From de65ad93b1b0a38c8a3f26eb1bc4090eb19db00f Mon Sep 17 00:00:00 2001 From: John Snow Date: Wed, 18 Jul 2018 22:55:02 +0200 Subject: [PATCH 244/268] nbd/server: add nbd_meta_empty_or_pattern helper RH-Author: John Snow Message-id: <20180718225511.14878-27-jsnow@redhat.com> Patchwork-id: 81398 O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 26/35] nbd/server: add nbd_meta_empty_or_pattern helper Bugzilla: 1207657 RH-Acked-by: Eric Blake RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Fam Zheng From: Vladimir Sementsov-Ogievskiy 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 Message-Id: <20180609151758.17343-4-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake [eblake: comment tweaks] Signed-off-by: Eric Blake (cherry picked from commit b0769d8f8df0b51881f1f15c9e29722cf6191a43) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- nbd/server.c | 89 ++++++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 62 insertions(+), 27 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 26cc41a..9171cd4 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -733,53 +733,87 @@ 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 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. +/* 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 the "base:allocation" - * namespace. It only means that there are no errors. + * 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_base_query(NBDClient *client, NBDExportMetaContexts *meta, - uint32_t len, Error **errp) +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"); - - if (len == 0) { - if (client->opt == NBD_OPT_LIST_META_CONTEXT) { - meta->base_allocation = true; - } - trace_nbd_negotiate_meta_query_parse("base:"); - return 1; - } + char *query; + size_t len = strlen(pattern); - if (len != alen) { - trace_nbd_negotiate_meta_query_skip("not base:allocation"); - return nbd_opt_skip(client, len, errp); - } + 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, "allocation", alen) == 0) { - trace_nbd_negotiate_meta_query_parse("base:allocation"); - meta->base_allocation = true; + if (strncmp(query, pattern, len) == 0) { + trace_nbd_negotiate_meta_query_parse(pattern); + *match = true; } else { - trace_nbd_negotiate_meta_query_skip("not base:allocation"); + 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 + * 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. + */ +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 * * Parse namespace name and call corresponding function to parse body of the @@ -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); } -- 1.8.3.1