gbm_abi_check.c

/*
 * Copyright © 2021 NVIDIA Corporation
 *
 * 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 (including the next
 * paragraph) 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.
 */

#include "gbm_backend_abi.h" /* Current GBM backend ABI implementation */

#include <stddef.h> /* offsetof */
#include <stdio.h> /* printf */

/*
 * The following are previous implementations of the structures defined in
 * gbm_backend_abi.h, with their ABI version appended.
 *
 * DO NOT EVER CHANGE EXISTING DEFINITIONS HERE!
 *
 * Changing them implies breaking the GBM backend ABI. Instead, to extend the
 * ABI, in gbm_backend_abi.h:
 *
 * -Add a new versioned struct
 * -Append it to the associated top-level object's struct
 * -Increment GBM_BACKEND_ABI_VERSION
 *
 * Then, here:
 *
 * -Add a new block of definitions below for the new ABI content
 * -Add a new block of checks in main()
 */

/* From: 49a7331cb02 - James Jones - gbm: Version the backend interface */
#define GBM_BACKEND_ABI_VERSION_abi0 0
struct gbm_device_v0_abi0 {
   const struct gbm_backend_desc *backend_desc;
   uint32_t backend_version;
   int fd;
   const char *name;
   void (*destroy)(struct gbm_device *gbm);
   int (*is_format_supported)(struct gbm_device *gbm,
                              uint32_t format,
                              uint32_t usage);
   int (*get_format_modifier_plane_count)(struct gbm_device *device,
                                          uint32_t format,
                                          uint64_t modifier);
   struct gbm_bo *(*bo_create)(struct gbm_device *gbm,
                               uint32_t width, uint32_t height,
                               uint32_t format,
                               uint32_t usage,
                               const uint64_t *modifiers,
                               const unsigned int count);
   struct gbm_bo *(*bo_import)(struct gbm_device *gbm, uint32_t type,
                               void *buffer, uint32_t usage);
   void *(*bo_map)(struct gbm_bo *bo,
                               uint32_t x, uint32_t y,
                               uint32_t width, uint32_t height,
                               uint32_t flags, uint32_t *stride,
                               void **map_data);
   void (*bo_unmap)(struct gbm_bo *bo, void *map_data);
   int (*bo_write)(struct gbm_bo *bo, const void *buf, size_t data);
   int (*bo_get_fd)(struct gbm_bo *bo);
   int (*bo_get_planes)(struct gbm_bo *bo);
   union gbm_bo_handle (*bo_get_handle)(struct gbm_bo *bo, int plane);
   int (*bo_get_plane_fd)(struct gbm_bo *bo, int plane);
   uint32_t (*bo_get_stride)(struct gbm_bo *bo, int plane);
   uint32_t (*bo_get_offset)(struct gbm_bo *bo, int plane);
   uint64_t (*bo_get_modifier)(struct gbm_bo *bo);
   void (*bo_destroy)(struct gbm_bo *bo);
   struct gbm_surface *(*surface_create)(struct gbm_device *gbm,
                                         uint32_t width, uint32_t height,
                                         uint32_t format, uint32_t flags,
                                         const uint64_t *modifiers,
                                         const unsigned count);
   struct gbm_bo *(*surface_lock_front_buffer)(struct gbm_surface *surface);
   void (*surface_release_buffer)(struct gbm_surface *surface,
                                  struct gbm_bo *bo);
   int (*surface_has_free_buffers)(struct gbm_surface *surface);
   void (*surface_destroy)(struct gbm_surface *surface);
};

struct gbm_device_abi0 {
   /* Hack to make a gbm_device detectable by its first element. */
   struct gbm_device *(*dummy)(int);
   struct gbm_device_v0_abi0 v0;
};

/**
 * GBM buffer object interface corresponding to GBM_BACKEND_ABI_VERSION = 0
 *
 * DO NOT MODIFY THIS STRUCT. Instead, introduce a gbm_bo_v1, increment
 * GBM_BACKEND_ABI_VERSION, and append gbm_bo_v1 to gbm_bo.
 */
struct gbm_bo_v0_abi0 {
   uint32_t width;
   uint32_t height;
   uint32_t stride;
   uint32_t format;
   union gbm_bo_handle  handle;
   void *user_data;
   void (*destroy_user_data)(struct gbm_bo *, void *);
};

/**
 * The allocated buffer object.
 *
 * The members in this structure should not be accessed directly.
 *
 * To modify this structure, introduce a new gbm_bo_v<N> structure, add it to
 * the end of this structure, and increment GBM_BACKEND_ABI_VERSION.
 */
struct gbm_bo_abi0 {
   struct gbm_device *gbm;
   struct gbm_bo_v0_abi0 v0;
};

/**
 * GBM surface interface corresponding to GBM_BACKEND_ABI_VERSION = 0
 *
 * DO NOT MODIFY THIS STRUCT. Instead, introduce a gbm_surface_v1, increment
 * GBM_BACKEND_ABI_VERSION, and append gbm_surface_v1 to gbm_surface.
 */
struct gbm_surface_v0_abi0 {
   uint32_t width;
   uint32_t height;
   uint32_t format;
   uint32_t flags;
   struct {
      uint64_t *modifiers;
      unsigned count;
   };
};

/**
 * An allocated GBM surface.
 *
 * To modify this structure, introduce a new gbm_surface_v<N> structure, add it
 * to the end of this structure, and increment GBM_BACKEND_ABI_VERSION.
 */
struct gbm_surface_abi0 {
   struct gbm_device *gbm;
   struct gbm_surface_v0_abi0 v0;
};

/**
 * GBM backend interfaces corresponding to GBM_BACKEND_ABI_VERSION = 0
 *
 * DO NOT MODIFY THIS STRUCT. Instead, introduce a gbm_backend_v1, increment
 * GBM_BACKEND_ABI_VERSION, append gbm_backend_v1 to gbm_backend.
 */
struct gbm_backend_v0_abi0 {
   /**
    * The version of the GBM backend interface supported by this backend. This
    * is set by the backend itself, and may be greater or less than the version
    * supported by the loader. It is the responsibility of the GBM loader to
    * respect this version when accessing fields in this structure.
    */
   uint32_t backend_version;

   const char *backend_name;
   struct gbm_device *(*create_device)(int fd, uint32_t gbm_backend_version);
};

/**
 * The interface exposed by an external GBM backend.
 *
 * To modify this structure, introduce a new gbm_backend_v<N> structure, add it
 * to the end of this structure, and increment GBM_BACKEND_ABI_VERSION.
 */
struct gbm_backend_abi0 {
   struct gbm_backend_v0_abi0 v0;
};

/**
 * GBM interfaces exposed to GBM backends at GBM_BACKEND_ABI_VERSION >= 0
 *
 * DO NOT MODIFY THIS STRUCT. Instead, introduce a gbm_core_v1, increment
 * GBM_BACKEND_ABI_VERSION, and append gbm_core_v1 to gbm_backend.
 */
struct gbm_core_v0_abi0 {
   /**
    * The version of the GBM backend interface supported by the GBM loader. This
    * is set by the loader, and may be greater or less than the version
    * supported by a given backend. It is the responsibility of the backend to
    * respect this version when accessing fields in this structure and other
    * structures allocated or modified by the loader.
    */
   uint32_t core_version;

   uint32_t (*format_canonicalize)(uint32_t gbm_format);
};

/**
 * The interface exposed by the GBM core/loader code to GBM backends.
 *
 * To modify this structure, introduce a new gbm_core_v<N> structure, add it
 * to the end of this structure, and increment GBM_BACKEND_ABI_VERSION.
 */
struct gbm_core_abi0 {
   struct gbm_core_v0_abi0 v0;
};

typedef const struct gbm_backend *(*GBM_GET_BACKEND_PROC_PTR_abi0)(const struct gbm_core *gbm_core);

/*
 * Structure/member ABI-checking helper macros
 */
#define MEMBER_SIZE(type, member) sizeof(((type *)0)->member)

#define CHECK_RENAMED_MEMBER_BASE(type, a_ver, b_ver, a_member, b_member)     \
   do {                                                                       \
      if (offsetof(struct type ## a_ver, a_member) !=                         \
          offsetof(struct type ## b_ver, b_member)) {                         \
         printf("Backards incompatible change detected!\n   "                 \
                "offsetof(struct " #type #a_ver "::" #a_member ") != "        \
                "offsetof(struct " #type #b_ver "::" #b_member ")\n");        \
         return 1;                                                            \
      }                                                                       \
                                                                              \
      if (MEMBER_SIZE(struct type ## a_ver, a_member) !=                      \
          MEMBER_SIZE(struct type ## b_ver, b_member)) {                      \
         printf("Backards incompatible change detected!\n   "                 \
                "MEMBER_SIZE(struct " #type #a_ver "::" #a_member ") != "     \
                "MEMBER_SIZE(struct " #type #b_ver "::" #b_member ")\n");     \
         return 1;                                                            \
      }                                                                       \
   } while (0)

#define CHECK_RENAMED_MEMBER_TYPE(type, a_ver, b_ver, a_member, b_member)     \
   do {                                                                       \
      /* Compile-time type compatibility check */                             \
      struct type ## a_ver a;                                                 \
      struct type ## b_ver b = {0};                                           \
      a.a_member = b.b_member;                                                \
      (void)a;                                                                \
   } while (0)

#define CHECK_RENAMED_MEMBER(type, a_ver, b_ver, a_member, b_member)          \
   do {                                                                       \
      CHECK_RENAMED_MEMBER_BASE(type, a_ver, b_ver, a_member, b_member);      \
      CHECK_RENAMED_MEMBER_TYPE(type, a_ver, b_ver, a_member, b_member);      \
   } while (0)
#define CHECK_RENAMED_MEMBER_NO_TYPE(type, a_ver, b_ver, a_member, b_member)  \
      CHECK_RENAMED_MEMBER_BASE(type, a_ver, b_ver, a_member, b_member);

#define CHECK_MEMBER(type, a_ver, b_ver, member) \
   CHECK_RENAMED_MEMBER(type, a_ver, b_ver, member, member)
#define CHECK_MEMBER_NO_TYPE(type, a_ver, b_ver, member) \
   CHECK_RENAMED_MEMBER_NO_TYPE(type, a_ver, b_ver, member, member)
#define CHECK_MEMBER_CURRENT(type, a_ver, member) \
   CHECK_MEMBER(type, a_ver,, member)
#define CHECK_MEMBER_CURRENT_NO_TYPE(type, a_ver, member) \
   CHECK_MEMBER_NO_TYPE(type, a_ver,, member)

#define CHECK_SIZE(type, a_ver, b_ver)                                     \
   do {                                                                    \
      if (sizeof(struct type ## a_ver) >                                   \
          sizeof(struct type ## b_ver)) {                                  \
         printf("Backards incompatible change detected!\n   "              \
                "sizeof(struct " #type #a_ver ") > "                       \
                "sizeof(struct " #type #b_ver ")\n");                      \
         return 1;                                                         \
      }                                                                    \
   } while (0)

#define CHECK_SIZE_CURRENT(type, a_ver)                                    \
   do {                                                                    \
      if (sizeof(struct type ## a_ver) !=                                  \
          sizeof(struct type)) {                                           \
         printf("Backards incompatible change detected!\n   "              \
                "sizeof(struct " #type #a_ver ") != "                      \
                "sizeof(struct " #type ")\n");                             \
         return 1;                                                         \
      }                                                                    \
   } while (0)

#define CHECK_VERSION(a_ver, b_ver)                                        \
   do {                                                                    \
      if ((GBM_BACKEND_ABI_VERSION ## a_ver) >=                            \
          (GBM_BACKEND_ABI_VERSION ## b_ver)) {                            \
         printf("Backards incompatible change detected!\n   "              \
                "GBM_BACKEND_ABI_VERSION" #a_ver " >= "                    \
                "GBM_BACKEND_ABI_VERSION" #b_ver "\n");                    \
         return 1;                                                         \
      }                                                                    \
   } while (0)

#define CHECK_VERSION_CURRENT(a_ver)                                       \
   do {                                                                    \
      if ((GBM_BACKEND_ABI_VERSION ## a_ver) !=                            \
          (GBM_BACKEND_ABI_VERSION)) {                                     \
         printf("Backards incompatible change detected!\n   "              \
                "GBM_BACKEND_ABI_VERSION" #a_ver " != "                    \
                "GBM_BACKEND_ABI_VERSION\n");                              \
         return 1;                                                         \
      }                                                                    \
   } while (0)

#define CHECK_PROC(proc, a_ver, b_ver)                                     \
   do {                                                                    \
      proc ## a_ver a;                                                     \
      proc ## b_ver b = NULL;                                              \
      a = b;                                                               \
      (void)a;                                                             \
   } while (0)

#define CHECK_PROC_CURRENT(proc, a_ver)                                    \
   CHECK_PROC(proc, a_ver,)

int main(int argc, char **argv)
{
   /********************************************/
   /*** Compare Current ABI to ABI version 0 ***/
   /********************************************/

   /* Check current gbm_device ABI against gbm_device_abi0*/
   CHECK_MEMBER_CURRENT(gbm_device, _abi0, dummy);
   CHECK_MEMBER_CURRENT_NO_TYPE(gbm_device, _abi0, v0);

   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, backend_desc);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, backend_version);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, fd);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, name);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, destroy);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, is_format_supported);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, get_format_modifier_plane_count);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_create);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_import);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_map);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_unmap);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_write);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_fd);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_planes);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_handle);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_plane_fd);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_stride);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_offset);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_get_modifier);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, bo_destroy);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, surface_create);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, surface_lock_front_buffer);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, surface_release_buffer);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, surface_has_free_buffers);
   CHECK_MEMBER_CURRENT(gbm_device_v0, _abi0, surface_destroy);

   /* Size of ABI-versioned substructures verified by above member checks */
   CHECK_SIZE_CURRENT  (gbm_device, _abi0);


   /* Check current gbm_bo ABI against gbm_bo_abi0*/
   CHECK_MEMBER_CURRENT(gbm_bo, _abi0, gbm);
   CHECK_MEMBER_CURRENT_NO_TYPE(gbm_bo, _abi0, v0);

   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, width);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, height);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, stride);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, format);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, handle);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, user_data);
   CHECK_MEMBER_CURRENT(gbm_bo_v0, _abi0, destroy_user_data);

   /* Size of ABI-versioned substructures verified by above member checks */
   CHECK_SIZE_CURRENT  (gbm_bo, _abi0);


   /* Check current gbm_surface ABI against gbm_surface_abi0 */
   CHECK_MEMBER_CURRENT(gbm_surface, _abi0, gbm);
   CHECK_MEMBER_CURRENT_NO_TYPE(gbm_surface, _abi0, v0);

   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, width);
   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, height);
   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, format);
   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, flags);
   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, modifiers);
   CHECK_MEMBER_CURRENT(gbm_surface_v0, _abi0, count);

   /* Size of ABI-versioned substructures verified by above member checks */
   CHECK_SIZE_CURRENT  (gbm_surface, _abi0);


   /* Check current gbm_backend ABI against gbm_backend_abi0 */
   CHECK_MEMBER_CURRENT_NO_TYPE(gbm_backend, _abi0, v0);

   CHECK_MEMBER_CURRENT(gbm_backend_v0, _abi0, backend_version);
   CHECK_MEMBER_CURRENT(gbm_backend_v0, _abi0, backend_name);
   CHECK_MEMBER_CURRENT(gbm_backend_v0, _abi0, create_device);

   /* Size of ABI-versioned substructures verified by above member checks */
   CHECK_SIZE_CURRENT  (gbm_backend, _abi0);


   /* Check current gbm_core ABI against gbm_core_abi0 */
   CHECK_MEMBER_CURRENT_NO_TYPE(gbm_core, _abi0, v0);

   CHECK_MEMBER_CURRENT(gbm_core_v0, _abi0, core_version);
   CHECK_MEMBER_CURRENT(gbm_core_v0, _abi0, format_canonicalize);

   /* Size of ABI-versioned substructures verified by above member checks */
   CHECK_SIZE_CURRENT  (gbm_core, _abi0);


   CHECK_PROC_CURRENT  (GBM_GET_BACKEND_PROC_PTR, _abi0);

   return 0;
}