xen_internal.c

/*
 * xen_internal.c: direct access to Xen hypervisor level
 *
 * Copyright (C) 2005 Red Hat, Inc.
 *
 * See COPYING.LIB for the License of this software
 *
 * Daniel Veillard <veillard@redhat.com>
 */

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

#include <xen/dom0_ops.h>
#include <xen/version.h>
#include <xen/xen.h>

#ifndef __LINUX_PUBLIC_PRIVCMD_H__
typedef struct hypercall_struct
{
    unsigned long op;
    unsigned long arg[5];
} hypercall_t;
#endif


#include "internal.h"
#include "xen_internal.h"

#define XEN_HYPERVISOR_SOCKET "/proc/xen/privcmd"

/**
 * xenHypervisorOpen:
 *
 * Connects to the Xen hypervisor.
 *
 * Returns the handle or -1 in case of error.
 */
int xenHypervisorOpen(void) {
    int ret;

    ret = open(XEN_HYPERVISOR_SOCKET, O_RDWR);
    if (ret < 0)
        return(-1);

    return(ret);
}

/**
 * xenHypervisorClose:
 * @handle: the handle to the Xen hypervisor
 *
 * Close the connection to the Xen hypervisor.
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int xenHypervisorClose(int handle) {
    int ret;

    if (handle < 0)
        return(-1);

    ret = close(handle);
    if (ret < 0)
        return(-1);
    return(0);
}

/**
 * xenHypervisorDoOp:
 * @handle: the handle to the Xen hypervisor
 * @op: pointer to the hyperviros operation structure
 *
 * Do an hypervisor operation, this leads to an hypervisor call through ioctl.
 *
 * Returns 0 in case of success and -1 in case of error.
 */
static int
xenHypervisorDoOp(int handle, dom0_op_t *op) {
    int ret;
    unsigned int cmd;
    hypercall_t hc;

    op->interface_version = DOM0_INTERFACE_VERSION;
    hc.op = __HYPERVISOR_dom0_op;
    hc.arg[0] = (unsigned long)op; 

    if (mlock(op, sizeof(dom0_op_t)) < 0)
        return(-1);

    cmd = _IOC(_IOC_NONE, 'P', 0, sizeof(hc));
    ret = ioctl(handle, cmd, (unsigned long) &hc);

    if (munlock(op, sizeof(dom0_op_t)) < 0)
        ret = -1;

    if (ret < 0)
        return(-1);
        
    return(0);
}

/**
 * xenHypervisorGetVersion:
 * @handle: the handle to the Xen hypervisor
 *
 * Call the hypervisor to extracts his own internal API version
 *
 * Returns the hypervisor running version or 0 in case of error.
 */
unsigned long
xenHypervisorGetVersion(int handle) {
    int ret;
    unsigned int cmd;
    hypercall_t hc;

    hc.op = __HYPERVISOR_xen_version;
    hc.arg[0] = (unsigned long) XENVER_version; 
    hc.arg[1] = 0;

    cmd = _IOC(_IOC_NONE, 'P', 0, sizeof(hc));
    ret = ioctl(handle, cmd, (unsigned long) &hc);

    if (ret < 0)
        return(0);
    /*
     * use unsigned long in case the version grows behind expectations
     * allowed by int
     */
    return((unsigned long) ret);
}

/**
 * xenHypervisorGetDomainInfo:
 * @handle: the handle to the Xen hypervisor
 * @domain: the domain ID
 * @info: the place where informations should be stored
 *
 * Do an hypervisor call to get the related set of domain informations.
 *
 * Returns 0 in case of success, -1 in case of error.
 */
int
xenHypervisorGetDomainInfo(int handle, int domain, dom0_getdomaininfo_t *info) {
    dom0_op_t op;
    int ret;

    if (info == NULL)
        return(-1);

    memset(info, 0, sizeof(dom0_getdomaininfo_t));

    if (mlock(info, sizeof(dom0_getdomaininfo_t)) < 0)
        return(-1);

    op.cmd = DOM0_GETDOMAININFOLIST;
    op.u.getdomaininfolist.first_domain = (domid_t) domain;
    op.u.getdomaininfolist.max_domains = 1;
    op.u.getdomaininfolist.buffer = info;
    op.u.getdomaininfolist.num_domains = 1;
    info->domain = domain;

    ret = xenHypervisorDoOp(handle, &op);

    if (munlock(info, sizeof(dom0_getdomaininfo_t)) < 0)
        ret = -1;

    if (ret < 0)
        return(-1);
    return(0);
}