The nbd_receive_negotiate() method takes different code paths based on whether 'name == NULL', and then checks the expected protocol version in each branch. This patch inverts the logic, so that it takes different code paths based on what protocol version it receives and then checks if name is NULL or not as needed. This facilitates later code which allows the client to be capable of using the new style protocol regardless of whether an export name is listed or not. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1455129674-17255-8-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
361 lines
9.4 KiB
C
361 lines
9.4 KiB
C
/*
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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 "nbd-internal.h"
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static int nbd_errno_to_system_errno(int err)
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{
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switch (err) {
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case NBD_SUCCESS:
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return 0;
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case NBD_EPERM:
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return EPERM;
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case NBD_EIO:
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return EIO;
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case NBD_ENOMEM:
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return ENOMEM;
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case NBD_ENOSPC:
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return ENOSPC;
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case NBD_EINVAL:
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default:
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return EINVAL;
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}
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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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int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
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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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uint16_t tmp;
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int rc;
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TRACE("Receiving negotiation.");
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rc = -EINVAL;
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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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}
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if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
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error_setg(errp, "Failed to read magic");
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goto fail;
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}
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magic = be64_to_cpu(magic);
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TRACE("Magic is 0x%" PRIx64, magic);
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if (magic == NBD_OPTS_MAGIC) {
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uint32_t reserved = 0;
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uint32_t opt;
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uint32_t namesize;
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if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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error_setg(errp, "Failed to read server flags");
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goto fail;
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}
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*flags = be16_to_cpu(tmp) << 16;
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/* reserved for future use */
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if (write_sync(ioc, &reserved, sizeof(reserved)) !=
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sizeof(reserved)) {
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error_setg(errp, "Failed to read reserved field");
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goto fail;
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}
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/* write the export name */
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if (!name) {
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error_setg(errp, "Server requires an export name");
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goto fail;
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}
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magic = cpu_to_be64(magic);
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if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
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error_setg(errp, "Failed to send export name magic");
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goto fail;
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}
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opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
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if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
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error_setg(errp, "Failed to send export name option number");
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goto fail;
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}
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namesize = cpu_to_be32(strlen(name));
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if (write_sync(ioc, &namesize, sizeof(namesize)) !=
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sizeof(namesize)) {
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error_setg(errp, "Failed to send export name length");
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goto fail;
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}
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if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
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error_setg(errp, "Failed to send export name");
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goto fail;
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}
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if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
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error_setg(errp, "Failed to read export length");
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goto fail;
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}
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*size = be64_to_cpu(s);
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TRACE("Size is %" PRIu64, *size);
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if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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error_setg(errp, "Failed to read export flags");
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goto fail;
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}
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*flags |= be16_to_cpu(tmp);
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} else if (magic == NBD_CLIENT_MAGIC) {
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if (name) {
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error_setg(errp, "Server does not support export names");
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goto fail;
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}
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if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
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error_setg(errp, "Failed to read export length");
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goto fail;
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}
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*size = be64_to_cpu(s);
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TRACE("Size is %" PRIu64, *size);
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if (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) {
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error_setg(errp, "Failed to read export flags");
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goto fail;
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}
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*flags = be32_to_cpup(flags);
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} else {
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error_setg(errp, "Bad magic received");
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goto fail;
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}
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if (read_sync(ioc, &buf, 124) != 124) {
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error_setg(errp, "Failed to read reserved block");
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goto fail;
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}
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rc = 0;
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fail:
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return rc;
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}
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#ifdef __linux__
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int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size)
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{
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TRACE("Setting NBD socket");
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if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 0) {
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int serrno = errno;
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LOG("Failed to set NBD socket");
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return -serrno;
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}
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TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
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if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
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int serrno = errno;
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LOG("Failed setting NBD block size");
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return -serrno;
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}
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TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
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if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
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int serrno = errno;
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LOG("Failed setting size (in blocks)");
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return -serrno;
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}
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if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
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if (errno == ENOTTY) {
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int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
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TRACE("Setting readonly attribute");
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if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
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int serrno = errno;
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LOG("Failed setting read-only attribute");
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return -serrno;
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}
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} else {
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int serrno = errno;
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LOG("Failed setting flags");
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return -serrno;
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}
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}
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TRACE("Negotiation ended");
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return 0;
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}
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int nbd_client(int fd)
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{
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int ret;
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int serrno;
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TRACE("Doing NBD loop");
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ret = ioctl(fd, NBD_DO_IT);
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if (ret < 0 && errno == EPIPE) {
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/* NBD_DO_IT normally returns EPIPE when someone has disconnected
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* the socket via NBD_DISCONNECT. We do not want to return 1 in
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* that case.
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*/
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ret = 0;
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}
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serrno = errno;
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TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
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TRACE("Clearing NBD queue");
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ioctl(fd, NBD_CLEAR_QUE);
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TRACE("Clearing NBD socket");
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ioctl(fd, NBD_CLEAR_SOCK);
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errno = serrno;
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return ret;
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}
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#else
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int nbd_init(int fd, QIOChannelSocket *ioc, uint32_t flags, off_t size)
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{
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return -ENOTSUP;
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}
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int nbd_client(int fd)
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{
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return -ENOTSUP;
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}
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#endif
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ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request)
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{
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uint8_t buf[NBD_REQUEST_SIZE];
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ssize_t ret;
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cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
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cpu_to_be32w((uint32_t*)(buf + 4), request->type);
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cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
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cpu_to_be64w((uint64_t*)(buf + 16), request->from);
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cpu_to_be32w((uint32_t*)(buf + 24), request->len);
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TRACE("Sending request to client: "
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"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
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request->from, request->len, request->handle, request->type);
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ret = write_sync(ioc, buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (ret != sizeof(buf)) {
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LOG("writing to socket failed");
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return -EINVAL;
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}
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return 0;
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}
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ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply)
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{
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uint8_t buf[NBD_REPLY_SIZE];
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uint32_t magic;
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ssize_t ret;
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ret = read_sync(ioc, buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (ret != sizeof(buf)) {
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LOG("read failed");
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return -EINVAL;
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}
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/* Reply
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[ 0 .. 3] magic (NBD_REPLY_MAGIC)
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[ 4 .. 7] error (0 == no error)
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[ 7 .. 15] handle
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*/
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magic = be32_to_cpup((uint32_t*)buf);
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reply->error = be32_to_cpup((uint32_t*)(buf + 4));
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reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
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reply->error = nbd_errno_to_system_errno(reply->error);
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TRACE("Got reply: "
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"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
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magic, reply->error, reply->handle);
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if (magic != NBD_REPLY_MAGIC) {
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LOG("invalid magic (got 0x%x)", magic);
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return -EINVAL;
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}
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return 0;
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}
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