/*
* Copyright (c) 2016 David Lamparter, for NetDEF, Inc.
*
- * 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.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef _FRR_HOOK_H
* hook_register_arg (some_update_event, event_handler, addonptr);
*
* (addonptr isn't typesafe, but that should be manageable.)
+ *
+ * Hooks also support a "priority" value for ordering registered calls
+ * relative to each other. The priority is a signed integer where lower
+ * values are called earlier. There is also "Koohs", which is hooks with
+ * reverse priority ordering (for cleanup/deinit hooks, so you can use the
+ * same priority value).
+ *
+ * Recommended priority value ranges are:
+ *
+ * -999 ... 0 ... 999 - main executable / daemon, or library
+ * -1999 ... -1000 - modules registering calls that should run before
+ * the daemon's bits
+ * 1000 ... 1999 - modules calls that should run after daemon's
+ *
+ * Note: the default value is 1000, based on the following 2 expectations:
+ * - most hook_register() usage will be in loadable modules
+ * - usage of hook_register() in the daemon itself may need relative ordering
+ * to itself, making an explicit value the expected case
+ *
+ * The priority value is passed as extra argument on hook_register_prio() /
+ * hook_register_arg_prio(). Whether a hook runs in reverse is determined
+ * solely by the code defining / calling the hook. (DECLARE_KOOH is actually
+ * the same thing as DECLARE_HOOK, it's just there to make it obvious.)
*/
/* TODO:
void *hookfn; /* actually a function pointer */
void *hookarg;
bool has_arg;
+ int priority;
struct frrmod_runtime *module;
const char *fnname;
};
struct hook {
const char *name;
struct hookent *entries;
+ bool reverse;
};
+#define HOOK_DEFAULT_PRIORITY 1000
+
/* subscribe/add callback function to a hook
*
* always use hook_register(), which uses the static inline helper from
*/
extern void _hook_register(struct hook *hook, void *funcptr, void *arg,
bool has_arg, struct frrmod_runtime *module,
- const char *funcname);
+ const char *funcname, int priority);
#define hook_register(hookname, func) \
_hook_register(&_hook_##hookname, _hook_typecheck_##hookname(func), \
- NULL, false, THIS_MODULE, #func)
+ NULL, false, THIS_MODULE, #func, HOOK_DEFAULT_PRIORITY)
#define hook_register_arg(hookname, func, arg) \
_hook_register(&_hook_##hookname, \
_hook_typecheck_arg_##hookname(func), arg, true, \
- THIS_MODULE, #func)
+ THIS_MODULE, #func, HOOK_DEFAULT_PRIORITY)
+#define hook_register_prio(hookname, prio, func) \
+ _hook_register(&_hook_##hookname, _hook_typecheck_##hookname(func), \
+ NULL, false, THIS_MODULE, #func, prio)
+#define hook_register_arg_prio(hookname, prio, func, arg) \
+ _hook_register(&_hook_##hookname, \
+ _hook_typecheck_arg_##hookname(func), arg, true, \
+ THIS_MODULE, #func, prio)
extern void _hook_unregister(struct hook *hook, void *funcptr, void *arg,
bool has_arg);
{ \
return (void *)funcptr; \
}
+#define DECLARE_KOOH(hookname, arglist, passlist) \
+ DECLARE_HOOK(hookname, arglist, passlist)
/* use in source file - contains hook-related definitions.
*/
-#define DEFINE_HOOK(hookname, arglist, passlist) \
+#define DEFINE_HOOK_INT(hookname, arglist, passlist, rev) \
struct hook _hook_##hookname = { \
- .name = #hookname, .entries = NULL, \
+ .name = #hookname, .entries = NULL, .reverse = rev, \
}; \
static int hook_call_##hookname arglist \
{ \
return hooksum; \
}
+#define DEFINE_HOOK(hookname, arglist, passlist) \
+ DEFINE_HOOK_INT(hookname, arglist, passlist, false)
+#define DEFINE_KOOH(hookname, arglist, passlist) \
+ DEFINE_HOOK_INT(hookname, arglist, passlist, true)
+
#endif /* _FRR_HOOK_H */
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