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/* nbdkit
* Copyright Red Hat
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Red Hat nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* See nbdkit-filter(3) for documentation and how to write a filter. */
#ifndef NBDKIT_FILTER_H
#define NBDKIT_FILTER_H
#include <stdlib.h>
#include <nbdkit-common.h>
#ifdef __cplusplus
extern "C" {
#endif
#define NBDKIT_FILTER_API_VERSION 6 /* Corresponding to v1.16+ */
#define NBDKIT_ZERO_NONE 0
#define NBDKIT_ZERO_EMULATE 1
#define NBDKIT_ZERO_NATIVE 2
#ifdef NBDKIT_INTERNAL
/* Opaque types encapsulating all information needed for calling into
* the next filter or plugin.
*/
typedef struct backend nbdkit_backend;
typedef struct context nbdkit_context;
typedef struct context nbdkit_next;
#else
typedef struct nbdkit_backend nbdkit_backend;
typedef struct nbdkit_context nbdkit_context;
typedef struct nbdkit_next_ops nbdkit_next;
#endif
/* Next ops. */
typedef int nbdkit_next_config (nbdkit_backend *nxdata,
const char *key, const char *value)
NBDKIT_ATTRIBUTE_NONNULL ((1, 2, 3));
typedef int nbdkit_next_config_complete (nbdkit_backend *nxdata)
NBDKIT_ATTRIBUTE_NONNULL ((1));
typedef int nbdkit_next_preconnect (nbdkit_backend *nxdata, int readonly)
NBDKIT_ATTRIBUTE_NONNULL ((1));
typedef int nbdkit_next_list_exports (nbdkit_backend *nxdata, int readonly,
struct nbdkit_exports *exports)
NBDKIT_ATTRIBUTE_NONNULL ((1, 3));
typedef const char *nbdkit_next_default_export (nbdkit_backend *nxdata,
int readonly)
NBDKIT_ATTRIBUTE_NONNULL ((1));
typedef int nbdkit_next_open (nbdkit_context *context,
int readonly, const char *exportname)
NBDKIT_ATTRIBUTE_NONNULL ((1, 3));
struct nbdkit_next_ops {
/* These callbacks are only needed when managing the backend manually
* rather than via nbdkit_next_open.
*/
int (*prepare) (nbdkit_next *nxdata);
int (*finalize) (nbdkit_next *nxdata);
/* These callbacks are the same as normal plugin operations. */
int64_t (*get_size) (nbdkit_next *nxdata);
const char * (*export_description) (nbdkit_next *nxdata);
int (*block_size) (nbdkit_next *nxdata,
uint32_t *minimum, uint32_t *preferred, uint32_t *maximum);
int (*can_write) (nbdkit_next *nxdata);
int (*can_flush) (nbdkit_next *nxdata);
int (*is_rotational) (nbdkit_next *nxdata);
int (*can_trim) (nbdkit_next *nxdata);
int (*can_zero) (nbdkit_next *nxdata);
int (*can_fast_zero) (nbdkit_next *nxdata);
int (*can_extents) (nbdkit_next *nxdata);
int (*can_fua) (nbdkit_next *nxdata);
int (*can_multi_conn) (nbdkit_next *nxdata);
int (*can_cache) (nbdkit_next *nxdata);
int (*pread) (nbdkit_next *nxdata,
void *buf, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*pwrite) (nbdkit_next *nxdata,
const void *buf, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*flush) (nbdkit_next *nxdata, uint32_t flags, int *err);
int (*trim) (nbdkit_next *nxdata, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*zero) (nbdkit_next *nxdata, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*extents) (nbdkit_next *nxdata, uint32_t count, uint64_t offset,
uint32_t flags, struct nbdkit_extents *extents, int *err);
int (*cache) (nbdkit_next *nxdata, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
/* Note: Actual instances of this struct contain additional opaque
* data not listed in this header; you cannot manually copy or
* initialize sizeof(struct nbdkit_next_ops) bytes, but must instead
* use unchanged pointers obtained from the nbdkit API.
*/
};
/* Extent helpers. */
NBDKIT_EXTERN_DECL (struct nbdkit_extents *, nbdkit_extents_full,
(nbdkit_next *next,
uint32_t count, uint64_t offset,
uint32_t flags, int *err)
NBDKIT_ATTRIBUTE_NONNULL ((1, 5)));
NBDKIT_EXTERN_DECL (int, nbdkit_extents_aligned,
(nbdkit_next *next,
uint64_t count, uint64_t offset,
uint32_t flags, uint32_t align,
struct nbdkit_extents *extents, int *err)
NBDKIT_ATTRIBUTE_NONNULL ((1, 6, 7)));
/* Export functions. */
struct nbdkit_export {
char *name;
char *description;
};
NBDKIT_EXTERN_DECL (void, nbdkit_exports_free, (struct nbdkit_exports *));
NBDKIT_EXTERN_DECL (struct nbdkit_exports *, nbdkit_exports_new,
(void) NBDKIT_ATTRIBUTE_MALLOC (nbdkit_exports_free));
NBDKIT_EXTERN_DECL (size_t, nbdkit_exports_count,
(const struct nbdkit_exports *)
NBDKIT_ATTRIBUTE_NONNULL ((1)));
NBDKIT_EXTERN_DECL (const struct nbdkit_export, nbdkit_get_export,
(const struct nbdkit_exports *, size_t)
NBDKIT_ATTRIBUTE_NONNULL ((1)));
/* Manual management of backend access. */
NBDKIT_EXTERN_DECL (nbdkit_backend *, nbdkit_context_get_backend,
(nbdkit_context *context)
NBDKIT_ATTRIBUTE_NONNULL ((1)));
NBDKIT_EXTERN_DECL (nbdkit_next *, nbdkit_next_context_open,
(nbdkit_backend *backend, int readonly,
const char *exportname, int shared)
NBDKIT_ATTRIBUTE_NONNULL ((1, 3)));
NBDKIT_EXTERN_DECL (void, nbdkit_next_context_close, (nbdkit_next *next));
NBDKIT_EXTERN_DECL (nbdkit_next *, nbdkit_context_set_next,
(nbdkit_context *context, nbdkit_next *next)
NBDKIT_ATTRIBUTE_NONNULL ((1)));
/* Filter struct. */
struct nbdkit_filter {
/* Do not set these fields directly; use NBDKIT_REGISTER_FILTER.
* They exist so that we can diagnose filters compiled against one
* version of the header with a runtime compiled against a different
* version. As of API version 6, _version is also part of the
* guaranteed ABI, so we no longer have to remember to bump API
* versions regardless of other API/ABI changes later in the struct.
*/
int _api_version;
const char *_version;
/* Because there is no ABI guarantee, new fields may be added where
* logically appropriate.
*/
const char *name;
const char *longname;
const char *description;
void (*load) (void);
void (*unload) (void);
int (*config) (nbdkit_next_config *next, nbdkit_backend *nxdata,
const char *key, const char *value);
int (*config_complete) (nbdkit_next_config_complete *next,
nbdkit_backend *nxdata);
const char *config_help;
int (*thread_model) (int next_thread_model);
void (*dump_plugin) (void);
int (*get_ready) (int final_thread_model);
int (*after_fork) (nbdkit_backend *backend);
void (*cleanup) (nbdkit_backend *backend);
int (*preconnect) (nbdkit_next_preconnect *next, nbdkit_backend *nxdata,
int readonly);
int (*list_exports) (nbdkit_next_list_exports *next, nbdkit_backend *nxdata,
int readonly, int is_tls,
struct nbdkit_exports *exports);
const char * (*default_export) (nbdkit_next_default_export *next,
nbdkit_backend *nxdata,
int readonly, int is_tls);
void * (*open) (nbdkit_next_open *next, nbdkit_context *context,
int readonly, const char *exportname, int is_tls);
void (*close) (void *handle);
int (*prepare) (nbdkit_next *next,
void *handle, int readonly);
int (*finalize) (nbdkit_next *next,
void *handle);
int64_t (*get_size) (nbdkit_next *next,
void *handle);
const char * (*export_description) (nbdkit_next *next, void *handle);
int (*block_size) (nbdkit_next *next, void *handle,
uint32_t *minimum, uint32_t *preferred, uint32_t *maximum);
int (*can_write) (nbdkit_next *next,
void *handle);
int (*can_flush) (nbdkit_next *next,
void *handle);
int (*is_rotational) (nbdkit_next *next, void *handle);
int (*can_trim) (nbdkit_next *next,
void *handle);
int (*can_zero) (nbdkit_next *next,
void *handle);
int (*can_fast_zero) (nbdkit_next *next, void *handle);
int (*can_extents) (nbdkit_next *next,
void *handle);
int (*can_fua) (nbdkit_next *next,
void *handle);
int (*can_multi_conn) (nbdkit_next *next, void *handle);
int (*can_cache) (nbdkit_next *next,
void *handle);
int (*pread) (nbdkit_next *next,
void *handle, void *buf, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*pwrite) (nbdkit_next *next,
void *handle,
const void *buf, uint32_t count, uint64_t offset,
uint32_t flags, int *err);
int (*flush) (nbdkit_next *next,
void *handle, uint32_t flags, int *err);
int (*trim) (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offset, uint32_t flags,
int *err);
int (*zero) (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offset, uint32_t flags,
int *err);
int (*extents) (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offset, uint32_t flags,
struct nbdkit_extents *extents, int *err);
int (*cache) (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offset, uint32_t flags,
int *err);
};
#define NBDKIT_REGISTER_FILTER(filter) \
NBDKIT_CXX_LANG_C \
NBDKIT_DLL_PUBLIC \
struct nbdkit_filter * \
filter_init (void) \
{ \
(filter)._api_version = NBDKIT_FILTER_API_VERSION; \
(filter)._version = NBDKIT_VERSION_STRING; \
return &(filter); \
}
#ifdef __cplusplus
}
#endif
#endif /* NBDKIT_FILTER_H */
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