/*
 * storage_file_backend_gluster.c: storage file backend for Gluster handling
 *
 * Copyright (C) 2013-2018 Red Hat, Inc.
 *
 * 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 <glusterfs/api/glfs.h>

#include "storage_file_backend.h"
#include "storage_file_backend_gluster.h"
#include "viralloc.h"
#include "virerror.h"
#include "virlog.h"

#define VIR_FROM_THIS VIR_FROM_STORAGE

VIR_LOG_INIT("storage.storage_file_gluster");


typedef struct _virStorageFileBackendGlusterPriv virStorageFileBackendGlusterPriv;
struct _virStorageFileBackendGlusterPriv {
    glfs_t *vol;
};

static void
virStorageFileBackendGlusterDeinit(virStorageSource *src)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;

    VIR_DEBUG("deinitializing gluster storage file %p (gluster://%s:%u/%s%s)",
              src, src->hosts->name, src->hosts->port, src->volume, src->path);

    if (priv->vol)
        glfs_fini(priv->vol);

    VIR_FREE(priv);
    drv->priv = NULL;
}

static int
virStorageFileBackendGlusterInitServer(virStorageFileBackendGlusterPriv *priv,
                                       virStorageNetHostDef *host)
{
    const char *transport = virStorageNetHostTransportTypeToString(host->transport);
    const char *hoststr = NULL;
    int port = 0;

    switch ((virStorageNetHostTransport) host->transport) {
    case VIR_STORAGE_NET_HOST_TRANS_RDMA:
    case VIR_STORAGE_NET_HOST_TRANS_TCP:
        hoststr = host->name;
        port = host->port;
        break;

    case VIR_STORAGE_NET_HOST_TRANS_UNIX:
        hoststr = host->socket;
        break;

    case VIR_STORAGE_NET_HOST_TRANS_LAST:
        break;
    }

    VIR_DEBUG("adding gluster host for %p: transport=%s host=%s port=%d",
              priv, transport, hoststr, port);

    if (glfs_set_volfile_server(priv->vol, transport, hoststr, port) < 0) {
        virReportSystemError(errno,
                             _("failed to set gluster volfile server '%1$s'"),
                             hoststr);
        return -1;
    }

    return 0;
}


static int
virStorageFileBackendGlusterInit(virStorageSource *src)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = NULL;
    size_t i;

    if (!src->volume) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("missing gluster volume name for path '%1$s'"),
                       src->path);
        return -1;
    }

    priv = g_new0(virStorageFileBackendGlusterPriv, 1);

    VIR_DEBUG("initializing gluster storage file %p "
              "(priv='%p' volume='%s' path='%s') as [%u:%u]",
              src, priv, src->volume, src->path,
              (unsigned int)drv->uid, (unsigned int)drv->gid);

    if (!(priv->vol = glfs_new(src->volume))) {
        virReportError(VIR_ERR_OPERATION_FAILED,
                       _("failed to create glfs object for '%1$s'"), src->volume);
        goto error;
    }

    for (i = 0; i < src->nhosts; i++) {
        if (virStorageFileBackendGlusterInitServer(priv, src->hosts + i) < 0)
            goto error;
    }

    if (glfs_init(priv->vol) < 0) {
        virReportSystemError(errno,
                             _("failed to initialize gluster connection (src=%1$p priv=%2$p)"),
                             src, priv);
        goto error;
    }

    drv->priv = priv;

    return 0;

 error:
    if (priv->vol)
        glfs_fini(priv->vol);
    VIR_FREE(priv);

    return -1;
}


static int
virStorageFileBackendGlusterCreate(virStorageSource *src)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;
    glfs_fd_t *fd = NULL;

    if (!(fd = glfs_creat(priv->vol, src->path,
                          O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR)))
        return -1;

    ignore_value(glfs_close(fd));
    return 0;
}


static int
virStorageFileBackendGlusterUnlink(virStorageSource *src)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;

    return glfs_unlink(priv->vol, src->path);
}


static int
virStorageFileBackendGlusterStat(virStorageSource *src,
                                 struct stat *st)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;

    return glfs_stat(priv->vol, src->path, st);
}


static ssize_t
virStorageFileBackendGlusterRead(virStorageSource *src,
                                 size_t offset,
                                 size_t len,
                                 char **buf)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;
    glfs_fd_t *fd = NULL;
    ssize_t ret = -1;
    char *s;
    size_t nread = 0;

    *buf = NULL;

    if (!(fd = glfs_open(priv->vol, src->path, O_RDONLY))) {
        virReportSystemError(errno, _("Failed to open file '%1$s'"),
                             src->path);
        return -1;
    }

    if (offset > 0) {
        if (glfs_lseek(fd, offset, SEEK_SET) == (off_t) -1) {
            virReportSystemError(errno, _("cannot seek into '%1$s'"), src->path);
            goto cleanup;
        }
    }


    *buf = g_new0(char, len);

    s = *buf;
    while (len) {
        ssize_t r = glfs_read(fd, s, len, 0);
        if (r < 0 && errno == EINTR)
            continue;
        if (r < 0) {
            VIR_FREE(*buf);
            virReportSystemError(errno, _("unable to read '%1$s'"), src->path);
            return r;
        }
        if (r == 0)
            return nread;
        s += r;
        len -= r;
        nread += r;
    }

    ret = nread;

 cleanup:
    if (fd)
        glfs_close(fd);

    return ret;
}


static int
virStorageFileBackendGlusterAccess(virStorageSource *src,
                                   int mode)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;

    return glfs_access(priv->vol, src->path, mode);
}

static int
virStorageFileBackendGlusterChown(const virStorageSource *src,
                                  uid_t uid,
                                  gid_t gid)
{
    virStorageDriverData *drv = src->drv;
    virStorageFileBackendGlusterPriv *priv = drv->priv;

    return glfs_chown(priv->vol, src->path, uid, gid);
}


virStorageFileBackend virStorageFileBackendGluster = {
    .type = VIR_STORAGE_TYPE_NETWORK,
    .protocol = VIR_STORAGE_NET_PROTOCOL_GLUSTER,

    .backendInit = virStorageFileBackendGlusterInit,
    .backendDeinit = virStorageFileBackendGlusterDeinit,

    .storageFileCreate = virStorageFileBackendGlusterCreate,
    .storageFileUnlink = virStorageFileBackendGlusterUnlink,
    .storageFileStat = virStorageFileBackendGlusterStat,
    .storageFileRead = virStorageFileBackendGlusterRead,
    .storageFileAccess = virStorageFileBackendGlusterAccess,
    .storageFileChown = virStorageFileBackendGlusterChown,
};


int
virStorageFileGlusterRegister(void)
{
    if (virStorageFileBackendRegister(&virStorageFileBackendGluster) < 0)
        return -1;

    return 0;
}