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/* NBD client library in userspace
* Copyright Red Hat
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Demonstrate low-level use of nbd_opt_extended_headers(). */
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <libnbd.h>
#define check(got, exp) do_check (#got, got, exp)
static void
do_check (const char *act, int64_t got, int64_t exp)
{
fprintf (stderr, "trying %s\n", act);
if (got == -1)
fprintf (stderr, "%s\n", nbd_get_error ());
else
fprintf (stderr, "succeeded, result %" PRId64 "\n", got);
if (got != exp) {
fprintf (stderr, "got %" PRId64 ", but expected %" PRId64 "\n", got, exp);
exit (EXIT_FAILURE);
}
}
static int
cb (void *data, const char *metacontext, uint64_t offset,
nbd_extent *entries, size_t nr_entries, int *error)
{
/* If we got here, extents worked, implying at least structured replies */
bool *seen = data;
*seen = true;
return 0;
}
struct nbd_handle *
prep (bool sr, bool eh, char **cmd)
{
struct nbd_handle *nbd;
nbd = nbd_create ();
if (nbd == NULL) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Connect to the server in opt mode, disable client-side failsafes so
* that we are testing server response even when client breaks protocol.
*/
check (nbd_set_opt_mode (nbd, true), 0);
check (nbd_set_strict_mode (nbd, 0), 0);
check (nbd_add_meta_context (nbd, LIBNBD_CONTEXT_BASE_ALLOCATION), 0);
check (nbd_set_request_structured_replies (nbd, sr), 0);
check (nbd_set_request_extended_headers (nbd, eh), 0);
check (nbd_connect_systemd_socket_activation (nbd, cmd), 0);
return nbd;
}
void
cleanup (struct nbd_handle *nbd, bool extents_exp)
{
bool extents = false;
check (nbd_opt_go (nbd), 0);
check (nbd_can_meta_context (nbd, LIBNBD_CONTEXT_BASE_ALLOCATION),
extents_exp);
check (nbd_block_status_64 (nbd, 512, 0,
(nbd_extent64_callback) { .callback = cb,
.user_data = &extents },
0), extents_exp ? 0 : -1);
check (extents, extents_exp);
nbd_close (nbd);
}
int
main (int argc, char *argv[])
{
struct nbd_handle *nbd;
int64_t bytes_sent;
if (argc < 2) {
fprintf (stderr, "%s qemu-nbd [args ...]\n", argv[0]);
exit (EXIT_FAILURE);
}
/* Default setup tries eh first, and skips sr request when eh works... */
nbd = prep (true, true, &argv[1]);
bytes_sent = nbd_stats_bytes_sent (nbd);
check (nbd_get_extended_headers_negotiated (nbd), true);
check (nbd_get_structured_replies_negotiated (nbd), true);
/* Duplicate eh request is no-op as redundant, but does not change state */
check (nbd_opt_extended_headers (nbd), false);
/* Trying sr after eh is no-op as redundant, but does not change state */
check (nbd_opt_structured_reply (nbd), false);
check (nbd_get_extended_headers_negotiated (nbd), true);
check (nbd_get_structured_replies_negotiated (nbd), true);
cleanup (nbd, true);
/* ...which should result in the same amount of initial negotiation
* traffic as explicitly requesting just structured replies, albeit
* with different results on what got negotiated.
*/
nbd = prep (true, false, &argv[1]);
check (nbd_stats_bytes_sent (nbd), bytes_sent);
check (nbd_get_extended_headers_negotiated (nbd), false);
check (nbd_get_structured_replies_negotiated (nbd), true);
cleanup (nbd, true);
/* request_eh is ignored if request_sr is false. */
nbd = prep (false, true, &argv[1]);
check (nbd_get_extended_headers_negotiated (nbd), false);
check (nbd_get_structured_replies_negotiated (nbd), false);
cleanup (nbd, false);
/* Swap order, requesting structured replies before extended headers */
nbd = prep (false, false, &argv[1]);
check (nbd_get_extended_headers_negotiated (nbd), false);
check (nbd_get_structured_replies_negotiated (nbd), false);
check (nbd_opt_structured_reply (nbd), true);
check (nbd_get_extended_headers_negotiated (nbd), false);
check (nbd_get_structured_replies_negotiated (nbd), true);
check (nbd_opt_extended_headers (nbd), true);
check (nbd_get_extended_headers_negotiated (nbd), true);
check (nbd_get_structured_replies_negotiated (nbd), true);
cleanup (nbd, true);
exit (EXIT_SUCCESS);
}
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