lib/module.h

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRR_MODULE_H
  18 #define _FRR_MODULE_H
  19
  20 #include <stdint.h>
  21 #include <stdbool.h>
  22
  23 #ifdef __cplusplus
  24 extern "C" {
  25 #endif
  26
  27 struct frrmod_runtime;
  28
  29 struct frrmod_info {
  30         /* single-line few-word title */
  31         const char *name;
  32         /* human-readable version number, should not contain spaces */
  33         const char *version;
  34         /* one-paragraph description */
  35         const char *description;
  36
  37         int (*init)(void);
  38 };
  39
  40 /* primary entry point structure to be present in loadable module under
  41  * "_frrmod_this_module" dlsym() name
  42  *
  43  * note space for future extensions is reserved below, so other modules
  44  * (e.g. memory management, hooks) can add fields
  45  *
  46  * const members/info are in frrmod_info.
  47  */
  48 struct frrmod_runtime {
  49         struct frrmod_runtime *next;
  50
  51         const struct frrmod_info *info;
  52         void *dl_handle;
  53         bool finished_loading;
  54
  55         char *load_name;
  56         char *load_args;
  57 };
  58
  59 /* space-reserving foo */
  60 struct _frrmod_runtime_size {
  61         struct frrmod_runtime r;
  62         /* this will barf if frrmod_runtime exceeds 1024 bytes ... */
  63         uint8_t space[1024 - sizeof(struct frrmod_runtime)];
  64 };
  65 union _frrmod_runtime_u {
  66         struct frrmod_runtime r;
  67         struct _frrmod_runtime_size s;
  68 };
  69
  70 extern union _frrmod_runtime_u _frrmod_this_module;
  71 #define THIS_MODULE (&_frrmod_this_module.r)
  72
  73 #define FRR_COREMOD_SETUP(...)                                                 \
  74         static const struct frrmod_info _frrmod_info = {__VA_ARGS__};          \
  75         DSO_LOCAL union _frrmod_runtime_u _frrmod_this_module = {{             \
  76                 NULL,                                                          \
  77                 &_frrmod_info,                                                 \
  78         }};
  79 #define FRR_MODULE_SETUP(...)                                                  \
  80         FRR_COREMOD_SETUP(__VA_ARGS__)                                         \
  81         DSO_SELF struct frrmod_runtime *frr_module = &_frrmod_this_module.r;
  82
  83 extern struct frrmod_runtime *frrmod_list;
  84
  85 extern void frrmod_init(struct frrmod_runtime *modinfo);
  86 extern struct frrmod_runtime *frrmod_load(const char *spec, const char *dir,
  87                                           char *err, size_t err_len);
  88 #if 0
  89 /* not implemented yet */
  90 extern void frrmod_unload(struct frrmod_runtime *module);
  91 #endif
  92
  93 #ifdef __cplusplus
  94 }
  95 #endif
  96
  97 #endif /* _FRR_MODULE_H */