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/* This example shows how to connect to an NBD server
* and fetch and print the first sector (usually the
* boot sector or partition table or filesystem
* superblock).
*
* You can test it with nbdkit like this:
*
* nbdkit -U - floppy . \
* --run './fetch-first-sector $unixsocket'
*
* The nbdkit floppy plugin creates an MBR disk so the
* first sector is the partition table.
*/
#include <stdio.h>
#include <stdlib.h>
#include <libnbd.h>
int
main (int argc, char *argv[])
{
struct nbd_handle *nbd;
char buf[512];
FILE *pp;
if (argc != 2) {
fprintf (stderr, "%s socket\n", argv[0]);
exit (EXIT_FAILURE);
}
/* Create the libnbd handle. */
nbd = nbd_create ();
if (nbd == NULL) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Connect to the NBD server over a
* Unix domain socket.
*/
if (nbd_connect_unix (nbd, argv[1]) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Read the first sector synchronously. */
if (nbd_pread (nbd, buf, sizeof buf, 0, 0) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Close the libnbd handle. */
nbd_close (nbd);
/* Print the first sector. */
pp = popen ("hexdump -C", "w");
if (pp == NULL) {
perror ("popen: hexdump");
exit (EXIT_FAILURE);
}
fwrite (buf, sizeof buf, 1, pp);
pclose (pp);
exit (EXIT_SUCCESS);
}
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