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-rw-r--r--nbd/server.c189
1 files changed, 68 insertions, 121 deletions
diff --git a/nbd/server.c b/nbd/server.c
index 50f95abe31..e75c825879 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2016-2018 Red Hat, Inc.
+ * Copyright (C) 2016-2020 Red Hat, Inc.
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device Server Side
@@ -797,135 +797,95 @@ 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.
+/*
+ * Return true if @query matches @pattern, or if @query is empty when
+ * the @client is performing _LIST_.
*/
-static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
- Error **errp)
+static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
+ const char *query)
{
- int ret;
- char *query;
- size_t len = strlen(pattern);
-
- assert(len);
-
- query = g_malloc(len);
- ret = nbd_opt_read(client, query, len, true, errp);
- if (ret <= 0) {
- g_free(query);
- return ret;
+ if (!*query) {
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return client->opt == NBD_OPT_LIST_META_CONTEXT;
}
-
- if (strncmp(query, pattern, len) == 0) {
+ if (strcmp(query, pattern) == 0) {
trace_nbd_negotiate_meta_query_parse(pattern);
- *match = true;
- } else {
- trace_nbd_negotiate_meta_query_skip("pattern not matched");
+ return true;
}
- g_free(query);
-
- return 1;
+ trace_nbd_negotiate_meta_query_skip("pattern not matched");
+ return false;
}
/*
- * 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.
+ * Return true and adjust @str in place if it begins with @prefix.
*/
-static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
- uint32_t len, bool *match, Error **errp)
+static bool nbd_strshift(const char **str, const char *prefix)
{
- if (len == 0) {
- if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
- *match = true;
- }
- trace_nbd_negotiate_meta_query_parse("empty");
- return 1;
- }
+ size_t len = strlen(prefix);
- if (len != strlen(pattern)) {
- trace_nbd_negotiate_meta_query_skip("different lengths");
- return nbd_opt_skip(client, len, errp);
+ if (strncmp(*str, prefix, len) == 0) {
+ *str += len;
+ return true;
}
-
- return nbd_meta_pattern(client, pattern, match, errp);
+ return false;
}
/* nbd_meta_base_query
*
* Handle queries to 'base' namespace. For now, only the base:allocation
- * context is available. '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.
+ * context is available. Return true if @query has been handled.
*/
-static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
- uint32_t len, Error **errp)
+static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
+ const char *query)
{
- return nbd_meta_empty_or_pattern(client, "allocation", len,
- &meta->base_allocation, errp);
+ if (!nbd_strshift(&query, "base:")) {
+ return false;
+ }
+ trace_nbd_negotiate_meta_query_parse("base:");
+
+ if (nbd_meta_empty_or_pattern(client, "allocation", query)) {
+ meta->base_allocation = true;
+ }
+ return true;
}
-/* nbd_meta_bitmap_query
+/* nbd_meta_qemu_query
*
- * Handle query to 'qemu:' namespace.
- * @len is the amount of text remaining to be read from the current name, after
- * the 'qemu:' 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_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
- uint32_t len, Error **errp)
+ * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap:
+ * context is available. Return true if @query has been handled.
+ */
+static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
+ const char *query)
{
- bool dirty_bitmap = false;
- size_t dirty_bitmap_len = strlen("dirty-bitmap:");
- int ret;
-
- if (!meta->exp->export_bitmap) {
- trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
- return nbd_opt_skip(client, len, errp);
+ if (!nbd_strshift(&query, "qemu:")) {
+ return false;
}
+ trace_nbd_negotiate_meta_query_parse("qemu:");
- if (len == 0) {
+ if (!*query) {
if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
- meta->bitmap = true;
+ meta->bitmap = !!meta->exp->export_bitmap;
}
trace_nbd_negotiate_meta_query_parse("empty");
- return 1;
- }
-
- if (len < dirty_bitmap_len) {
- trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
- return nbd_opt_skip(client, len, errp);
+ return true;
}
- len -= dirty_bitmap_len;
- ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
- if (ret <= 0) {
- return ret;
- }
- if (!dirty_bitmap) {
- trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
- return nbd_opt_skip(client, len, errp);
+ if (nbd_strshift(&query, "dirty-bitmap:")) {
+ trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
+ if (!meta->exp->export_bitmap) {
+ trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
+ return true;
+ }
+ if (nbd_meta_empty_or_pattern(client,
+ meta->exp->export_bitmap_context +
+ strlen("qemu:dirty-bitmap:"), query)) {
+ meta->bitmap = true;
+ }
+ return true;
}
- trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
-
- return nbd_meta_empty_or_pattern(
- client, meta->exp->export_bitmap_context +
- strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
+ trace_nbd_negotiate_meta_query_skip("not dirty-bitmap");
+ return true;
}
/* nbd_negotiate_meta_query
@@ -935,22 +895,13 @@ static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
*
* The only supported namespaces are 'base' and 'qemu'.
*
- * The function aims not wasting time and memory to read long unknown namespace
- * names.
- *
* 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_negotiate_meta_query(NBDClient *client,
NBDExportMetaContexts *meta, Error **errp)
{
- /*
- * Both 'qemu' and 'base' namespaces have length = 5 including a
- * colon. If another length namespace is later introduced, this
- * should certainly be refactored.
- */
int ret;
- size_t ns_len = 5;
- char ns[5];
+ g_autofree char *query = NULL;
uint32_t len;
ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
@@ -963,27 +914,23 @@ static int nbd_negotiate_meta_query(NBDClient *client,
trace_nbd_negotiate_meta_query_skip("length too long");
return nbd_opt_skip(client, len, errp);
}
- if (len < ns_len) {
- trace_nbd_negotiate_meta_query_skip("length too short");
- return nbd_opt_skip(client, len, errp);
- }
- len -= ns_len;
- ret = nbd_opt_read(client, ns, ns_len, true, errp);
+ query = g_malloc(len + 1);
+ ret = nbd_opt_read(client, query, len, true, errp);
if (ret <= 0) {
return ret;
}
+ query[len] = '\0';
- if (!strncmp(ns, "base:", ns_len)) {
- trace_nbd_negotiate_meta_query_parse("base:");
- return nbd_meta_base_query(client, meta, len, errp);
- } else if (!strncmp(ns, "qemu:", ns_len)) {
- trace_nbd_negotiate_meta_query_parse("qemu:");
- return nbd_meta_qemu_query(client, meta, len, errp);
+ if (nbd_meta_base_query(client, meta, query)) {
+ return 1;
+ }
+ if (nbd_meta_qemu_query(client, meta, query)) {
+ return 1;
}
trace_nbd_negotiate_meta_query_skip("unknown namespace");
- return nbd_opt_skip(client, len, errp);
+ return 1;
}
/* nbd_negotiate_meta_queries
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-11-21 18:56:32 +0100