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[Qemu-devel] [PULL 4/7] nbd/server: add nbd_meta_empty_or_pattern helper
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 4/7] nbd/server: add nbd_meta_empty_or_pattern helper |
Date: |
Wed, 20 Jun 2018 22:19:54 -0500 |
From: Vladimir Sementsov-Ogievskiy <address@hidden>
Add nbd_meta_pattern() and nbd_meta_empty_or_pattern() helpers for
metadata query parsing. nbd_meta_pattern() will be reused for the
"qemu" namespace in following patches.
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
[eblake: comment tweaks]
Signed-off-by: Eric Blake <address@hidden>
---
nbd/server.c | 101 ++++++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 68 insertions(+), 33 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index bbdc3c01b9f..cea5192addb 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -733,6 +733,71 @@ static int nbd_negotiate_send_meta_context(NBDClient
*client,
return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
}
+/* 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 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;
+ size_t 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;
+ } else {
+ trace_nbd_negotiate_meta_query_skip("pattern not matched");
+ }
+ 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) {
+ *match = true;
+ }
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return 1;
+ }
+
+ if (len != strlen(pattern)) {
+ trace_nbd_negotiate_meta_query_skip("different lengths");
+ return nbd_opt_skip(client, len, errp);
+ }
+
+ return nbd_meta_pattern(client, pattern, match, errp);
+}
+
/* nbd_meta_base_query
*
* Handle queries to 'base' namespace. For now, only the base:allocation
@@ -741,43 +806,12 @@ static int nbd_negotiate_send_meta_context(NBDClient
*client,
*
* 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 the "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)
{
- int ret;
- char query[sizeof("allocation") - 1];
- size_t alen = strlen("allocation");
-
- if (len == 0) {
- if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
- meta->base_allocation = true;
- }
- trace_nbd_negotiate_meta_query_parse("base:");
- return 1;
- }
-
- if (len != alen) {
- trace_nbd_negotiate_meta_query_skip("not base:allocation");
- 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;
- } else {
- trace_nbd_negotiate_meta_query_skip("not base:allocation");
- }
-
- return 1;
+ return nbd_meta_empty_or_pattern(client, "allocation", len,
+ &meta->base_allocation, errp);
}
/* nbd_negotiate_meta_query
@@ -823,6 +857,7 @@ 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);
}
--
2.14.4
- [Qemu-devel] [PULL 0/7] bitmap export over NBD, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 1/7] tests: Simplify .gitignore, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 3/7] nbd/server: refactor NBDExportMetaContexts, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 2/7] nbd/server: fix trace, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 4/7] nbd/server: add nbd_meta_empty_or_pattern helper,
Eric Blake <=
- [Qemu-devel] [PULL 6/7] qapi: new qmp command nbd-server-add-bitmap, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 7/7] docs/interop: add nbd.txt, Eric Blake, 2018/06/20
- [Qemu-devel] [PULL 5/7] nbd/server: implement dirty bitmap export, Eric Blake, 2018/06/20
- Re: [Qemu-devel] [PULL 0/7] bitmap export over NBD, no-reply, 2018/06/21
- Re: [Qemu-devel] [PULL 0/7] bitmap export over NBD, no-reply, 2018/06/21
- Re: [Qemu-devel] [PULL 0/7] bitmap export over NBD, Peter Maydell, 2018/06/21