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/* This example shows how to run an NBD server
* (nbdkit) as a subprocess of libnbd.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libnbd.h>
int
main (int argc, char *argv[])
{
struct nbd_handle *nbd;
char wbuf[512], rbuf[512];
size_t i;
/* Create the libnbd handle. */
nbd = nbd_create ();
if (nbd == NULL) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Run nbdkit as a subprocess. */
char *args[] = {
"nbdkit",
/* You must use ‘-s’ (which tells nbdkit to serve
* a single connection on stdin/stdout).
*/
"-s",
/* It is recommended to use ‘--exit-with-parent’
* to ensure nbdkit is always cleaned up even
* if the main program crashes.
*/
"--exit-with-parent",
/* Use this to enable nbdkit debugging. */
"-v",
/* The nbdkit plugin name - this is a RAM disk. */
"memory", "size=1M",
/* Use NULL to terminate the arg list. */
NULL
};
if (nbd_connect_command (nbd, args) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Write some random data to the first sector. */
for (i = 0; i < sizeof wbuf; ++i)
wbuf[i] = i % 13;
if (nbd_pwrite (nbd, wbuf, sizeof wbuf, 0, 0) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Read the first sector back. */
if (nbd_pread (nbd, rbuf, sizeof rbuf, 0, 0) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Close the libnbd handle. */
nbd_close (nbd);
/* What was read must be exactly the same as what
* was written.
*/
if (memcmp (rbuf, wbuf, sizeof rbuf) != 0) {
fprintf (stderr, "FAILED: "
"read data did not match written data\n");
exit (EXIT_FAILURE);
}
exit (EXIT_SUCCESS);
}
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