From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35965) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLQxQ-000848-5A for qemu-devel@nongnu.org; Wed, 23 May 2018 06:25:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLQxK-0003tU-3H for qemu-devel@nongnu.org; Wed, 23 May 2018 06:25:23 -0400 From: Vladimir Sementsov-Ogievskiy Date: Wed, 23 May 2018 13:24:16 +0300 Message-Id: <20180523102419.28665-3-vsementsov@virtuozzo.com> In-Reply-To: <20180523102419.28665-1-vsementsov@virtuozzo.com> References: <20180523102419.28665-1-vsementsov@virtuozzo.com> Subject: [Qemu-devel] [PATCH v3 2/5] nbd/server: add nbd_meta_empty_or_pattern helper List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: armbru@redhat.com, pbonzini@redhat.com, eblake@redhat.com, mreitz@redhat.com, kwolf@redhat.com, vsementsov@virtuozzo.com, den@openvz.org 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 --- 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