From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Tue, 31 Oct 2017 15:20:22 +0000 (+0200)
Subject: lib-fs: fs-metawrap - Don't try to write to an already finished ostream
X-Git-Tag: 2.3.0.rc1~668
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=03e102ddccaae9e944c503d4269de755731798e8;p=thirdparty%2Fdovecot%2Fcore.git

lib-fs: fs-metawrap - Don't try to write to an already finished ostream

Fixes a crash after recent changes when trying to write an empty file via
fs-metawrap.
---

diff --git a/src/lib-fs/fs-metawrap.c b/src/lib-fs/fs-metawrap.c
index ae99da3f58..c62b9694ac 100644
--- a/src/lib-fs/fs-metawrap.c
+++ b/src/lib-fs/fs-metawrap.c
@@ -391,10 +391,16 @@ static int fs_metawrap_write_stream_finish(struct fs_file *_file, bool success)
 	}
 	/* finish writing the temporary file */
 	if (file->temp_output->offset == 0) {
-		/* empty file */
-		fs_metawrap_write_metadata_to(file, file->temp_output);
+		/* empty file - temp_output is already finished,
+		   so we can't write to it. */
+		string_t *str = t_str_new(128);
+
+		o_stream_destroy(&file->temp_output);
+		fs_metawrap_append_metadata(file, str);
+		input = i_stream_create_copy_from_data(str_data(str), str_len(str));
+	} else {
+		input = iostream_temp_finish(&file->temp_output, IO_BLOCK_SIZE);
 	}
-	input = iostream_temp_finish(&file->temp_output, IO_BLOCK_SIZE);
 	if (file->metadata_changed_since_write) {
 		/* we'll need to recreate the metadata. do this by creating a
 		   new istream combining the new metadata header and the