Mercurial > dovecot > core-2.2

changeset 20745:244720af3113

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iostream-temp: If write() to temp file fails at any time, move it back to memory. Similarly to if the write() to temp fails during the initial move attempt. This way even if write() fails due to out of disk space, it's not visible to caller. An error message is logged in any case.
author Timo Sirainen <timo.sirainen@dovecot.fi>
date Wed, 14 Sep 2016 14:19:39 +0300
parents cf26a89ceb9a
children 6c827dbef85e
files src/lib/iostream-temp.c src/lib/iostream-temp.h
diffstat 2 files changed, 45 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/src/lib/iostream-temp.c	Wed Sep 14 19:06:29 2016 +0300
+++ b/src/lib/iostream-temp.c	Wed Sep 14 14:19:39 2016 +0300
@@ -76,6 +76,36 @@
 	return 0;
 }
 
+int o_stream_temp_move_to_memory(struct ostream *output)
+{
+	struct temp_ostream *tstream =
+		(struct temp_ostream *)output->real_stream;
+	unsigned char buf[IO_BLOCK_SIZE];
+	uoff_t offset = 0;
+	ssize_t ret = 0;
+
+	i_assert(tstream->buf == NULL);
+	tstream->buf = buffer_create_dynamic(default_pool, 8192);
+	while (offset < tstream->ostream.ostream.offset &&
+	       (ret = pread(tstream->fd, buf, sizeof(buf), offset)) > 0) {
+		if ((size_t)ret > tstream->ostream.ostream.offset - offset)
+			ret = tstream->ostream.ostream.offset - offset;
+		buffer_append(tstream->buf, buf, ret);
+		offset += ret;
+	}
+	if (ret < 0) {
+		/* not really expecting this to happen */
+		i_error("iostream-temp %s: read(%s*) failed: %m",
+			o_stream_get_name(&tstream->ostream.ostream),
+			tstream->temp_path_prefix);
+		tstream->ostream.ostream.stream_errno = EIO;
+		return -1;
+	}
+	i_close_fd(&tstream->fd);
+	tstream->ostream.fd = -1;
+	return 0;
+}
+
 static ssize_t
 o_stream_temp_fd_sendv(struct temp_ostream *tstream,
 		       const struct const_iovec *iov, unsigned int iov_count)
@@ -85,8 +115,18 @@
 
 	for (i = 0; i < iov_count; i++) {
 		if (write_full(tstream->fd, iov[i].iov_base, iov[i].iov_len) < 0) {
-			tstream->ostream.ostream.stream_errno = errno;
-			return -1;
+			i_error("iostream-temp %s: write(%s*) failed: %m - moving to memory",
+				o_stream_get_name(&tstream->ostream.ostream),
+				tstream->temp_path_prefix);
+			if (o_stream_temp_move_to_memory(&tstream->ostream.ostream) < 0)
+				return -1;
+			for (; i < iov_count; i++) {
+				buffer_append(tstream->buf, iov[i].iov_base, iov[i].iov_len);
+				bytes += iov[i].iov_len;
+				tstream->ostream.ostream.offset += iov[i].iov_len;
+			}
+			i_assert(tstream->fd_tried);
+			return bytes;
 		}
 		bytes += iov[i].iov_len;
 		tstream->ostream.ostream.offset += iov[i].iov_len;
--- a/src/lib/iostream-temp.h	Wed Sep 14 19:06:29 2016 +0300
+++ b/src/lib/iostream-temp.h	Wed Sep 14 14:19:39 2016 +0300
@@ -25,4 +25,7 @@
 struct istream *iostream_temp_finish(struct ostream **output,
 				     size_t max_buffer_size);
 
+/* For internal testing: */
+int o_stream_temp_move_to_memory(struct ostream *output);
+
 #endif