b6f5d3b573
NBD commit 6d34500b clarified how clients and servers are supposed to behave before closing a connection. It added NBD_REP_ERR_SHUTDOWN (for the server to announce it is about to go away during option haggling, so the client should quit sending NBD_OPT_* other than NBD_OPT_ABORT) and ESHUTDOWN (for the server to announce it is about to go away during transmission, so the client should quit sending NBD_CMD_* other than NBD_CMD_DISC). It also clarified that NBD_OPT_ABORT gets a reply, while NBD_CMD_DISC does not. This patch merely adds the missing reply to NBD_OPT_ABORT and teaches the client to recognize server errors. Actually teaching the server to send NBD_REP_ERR_SHUTDOWN or ESHUTDOWN would require knowing that the server has been requested to shut down soon (maybe we could do that by installing a SIGINT handler in qemu-nbd, which transitions from RUNNING to a new state that waits for the client to react, rather than just out-right quitting - but that's a bigger task for another day). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-15-git-send-email-eblake@redhat.com> [Move dummy ESHUTDOWN to include/qemu/osdep.h. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
817 lines
23 KiB
C
817 lines
23 KiB
C
/*
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* Copyright (C) 2016 Red Hat, Inc.
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device Client Side
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "nbd-internal.h"
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static int nbd_errno_to_system_errno(int err)
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{
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int ret;
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switch (err) {
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case NBD_SUCCESS:
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ret = 0;
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break;
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case NBD_EPERM:
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ret = EPERM;
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break;
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case NBD_EIO:
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ret = EIO;
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break;
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case NBD_ENOMEM:
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ret = ENOMEM;
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break;
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case NBD_ENOSPC:
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ret = ENOSPC;
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break;
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case NBD_ESHUTDOWN:
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ret = ESHUTDOWN;
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break;
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default:
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TRACE("Squashing unexpected error %d to EINVAL", err);
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/* fallthrough */
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case NBD_EINVAL:
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ret = EINVAL;
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break;
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}
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return ret;
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}
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/* Definitions for opaque data types */
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static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
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/* That's all folks */
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/* Basic flow for negotiation
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Server Client
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Negotiate
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or
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Server Client
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Negotiate #1
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Option
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Negotiate #2
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----
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followed by
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Server Client
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Request
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Response
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Request
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Response
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...
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...
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Request (type == 2)
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*/
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/* Discard length bytes from channel. Return -errno on failure, or
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* the amount of bytes consumed. */
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static ssize_t drop_sync(QIOChannel *ioc, size_t size)
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{
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ssize_t ret, dropped = size;
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char small[1024];
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char *buffer;
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buffer = sizeof(small) < size ? small : g_malloc(MIN(65536, size));
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while (size > 0) {
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ret = read_sync(ioc, buffer, MIN(65536, size));
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if (ret < 0) {
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goto cleanup;
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}
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assert(ret <= size);
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size -= ret;
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}
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ret = dropped;
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cleanup:
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if (buffer != small) {
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g_free(buffer);
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}
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return ret;
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}
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/* Send an option request.
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*
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* The request is for option @opt, with @data containing @len bytes of
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* additional payload for the request (@len may be -1 to treat @data as
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* a C string; and @data may be NULL if @len is 0).
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* Return 0 if successful, -1 with errp set if it is impossible to
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* continue. */
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static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
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uint32_t len, const char *data,
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Error **errp)
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{
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nbd_option req;
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QEMU_BUILD_BUG_ON(sizeof(req) != 16);
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if (len == -1) {
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req.length = len = strlen(data);
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}
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TRACE("Sending option request %" PRIu32", len %" PRIu32, opt, len);
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stq_be_p(&req.magic, NBD_OPTS_MAGIC);
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stl_be_p(&req.option, opt);
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stl_be_p(&req.length, len);
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if (write_sync(ioc, &req, sizeof(req)) != sizeof(req)) {
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error_setg(errp, "Failed to send option request header");
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return -1;
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}
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if (len && write_sync(ioc, (char *) data, len) != len) {
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error_setg(errp, "Failed to send option request data");
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return -1;
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}
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return 0;
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}
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/* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
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* not going to attempt further negotiation. */
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static void nbd_send_opt_abort(QIOChannel *ioc)
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{
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/* Technically, a compliant server is supposed to reply to us; but
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* older servers disconnected instead. At any rate, we're allowed
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* to disconnect without waiting for the server reply, so we don't
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* even care if the request makes it to the server, let alone
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* waiting around for whether the server replies. */
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nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
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}
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/* Receive the header of an option reply, which should match the given
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* opt. Read through the length field, but NOT the length bytes of
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* payload. Return 0 if successful, -1 with errp set if it is
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* impossible to continue. */
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static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
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nbd_opt_reply *reply, Error **errp)
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{
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QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
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if (read_sync(ioc, reply, sizeof(*reply)) != sizeof(*reply)) {
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error_setg(errp, "failed to read option reply");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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be64_to_cpus(&reply->magic);
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be32_to_cpus(&reply->option);
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be32_to_cpus(&reply->type);
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be32_to_cpus(&reply->length);
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TRACE("Received option reply %" PRIx32", type %" PRIx32", len %" PRIu32,
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reply->option, reply->type, reply->length);
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if (reply->magic != NBD_REP_MAGIC) {
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error_setg(errp, "Unexpected option reply magic");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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if (reply->option != opt) {
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error_setg(errp, "Unexpected option type %x expected %x",
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reply->option, opt);
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nbd_send_opt_abort(ioc);
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return -1;
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}
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return 0;
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}
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/* If reply represents success, return 1 without further action.
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* If reply represents an error, consume the optional payload of
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* the packet on ioc. Then return 0 for unsupported (so the client
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* can fall back to other approaches), or -1 with errp set for other
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* errors.
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*/
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static int nbd_handle_reply_err(QIOChannel *ioc, nbd_opt_reply *reply,
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Error **errp)
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{
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char *msg = NULL;
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int result = -1;
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if (!(reply->type & (1 << 31))) {
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return 1;
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}
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if (reply->length) {
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if (reply->length > NBD_MAX_BUFFER_SIZE) {
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error_setg(errp, "server's error message is too long");
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goto cleanup;
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}
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msg = g_malloc(reply->length + 1);
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if (read_sync(ioc, msg, reply->length) != reply->length) {
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error_setg(errp, "failed to read option error message");
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goto cleanup;
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}
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msg[reply->length] = '\0';
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}
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switch (reply->type) {
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case NBD_REP_ERR_UNSUP:
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TRACE("server doesn't understand request %" PRIx32
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", attempting fallback", reply->option);
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result = 0;
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goto cleanup;
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case NBD_REP_ERR_POLICY:
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error_setg(errp, "Denied by server for option %" PRIx32,
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reply->option);
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break;
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case NBD_REP_ERR_INVALID:
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error_setg(errp, "Invalid data length for option %" PRIx32,
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reply->option);
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break;
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case NBD_REP_ERR_PLATFORM:
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error_setg(errp, "Server lacks support for option %" PRIx32,
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reply->option);
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break;
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case NBD_REP_ERR_TLS_REQD:
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error_setg(errp, "TLS negotiation required before option %" PRIx32,
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reply->option);
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break;
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case NBD_REP_ERR_SHUTDOWN:
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error_setg(errp, "Server shutting down before option %" PRIx32,
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reply->option);
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break;
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default:
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error_setg(errp, "Unknown error code when asking for option %" PRIx32,
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reply->option);
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break;
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}
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if (msg) {
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error_append_hint(errp, "%s\n", msg);
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}
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cleanup:
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g_free(msg);
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if (result < 0) {
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nbd_send_opt_abort(ioc);
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}
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return result;
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}
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/* Process another portion of the NBD_OPT_LIST reply. Set *@match if
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* the current reply matches @want or if the server does not support
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* NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration
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* is complete, positive if more replies are expected, or negative
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* with @errp set if an unrecoverable error occurred. */
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static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
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Error **errp)
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{
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nbd_opt_reply reply;
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uint32_t len;
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uint32_t namelen;
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char name[NBD_MAX_NAME_SIZE + 1];
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int error;
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if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
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return -1;
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}
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error = nbd_handle_reply_err(ioc, &reply, errp);
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if (error <= 0) {
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/* The server did not support NBD_OPT_LIST, so set *match on
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* the assumption that any name will be accepted. */
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*match = true;
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return error;
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}
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len = reply.length;
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if (reply.type == NBD_REP_ACK) {
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if (len != 0) {
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error_setg(errp, "length too long for option end");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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return 0;
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} else if (reply.type != NBD_REP_SERVER) {
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error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
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reply.type, NBD_REP_SERVER);
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nbd_send_opt_abort(ioc);
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return -1;
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}
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if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
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error_setg(errp, "incorrect option length %" PRIu32, len);
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nbd_send_opt_abort(ioc);
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return -1;
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}
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if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
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error_setg(errp, "failed to read option name length");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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namelen = be32_to_cpu(namelen);
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len -= sizeof(namelen);
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if (len < namelen) {
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error_setg(errp, "incorrect option name length");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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if (namelen != strlen(want)) {
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if (drop_sync(ioc, len) != len) {
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error_setg(errp, "failed to skip export name with wrong length");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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return 1;
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}
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assert(namelen < sizeof(name));
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if (read_sync(ioc, name, namelen) != namelen) {
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error_setg(errp, "failed to read export name");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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name[namelen] = '\0';
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len -= namelen;
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if (drop_sync(ioc, len) != len) {
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error_setg(errp, "failed to read export description");
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nbd_send_opt_abort(ioc);
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return -1;
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}
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if (!strcmp(name, want)) {
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*match = true;
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}
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return 1;
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}
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/* Return -1 on failure, 0 if wantname is an available export. */
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static int nbd_receive_query_exports(QIOChannel *ioc,
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const char *wantname,
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Error **errp)
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{
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bool foundExport = false;
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TRACE("Querying export list for '%s'", wantname);
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if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
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return -1;
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}
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TRACE("Reading available export names");
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while (1) {
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int ret = nbd_receive_list(ioc, wantname, &foundExport, errp);
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if (ret < 0) {
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/* Server gave unexpected reply */
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return -1;
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} else if (ret == 0) {
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/* Done iterating. */
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if (!foundExport) {
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error_setg(errp, "No export with name '%s' available",
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wantname);
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nbd_send_opt_abort(ioc);
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return -1;
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}
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TRACE("Found desired export name '%s'", wantname);
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return 0;
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}
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}
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}
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static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
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QCryptoTLSCreds *tlscreds,
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const char *hostname, Error **errp)
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{
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nbd_opt_reply reply;
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QIOChannelTLS *tioc;
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struct NBDTLSHandshakeData data = { 0 };
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TRACE("Requesting TLS from server");
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if (nbd_send_option_request(ioc, NBD_OPT_STARTTLS, 0, NULL, errp) < 0) {
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return NULL;
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}
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TRACE("Getting TLS reply from server");
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if (nbd_receive_option_reply(ioc, NBD_OPT_STARTTLS, &reply, errp) < 0) {
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return NULL;
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}
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if (reply.type != NBD_REP_ACK) {
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error_setg(errp, "Server rejected request to start TLS %" PRIx32,
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reply.type);
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nbd_send_opt_abort(ioc);
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return NULL;
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}
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if (reply.length != 0) {
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error_setg(errp, "Start TLS response was not zero %" PRIu32,
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reply.length);
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nbd_send_opt_abort(ioc);
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return NULL;
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}
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TRACE("TLS request approved, setting up TLS");
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tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
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if (!tioc) {
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return NULL;
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}
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qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls");
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data.loop = g_main_loop_new(g_main_context_default(), FALSE);
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TRACE("Starting TLS handshake");
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qio_channel_tls_handshake(tioc,
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nbd_tls_handshake,
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&data,
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NULL);
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if (!data.complete) {
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g_main_loop_run(data.loop);
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}
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g_main_loop_unref(data.loop);
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if (data.error) {
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error_propagate(errp, data.error);
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object_unref(OBJECT(tioc));
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return NULL;
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}
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return QIO_CHANNEL(tioc);
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}
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int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
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QCryptoTLSCreds *tlscreds, const char *hostname,
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QIOChannel **outioc,
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off_t *size, Error **errp)
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{
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char buf[256];
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uint64_t magic, s;
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int rc;
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bool zeroes = true;
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TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
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tlscreds, hostname ? hostname : "<null>");
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rc = -EINVAL;
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if (outioc) {
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*outioc = NULL;
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}
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if (tlscreds && !outioc) {
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error_setg(errp, "Output I/O channel required for TLS");
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goto fail;
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}
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if (read_sync(ioc, buf, 8) != 8) {
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error_setg(errp, "Failed to read data");
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goto fail;
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}
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buf[8] = '\0';
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if (strlen(buf) == 0) {
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error_setg(errp, "Server connection closed unexpectedly");
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goto fail;
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}
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TRACE("Magic is %c%c%c%c%c%c%c%c",
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qemu_isprint(buf[0]) ? buf[0] : '.',
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qemu_isprint(buf[1]) ? buf[1] : '.',
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qemu_isprint(buf[2]) ? buf[2] : '.',
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qemu_isprint(buf[3]) ? buf[3] : '.',
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qemu_isprint(buf[4]) ? buf[4] : '.',
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qemu_isprint(buf[5]) ? buf[5] : '.',
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qemu_isprint(buf[6]) ? buf[6] : '.',
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qemu_isprint(buf[7]) ? buf[7] : '.');
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if (memcmp(buf, "NBDMAGIC", 8) != 0) {
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error_setg(errp, "Invalid magic received");
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goto fail;
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|
}
|
|
|
|
if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
|
|
error_setg(errp, "Failed to read magic");
|
|
goto fail;
|
|
}
|
|
magic = be64_to_cpu(magic);
|
|
TRACE("Magic is 0x%" PRIx64, magic);
|
|
|
|
if (magic == NBD_OPTS_MAGIC) {
|
|
uint32_t clientflags = 0;
|
|
uint16_t globalflags;
|
|
bool fixedNewStyle = false;
|
|
|
|
if (read_sync(ioc, &globalflags, sizeof(globalflags)) !=
|
|
sizeof(globalflags)) {
|
|
error_setg(errp, "Failed to read server flags");
|
|
goto fail;
|
|
}
|
|
globalflags = be16_to_cpu(globalflags);
|
|
TRACE("Global flags are %" PRIx32, globalflags);
|
|
if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
|
|
fixedNewStyle = true;
|
|
TRACE("Server supports fixed new style");
|
|
clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
|
|
}
|
|
if (globalflags & NBD_FLAG_NO_ZEROES) {
|
|
zeroes = false;
|
|
TRACE("Server supports no zeroes");
|
|
clientflags |= NBD_FLAG_C_NO_ZEROES;
|
|
}
|
|
/* client requested flags */
|
|
clientflags = cpu_to_be32(clientflags);
|
|
if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
|
|
sizeof(clientflags)) {
|
|
error_setg(errp, "Failed to send clientflags field");
|
|
goto fail;
|
|
}
|
|
if (tlscreds) {
|
|
if (fixedNewStyle) {
|
|
*outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
|
|
if (!*outioc) {
|
|
goto fail;
|
|
}
|
|
ioc = *outioc;
|
|
} else {
|
|
error_setg(errp, "Server does not support STARTTLS");
|
|
goto fail;
|
|
}
|
|
}
|
|
if (!name) {
|
|
TRACE("Using default NBD export name \"\"");
|
|
name = "";
|
|
}
|
|
if (fixedNewStyle) {
|
|
/* 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 good error reporting if the
|
|
* server required TLS
|
|
*/
|
|
if (nbd_receive_query_exports(ioc, name, errp) < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
/* write the export name request */
|
|
if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name,
|
|
errp) < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* Read the response */
|
|
if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
|
|
error_setg(errp, "Failed to read export length");
|
|
goto fail;
|
|
}
|
|
*size = be64_to_cpu(s);
|
|
|
|
if (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) {
|
|
error_setg(errp, "Failed to read export flags");
|
|
goto fail;
|
|
}
|
|
be16_to_cpus(flags);
|
|
} else if (magic == NBD_CLIENT_MAGIC) {
|
|
uint32_t oldflags;
|
|
|
|
if (name) {
|
|
error_setg(errp, "Server does not support export names");
|
|
goto fail;
|
|
}
|
|
if (tlscreds) {
|
|
error_setg(errp, "Server does not support STARTTLS");
|
|
goto fail;
|
|
}
|
|
|
|
if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
|
|
error_setg(errp, "Failed to read export length");
|
|
goto fail;
|
|
}
|
|
*size = be64_to_cpu(s);
|
|
TRACE("Size is %" PRIu64, *size);
|
|
|
|
if (read_sync(ioc, &oldflags, sizeof(oldflags)) != sizeof(oldflags)) {
|
|
error_setg(errp, "Failed to read export flags");
|
|
goto fail;
|
|
}
|
|
be32_to_cpus(&oldflags);
|
|
if (oldflags & ~0xffff) {
|
|
error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
|
|
goto fail;
|
|
}
|
|
*flags = oldflags;
|
|
} else {
|
|
error_setg(errp, "Bad magic received");
|
|
goto fail;
|
|
}
|
|
|
|
TRACE("Size is %" PRIu64 ", export flags %" PRIx16, *size, *flags);
|
|
if (zeroes && drop_sync(ioc, 124) != 124) {
|
|
error_setg(errp, "Failed to read reserved block");
|
|
goto fail;
|
|
}
|
|
rc = 0;
|
|
|
|
fail:
|
|
return rc;
|
|
}
|
|
|
|
#ifdef __linux__
|
|
int nbd_init(int fd, QIOChannelSocket *sioc, uint16_t flags, off_t size)
|
|
{
|
|
unsigned long sectors = size / BDRV_SECTOR_SIZE;
|
|
if (size / BDRV_SECTOR_SIZE != sectors) {
|
|
LOG("Export size %lld too large for 32-bit kernel", (long long) size);
|
|
return -E2BIG;
|
|
}
|
|
|
|
TRACE("Setting NBD socket");
|
|
|
|
if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) {
|
|
int serrno = errno;
|
|
LOG("Failed to set NBD socket");
|
|
return -serrno;
|
|
}
|
|
|
|
TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
|
|
|
|
if (ioctl(fd, NBD_SET_BLKSIZE, (unsigned long)BDRV_SECTOR_SIZE) < 0) {
|
|
int serrno = errno;
|
|
LOG("Failed setting NBD block size");
|
|
return -serrno;
|
|
}
|
|
|
|
TRACE("Setting size to %lu block(s)", sectors);
|
|
if (size % BDRV_SECTOR_SIZE) {
|
|
TRACE("Ignoring trailing %d bytes of export",
|
|
(int) (size % BDRV_SECTOR_SIZE));
|
|
}
|
|
|
|
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) {
|
|
int serrno = errno;
|
|
LOG("Failed setting size (in blocks)");
|
|
return -serrno;
|
|
}
|
|
|
|
if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) flags) < 0) {
|
|
if (errno == ENOTTY) {
|
|
int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
|
|
TRACE("Setting readonly attribute");
|
|
|
|
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
|
|
int serrno = errno;
|
|
LOG("Failed setting read-only attribute");
|
|
return -serrno;
|
|
}
|
|
} else {
|
|
int serrno = errno;
|
|
LOG("Failed setting flags");
|
|
return -serrno;
|
|
}
|
|
}
|
|
|
|
TRACE("Negotiation ended");
|
|
|
|
return 0;
|
|
}
|
|
|
|
int nbd_client(int fd)
|
|
{
|
|
int ret;
|
|
int serrno;
|
|
|
|
TRACE("Doing NBD 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 loop returned %d: %s", ret, strerror(serrno));
|
|
|
|
TRACE("Clearing NBD queue");
|
|
ioctl(fd, NBD_CLEAR_QUE);
|
|
|
|
TRACE("Clearing NBD 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;
|
|
}
|
|
|
|
#else
|
|
int nbd_init(int fd, QIOChannelSocket *ioc, uint16_t flags, off_t size)
|
|
{
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
int nbd_client(int fd)
|
|
{
|
|
return -ENOTSUP;
|
|
}
|
|
int nbd_disconnect(int fd)
|
|
{
|
|
return -ENOTSUP;
|
|
}
|
|
#endif
|
|
|
|
ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request)
|
|
{
|
|
uint8_t buf[NBD_REQUEST_SIZE];
|
|
ssize_t ret;
|
|
|
|
TRACE("Sending request to server: "
|
|
"{ .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64
|
|
", .flags = %" PRIx16 ", .type = %" PRIu16 " }",
|
|
request->from, request->len, request->handle,
|
|
request->flags, 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);
|
|
|
|
ret = write_sync(ioc, buf, sizeof(buf));
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (ret != sizeof(buf)) {
|
|
LOG("writing to socket failed");
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply)
|
|
{
|
|
uint8_t buf[NBD_REPLY_SIZE];
|
|
uint32_t magic;
|
|
ssize_t ret;
|
|
|
|
ret = read_sync(ioc, buf, sizeof(buf));
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (ret != sizeof(buf)) {
|
|
LOG("read failed");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Reply
|
|
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
|
|
[ 4 .. 7] error (0 == no error)
|
|
[ 7 .. 15] handle
|
|
*/
|
|
|
|
magic = ldl_be_p(buf);
|
|
reply->error = ldl_be_p(buf + 4);
|
|
reply->handle = ldq_be_p(buf + 8);
|
|
|
|
reply->error = nbd_errno_to_system_errno(reply->error);
|
|
|
|
if (reply->error == ESHUTDOWN) {
|
|
/* This works even on mingw which lacks a native ESHUTDOWN */
|
|
LOG("server shutting down");
|
|
return -EINVAL;
|
|
}
|
|
TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32
|
|
", handle = %" PRIu64" }",
|
|
magic, reply->error, reply->handle);
|
|
|
|
if (magic != NBD_REPLY_MAGIC) {
|
|
LOG("invalid magic (got 0x%" PRIx32 ")", magic);
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|