libvirt/src/util/virscsivhost.c

/*
 * virscsivhost.c: helper APIs for managing scsi_host devices
 *
 * Copyright (C) 2016 IBM Corporation
 *
 * 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/>.
 *
 * Authors:
 *     Eric Farman <farman@linux.vnet.ibm.com>
 */

#include <config.h>
#include <fcntl.h>

#include "virscsivhost.h"
#include "virlog.h"
#include "viralloc.h"
#include "virerror.h"
#include "virfile.h"
#include "virstring.h"

/* For virReportOOMError()  and virReportSystemError() */
#define VIR_FROM_THIS VIR_FROM_NONE

VIR_LOG_INIT("util.scsihost");

#define SYSFS_VHOST_SCSI_DEVICES "/sys/kernel/config/target/vhost/"
#define VHOST_SCSI_DEVICE "/dev/vhost-scsi"

struct _virSCSIVHostDevice {
    char *name; /* naa.<wwn> */
    char *path;
    char *used_by_drvname;
    char *used_by_domname;
};

struct _virSCSIVHostDeviceList {
    virObjectLockable parent;
    size_t count;
    virSCSIVHostDevicePtr *devs;
};

static virClassPtr virSCSIVHostDeviceListClass;

static void
virSCSIVHostDeviceListDispose(void *obj)
{
    virSCSIVHostDeviceListPtr list = obj;
    size_t i;

    for (i = 0; i < list->count; i++)
        virSCSIVHostDeviceFree(list->devs[i]);

    VIR_FREE(list->devs);
}


static int
virSCSIVHostOnceInit(void)
{
    if (!(virSCSIVHostDeviceListClass = virClassNew(virClassForObjectLockable(),
                                                    "virSCSIVHostDeviceList",
                                                    sizeof(virSCSIVHostDeviceList),
                                                    virSCSIVHostDeviceListDispose)))
        return -1;

    return 0;
}


VIR_ONCE_GLOBAL_INIT(virSCSIVHost)


int
virSCSIVHostOpenVhostSCSI(int *vhostfd)
{
    if (!virFileExists(VHOST_SCSI_DEVICE))
        return -1;

    *vhostfd = open(VHOST_SCSI_DEVICE, O_RDWR);

    if (*vhostfd < 0) {
        virReportSystemError(errno, _("Failed to open %s"), VHOST_SCSI_DEVICE);
        goto error;
    }

    return 0;

 error:
    VIR_FORCE_CLOSE(*vhostfd);

    return -1;
}


void
virSCSIVHostDeviceListDel(virSCSIVHostDeviceListPtr list,
                          virSCSIVHostDevicePtr dev)
{
    virSCSIVHostDevicePtr tmp = virSCSIVHostDeviceListSteal(list, dev);
    virSCSIVHostDeviceFree(tmp);
}


static int
virSCSIVHostDeviceListFindIndex(virSCSIVHostDeviceListPtr list,
                                virSCSIVHostDevicePtr dev)
{
    size_t i;

    for (i = 0; i < list->count; i++) {
        virSCSIVHostDevicePtr other = list->devs[i];
        if (STREQ_NULLABLE(other->name, dev->name))
            return i;
    }
    return -1;
}


virSCSIVHostDevicePtr
virSCSIVHostDeviceListGet(virSCSIVHostDeviceListPtr list, int idx)
{
    if (idx >= list->count || idx < 0)
        return NULL;

    return list->devs[idx];
}


size_t
virSCSIVHostDeviceListCount(virSCSIVHostDeviceListPtr list)
{
    return list->count;
}


virSCSIVHostDevicePtr
virSCSIVHostDeviceListSteal(virSCSIVHostDeviceListPtr list,
                            virSCSIVHostDevicePtr dev)
{
    virSCSIVHostDevicePtr ret = NULL;
    size_t i;

    for (i = 0; i < list->count; i++) {
        if (STREQ_NULLABLE(list->devs[i]->name, dev->name)) {
            ret = list->devs[i];
            VIR_DELETE_ELEMENT(list->devs, i, list->count);
            break;
        }
    }

    return ret;
}


virSCSIVHostDevicePtr
virSCSIVHostDeviceListFind(virSCSIVHostDeviceListPtr list,
                           virSCSIVHostDevicePtr dev)
{
    int idx;

    if ((idx = virSCSIVHostDeviceListFindIndex(list, dev)) >= 0)
        return list->devs[idx];
    else
        return NULL;
}


int
virSCSIVHostDeviceListAdd(virSCSIVHostDeviceListPtr list,
                          virSCSIVHostDevicePtr dev)
{
    if (virSCSIVHostDeviceListFind(list, dev)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Device %s is already in use"), dev->name);
        return -1;
    }
    return VIR_APPEND_ELEMENT(list->devs, list->count, dev);
}


virSCSIVHostDeviceListPtr
virSCSIVHostDeviceListNew(void)
{
    if (virSCSIVHostInitialize() < 0)
        return NULL;

    return virObjectLockableNew(virSCSIVHostDeviceListClass);
}


int
virSCSIVHostDeviceSetUsedBy(virSCSIVHostDevicePtr dev,
                            const char *drvname,
                            const char *domname)
{
    VIR_FREE(dev->used_by_drvname);
    VIR_FREE(dev->used_by_domname);
    if (VIR_STRDUP(dev->used_by_drvname, drvname) < 0)
        return -1;
    if (VIR_STRDUP(dev->used_by_domname, domname) < 0)
        return -1;

    return 0;
}


void
virSCSIVHostDeviceGetUsedBy(virSCSIVHostDevicePtr dev,
                            const char **drv_name,
                            const char **dom_name)
{
    *drv_name = dev->used_by_drvname;
    *dom_name = dev->used_by_domname;
 }


int
virSCSIVHostDeviceFileIterate(virSCSIVHostDevicePtr dev,
                              virSCSIVHostDeviceFileActor actor,
                              void *opaque)
{
    return (actor)(dev, dev->path, opaque);
}


const char *
virSCSIVHostDeviceGetName(virSCSIVHostDevicePtr dev)
{
    return dev->name;
}


const char *
virSCSIVHostDeviceGetPath(virSCSIVHostDevicePtr dev)
{
    return dev->path;
}


virSCSIVHostDevicePtr
virSCSIVHostDeviceNew(const char *name)
{
    virSCSIVHostDevicePtr dev;

    if (VIR_ALLOC(dev) < 0)
        return NULL;

    if (VIR_STRDUP(dev->name, name) < 0) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("dev->name buffer overflow: %s"),
                       name);
        goto error;
    }

    if (virAsprintf(&dev->path, "%s/%s",
                    SYSFS_VHOST_SCSI_DEVICES, name) < 0)
        goto error;

    VIR_DEBUG("%s: initialized", dev->name);

 cleanup:
    return dev;

 error:
    virSCSIVHostDeviceFree(dev);
    dev = NULL;
    goto cleanup;
}


void
virSCSIVHostDeviceFree(virSCSIVHostDevicePtr dev)
{
    if (!dev)
        return;
    VIR_DEBUG("%s: freeing", dev->name);
    VIR_FREE(dev->name);
    VIR_FREE(dev->path);
    VIR_FREE(dev->used_by_drvname);
    VIR_FREE(dev->used_by_domname);
    VIR_FREE(dev);
}