libvirt/src/util/virvsock.c
Ján Tomko 950c46f1a4 util: create virvsock.c
A file for vsock-related helper functions.
virVsockSetGuestCid to set an already-known CID,
virVsockAcquireGuestCid that will use the first available CID

https://bugzilla.redhat.com/show_bug.cgi?id=1291851

Signed-off-by: Ján Tomko <jtomko@redhat.com>
2018-05-29 15:42:03 +02:00

106 lines
2.5 KiB
C

/*
* 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 2.1 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, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include <sys/ioctl.h>
#if HAVE_DECL_VHOST_VSOCK_SET_GUEST_CID
# include <linux/vhost.h>
#endif
#include "virvsock.h"
#include "virerror.h"
#include "virlog.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.vsock");
#if HAVE_DECL_VHOST_VSOCK_SET_GUEST_CID
static int
virVsockSetGuestCidQuiet(int fd,
unsigned int guest_cid)
{
uint64_t val = guest_cid;
return ioctl(fd, VHOST_VSOCK_SET_GUEST_CID, &val);
}
#else
static int
virVsockSetGuestCidQuiet(int fd ATTRIBUTE_UNUSED,
unsigned int guest_cid ATTRIBUTE_UNUSED)
{
errno = ENOSYS;
return -1;
}
#endif
/**
* virVsockSetGuestCid:
* @fd: file descriptor of a vsock interface
* @guest_cid: guest CID to be set
*
* Wrapper for VHOST_VSOCK_SET_GUEST_CID ioctl.
* Returns: 0 on success, -1 on error.
*/
int
virVsockSetGuestCid(int fd,
unsigned int guest_cid)
{
if (virVsockSetGuestCidQuiet(fd, guest_cid) < 0) {
virReportSystemError(errno, "%s",
_("failed to set guest cid"));
return -1;
}
return 0;
}
#define VIR_VSOCK_GUEST_CID_MIN 3
/**
* virVsockAcquireGuestCid:
* @fd: file descriptor of a vsock interface
* @guest_cid: where to store the guest CID
*
* Iterates over usable CIDs until a free one is found.
* Returns: 0 on success, with the acquired CID stored in guest_cid
* -1 on error.
*/
int
virVsockAcquireGuestCid(int fd,
unsigned int *guest_cid)
{
unsigned int cid = VIR_VSOCK_GUEST_CID_MIN;
for (; virVsockSetGuestCidQuiet(fd, cid) < 0; cid++) {
if (errno != EADDRINUSE) {
virReportSystemError(errno, "%s",
_("failed to acquire guest cid"));
return -1;
}
}
*guest_cid = cid;
return 0;
}