qemu/nbd/common.c
Eric Blake 3736cc5be3 nbd: Expose and debug more NBD constants
The NBD protocol has several constants defined in various extensions
that we are about to implement.  Expose them to the code, along with
an easy way to map various constants to strings during diagnostic
messages.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170707203049.534-4-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-07-14 12:04:41 +02:00

196 lines
4.8 KiB
C

/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device Common Code
*
* 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 "nbd-internal.h"
/* nbd_wr_syncv
* The function may be called from coroutine or from non-coroutine context.
* When called from non-coroutine context @ioc must be in blocking mode.
*/
ssize_t nbd_rwv(QIOChannel *ioc, struct iovec *iov, size_t niov, size_t length,
bool do_read, Error **errp)
{
ssize_t done = 0;
struct iovec *local_iov = g_new(struct iovec, niov);
struct iovec *local_iov_head = local_iov;
unsigned int nlocal_iov = niov;
nlocal_iov = iov_copy(local_iov, nlocal_iov, iov, niov, 0, length);
while (nlocal_iov > 0) {
ssize_t len;
if (do_read) {
len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
} else {
len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
}
if (len == QIO_CHANNEL_ERR_BLOCK) {
/* errp should not be set */
assert(qemu_in_coroutine());
qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
continue;
}
if (len < 0) {
done = -EIO;
goto cleanup;
}
if (do_read && len == 0) {
break;
}
iov_discard_front(&local_iov, &nlocal_iov, len);
done += len;
}
cleanup:
g_free(local_iov_head);
return done;
}
/* Discard length bytes from channel. Return -errno on failure and 0 on
* success */
int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
{
ssize_t ret = 0;
char small[1024];
char *buffer;
buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
while (size > 0) {
ssize_t count = MIN(65536, size);
ret = nbd_read(ioc, buffer, MIN(65536, size), errp);
if (ret < 0) {
goto cleanup;
}
size -= count;
}
cleanup:
if (buffer != small) {
g_free(buffer);
}
return ret;
}
void nbd_tls_handshake(QIOTask *task,
void *opaque)
{
struct NBDTLSHandshakeData *data = opaque;
qio_task_propagate_error(task, &data->error);
data->complete = true;
g_main_loop_quit(data->loop);
}
const char *nbd_opt_lookup(uint32_t opt)
{
switch (opt) {
case NBD_OPT_EXPORT_NAME:
return "export name";
case NBD_OPT_ABORT:
return "abort";
case NBD_OPT_LIST:
return "list";
case NBD_OPT_STARTTLS:
return "starttls";
case NBD_OPT_INFO:
return "info";
case NBD_OPT_GO:
return "go";
case NBD_OPT_STRUCTURED_REPLY:
return "structured reply";
default:
return "<unknown>";
}
}
const char *nbd_rep_lookup(uint32_t rep)
{
switch (rep) {
case NBD_REP_ACK:
return "ack";
case NBD_REP_SERVER:
return "server";
case NBD_REP_INFO:
return "info";
case NBD_REP_ERR_UNSUP:
return "unsupported";
case NBD_REP_ERR_POLICY:
return "denied by policy";
case NBD_REP_ERR_INVALID:
return "invalid";
case NBD_REP_ERR_PLATFORM:
return "platform lacks support";
case NBD_REP_ERR_TLS_REQD:
return "TLS required";
case NBD_REP_ERR_UNKNOWN:
return "export unknown";
case NBD_REP_ERR_SHUTDOWN:
return "server shutting down";
case NBD_REP_ERR_BLOCK_SIZE_REQD:
return "block size required";
default:
return "<unknown>";
}
}
const char *nbd_info_lookup(uint16_t info)
{
switch (info) {
case NBD_INFO_EXPORT:
return "export";
case NBD_INFO_NAME:
return "name";
case NBD_INFO_DESCRIPTION:
return "description";
case NBD_INFO_BLOCK_SIZE:
return "block size";
default:
return "<unknown>";
}
}
const char *nbd_cmd_lookup(uint16_t cmd)
{
switch (cmd) {
case NBD_CMD_READ:
return "read";
case NBD_CMD_WRITE:
return "write";
case NBD_CMD_DISC:
return "discard";
case NBD_CMD_FLUSH:
return "flush";
case NBD_CMD_TRIM:
return "trim";
case NBD_CMD_WRITE_ZEROES:
return "write zeroes";
default:
return "<unknown>";
}
}