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 #include "compiler.h"
  24 #include "xref.h"
  25
  26 #ifdef __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 struct frrmod_runtime;
  31
  32 struct frrmod_info {
  33         /* single-line few-word title */
  34         const char *name;
  35         /* human-readable version number, should not contain spaces */
  36         const char *version;
  37         /* one-paragraph description */
  38         const char *description;
  39
  40         int (*init)(void);
  41 };
  42
  43 /* primary entry point structure to be present in loadable module under
  44  * "_frrmod_this_module" dlsym() name
  45  *
  46  * note space for future extensions is reserved below, so other modules
  47  * (e.g. memory management, hooks) can add fields
  48  *
  49  * const members/info are in frrmod_info.
  50  */
  51 struct frrmod_runtime {
  52         struct frrmod_runtime *next;
  53
  54         const struct frrmod_info *info;
  55         void *dl_handle;
  56         bool finished_loading;
  57
  58         char *load_name;
  59         char *load_args;
  60 };
  61
  62 /* space-reserving foo */
  63 struct _frrmod_runtime_size {
  64         struct frrmod_runtime r;
  65         /* this will barf if frrmod_runtime exceeds 1024 bytes ... */
  66         uint8_t space[1024 - sizeof(struct frrmod_runtime)];
  67 };
  68 union _frrmod_runtime_u {
  69         struct frrmod_runtime r;
  70         struct _frrmod_runtime_size s;
  71 };
  72
  73 extern union _frrmod_runtime_u _frrmod_this_module;
  74 #define THIS_MODULE (&_frrmod_this_module.r)
  75
  76 #define FRR_COREMOD_SETUP(...)                                                 \
  77         static const struct frrmod_info _frrmod_info = {__VA_ARGS__};          \
  78         DSO_LOCAL union _frrmod_runtime_u _frrmod_this_module = {{             \
  79                 NULL,                                                          \
  80                 &_frrmod_info,                                                 \
  81         }};                                                                    \
  82         XREF_SETUP();                                                          \
  83         MACRO_REQUIRE_SEMICOLON() /* end */
  84
  85 #define FRR_MODULE_SETUP(...)                                                  \
  86         FRR_COREMOD_SETUP(__VA_ARGS__);                                        \
  87         DSO_SELF struct frrmod_runtime *frr_module = &_frrmod_this_module.r;   \
  88         MACRO_REQUIRE_SEMICOLON() /* end */
  89
  90 extern struct frrmod_runtime *frrmod_list;
  91
  92 extern void frrmod_init(struct frrmod_runtime *modinfo);
  93 extern struct frrmod_runtime *frrmod_load(const char *spec, const char *dir,
  94                                           void (*pFerrlog)(const void *,
  95                                                            const char *),
  96                                           const void *pErrlogCookie);
  97 #if 0
  98 /* not implemented yet */
  99 extern void frrmod_unload(struct frrmod_runtime *module);
 100 #endif
 101
 102 #ifdef __cplusplus
 103 }
 104 #endif
 105
 106 #endif /* _FRR_MODULE_H */