Add nbd_meta_pattern() and nbd_meta_empty_or_pattern() helpers for
metadata query parsing. nbd_meta_pattern() will be reused for "qemu"
namespace in following patches.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
nbd/server.c | 82 ++++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 57 insertions(+), 25 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 7584ff7dcc..8869dfe1f9 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -734,48 +734,79 @@ static int nbd_negotiate_send_meta_context(NBDClient
*client,
return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
}
-/* nbd_meta_base_query
- *
- * Handle query to 'base' namespace. For now, only base:allocation context is
- * available in it. 'len' is the amount of text remaining to be read from
- * the current name, after the 'base:' portion has been stripped.
+/* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
+ * @match is never set to false.
*
* Return -errno on I/O error, 0 if option was completely handled by
* sending a reply about inconsistent lengths, or 1 on success.
*
- * Note: return code = 1 doesn't mean that we've parsed "base:allocation"
- * namespace. It only means that there are no errors.*/
-static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
- uint32_t len, Error **errp)
+ * Note: return code = 1 doesn't mean that we've read exactly @pattern
+ * It only means that there are no errors. */
+static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool
*match,
+ Error **errp)
{
int ret;
- char query[sizeof("allocation") - 1];
- size_t alen = strlen("allocation");
+ char *query;
+ int len = strlen(pattern);
+
+ assert(len);
+
+ query = g_malloc(len);
+ ret = nbd_opt_read(client, query, len, errp);
+ if (ret <= 0) {
+ g_free(query);
+ return ret;
+ }
+
+ if (strncmp(query, pattern, len) == 0) {
+ trace_nbd_negotiate_meta_query_parse(pattern);
+ *match = true;
+ }
+ g_free(query);
+ return 1;
+}
+
+/* Read @len bytes, and set @match to true if they match @pattern, or if @len
+ * is 0 and the client is performing _LIST_. @match is never set to false.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success.
+ *
+ * Note: return code = 1 doesn't mean that we've read exactly @pattern
+ * It only means that there are no errors. */
+static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
+ uint32_t len, bool *match, Error **errp)
+{
if (len == 0) {
if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
- meta->base_allocation = true;
+ *match = true;
}
- trace_nbd_negotiate_meta_query_parse("base:");
+ trace_nbd_negotiate_meta_query_parse("empty");
return 1;
}
- if (len != alen) {
- trace_nbd_negotiate_meta_query_skip("not base:allocation");
+ if (len != strlen(pattern)) {
+ trace_nbd_negotiate_meta_query_skip("different lengths");
return nbd_opt_skip(client, len, errp);
}
- ret = nbd_opt_read(client, query, len, errp);
- if (ret <= 0) {
- return ret;
- }
-
- if (strncmp(query, "allocation", alen) == 0) {
- trace_nbd_negotiate_meta_query_parse("base:allocation");
- meta->base_allocation = true;
- }
+ return nbd_meta_pattern(client, pattern, match, errp);
+}
- return 1;
+/* nbd_meta_base_query
+ *
+ * Handle query to 'base' namespace. For now, only base:allocation context is
+ * available in it. 'len' is the amount of text remaining to be read from
+ * the current name, after the 'base:' portion has been stripped.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success. */
+static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
+ uint32_t len, Error **errp)
+{
+ return nbd_meta_empty_or_pattern(client, "allocation", len,
+ &meta->base_allocation, errp);
}
/* nbd_negotiate_meta_query
@@ -821,6 +852,7 @@ static int nbd_negotiate_meta_query(NBDClient *client,
return nbd_opt_skip(client, len, errp);
}
+ trace_nbd_negotiate_meta_query_parse("base:");
return nbd_meta_base_query(client, meta, len, errp);
}
--
2.11.1
