diff options
| -rw-r--r-- | nbd/server.c | 189 |
1 files changed, 68 insertions, 121 deletions
diff --git a/nbd/server.c b/nbd/server.c index 50f95ab..e75c825 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 |