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#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include "tapdisk.h"
#include "blktaplib.h"
#include "blktapctrl.h"
static void make_blktap_dev(char *devname, int major, int minor)
{
struct stat st;
if (lstat(devname, &st) != 0) {
/*Need to create device*/
if (mkdir(BLKTAP_DEV_DIR, 0755) == 0)
DPRINTF("Created %s directory\n",BLKTAP_DEV_DIR);
if (mknod(devname, S_IFCHR|0600,
makedev(major, minor)) == 0)
DPRINTF("Created %s device\n",devname);
} else {
DPRINTF("%s device already exists\n",devname);
/* it already exists, but is it the same major number */
if (((st.st_rdev>>8) & 0xff) != major) {
DPRINTF("%s has old major %d\n",
devname,
(unsigned int)((st.st_rdev >> 8) & 0xff));
/* only try again if we succed in deleting it */
if (!unlink(devname))
make_blktap_dev(devname, major, minor);
}
}
}
int blktap_interface_create(int ctlfd, int *major, int *minor, blkif_t *blkif)
{
domid_translate_t tr;
domid_translate_ext_t tr_ext;
int ret;
char *devname;
if (blkif->be_id >= (1<<28)) {
/* new-style backend-id, so use the extended structure */
tr_ext.domid = blkif->domid;
tr_ext.busid = blkif->be_id;
ret = ioctl(ctlfd, BLKTAP_IOCTL_NEWINTF_EXT, &tr_ext);
DPRINTF("Sent domid %d and be_id %d\n", tr_ext.domid,
tr_ext.busid);
}
else {
/* old-style backend-id; use the old structure */
tr.domid = blkif->domid;
tr.busid = (unsigned short)blkif->be_id;
ret = ioctl(ctlfd, BLKTAP_IOCTL_NEWINTF, tr);
DPRINTF("Sent domid %d and be_id %d\n", tr.domid, tr.busid);
}
if ( (ret <= 0)||(ret > MAX_TAP_DEV) ) {
DPRINTF("Incorrect Dev ID [%d]\n",ret);
return -1;
}
*minor = ret;
*major = ioctl(ctlfd, BLKTAP_IOCTL_MAJOR, ret );
if (*major < 0) {
DPRINTF("Incorrect Major ID [%d]\n",*major);
return -1;
}
if (asprintf(&devname,"%s/%s%d",BLKTAP_DEV_DIR, BLKTAP_DEV_NAME, *minor) == -1)
return -1;
make_blktap_dev(devname,*major,*minor);
DPRINTF("Received device id %d and major %d\n",
*minor, *major);
return 0;
}
int blktap_interface_open(void)
{
int ctlfd;
ctlfd = open(BLKTAP_DEV_DIR "/" BLKTAP_DEV_NAME "0", O_RDWR);
if (ctlfd == -1)
DPRINTF("blktap0 open failed\n");
return ctlfd;
}
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