From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Tue, 19 Feb 2019 08:17:45 +0000 (+0200)
Subject: lib: istream-seekable - Change stream to be blocking=TRUE after reaching EOF
X-Git-Tag: 2.3.9~818
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1372692923ad0cef8e0671be9664644ddf61ba75;p=thirdparty%2Fdovecot%2Fcore.git

lib: istream-seekable - Change stream to be blocking=TRUE after reaching EOF

After EOF is reached, the stream is now fully read into file or memory.
read()s can no longer return 0, so blocking=TRUE can be used.

Some callers were reusing the seekable stream in places that required
blocking=TRUE.

Fixes at least with imapsieve vnd.dovecot report extension:
Panic: file ostream.c: line 427 (o_stream_nsend_istream): assertion failed: (instream->blocking)
---

diff --git a/src/lib/istream-seekable.c b/src/lib/istream-seekable.c
index 875bba667f..67ff65620b 100644
--- a/src/lib/istream-seekable.c
+++ b/src/lib/istream-seekable.c
@@ -164,6 +164,10 @@ static ssize_t read_more(struct seekable_istream *sstream)
 			/* last one, EOF */
 			sstream->size = sstream->istream.istream.v_offset;
 			sstream->istream.istream.eof = TRUE;
+			/* Now that EOF is reached, the stream can't return 0
+			   anymore. Callers can now use this stream in places
+			   that assert that blocking==TRUE. */
+			sstream->istream.istream.blocking = TRUE;
 			unref_streams(sstream);
 			return -1;
 		}