
 		cstream->istream.pos = 0;
 		cstream->istream.skip = 0;
diff --git a/src/lib/test-istream-chain.c b/src/lib/test-istream-chain.c
index 7ce37e5649..c9f597050d 100644
--- a/src/lib/test-istream-chain.c
+++ b/src/lib/test-istream-chain.c
@@ -80,8 +80,106 @@ static void test_istream_chain_early_end(void)
 	test_end();
 }
 
+static void test_istream_chain_accumulate(void)
+{
+	struct istream *input;
+	struct istream  *test_input, *test_input2, *test_input3, *test_input4,
+		*test_input5;
+	struct istream_chain *chain;
+	const unsigned char *data;
+	size_t size;
+
+	test_begin("istream chain");
+
+	test_input = test_istream_create("aaaaaaaaaaaaaaaaaaaa");
+	test_input2 = test_istream_create("bbbbbbbbbbbbbbbbbbbbbbbbb");
+	test_input3 = test_istream_create("cccccccccccccccccccccccccccccc");
+	test_input4 = test_istream_create("ddddddddddddddddddddddddd");
+	test_input5 = test_istream_create("eeeeeeeeeeeeeeeeeeee");
+
+	input = i_stream_create_chain(&chain);
+	/* no input */
+	test_assert(i_stream_read(input) == 0);
+
+	/* first stream */
+	i_stream_chain_append(chain, test_input);
+	test_assert(i_stream_read_data(input, &data, &size, 0) == 1);
+	test_assert(size == 20);
+	test_assert(memcmp(data, "aaaaaaaaaaaaaaaaaaaa", 20) == 0);
+
+	/* partially skip */
+	i_stream_skip(input, 12);
+
+	/* second stream */
+	i_stream_chain_append(chain, test_input2);
+	test_assert(i_stream_read_data(input, &data, &size, 10) == 1);
+	test_assert(size == 33);
+	test_assert(memcmp(data, "aaaaaaaa"
+		"bbbbbbbbbbbbbbbbbbbbbbbbb", 33) == 0);
+
+	/* partially skip */
+	i_stream_skip(input, 12);
+
+	/* third stream */
+	i_stream_chain_append(chain, test_input3);
+	test_assert(i_stream_read_data(input, &data, &size, 25) == 1);
+	test_assert(size == 51);
+	test_assert(memcmp(data, "bbbbbbbbbbbbbbbbbbbbb"
+		"cccccccccccccccccccccccccccccc", 51) == 0);
+
+	/* partially skip */
+	i_stream_skip(input, 12);
+
+	/* forth stream */
+	i_stream_chain_append(chain, test_input4);
+	test_assert(i_stream_read_data(input, &data, &size, 40) == 1);
+	test_assert(size == 64);
+	test_assert(memcmp(data, "bbbbbbbbb"
+		"cccccccccccccccccccccccccccccc"
+		"ddddddddddddddddddddddddd", 64) == 0);
+
+	/* partially skip */
+	i_stream_skip(input, 6);
+
+	/* fifth stream */
+	i_stream_chain_append(chain, test_input5);
+	test_assert(i_stream_read_data(input, &data, &size, 60) == 1);
+	test_assert(size == 78);
+	test_assert(memcmp(data, "bbb"
+		"cccccccccccccccccccccccccccccc"
+		"ddddddddddddddddddddddddd"
+		"eeeeeeeeeeeeeeeeeeee", 78) == 0);
+
+	/* EOF */
+	i_stream_chain_append_eof(chain);
+	test_assert(i_stream_read(input) == -1);
+	test_assert(input->eof && input->stream_errno == 0);
+	test_assert(i_stream_read_data(input, &data, &size, 78) == -1);
+	test_assert(size == 78);
+	test_assert(memcmp(data, "bbb"
+		"cccccccccccccccccccccccccccccc"
+		"ddddddddddddddddddddddddd"
+		"eeeeeeeeeeeeeeeeeeee", 78) == 0);
+
+	/* skip rest */
+	i_stream_skip(input, 78);
+
+	test_assert(i_stream_read(input) == -1);
+	test_assert(input->eof && input->stream_errno == 0);
+	data = i_stream_get_data(input, &size);
+	test_assert(size == 0);
+
+	i_stream_unref(&input);
+
+	i_stream_unref(&test_input);
+	i_stream_unref(&test_input2);
+	i_stream_unref(&test_input3);
+	test_end();
+}
+
 void test_istream_chain(void)
 {
 	test_istream_chain_basic();
 	test_istream_chain_early_end();
+	test_istream_chain_accumulate();
 }