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[Qemu-block] [PATCH v4 05/14] nbd: Share common reply-sending code in se
From: |
Eric Blake |
Subject: |
[Qemu-block] [PATCH v4 05/14] nbd: Share common reply-sending code in server |
Date: |
Sat, 25 Jun 2016 16:15:45 -0600 |
Rather than open-coding NBD_REP_SERVER, reuse the code we
already have by adding a length parameter. Additionally,
the refactoring will make adding NBD_OPT_GO in a later patch
easier.
Signed-off-by: Eric Blake <address@hidden>
---
v4: no change
v3: rebase to changes earlier in series
---
nbd/server.c | 48 +++++++++++++++++++++++-------------------------
1 file changed, 23 insertions(+), 25 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index ea0c412..a9bcecd 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -195,12 +195,15 @@ static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc,
size_t size)
*/
-static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
+/* Send a reply header, including length, but no payload.
+ * Return -errno to kill connection, 0 to continue negotiation. */
+static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
+ uint32_t opt, uint32_t len)
{
uint64_t magic;
- uint32_t len;
- TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt);
+ TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
+ type, opt, len);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
@@ -217,7 +220,7 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t
type, uint32_t opt)
LOG("write failed (rep type)");
return -EINVAL;
}
- len = cpu_to_be32(0);
+ len = cpu_to_be32(len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (rep data length)");
return -EINVAL;
@@ -225,37 +228,32 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc,
uint32_t type, uint32_t opt)
return 0;
}
+/* Send a reply header with default 0 length.
+ * Return -errno to kill connection, 0 to continue negotiation. */
+static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
+{
+ return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
+}
+
+/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
+ * Return -errno to kill connection, 0 to continue negotiation. */
static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
{
- uint64_t magic;
size_t name_len, desc_len;
- uint32_t opt, type, len;
+ uint32_t len;
const char *name = exp->name ? exp->name : "";
const char *desc = exp->description ? exp->description : "";
+ int rc;
TRACE("Advertising export name '%s' description '%s'", name, desc);
name_len = strlen(name);
desc_len = strlen(desc);
- magic = cpu_to_be64(NBD_REP_MAGIC);
- if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- LOG("write failed (magic)");
- return -EINVAL;
- }
- opt = cpu_to_be32(NBD_OPT_LIST);
- if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- LOG("write failed (opt)");
- return -EINVAL;
- }
- type = cpu_to_be32(NBD_REP_SERVER);
- if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
- LOG("write failed (reply type)");
- return -EINVAL;
- }
- len = cpu_to_be32(name_len + desc_len + sizeof(len));
- if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
- return -EINVAL;
+ len = name_len + desc_len + sizeof(len);
+ rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len);
+ if (rc < 0) {
+ return rc;
}
+
len = cpu_to_be32(name_len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (name length)");
--
2.5.5
- [Qemu-block] [PATCH v4 00/14] nbd: efficient write zeroes, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 01/14] nbd: Fix bad flag detection on server, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 09/14] nbd: Let client skip portions of server reply, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 10/14] nbd: Less allocation during NBD_OPT_LIST, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 08/14] nbd: Let server know when client gives up negotiation, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 02/14] nbd: Add qemu-nbd -D for human-readable description, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 03/14] nbd: Limit nbdflags to 16 bits, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 05/14] nbd: Share common reply-sending code in server,
Eric Blake <=
- [Qemu-block] [PATCH v4 06/14] nbd: Send message along with server NBD_REP_ERR errors, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 11/14] nbd: Support shorter handshake, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 07/14] nbd: Share common option-sending code in client, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 12/14] nbd: Improve server handling of shutdown requests, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 14/14] nbd: Implement NBD_CMD_WRITE_ZEROES on client, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 04/14] nbd: Treat flags vs. command type as separate fields, Eric Blake, 2016/06/25
- [Qemu-block] [PATCH v4 13/14] nbd: Implement NBD_CMD_WRITE_ZEROES on server, Eric Blake, 2016/06/25