/****************************************************************************
 * fs/rpmsgfs/rpmsgfs_client.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <string.h>
#include <stdio.h>
#include <sys/uio.h>
#include <termios.h>
#include <fcntl.h>

#include <nuttx/kmalloc.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/rptun/openamp.h>
#include <nuttx/semaphore.h>

#include "rpmsgfs.h"
#include "fs_heap.h"

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct rpmsgfs_s
{
  struct rpmsg_endpoint ept;
  char                  cpuname[RPMSG_NAME_SIZE];
  sem_t                 wait;
};

struct rpmsgfs_cookie_s
{
  sem_t    sem;
  int      result;
  FAR void *data;
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static int rpmsgfs_default_handler(FAR struct rpmsg_endpoint *ept,
                                   FAR void *data, size_t len,
                                   uint32_t src, FAR void *priv);
static int rpmsgfs_read_handler(FAR struct rpmsg_endpoint *ept,
                                FAR void *data, size_t len,
                                uint32_t src, FAR void *priv);
static int rpmsgfs_ioctl_handler(FAR struct rpmsg_endpoint *ept,
                                 FAR void *data, size_t len,
                                 uint32_t src, FAR void *priv);
static int rpmsgfs_readdir_handler(FAR struct rpmsg_endpoint *ept,
                                  FAR void *data, size_t len,
                                  uint32_t src, FAR void *priv);
static int rpmsgfs_statfs_handler(FAR struct rpmsg_endpoint *ept,
                                  FAR void *data, size_t len,
                                  uint32_t src, FAR void *priv);
static int rpmsgfs_stat_handler(FAR struct rpmsg_endpoint *ept,
                                 FAR void *data, size_t len,
                                 uint32_t src, FAR void *priv);
static void rpmsgfs_device_created(struct rpmsg_device *rdev,
                                   FAR void *priv_);
static void rpmsgfs_device_destroy(struct rpmsg_device *rdev,
                                   FAR void *priv_);
static int  rpmsgfs_ept_cb(FAR struct rpmsg_endpoint *ept,
                           FAR void *data, size_t len, uint32_t src,
                           FAR void *priv);
static int rpmsgfs_send_recv(FAR struct rpmsgfs_s *priv,
                             uint32_t command, bool copy,
                             FAR struct rpmsgfs_header_s *msg,
                             int len, FAR void *data);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const rpmsg_ept_cb g_rpmsgfs_handler[] =
{
  [RPMSGFS_OPEN]      = rpmsgfs_default_handler,
  [RPMSGFS_CLOSE]     = rpmsgfs_default_handler,
  [RPMSGFS_READ]      = rpmsgfs_read_handler,
  [RPMSGFS_WRITE]     = rpmsgfs_default_handler,
  [RPMSGFS_LSEEK]     = rpmsgfs_default_handler,
  [RPMSGFS_IOCTL]     = rpmsgfs_ioctl_handler,
  [RPMSGFS_SYNC]      = rpmsgfs_default_handler,
  [RPMSGFS_DUP]       = rpmsgfs_default_handler,
  [RPMSGFS_FSTAT]     = rpmsgfs_stat_handler,
  [RPMSGFS_FTRUNCATE] = rpmsgfs_default_handler,
  [RPMSGFS_OPENDIR]   = rpmsgfs_default_handler,
  [RPMSGFS_READDIR]   = rpmsgfs_readdir_handler,
  [RPMSGFS_REWINDDIR] = rpmsgfs_default_handler,
  [RPMSGFS_CLOSEDIR]  = rpmsgfs_default_handler,
  [RPMSGFS_STATFS]    = rpmsgfs_statfs_handler,
  [RPMSGFS_UNLINK]    = rpmsgfs_default_handler,
  [RPMSGFS_MKDIR]     = rpmsgfs_default_handler,
  [RPMSGFS_RMDIR]     = rpmsgfs_default_handler,
  [RPMSGFS_RENAME]    = rpmsgfs_default_handler,
  [RPMSGFS_STAT]      = rpmsgfs_stat_handler,
  [RPMSGFS_FCHSTAT]   = rpmsgfs_default_handler,
  [RPMSGFS_CHSTAT]    = rpmsgfs_default_handler,
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

static int rpmsgfs_default_handler(FAR struct rpmsg_endpoint *ept,
                                   FAR void *data, size_t len,
                                   uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;

  cookie->result = header->result;
  if (cookie->result >= 0 && cookie->data)
    {
      memcpy(cookie->data, data, len);
    }

  rpmsg_post(ept, &cookie->sem);

  return 0;
}

static int rpmsgfs_read_handler(FAR struct rpmsg_endpoint *ept,
                                FAR void *data, size_t len,
                                uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;
  FAR struct rpmsgfs_read_s *rsp = data;
  FAR struct iovec *read = cookie->data;

  cookie->result = header->result;
  if (cookie->result > 0)
    {
      memcpy(read->iov_base + read->iov_len, rsp->buf, cookie->result);
      read->iov_len += cookie->result;
    }

  if (cookie->result <= 0 || read->iov_len >= rsp->count)
    {
      rpmsg_post(ept, &cookie->sem);
    }

  return 0;
}

static int rpmsgfs_ioctl_handler(FAR struct rpmsg_endpoint *ept,
                                 FAR void *data, size_t len,
                                 uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (FAR struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;
  FAR struct rpmsgfs_ioctl_s *rsp = data;

  cookie->result = header->result;
  if (cookie->result >= 0 && rsp->arglen > 0)
    {
      memcpy(cookie->data, (FAR void *)(uintptr_t)rsp->buf, rsp->arglen);
    }

  rpmsg_post(ept, &cookie->sem);

  return 0;
}

static int rpmsgfs_readdir_handler(FAR struct rpmsg_endpoint *ept,
                                   FAR void *data, size_t len,
                                   uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;
  FAR struct rpmsgfs_readdir_s *rsp = data;
  FAR struct dirent *entry = cookie->data;

  cookie->result = header->result;
  if (cookie->result >= 0)
    {
      strlcpy(entry->d_name, rsp->name, sizeof(entry->d_name));
      entry->d_type = rsp->type;
    }

  rpmsg_post(ept, &cookie->sem);

  return 0;
}

static int rpmsgfs_statfs_handler(FAR struct rpmsg_endpoint *ept,
                                  FAR void *data, size_t len,
                                  uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;
  FAR struct rpmsgfs_statfs_s *rsp = data;
  FAR struct statfs *buf = cookie->data;

  cookie->result = header->result;
  if (cookie->result >= 0)
    {
      buf->f_type    = rsp->type;
      buf->f_namelen = rsp->namelen;
      buf->f_bsize   = rsp->bsize;
      buf->f_blocks  = rsp->blocks;
      buf->f_bfree   = rsp->bfree;
      buf->f_bavail  = rsp->bavail;
      buf->f_files   = rsp->files;
      buf->f_ffree   = rsp->ffree;
    }

  rpmsg_post(ept, &cookie->sem);

  return 0;
}

static int rpmsgfs_stat_handler(FAR struct rpmsg_endpoint *ept,
                                FAR void *data, size_t len,
                                uint32_t src, FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  FAR struct rpmsgfs_cookie_s *cookie =
      (struct rpmsgfs_cookie_s *)(uintptr_t)header->cookie;
  FAR struct rpmsgfs_stat_s *rsp = data;
  FAR struct stat *buf = cookie->data;

  cookie->result = header->result;
  if (cookie->result >= 0)
    {
      buf->st_dev          = rsp->buf.dev;
      buf->st_ino          = rsp->buf.ino;
      buf->st_mode         = rsp->buf.mode;
      buf->st_nlink        = rsp->buf.nlink;
      buf->st_uid          = rsp->buf.uid;
      buf->st_gid          = rsp->buf.gid;
      buf->st_rdev         = rsp->buf.rdev;
      buf->st_size         = rsp->buf.size;
      buf->st_atim.tv_sec  = rsp->buf.atim_sec;
      buf->st_atim.tv_nsec = rsp->buf.atim_nsec;
      buf->st_mtim.tv_sec  = rsp->buf.mtim_sec;
      buf->st_mtim.tv_nsec = rsp->buf.mtim_nsec;
      buf->st_ctim.tv_sec  = rsp->buf.ctim_sec;
      buf->st_ctim.tv_nsec = rsp->buf.ctim_nsec;
      buf->st_blksize      = rsp->buf.blksize;
      buf->st_blocks       = rsp->buf.blocks;
    }

  rpmsg_post(ept, &cookie->sem);

  return 0;
}

static FAR void *rpmsgfs_get_tx_payload_buffer(FAR struct rpmsgfs_s *priv,
                                               FAR uint32_t *len)
{
  int sval;

  nxsem_get_value(&priv->wait, &sval);
  if (sval <= 0)
    {
      rpmsg_wait(&priv->ept, &priv->wait);
      rpmsg_post(&priv->ept, &priv->wait);
    }

  return rpmsg_get_tx_payload_buffer(&priv->ept, len, true);
}

static void rpmsgfs_ns_bound(struct rpmsg_endpoint *ept)
{
  FAR struct rpmsgfs_s *priv = ept->priv;
  rpmsg_post(&priv->ept, &priv->wait);
}

static void rpmsgfs_device_created(FAR struct rpmsg_device *rdev,
                                   FAR void *priv_)
{
  FAR struct rpmsgfs_s *priv = priv_;
  char buf[RPMSG_NAME_SIZE];

  if (strcmp(priv->cpuname, rpmsg_get_cpuname(rdev)) == 0)
    {
      priv->ept.priv = priv;
      priv->ept.ns_bound_cb = rpmsgfs_ns_bound;
      snprintf(buf, sizeof(buf), "%s%p", RPMSGFS_NAME_PREFIX, priv);
      rpmsg_create_ept(&priv->ept, rdev, buf,
                       RPMSG_ADDR_ANY, RPMSG_ADDR_ANY,
                       rpmsgfs_ept_cb, NULL);
    }
}

static void rpmsgfs_device_destroy(FAR struct rpmsg_device *rdev,
                                   FAR void *priv_)
{
  struct rpmsgfs_s *priv = priv_;

  if (strcmp(priv->cpuname, rpmsg_get_cpuname(rdev)) == 0)
    {
      rpmsg_destroy_ept(&priv->ept);
    }
}

static int rpmsgfs_ept_cb(FAR struct rpmsg_endpoint *ept,
                          FAR void *data, size_t len, uint32_t src,
                          FAR void *priv)
{
  FAR struct rpmsgfs_header_s *header = data;
  uint32_t command = header->command;

  if (command < nitems(g_rpmsgfs_handler))
    {
      return g_rpmsgfs_handler[command](ept, data, len, src, priv);
    }

  return -EINVAL;
}

static int rpmsgfs_send_recv(FAR struct rpmsgfs_s *priv,
                             uint32_t command, bool copy,
                             FAR struct rpmsgfs_header_s *msg,
                             int len, FAR void *data)
{
  FAR struct rpmsgfs_cookie_s cookie;
  int ret;

  memset(&cookie, 0, sizeof(cookie));
  nxsem_init(&cookie.sem, 0, 0);

  if (data)
    {
      cookie.data = data;
    }
  else if (copy)
    {
      cookie.data = msg;
    }

  msg->command = command;
  msg->result  = -ENXIO;
  msg->cookie  = (uintptr_t)&cookie;

  if (copy)
    {
      ret = rpmsg_send(&priv->ept, msg, len);
    }
  else
    {
      ret = rpmsg_send_nocopy(&priv->ept, msg, len);
    }

  if (ret < 0)
    {
      goto fail;
    }

  ret = rpmsg_wait(&priv->ept, &cookie.sem);
  if (ret == 0)
    {
      ret = cookie.result;
    }

fail:
  nxsem_destroy(&cookie.sem);
  return ret;
}

static ssize_t rpmsgfs_ioctl_arglen(int cmd)
{
  switch (cmd)
    {
      case FIONBIO:
      case FIONWRITE:
      case FIONREAD:
        return sizeof(int);
      case FIOC_FILEPATH:
        return PATH_MAX;
      case TCDRN:
      case TCFLSH:
        return 0;
      case TCGETS:
      case TCSETS:
        return sizeof(struct termios);
      case FIOC_SETLK:
      case FIOC_GETLK:
      case FIOC_SETLKW:
        return sizeof(struct flock);
      default:
        return -ENOTTY;
    }
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

int rpmsgfs_client_open(FAR void *handle, FAR const char *pathname,
                        int flags, int mode)
{
  FAR struct rpmsgfs_s *priv = handle;
  FAR struct rpmsgfs_open_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(pathname) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  msg->flags = flags;
  msg->mode  = mode;
  strlcpy(msg->pathname, pathname, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_OPEN, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}

int rpmsgfs_client_close(FAR void *handle, int fd)
{
  struct rpmsgfs_close_s msg =
  {
    .fd = fd,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_CLOSE, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

ssize_t rpmsgfs_client_read(FAR void *handle, int fd,
                            FAR void *buf, size_t count)
{
  FAR struct rpmsgfs_s *priv = handle;
  struct iovec read =
    {
      .iov_base = buf,
      .iov_len  = 0,
    };

  struct rpmsgfs_cookie_s cookie;
  struct rpmsgfs_read_s msg;
  int ret = 0;

  if (!buf || count <= 0)
    {
      return 0;
    }

  memset(&cookie, 0, sizeof(cookie));

  nxsem_init(&cookie.sem, 0, 0);
  cookie.data = &read;

  msg.header.command = RPMSGFS_READ;
  msg.header.result  = -ENXIO;
  msg.header.cookie  = (uintptr_t)&cookie;
  msg.fd             = fd;
  msg.count          = count;

  ret = rpmsg_send(&priv->ept, &msg, sizeof(msg));
  if (ret < 0)
    {
      goto out;
    }

  ret = rpmsg_wait(&priv->ept, &cookie.sem);
  if (ret < 0)
    {
      goto out;
    }

  ret = cookie.result;

out:
  nxsem_destroy(&cookie.sem);
  return read.iov_len > 0 ? read.iov_len : ret;
}

ssize_t rpmsgfs_client_write(FAR void *handle, int fd,
                             FAR const void *buf, size_t count)
{
  FAR struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_cookie_s cookie;
  size_t written = 0;
  int ret = 0;

  if (!buf || count <= 0)
    {
      return 0;
    }

  memset(&cookie, 0, sizeof(cookie));
  nxsem_init(&cookie.sem, 0, 0);

  while (written < count)
    {
      FAR struct rpmsgfs_write_s *msg;
      uint32_t space;

      msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
      if (!msg)
        {
          ret = -ENOMEM;
          goto out;
        }

      space -= sizeof(*msg);
      if (space >= count - written)
        {
          space = count - written;
          msg->header.cookie = (uintptr_t)&cookie;
        }
      else
        {
          msg->header.cookie = 0;
        }

      msg->header.command = RPMSGFS_WRITE;
      msg->header.result  = -ENXIO;
      msg->fd             = fd;
      msg->count          = space;
      memcpy(msg->buf, buf + written, space);

      ret = rpmsg_send_nocopy(&priv->ept, msg, sizeof(*msg) + space);
      if (ret < 0)
        {
          goto out;
        }

      written += space;
    }

  ret = rpmsg_wait(&priv->ept, &cookie.sem);
  if (ret < 0)
    {
      goto out;
    }

  ret = cookie.result;

out:
  nxsem_destroy(&cookie.sem);
  return ret < 0 ? ret : count;
}

off_t rpmsgfs_client_lseek(FAR void *handle, int fd,
                           off_t offset, int whence)
{
  struct rpmsgfs_lseek_s msg =
  {
    .fd     = fd,
    .offset = offset,
    .whence = whence,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_LSEEK, true,
           (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_ioctl(FAR void *handle, int fd,
                         int request, unsigned long arg)
{
  ssize_t arglen = rpmsgfs_ioctl_arglen(request);
  FAR struct rpmsgfs_s *priv = handle;
  FAR struct rpmsgfs_ioctl_s *msg;
  uint32_t space;
  size_t len;
  int ret;

  if (arglen < 0)
    {
      return arglen;
    }

  len = sizeof(*msg) + arglen;

  while (1)
    {
      msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
      if (msg == NULL)
        {
          return -ENOMEM;
        }

      DEBUGASSERT(len <= space);

      msg->fd      = fd;
      msg->request = request == FIOC_SETLKW ? FIOC_SETLK : request;
      msg->arg     = arg;
      msg->arglen  = arglen;

      if (arglen > 0)
        {
          memcpy(msg->buf, (FAR void *)(uintptr_t)arg, arglen);
        }

      ret = rpmsgfs_send_recv(handle, RPMSGFS_IOCTL, false,
                              (FAR struct rpmsgfs_header_s *)msg, len,
                              arglen > 0 ? (FAR void *)arg : NULL);
      if (request != FIOC_SETLKW || ret != -EAGAIN)
        {
          break;
        }

      usleep(20000);
    }

  return ret;
}

void rpmsgfs_client_sync(FAR void *handle, int fd)
{
  struct rpmsgfs_sync_s msg =
  {
    .fd = fd,
  };

  rpmsgfs_send_recv(handle, RPMSGFS_SYNC, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_dup(FAR void *handle, int fd)
{
  struct rpmsgfs_dup_s msg =
  {
    .fd = fd,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_DUP, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_fstat(FAR void *handle, int fd, struct stat *buf)
{
  struct rpmsgfs_fstat_s msg =
  {
    .fd = fd,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_FSTAT, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), buf);
}

int rpmsgfs_client_ftruncate(FAR void *handle, int fd, off_t length)
{
  struct rpmsgfs_ftruncate_s msg =
  {
    .fd     = fd,
    .length = length,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_FTRUNCATE, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

FAR void *rpmsgfs_client_opendir(FAR void *handle, FAR const char *name)
{
  FAR struct rpmsgfs_s *priv = handle;
  FAR struct rpmsgfs_opendir_s *msg;
  uint32_t space;
  size_t len;
  int ret;

  len = sizeof(*msg) + strlen(name) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return NULL;
    }

  DEBUGASSERT(len <= space);

  strlcpy(msg->pathname, name, space - sizeof(*msg));

  ret = rpmsgfs_send_recv(priv, RPMSGFS_OPENDIR, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);

  return ret < 0 ? NULL : (FAR void *)((uintptr_t)ret);
}

int rpmsgfs_client_readdir(FAR void *handle, FAR void *dirp,
                           FAR struct dirent *entry)
{
  struct rpmsgfs_readdir_s msg =
  {
    .fd = (uintptr_t)dirp,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_READDIR, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), entry);
}

void rpmsgfs_client_rewinddir(FAR void *handle, FAR void *dirp)
{
  struct rpmsgfs_rewinddir_s msg =
  {
    .fd = (uintptr_t)dirp,
  };

  rpmsgfs_send_recv(handle, RPMSGFS_REWINDDIR, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_bind(FAR void **handle, FAR const char *cpuname)
{
  struct rpmsgfs_s *priv;
  int ret;

  if (!cpuname)
    {
      return -EINVAL;
    }

  priv = fs_heap_zalloc(sizeof(struct rpmsgfs_s));
  if (!priv)
    {
      return -ENOMEM;
    }

  nxsem_init(&priv->wait, 0, 0);
  strlcpy(priv->cpuname, cpuname, sizeof(priv->cpuname));
  ret = rpmsg_register_callback(priv,
                                rpmsgfs_device_created,
                                rpmsgfs_device_destroy,
                                NULL,
                                NULL);
  if (ret < 0)
    {
      nxsem_destroy(&priv->wait);
      fs_heap_free(priv);
      return ret;
    }

  *handle = priv;

  return 0;
}

int rpmsgfs_client_unbind(FAR void *handle)
{
  struct rpmsgfs_s *priv = handle;

  rpmsg_unregister_callback(priv,
                            rpmsgfs_device_created,
                            rpmsgfs_device_destroy,
                            NULL,
                            NULL);

  nxsem_destroy(&priv->wait);
  fs_heap_free(priv);
  return 0;
}

int rpmsgfs_client_closedir(FAR void *handle, FAR void *dirp)
{
  struct rpmsgfs_closedir_s msg =
  {
    .fd = (uintptr_t)dirp,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_CLOSEDIR, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_statfs(FAR void *handle, FAR const char *path,
                          FAR struct statfs *buf)
{
  struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_statfs_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(path) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  strlcpy(msg->pathname, path, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_STATFS, false,
          (struct rpmsgfs_header_s *)msg, len, buf);
}

int rpmsgfs_client_unlink(FAR void *handle, FAR const char *pathname)
{
  struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_unlink_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(pathname) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  strlcpy(msg->pathname, pathname, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_UNLINK, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}

int rpmsgfs_client_mkdir(FAR void *handle, FAR const char *pathname,
                         mode_t mode)
{
  struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_mkdir_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(pathname) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  msg->mode = mode;
  strlcpy(msg->pathname, pathname, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_MKDIR, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}

int rpmsgfs_client_rmdir(FAR void *handle, FAR const char *pathname)
{
  struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_rmdir_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(pathname) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  strlcpy(msg->pathname, pathname, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_RMDIR, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}

int rpmsgfs_client_rename(FAR void *handle, FAR const char *oldpath,
                          FAR const char *newpath)
{
  struct rpmsgfs_s *priv = handle;
  struct rpmsgfs_rename_s *msg;
  size_t len;
  size_t oldlen;
  size_t newlen;
  size_t alignlen;
  uint32_t space;

  oldlen   = strlen(oldpath) + 1;
  alignlen = (oldlen + 0x7) & ~0x7;
  newlen   = strlen(newpath) + 1;
  len      = sizeof(*msg) + alignlen + newlen;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  memcpy(msg->pathname, oldpath, oldlen);
  memcpy(msg->pathname + alignlen, newpath, newlen);

  return rpmsgfs_send_recv(priv, RPMSGFS_RENAME, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}

int rpmsgfs_client_stat(FAR void *handle, FAR const char *path,
                        FAR struct stat *buf)
{
  FAR struct rpmsgfs_s *priv = handle;
  FAR struct rpmsgfs_stat_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(path) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  strlcpy(msg->pathname, path, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_STAT, false,
          (struct rpmsgfs_header_s *)msg, len, buf);
}

int rpmsgfs_client_fchstat(FAR void *handle, int fd,
                           const struct stat *buf, int flags)
{
  struct rpmsgfs_fchstat_s msg =
  {
    .buf.dev       = buf->st_dev,
    .buf.ino       = buf->st_ino,
    .buf.mode      = buf->st_mode,
    .buf.nlink     = buf->st_nlink,
    .buf.uid       = buf->st_uid,
    .buf.gid       = buf->st_gid,
    .buf.rdev      = buf->st_rdev,
    .buf.size      = buf->st_size,
    .buf.atim_sec  = buf->st_atim.tv_sec,
    .buf.atim_nsec = buf->st_atim.tv_nsec,
    .buf.mtim_sec  = buf->st_mtim.tv_sec,
    .buf.mtim_nsec = buf->st_mtim.tv_nsec,
    .buf.ctim_sec  = buf->st_ctim.tv_sec,
    .buf.ctim_nsec = buf->st_ctim.tv_nsec,
    .buf.blksize   = buf->st_blksize,
    .buf.blocks    = buf->st_blocks,
    .flags            = flags,
    .fd               = fd,
  };

  return rpmsgfs_send_recv(handle, RPMSGFS_FCHSTAT, true,
          (struct rpmsgfs_header_s *)&msg, sizeof(msg), NULL);
}

int rpmsgfs_client_chstat(FAR void *handle, FAR const char *path,
                          FAR const struct stat *buf, int flags)
{
  FAR struct rpmsgfs_s *priv = handle;
  FAR struct rpmsgfs_chstat_s *msg;
  uint32_t space;
  size_t len;

  len = sizeof(*msg) + strlen(path) + 1;

  msg = rpmsgfs_get_tx_payload_buffer(priv, &space);
  if (!msg)
    {
      return -ENOMEM;
    }

  DEBUGASSERT(len <= space);

  msg->flags         = flags;
  msg->buf.dev       = buf->st_dev;
  msg->buf.ino       = buf->st_ino;
  msg->buf.mode      = buf->st_mode;
  msg->buf.nlink     = buf->st_nlink;
  msg->buf.uid       = buf->st_uid;
  msg->buf.gid       = buf->st_gid;
  msg->buf.rdev      = buf->st_rdev;
  msg->buf.size      = buf->st_size;
  msg->buf.atim_sec  = buf->st_atim.tv_sec;
  msg->buf.atim_nsec = buf->st_atim.tv_nsec;
  msg->buf.mtim_sec  = buf->st_mtim.tv_sec;
  msg->buf.mtim_nsec = buf->st_mtim.tv_nsec;
  msg->buf.ctim_sec  = buf->st_ctim.tv_sec;
  msg->buf.ctim_nsec = buf->st_ctim.tv_nsec;
  msg->buf.blksize   = buf->st_blksize;
  msg->buf.blocks    = buf->st_blocks;

  strlcpy(msg->pathname, path, space - sizeof(*msg));

  return rpmsgfs_send_recv(priv, RPMSGFS_CHSTAT, false,
          (struct rpmsgfs_header_s *)msg, len, NULL);
}