    /******************************************************************************
     * Xen Hypervisor Filesystem
     *
     * Copyright (c) 2019, SUSE Software Solutions Germany GmbH
     *
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to
     * deal in the Software without restriction, including without limitation the
     * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     * DEALINGS IN THE SOFTWARE.
     *
     */

    #ifndef __XEN_PUBLIC_HYPFS_H__
    #define __XEN_PUBLIC_HYPFS_H__

    #include "xen.h"

    /*
     * Definitions for the __HYPERVISOR_hypfs_op hypercall.
     */

    /* Highest version number of the hypfs interface currently defined. */
    #define XEN_HYPFS_VERSION      1

    /* Maximum length of a path in the filesystem. */
    #define XEN_HYPFS_MAX_PATHLEN  1024

    struct xen_hypfs_direntry {
        uint8_t type;
    #define XEN_HYPFS_TYPE_DIR     0
    #define XEN_HYPFS_TYPE_BLOB    1
    #define XEN_HYPFS_TYPE_STRING  2
    #define XEN_HYPFS_TYPE_UINT    3
    #define XEN_HYPFS_TYPE_INT     4
    #define XEN_HYPFS_TYPE_BOOL    5
        uint8_t encoding;
    #define XEN_HYPFS_ENC_PLAIN    0
    #define XEN_HYPFS_ENC_GZIP     1
        uint16_t pad;              /* Returned as 0. */
        uint32_t content_len;      /* Current length of data. */
        uint32_t max_write_len;    /* Max. length for writes (0 if read-only). */
    };
    typedef struct xen_hypfs_direntry xen_hypfs_direntry_t;

    struct xen_hypfs_dirlistentry {
        xen_hypfs_direntry_t e;
        /* Offset in bytes to next entry (0 == this is the last entry). */
        uint16_t off_next;
        /* Zero terminated entry name, possibly with some padding for alignment. */
        char name[XEN_FLEX_ARRAY_DIM];
    };

    /*
     * Hypercall operations.
     */

    /*
     * XEN_HYPFS_OP_get_version
     *
     * Read highest interface version supported by the hypervisor.
     *
     * arg1 - arg4: all 0/NULL
     *
     * Possible return values:
     * >0: highest supported interface version
     * <0: negative Xen errno value
     */
    #define XEN_HYPFS_OP_get_version     0

    /*
     * XEN_HYPFS_OP_read
     *
     * Read a filesystem entry.
     *
     * Returns the direntry and contents of an entry in the buffer supplied by the
     * caller (struct xen_hypfs_direntry with the contents following directly
     * after it).
     * The data buffer must be at least the size of the direntry returned. If the
     * data buffer was not large enough for all the data -ENOBUFS and no entry
     * data is returned, but the direntry will contain the needed size for the
     * returned data.
     * The format of the contents is according to its entry type and encoding.
     * The contents of a directory are multiple struct xen_hypfs_dirlistentry
     * items.
     *
     * arg1: XEN_GUEST_HANDLE(path name)
     * arg2: length of path name (including trailing zero byte)
     * arg3: XEN_GUEST_HANDLE(data buffer written by hypervisor)
     * arg4: data buffer size
     *
     * Possible return values:
     * 0: success
     * <0 : negative Xen errno value
     */
    #define XEN_HYPFS_OP_read              1

    /*
     * XEN_HYPFS_OP_write_contents
     *
     * Write contents of a filesystem entry.
     *
     * Writes an entry with the contents of a buffer supplied by the caller.
     * The data type and encoding can't be changed. The size can be changed only
     * for blobs and strings.
     *
     * arg1: XEN_GUEST_HANDLE(path name)
     * arg2: length of path name (including trailing zero byte)
     * arg3: XEN_GUEST_HANDLE(content buffer read by hypervisor)
     * arg4: content buffer size
     *
     * Possible return values:
     * 0: success
     * <0 : negative Xen errno value
     */
    #define XEN_HYPFS_OP_write_contents    2

    #endif /* __XEN_PUBLIC_HYPFS_H__ */