| /* |
| * Copyright (C) 2016-2019 Red Hat, Inc. |
| * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> |
| * |
| * Network Block Device Client Side |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; under version 2 of the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qapi/error.h" |
| #include "qemu/queue.h" |
| #include "trace.h" |
| #include "nbd-internal.h" |
| #include "qemu/cutils.h" |
| |
| /* Definitions for opaque data types */ |
| |
| static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); |
| |
| /* That's all folks */ |
| |
| /* Basic flow for negotiation |
| |
| Server Client |
| Negotiate |
| |
| or |
| |
| Server Client |
| Negotiate #1 |
| Option |
| Negotiate #2 |
| |
| ---- |
| |
| followed by |
| |
| Server Client |
| Request |
| Response |
| Request |
| Response |
| ... |
| ... |
| Request (type == 2) |
| |
| */ |
| |
| /* Send an option request. |
| * |
| * The request is for option @opt, with @data containing @len bytes of |
| * additional payload for the request (@len may be -1 to treat @data as |
| * a C string; and @data may be NULL if @len is 0). |
| * Return 0 if successful, -1 with errp set if it is impossible to |
| * continue. */ |
| static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt, |
| uint32_t len, const char *data, |
| Error **errp) |
| { |
| ERRP_GUARD(); |
| NBDOption req; |
| QEMU_BUILD_BUG_ON(sizeof(req) != 16); |
| |
| if (len == -1) { |
| req.length = len = strlen(data); |
| } |
| trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len); |
| |
| stq_be_p(&req.magic, NBD_OPTS_MAGIC); |
| stl_be_p(&req.option, opt); |
| stl_be_p(&req.length, len); |
| |
| if (nbd_write(ioc, &req, sizeof(req), errp) < 0) { |
| error_prepend(errp, "Failed to send option request header: "); |
| return -1; |
| } |
| |
| if (len && nbd_write(ioc, (char *) data, len, errp) < 0) { |
| error_prepend(errp, "Failed to send option request data: "); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are |
| * not going to attempt further negotiation. */ |
| static void nbd_send_opt_abort(QIOChannel *ioc) |
| { |
| /* Technically, a compliant server is supposed to reply to us; but |
| * older servers disconnected instead. At any rate, we're allowed |
| * to disconnect without waiting for the server reply, so we don't |
| * even care if the request makes it to the server, let alone |
| * waiting around for whether the server replies. */ |
| nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL); |
| } |
| |
| |
| /* Receive the header of an option reply, which should match the given |
| * opt. Read through the length field, but NOT the length bytes of |
| * payload. Return 0 if successful, -1 with errp set if it is |
| * impossible to continue. */ |
| static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt, |
| NBDOptionReply *reply, Error **errp) |
| { |
| QEMU_BUILD_BUG_ON(sizeof(*reply) != 20); |
| if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| reply->magic = be64_to_cpu(reply->magic); |
| reply->option = be32_to_cpu(reply->option); |
| reply->type = be32_to_cpu(reply->type); |
| reply->length = be32_to_cpu(reply->length); |
| |
| trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option), |
| reply->type, nbd_rep_lookup(reply->type), |
| reply->length); |
| |
| if (reply->magic != NBD_REP_MAGIC) { |
| error_setg(errp, "Unexpected option reply magic"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (reply->option != opt) { |
| error_setg(errp, "Unexpected option type %u (%s), expected %u (%s)", |
| reply->option, nbd_opt_lookup(reply->option), |
| opt, nbd_opt_lookup(opt)); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* |
| * If reply represents success, return 1 without further action. If |
| * reply represents an error, consume the optional payload of the |
| * packet on ioc. Then return 0 for unsupported (so the client can |
| * fall back to other approaches), where @strict determines if only |
| * ERR_UNSUP or all errors fit that category, or -1 with errp set for |
| * other errors. |
| */ |
| static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply, |
| bool strict, Error **errp) |
| { |
| ERRP_GUARD(); |
| g_autofree char *msg = NULL; |
| |
| if (!(reply->type & (1 << 31))) { |
| return 1; |
| } |
| |
| if (reply->length) { |
| if (reply->length > NBD_MAX_BUFFER_SIZE) { |
| error_setg(errp, "server error %" PRIu32 |
| " (%s) message is too long", |
| reply->type, nbd_rep_lookup(reply->type)); |
| goto err; |
| } |
| msg = g_malloc(reply->length + 1); |
| if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) { |
| error_prepend(errp, "Failed to read option error %" PRIu32 |
| " (%s) message: ", |
| reply->type, nbd_rep_lookup(reply->type)); |
| goto err; |
| } |
| msg[reply->length] = '\0'; |
| trace_nbd_server_error_msg(reply->type, |
| nbd_reply_type_lookup(reply->type), msg); |
| } |
| |
| if (reply->type == NBD_REP_ERR_UNSUP || !strict) { |
| trace_nbd_reply_err_ignored(reply->option, |
| nbd_opt_lookup(reply->option), |
| reply->type, nbd_rep_lookup(reply->type)); |
| return 0; |
| } |
| |
| switch (reply->type) { |
| case NBD_REP_ERR_POLICY: |
| error_setg(errp, "Denied by server for option %" PRIu32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_INVALID: |
| error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_PLATFORM: |
| error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_TLS_REQD: |
| error_setg(errp, "TLS negotiation required before option %" PRIu32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| error_append_hint(errp, "Did you forget a valid tls-creds?\n"); |
| break; |
| |
| case NBD_REP_ERR_UNKNOWN: |
| error_setg(errp, "Requested export not available"); |
| break; |
| |
| case NBD_REP_ERR_SHUTDOWN: |
| error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_BLOCK_SIZE_REQD: |
| error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| default: |
| error_setg(errp, "Unknown error code when asking for option %" PRIu32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| } |
| |
| if (msg) { |
| error_append_hint(errp, "server reported: %s\n", msg); |
| } |
| |
| err: |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| /* nbd_receive_list: |
| * Process another portion of the NBD_OPT_LIST reply, populating any |
| * name received into *@name. If @description is non-NULL, and the |
| * server provided a description, that is also populated. The caller |
| * must eventually call g_free() on success. |
| * Returns 1 if name and description were set and iteration must continue, |
| * 0 if iteration is complete (including if OPT_LIST unsupported), |
| * -1 with @errp set if an unrecoverable error occurred. |
| */ |
| static int nbd_receive_list(QIOChannel *ioc, char **name, char **description, |
| Error **errp) |
| { |
| NBDOptionReply reply; |
| uint32_t len; |
| uint32_t namelen; |
| g_autofree char *local_name = NULL; |
| g_autofree char *local_desc = NULL; |
| int error; |
| |
| if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { |
| return -1; |
| } |
| error = nbd_handle_reply_err(ioc, &reply, true, errp); |
| if (error <= 0) { |
| return error; |
| } |
| len = reply.length; |
| |
| if (reply.type == NBD_REP_ACK) { |
| if (len != 0) { |
| error_setg(errp, "length too long for option end"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 0; |
| } else if (reply.type != NBD_REP_SERVER) { |
| error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", |
| reply.type, nbd_rep_lookup(reply.type), |
| NBD_REP_SERVER, nbd_rep_lookup(NBD_REP_SERVER)); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { |
| error_setg(errp, "incorrect option length %" PRIu32, len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| len -= sizeof(namelen); |
| if (len < namelen || namelen > NBD_MAX_STRING_SIZE) { |
| error_setg(errp, "incorrect name length in server's list response"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| local_name = g_malloc(namelen + 1); |
| if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| local_name[namelen] = '\0'; |
| len -= namelen; |
| if (len) { |
| if (len > NBD_MAX_STRING_SIZE) { |
| error_setg(errp, "incorrect description length in server's " |
| "list response"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| local_desc = g_malloc(len + 1); |
| if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| local_desc[len] = '\0'; |
| } |
| |
| trace_nbd_receive_list(local_name, local_desc ?: ""); |
| *name = g_steal_pointer(&local_name); |
| if (description) { |
| *description = g_steal_pointer(&local_desc); |
| } |
| return 1; |
| } |
| |
| |
| /* |
| * nbd_opt_info_or_go: |
| * Send option for NBD_OPT_INFO or NBD_OPT_GO and parse the reply. |
| * Returns -1 if the option proves the export @info->name cannot be |
| * used, 0 if the option is unsupported (fall back to NBD_OPT_LIST and |
| * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to |
| * go (with the rest of @info populated). |
| */ |
| static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt, |
| NBDExportInfo *info, Error **errp) |
| { |
| ERRP_GUARD(); |
| NBDOptionReply reply; |
| uint32_t len = strlen(info->name); |
| uint16_t type; |
| int error; |
| char *buf; |
| |
| /* The protocol requires that the server send NBD_INFO_EXPORT with |
| * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so |
| * flags still 0 is a witness of a broken server. */ |
| info->flags = 0; |
| |
| assert(opt == NBD_OPT_GO || opt == NBD_OPT_INFO); |
| trace_nbd_opt_info_go_start(nbd_opt_lookup(opt), info->name); |
| buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1); |
| stl_be_p(buf, len); |
| memcpy(buf + 4, info->name, len); |
| /* At most one request, everything else up to server */ |
| stw_be_p(buf + 4 + len, info->request_sizes); |
| if (info->request_sizes) { |
| stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE); |
| } |
| error = nbd_send_option_request(ioc, opt, |
| 4 + len + 2 + 2 * info->request_sizes, |
| buf, errp); |
| g_free(buf); |
| if (error < 0) { |
| return -1; |
| } |
| |
| while (1) { |
| if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| return -1; |
| } |
| error = nbd_handle_reply_err(ioc, &reply, true, errp); |
| if (error <= 0) { |
| return error; |
| } |
| len = reply.length; |
| |
| if (reply.type == NBD_REP_ACK) { |
| /* |
| * Server is done sending info, and moved into transmission |
| * phase for NBD_OPT_GO, but make sure it sent flags |
| */ |
| if (len) { |
| error_setg(errp, "server sent invalid NBD_REP_ACK"); |
| return -1; |
| } |
| if (!info->flags) { |
| error_setg(errp, "broken server omitted NBD_INFO_EXPORT"); |
| return -1; |
| } |
| trace_nbd_opt_info_go_success(nbd_opt_lookup(opt)); |
| return 1; |
| } |
| if (reply.type != NBD_REP_INFO) { |
| error_setg(errp, "unexpected reply type %u (%s), expected %u (%s)", |
| reply.type, nbd_rep_lookup(reply.type), |
| NBD_REP_INFO, nbd_rep_lookup(NBD_REP_INFO)); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (len < sizeof(type)) { |
| error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short", |
| len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read16(ioc, &type, "info type", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| len -= sizeof(type); |
| switch (type) { |
| case NBD_INFO_EXPORT: |
| if (len != sizeof(info->size) + sizeof(info->flags)) { |
| error_setg(errp, "remaining export info len %" PRIu32 |
| " is unexpected size", len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read64(ioc, &info->size, "info size", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read16(ioc, &info->flags, "info flags", errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (info->min_block && |
| !QEMU_IS_ALIGNED(info->size, info->min_block)) { |
| error_setg(errp, "export size %" PRIu64 " is not multiple of " |
| "minimum block size %" PRIu32, info->size, |
| info->min_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| break; |
| |
| case NBD_INFO_BLOCK_SIZE: |
| if (len != sizeof(info->min_block) * 3) { |
| error_setg(errp, "remaining export info len %" PRIu32 |
| " is unexpected size", len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read32(ioc, &info->min_block, "info minimum block size", |
| errp) < 0) { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (!is_power_of_2(info->min_block)) { |
| error_setg(errp, "server minimum block size %" PRIu32 |
| " is not a power of two", info->min_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read32(ioc, &info->opt_block, "info preferred block size", |
| errp) < 0) |
| { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (!is_power_of_2(info->opt_block) || |
| info->opt_block < info->min_block) { |
| error_setg(errp, "server preferred block size %" PRIu32 |
| " is not valid", info->opt_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read32(ioc, &info->max_block, "info maximum block size", |
| errp) < 0) |
| { |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (info->max_block < info->min_block) { |
| error_setg(errp, "server maximum block size %" PRIu32 |
| " is not valid", info->max_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| trace_nbd_opt_info_block_size(info->min_block, info->opt_block, |
| info->max_block); |
| break; |
| |
| default: |
| /* |
| * Not worth the bother to check if NBD_INFO_NAME or |
| * NBD_INFO_DESCRIPTION exceed NBD_MAX_STRING_SIZE. |
| */ |
| trace_nbd_opt_info_unknown(type, nbd_info_lookup(type)); |
| if (nbd_drop(ioc, len, errp) < 0) { |
| error_prepend(errp, "Failed to read info payload: "); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| break; |
| } |
| } |
| } |
| |
| /* Return -1 on failure, 0 if wantname is an available export. */ |
| static int nbd_receive_query_exports(QIOChannel *ioc, |
| const char *wantname, |
| Error **errp) |
| { |
| bool list_empty = true; |
| bool found_export = false; |
| |
| trace_nbd_receive_query_exports_start(wantname); |
| if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { |
| return -1; |
| } |
| |
| while (1) { |
| char *name; |
| int ret = nbd_receive_list(ioc, &name, NULL, errp); |
| |
| if (ret < 0) { |
| /* Server gave unexpected reply */ |
| return -1; |
| } else if (ret == 0) { |
| /* Done iterating. */ |
| if (list_empty) { |
| /* |
| * We don't have enough context to tell a server that |
| * sent an empty list apart from a server that does |
| * not support the list command; but as this function |
| * is just used to trigger a nicer error message |
| * before trying NBD_OPT_EXPORT_NAME, assume the |
| * export is available. |
| */ |
| return 0; |
| } else if (!found_export) { |
| error_setg(errp, "No export with name '%s' available", |
| wantname); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| trace_nbd_receive_query_exports_success(wantname); |
| return 0; |
| } |
| list_empty = false; |
| if (!strcmp(name, wantname)) { |
| found_export = true; |
| } |
| g_free(name); |
| } |
| } |
| |
| /* |
| * nbd_request_simple_option: Send an option request, and parse the reply. |
| * @strict controls whether ERR_UNSUP or all errors produce 0 status. |
| * return 1 for successful negotiation, |
| * 0 if operation is unsupported, |
| * -1 with errp set for any other error |
| */ |
| static int nbd_request_simple_option(QIOChannel *ioc, int opt, bool strict, |
| Error **errp) |
| { |
| NBDOptionReply reply; |
| int error; |
| |
| if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) { |
| return -1; |
| } |
| |
| if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| return -1; |
| } |
| error = nbd_handle_reply_err(ioc, &reply, strict, errp); |
| if (error <= 0) { |
| return error; |
| } |
| |
| if (reply.type != NBD_REP_ACK) { |
| error_setg(errp, "Server answered option %d (%s) with unexpected " |
| "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt), |
| reply.type, nbd_rep_lookup(reply.type)); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| if (reply.length != 0) { |
| error_setg(errp, "Option %d ('%s') response length is %" PRIu32 |
| " (it should be zero)", opt, nbd_opt_lookup(opt), |
| reply.length); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| return 1; |
| } |
| |
| static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, |
| QCryptoTLSCreds *tlscreds, |
| const char *hostname, Error **errp) |
| { |
| int ret; |
| QIOChannelTLS *tioc; |
| struct NBDTLSHandshakeData data = { 0 }; |
| |
| ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, true, errp); |
| if (ret <= 0) { |
| if (ret == 0) { |
| error_setg(errp, "Server don't support STARTTLS option"); |
| nbd_send_opt_abort(ioc); |
| } |
| return NULL; |
| } |
| |
| trace_nbd_receive_starttls_new_client(); |
| tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); |
| if (!tioc) { |
| return NULL; |
| } |
| qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); |
| data.loop = g_main_loop_new(g_main_context_default(), FALSE); |
| trace_nbd_receive_starttls_tls_handshake(); |
| qio_channel_tls_handshake(tioc, |
| nbd_tls_handshake, |
| &data, |
| NULL, |
| NULL); |
| |
| if (!data.complete) { |
| g_main_loop_run(data.loop); |
| } |
| g_main_loop_unref(data.loop); |
| if (data.error) { |
| error_propagate(errp, data.error); |
| object_unref(OBJECT(tioc)); |
| return NULL; |
| } |
| |
| return QIO_CHANNEL(tioc); |
| } |
| |
| /* |
| * nbd_send_meta_query: |
| * Send 0 or 1 set/list meta context queries. |
| * Return 0 on success, -1 with errp set for any error |
| */ |
| static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt, |
| const char *export, const char *query, |
| Error **errp) |
| { |
| int ret; |
| uint32_t export_len = strlen(export); |
| uint32_t queries = !!query; |
| uint32_t query_len = 0; |
| uint32_t data_len; |
| char *data; |
| char *p; |
| |
| data_len = sizeof(export_len) + export_len + sizeof(queries); |
| assert(export_len <= NBD_MAX_STRING_SIZE); |
| if (query) { |
| query_len = strlen(query); |
| data_len += sizeof(query_len) + query_len; |
| assert(query_len <= NBD_MAX_STRING_SIZE); |
| } else { |
| assert(opt == NBD_OPT_LIST_META_CONTEXT); |
| } |
| p = data = g_malloc(data_len); |
| |
| trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export); |
| stl_be_p(p, export_len); |
| memcpy(p += sizeof(export_len), export, export_len); |
| stl_be_p(p += export_len, queries); |
| if (query) { |
| stl_be_p(p += sizeof(queries), query_len); |
| memcpy(p += sizeof(query_len), query, query_len); |
| } |
| |
| ret = nbd_send_option_request(ioc, opt, data_len, data, errp); |
| g_free(data); |
| return ret; |
| } |
| |
| /* |
| * nbd_receive_one_meta_context: |
| * Called in a loop to receive and trace one set/list meta context reply. |
| * Pass non-NULL @name or @id to collect results back to the caller, which |
| * must eventually call g_free(). |
| * return 1 if name is set and iteration must continue, |
| * 0 if iteration is complete (including if option is unsupported), |
| * -1 with errp set for any error |
| */ |
| static int nbd_receive_one_meta_context(QIOChannel *ioc, |
| uint32_t opt, |
| char **name, |
| uint32_t *id, |
| Error **errp) |
| { |
| int ret; |
| NBDOptionReply reply; |
| char *local_name = NULL; |
| uint32_t local_id; |
| |
| if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| return -1; |
| } |
| |
| ret = nbd_handle_reply_err(ioc, &reply, false, errp); |
| if (ret <= 0) { |
| return ret; |
| } |
| |
| if (reply.type == NBD_REP_ACK) { |
| if (reply.length != 0) { |
| error_setg(errp, "Unexpected length to ACK response"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 0; |
| } else if (reply.type != NBD_REP_META_CONTEXT) { |
| error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", |
| reply.type, nbd_rep_lookup(reply.type), |
| NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT)); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| if (reply.length <= sizeof(local_id) || |
| reply.length > NBD_MAX_BUFFER_SIZE) { |
| error_setg(errp, "Failed to negotiate meta context, server " |
| "answered with unexpected length %" PRIu32, |
| reply.length); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| if (nbd_read32(ioc, &local_id, "context id", errp) < 0) { |
| return -1; |
| } |
| |
| reply.length -= sizeof(local_id); |
| local_name = g_malloc(reply.length + 1); |
| if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) { |
| g_free(local_name); |
| return -1; |
| } |
| local_name[reply.length] = '\0'; |
| trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id); |
| |
| if (name) { |
| *name = local_name; |
| } else { |
| g_free(local_name); |
| } |
| if (id) { |
| *id = local_id; |
| } |
| return 1; |
| } |
| |
| /* |
| * nbd_negotiate_simple_meta_context: |
| * Request the server to set the meta context for export @info->name |
| * using @info->x_dirty_bitmap with a fallback to "base:allocation", |
| * setting @info->context_id to the resulting id. Fail if the server |
| * responds with more than one context or with a context different |
| * than the query. |
| * return 1 for successful negotiation, |
| * 0 if operation is unsupported, |
| * -1 with errp set for any other error |
| */ |
| static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, |
| NBDExportInfo *info, |
| Error **errp) |
| { |
| /* |
| * TODO: Removing the x_dirty_bitmap hack will mean refactoring |
| * this function to request and store ids for multiple contexts |
| * (both base:allocation and a dirty bitmap), at which point this |
| * function should lose the term _simple. |
| */ |
| int ret; |
| const char *context = info->x_dirty_bitmap ?: "base:allocation"; |
| bool received = false; |
| char *name = NULL; |
| |
| if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT, |
| info->name, context, errp) < 0) { |
| return -1; |
| } |
| |
| ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, |
| &name, &info->context_id, errp); |
| if (ret < 0) { |
| return -1; |
| } |
| if (ret == 1) { |
| if (strcmp(context, name)) { |
| error_setg(errp, "Failed to negotiate meta context '%s', server " |
| "answered with different context '%s'", context, |
| name); |
| g_free(name); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| g_free(name); |
| received = true; |
| |
| ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, |
| NULL, NULL, errp); |
| if (ret < 0) { |
| return -1; |
| } |
| } |
| if (ret != 0) { |
| error_setg(errp, "Server answered with more than one context"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return received; |
| } |
| |
| /* |
| * nbd_list_meta_contexts: |
| * Request the server to list all meta contexts for export @info->name. |
| * return 0 if list is complete (even if empty), |
| * -1 with errp set for any error |
| */ |
| static int nbd_list_meta_contexts(QIOChannel *ioc, |
| NBDExportInfo *info, |
| Error **errp) |
| { |
| int ret; |
| int seen_any = false; |
| int seen_qemu = false; |
| |
| if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, |
| info->name, NULL, errp) < 0) { |
| return -1; |
| } |
| |
| while (1) { |
| char *context; |
| |
| ret = nbd_receive_one_meta_context(ioc, NBD_OPT_LIST_META_CONTEXT, |
| &context, NULL, errp); |
| if (ret == 0 && seen_any && !seen_qemu) { |
| /* |
| * Work around qemu 3.0 bug: the server forgot to send |
| * "qemu:" replies to 0 queries. If we saw at least one |
| * reply (probably base:allocation), but none of them were |
| * qemu:, then run a more specific query to make sure. |
| */ |
| seen_qemu = true; |
| if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, |
| info->name, "qemu:", errp) < 0) { |
| return -1; |
| } |
| continue; |
| } |
| if (ret <= 0) { |
| return ret; |
| } |
| seen_any = true; |
| seen_qemu |= strstart(context, "qemu:", NULL); |
| info->contexts = g_renew(char *, info->contexts, ++info->n_contexts); |
| info->contexts[info->n_contexts - 1] = context; |
| } |
| } |
| |
| /* |
| * nbd_start_negotiate: |
| * Start the handshake to the server. After a positive return, the server |
| * is ready to accept additional NBD_OPT requests. |
| * Returns: negative errno: failure talking to server |
| * 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle |
| * 1: server is newstyle, but can only accept EXPORT_NAME |
| * 2: server is newstyle, but lacks structured replies |
| * 3: server is newstyle and set up for structured replies |
| */ |
| static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc, |
| QCryptoTLSCreds *tlscreds, |
| const char *hostname, QIOChannel **outioc, |
| bool structured_reply, bool *zeroes, |
| Error **errp) |
| { |
| ERRP_GUARD(); |
| uint64_t magic; |
| |
| trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>"); |
| |
| if (zeroes) { |
| *zeroes = true; |
| } |
| if (outioc) { |
| *outioc = NULL; |
| } |
| if (tlscreds && !outioc) { |
| error_setg(errp, "Output I/O channel required for TLS"); |
| return -EINVAL; |
| } |
| |
| if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) { |
| return -EINVAL; |
| } |
| trace_nbd_receive_negotiate_magic(magic); |
| |
| if (magic != NBD_INIT_MAGIC) { |
| error_setg(errp, "Bad initial magic received: 0x%" PRIx64, magic); |
| return -EINVAL; |
| } |
| |
| if (nbd_read64(ioc, &magic, "server magic", errp) < 0) { |
| return -EINVAL; |
| } |
| trace_nbd_receive_negotiate_magic(magic); |
| |
| if (magic == NBD_OPTS_MAGIC) { |
| uint32_t clientflags = 0; |
| uint16_t globalflags; |
| bool fixedNewStyle = false; |
| |
| if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) { |
| return -EINVAL; |
| } |
| trace_nbd_receive_negotiate_server_flags(globalflags); |
| if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { |
| fixedNewStyle = true; |
| clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; |
| } |
| if (globalflags & NBD_FLAG_NO_ZEROES) { |
| if (zeroes) { |
| *zeroes = false; |
| } |
| clientflags |= NBD_FLAG_C_NO_ZEROES; |
| } |
| /* client requested flags */ |
| clientflags = cpu_to_be32(clientflags); |
| if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { |
| error_prepend(errp, "Failed to send clientflags field: "); |
| return -EINVAL; |
| } |
| if (tlscreds) { |
| if (fixedNewStyle) { |
| *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); |
| if (!*outioc) { |
| return -EINVAL; |
| } |
| ioc = *outioc; |
| if (aio_context) { |
| qio_channel_set_blocking(ioc, false, NULL); |
| qio_channel_attach_aio_context(ioc, aio_context); |
| } |
| } else { |
| error_setg(errp, "Server does not support STARTTLS"); |
| return -EINVAL; |
| } |
| } |
| if (fixedNewStyle) { |
| int result = 0; |
| |
| if (structured_reply) { |
| result = nbd_request_simple_option(ioc, |
| NBD_OPT_STRUCTURED_REPLY, |
| false, errp); |
| if (result < 0) { |
| return -EINVAL; |
| } |
| } |
| return 2 + result; |
| } else { |
| return 1; |
| } |
| } else if (magic == NBD_CLIENT_MAGIC) { |
| if (tlscreds) { |
| error_setg(errp, "Server does not support STARTTLS"); |
| return -EINVAL; |
| } |
| return 0; |
| } else { |
| error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic); |
| return -EINVAL; |
| } |
| } |
| |
| /* |
| * nbd_negotiate_finish_oldstyle: |
| * Populate @info with the size and export flags from an oldstyle server, |
| * but does not consume 124 bytes of reserved zero padding. |
| * Returns 0 on success, -1 with @errp set on failure |
| */ |
| static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info, |
| Error **errp) |
| { |
| uint32_t oldflags; |
| |
| if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { |
| return -EINVAL; |
| } |
| |
| if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) { |
| return -EINVAL; |
| } |
| if (oldflags & ~0xffff) { |
| error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); |
| return -EINVAL; |
| } |
| info->flags = oldflags; |
| return 0; |
| } |
| |
| /* |
| * nbd_receive_negotiate: |
| * Connect to server, complete negotiation, and move into transmission phase. |
| * Returns: negative errno: failure talking to server |
| * 0: server is connected |
| */ |
| int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc, |
| QCryptoTLSCreds *tlscreds, |
| const char *hostname, QIOChannel **outioc, |
| NBDExportInfo *info, Error **errp) |
| { |
| ERRP_GUARD(); |
| int result; |
| bool zeroes; |
| bool base_allocation = info->base_allocation; |
| |
| assert(info->name && strlen(info->name) <= NBD_MAX_STRING_SIZE); |
| trace_nbd_receive_negotiate_name(info->name); |
| |
| result = nbd_start_negotiate(aio_context, ioc, tlscreds, hostname, outioc, |
| info->structured_reply, &zeroes, errp); |
| |
| info->structured_reply = false; |
| info->base_allocation = false; |
| if (tlscreds && *outioc) { |
| ioc = *outioc; |
| } |
| |
| switch (result) { |
| case 3: /* newstyle, with structured replies */ |
| info->structured_reply = true; |
| if (base_allocation) { |
| result = nbd_negotiate_simple_meta_context(ioc, info, errp); |
| if (result < 0) { |
| return -EINVAL; |
| } |
| info->base_allocation = result == 1; |
| } |
| /* fall through */ |
| case 2: /* newstyle, try OPT_GO */ |
| /* Try NBD_OPT_GO first - if it works, we are done (it |
| * also gives us a good message if the server requires |
| * TLS). If it is not available, fall back to |
| * NBD_OPT_LIST for nicer error messages about a missing |
| * export, then use NBD_OPT_EXPORT_NAME. */ |
| result = nbd_opt_info_or_go(ioc, NBD_OPT_GO, info, errp); |
| if (result < 0) { |
| return -EINVAL; |
| } |
| if (result > 0) { |
| return 0; |
| } |
| /* Check our desired export is present in the |
| * server export list. Since NBD_OPT_EXPORT_NAME |
| * cannot return an error message, running this |
| * query gives us better error reporting if the |
| * export name is not available. |
| */ |
| if (nbd_receive_query_exports(ioc, info->name, errp) < 0) { |
| return -EINVAL; |
| } |
| /* fall through */ |
| case 1: /* newstyle, but limited to EXPORT_NAME */ |
| /* write the export name request */ |
| if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, info->name, |
| errp) < 0) { |
| return -EINVAL; |
| } |
| |
| /* Read the response */ |
| if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { |
| return -EINVAL; |
| } |
| |
| if (nbd_read16(ioc, &info->flags, "export flags", errp) < 0) { |
| return -EINVAL; |
| } |
| break; |
| case 0: /* oldstyle, parse length and flags */ |
| if (*info->name) { |
| error_setg(errp, "Server does not support non-empty export names"); |
| return -EINVAL; |
| } |
| if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) { |
| return -EINVAL; |
| } |
| break; |
| default: |
| return result; |
| } |
| |
| trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| if (zeroes && nbd_drop(ioc, 124, errp) < 0) { |
| error_prepend(errp, "Failed to read reserved block: "); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| /* Clean up result of nbd_receive_export_list */ |
| void nbd_free_export_list(NBDExportInfo *info, int count) |
| { |
| int i, j; |
| |
| if (!info) { |
| return; |
| } |
| |
| for (i = 0; i < count; i++) { |
| g_free(info[i].name); |
| g_free(info[i].description); |
| for (j = 0; j < info[i].n_contexts; j++) { |
| g_free(info[i].contexts[j]); |
| } |
| g_free(info[i].contexts); |
| } |
| g_free(info); |
| } |
| |
| /* |
| * nbd_receive_export_list: |
| * Query details about a server's exports, then disconnect without |
| * going into transmission phase. Return a count of the exports listed |
| * in @info by the server, or -1 on error. Caller must free @info using |
| * nbd_free_export_list(). |
| */ |
| int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, |
| const char *hostname, NBDExportInfo **info, |
| Error **errp) |
| { |
| int result; |
| int count = 0; |
| int i; |
| int rc; |
| int ret = -1; |
| NBDExportInfo *array = NULL; |
| QIOChannel *sioc = NULL; |
| |
| *info = NULL; |
| result = nbd_start_negotiate(NULL, ioc, tlscreds, hostname, &sioc, true, |
| NULL, errp); |
| if (tlscreds && sioc) { |
| ioc = sioc; |
| } |
| |
| switch (result) { |
| case 2: |
| case 3: |
| /* newstyle - use NBD_OPT_LIST to populate array, then try |
| * NBD_OPT_INFO on each array member. If structured replies |
| * are enabled, also try NBD_OPT_LIST_META_CONTEXT. */ |
| if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { |
| goto out; |
| } |
| while (1) { |
| char *name; |
| char *desc; |
| |
| rc = nbd_receive_list(ioc, &name, &desc, errp); |
| if (rc < 0) { |
| goto out; |
| } else if (rc == 0) { |
| break; |
| } |
| array = g_renew(NBDExportInfo, array, ++count); |
| memset(&array[count - 1], 0, sizeof(*array)); |
| array[count - 1].name = name; |
| array[count - 1].description = desc; |
| array[count - 1].structured_reply = result == 3; |
| } |
| |
| for (i = 0; i < count; i++) { |
| array[i].request_sizes = true; |
| rc = nbd_opt_info_or_go(ioc, NBD_OPT_INFO, &array[i], errp); |
| if (rc < 0) { |
| goto out; |
| } else if (rc == 0) { |
| /* |
| * Pointless to try rest of loop. If OPT_INFO doesn't work, |
| * it's unlikely that meta contexts work either |
| */ |
| break; |
| } |
| |
| if (result == 3 && |
| nbd_list_meta_contexts(ioc, &array[i], errp) < 0) { |
| goto out; |
| } |
| } |
| |
| /* Send NBD_OPT_ABORT as a courtesy before hanging up */ |
| nbd_send_opt_abort(ioc); |
| break; |
| case 1: /* newstyle, but limited to EXPORT_NAME */ |
| error_setg(errp, "Server does not support export lists"); |
| /* We can't even send NBD_OPT_ABORT, so merely hang up */ |
| goto out; |
| case 0: /* oldstyle, parse length and flags */ |
| array = g_new0(NBDExportInfo, 1); |
| array->name = g_strdup(""); |
| count = 1; |
| |
| if (nbd_negotiate_finish_oldstyle(ioc, array, errp) < 0) { |
| goto out; |
| } |
| |
| /* Send NBD_CMD_DISC as a courtesy to the server, but ignore all |
| * errors now that we have the information we wanted. */ |
| if (nbd_drop(ioc, 124, NULL) == 0) { |
| NBDRequest request = { .type = NBD_CMD_DISC }; |
| |
| nbd_send_request(ioc, &request); |
| } |
| break; |
| default: |
| goto out; |
| } |
| |
| *info = array; |
| array = NULL; |
| ret = count; |
| |
| out: |
| qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); |
| qio_channel_close(ioc, NULL); |
| object_unref(OBJECT(sioc)); |
| nbd_free_export_list(array, count); |
| return ret; |
| } |
| |
| #ifdef __linux__ |
| int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, |
| Error **errp) |
| { |
| unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block); |
| unsigned long sectors = info->size / sector_size; |
| |
| /* FIXME: Once the kernel module is patched to honor block sizes, |
| * and to advertise that fact to user space, we should update the |
| * hand-off to the kernel to use any block sizes we learned. */ |
| assert(!info->request_sizes); |
| if (info->size / sector_size != sectors) { |
| error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel", |
| info->size); |
| return -E2BIG; |
| } |
| |
| trace_nbd_init_set_socket(); |
| |
| if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed to set NBD socket"); |
| return -serrno; |
| } |
| |
| trace_nbd_init_set_block_size(sector_size); |
| |
| if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting NBD block size"); |
| return -serrno; |
| } |
| |
| trace_nbd_init_set_size(sectors); |
| if (info->size % sector_size) { |
| trace_nbd_init_trailing_bytes(info->size % sector_size); |
| } |
| |
| if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting size (in blocks)"); |
| return -serrno; |
| } |
| |
| if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) { |
| if (errno == ENOTTY) { |
| int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0; |
| trace_nbd_init_set_readonly(); |
| |
| if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting read-only attribute"); |
| return -serrno; |
| } |
| } else { |
| int serrno = errno; |
| error_setg(errp, "Failed setting flags"); |
| return -serrno; |
| } |
| } |
| |
| trace_nbd_init_finish(); |
| |
| return 0; |
| } |
| |
| int nbd_client(int fd) |
| { |
| int ret; |
| int serrno; |
| |
| trace_nbd_client_loop(); |
| |
| ret = ioctl(fd, NBD_DO_IT); |
| if (ret < 0 && errno == EPIPE) { |
| /* NBD_DO_IT normally returns EPIPE when someone has disconnected |
| * the socket via NBD_DISCONNECT. We do not want to return 1 in |
| * that case. |
| */ |
| ret = 0; |
| } |
| serrno = errno; |
| |
| trace_nbd_client_loop_ret(ret, strerror(serrno)); |
| |
| trace_nbd_client_clear_queue(); |
| ioctl(fd, NBD_CLEAR_QUE); |
| |
| trace_nbd_client_clear_socket(); |
| ioctl(fd, NBD_CLEAR_SOCK); |
| |
| errno = serrno; |
| return ret; |
| } |
| |
| int nbd_disconnect(int fd) |
| { |
| ioctl(fd, NBD_CLEAR_QUE); |
| ioctl(fd, NBD_DISCONNECT); |
| ioctl(fd, NBD_CLEAR_SOCK); |
| return 0; |
| } |
| |
| #endif /* __linux__ */ |
| |
| int nbd_send_request(QIOChannel *ioc, NBDRequest *request) |
| { |
| uint8_t buf[NBD_REQUEST_SIZE]; |
| |
| trace_nbd_send_request(request->from, request->len, request->handle, |
| request->flags, request->type, |
| nbd_cmd_lookup(request->type)); |
| |
| stl_be_p(buf, NBD_REQUEST_MAGIC); |
| stw_be_p(buf + 4, request->flags); |
| stw_be_p(buf + 6, request->type); |
| stq_be_p(buf + 8, request->handle); |
| stq_be_p(buf + 16, request->from); |
| stl_be_p(buf + 24, request->len); |
| |
| return nbd_write(ioc, buf, sizeof(buf), NULL); |
| } |
| |
| /* nbd_receive_simple_reply |
| * Read simple reply except magic field (which should be already read). |
| * Payload is not read (payload is possible for CMD_READ, but here we even |
| * don't know whether it take place or not). |
| */ |
| static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply, |
| Error **errp) |
| { |
| int ret; |
| |
| assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC); |
| |
| ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic), |
| sizeof(*reply) - sizeof(reply->magic), "reply", errp); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| reply->error = be32_to_cpu(reply->error); |
| reply->handle = be64_to_cpu(reply->handle); |
| |
| return 0; |
| } |
| |
| /* nbd_receive_structured_reply_chunk |
| * Read structured reply chunk except magic field (which should be already |
| * read). |
| * Payload is not read. |
| */ |
| static int nbd_receive_structured_reply_chunk(QIOChannel *ioc, |
| NBDStructuredReplyChunk *chunk, |
| Error **errp) |
| { |
| int ret; |
| |
| assert(chunk->magic == NBD_STRUCTURED_REPLY_MAGIC); |
| |
| ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic), |
| sizeof(*chunk) - sizeof(chunk->magic), "structured chunk", |
| errp); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| chunk->flags = be16_to_cpu(chunk->flags); |
| chunk->type = be16_to_cpu(chunk->type); |
| chunk->handle = be64_to_cpu(chunk->handle); |
| chunk->length = be32_to_cpu(chunk->length); |
| |
| return 0; |
| } |
| |
| /* nbd_read_eof |
| * Tries to read @size bytes from @ioc. |
| * Returns 1 on success |
| * 0 on eof, when no data was read (errp is not set) |
| * negative errno on failure (errp is set) |
| */ |
| static inline int coroutine_fn |
| nbd_read_eof(BlockDriverState *bs, QIOChannel *ioc, void *buffer, size_t size, |
| Error **errp) |
| { |
| bool partial = false; |
| |
| assert(size); |
| while (size > 0) { |
| struct iovec iov = { .iov_base = buffer, .iov_len = size }; |
| ssize_t len; |
| |
| len = qio_channel_readv(ioc, &iov, 1, errp); |
| if (len == QIO_CHANNEL_ERR_BLOCK) { |
| bdrv_dec_in_flight(bs); |
| qio_channel_yield(ioc, G_IO_IN); |
| bdrv_inc_in_flight(bs); |
| continue; |
| } else if (len < 0) { |
| return -EIO; |
| } else if (len == 0) { |
| if (partial) { |
| error_setg(errp, |
| "Unexpected end-of-file before all bytes were read"); |
| return -EIO; |
| } else { |
| return 0; |
| } |
| } |
| |
| partial = true; |
| size -= len; |
| buffer = (uint8_t*) buffer + len; |
| } |
| return 1; |
| } |
| |
| /* nbd_receive_reply |
| * |
| * Decreases bs->in_flight while waiting for a new reply. This yield is where |
| * we wait indefinitely and the coroutine must be able to be safely reentered |
| * for nbd_client_attach_aio_context(). |
| * |
| * Returns 1 on success |
| * 0 on eof, when no data was read (errp is not set) |
| * negative errno on failure (errp is set) |
| */ |
| int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, |
| NBDReply *reply, Error **errp) |
| { |
| int ret; |
| const char *type; |
| |
| ret = nbd_read_eof(bs, ioc, &reply->magic, sizeof(reply->magic), errp); |
| if (ret <= 0) { |
| return ret; |
| } |
| |
| reply->magic = be32_to_cpu(reply->magic); |
| |
| switch (reply->magic) { |
| case NBD_SIMPLE_REPLY_MAGIC: |
| ret = nbd_receive_simple_reply(ioc, &reply->simple, errp); |
| if (ret < 0) { |
| break; |
| } |
| trace_nbd_receive_simple_reply(reply->simple.error, |
| nbd_err_lookup(reply->simple.error), |
| reply->handle); |
| break; |
| case NBD_STRUCTURED_REPLY_MAGIC: |
| ret = nbd_receive_structured_reply_chunk(ioc, &reply->structured, errp); |
| if (ret < 0) { |
| break; |
| } |
| type = nbd_reply_type_lookup(reply->structured.type); |
| trace_nbd_receive_structured_reply_chunk(reply->structured.flags, |
| reply->structured.type, type, |
| reply->structured.handle, |
| reply->structured.length); |
| break; |
| default: |
| error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", reply->magic); |
| return -EINVAL; |
| } |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return 1; |
| } |
| |
