/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR 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.
 */

#ifndef _SYS_EVENTHANDLER_H_
#define _SYS_EVENTHANDLER_H_

#include <sys/_eventhandler.h>
#include <sys/lock.h>
#include <sys/ktr.h>
#include <sys/mutex.h>
#include <sys/power.h>
#include <sys/queue.h>

#ifdef VIMAGE
struct eventhandler_entry_vimage {
        void    (* func)(void);         /* Original function registered. */
        void    *ee_arg;                /* Original argument registered. */
        void    *sparep[2];
};
#endif

struct eventhandler_list {
        char                            *el_name;
        u_int                           el_deadcount;
        u_int                           el_runcount;
        struct mtx                      el_lock;
        TAILQ_ENTRY(eventhandler_list)  el_link;
        TAILQ_HEAD(,eventhandler_entry) el_entries;
};

#define EHL_LOCK(p)             mtx_lock(&(p)->el_lock)
#define EHL_UNLOCK(p)           mtx_unlock(&(p)->el_lock)
#define EHL_LOCK_ASSERT(p, x)   mtx_assert(&(p)->el_lock, x)

/*
 * Macro to invoke the handlers for a given event.
 */
#define _EVENTHANDLER_INVOKE(name, list, ...) do {                      \
        struct eventhandler_entry *_ep;                                 \
        struct eventhandler_entry_ ## name *_t;                         \
                                                                        \
        EHL_LOCK_ASSERT((list), MA_OWNED);                              \
        (list)->el_runcount++;                                          \
        KASSERT((list)->el_runcount > 0,                                \
            ("eventhandler_invoke: runcount overflow"));                \
        CTR0(KTR_EVH, "eventhandler_invoke(\"" __STRING(name) "\")");   \
        TAILQ_FOREACH(_ep, &((list)->el_entries), ee_link) {            \
                if (_ep->ee_priority != EHE_DEAD_PRIORITY) {            \
                        EHL_UNLOCK((list));                             \
                        _t = (struct eventhandler_entry_ ## name *)_ep; \
                        CTR1(KTR_EVH, "eventhandler_invoke: executing %p", \
                            (void *)_t->eh_func);                       \
                        _t->eh_func(_ep->ee_arg , ## __VA_ARGS__);      \
                        EHL_LOCK((list));                               \
                }                                                       \
        }                                                               \
        KASSERT((list)->el_runcount > 0,                                \
            ("eventhandler_invoke: runcount underflow"));               \
        (list)->el_runcount--;                                          \
        if ((list)->el_runcount == 0 && (list)->el_deadcount != 0)      \
                eventhandler_prune_list(list);                          \
        EHL_UNLOCK((list));                                             \
} while (0)

/*
 * You can optionally use the EVENTHANDLER_LIST and EVENTHANDLER_DIRECT macros
 * to pre-define a symbol for the eventhandler list. This symbol can be used by
 * EVENTHANDLER_DIRECT_INVOKE, which has the advantage of not needing to do a
 * locked search of the global list of eventhandler lists. At least
 * EVENTHANDLER_LIST_DEFINE must be used for EVENTHANDLER_DIRECT_INVOKE to
 * work. EVENTHANDLER_LIST_DECLARE is only needed if the call to
 * EVENTHANDLER_DIRECT_INVOKE is in a different compilation unit from
 * EVENTHANDLER_LIST_DEFINE. If the events are even relatively high frequency
 * it is suggested that you directly define a list for them.
 */
#define EVENTHANDLER_LIST_DEFINE(name)                                  \
struct eventhandler_list *_eventhandler_list_ ## name ;                 \
static void _ehl_init_ ## name (void * ctx __unused)                    \
{                                                                       \
        _eventhandler_list_ ## name = eventhandler_create_list(#name);  \
}                                                                       \
SYSINIT(name ## _ehl_init, SI_SUB_EVENTHANDLER, SI_ORDER_ANY,           \
            _ehl_init_ ## name, NULL);                                  \
        struct __hack

#define EVENTHANDLER_DIRECT_INVOKE(name, ...) do {                      \
        struct eventhandler_list *_el;                                  \
                                                                        \
        _el = _eventhandler_list_ ## name ;                             \
        if (!TAILQ_EMPTY(&_el->el_entries)) {                           \
                EHL_LOCK(_el);                                          \
                _EVENTHANDLER_INVOKE(name, _el , ## __VA_ARGS__);       \
        }                                                               \
} while (0)

#define EVENTHANDLER_DEFINE(name, func, arg, priority)                  \
        static eventhandler_tag name ## _tag;                           \
        static void name ## _evh_init(void *ctx)                        \
        {                                                               \
                name ## _tag = EVENTHANDLER_REGISTER(name, func, ctx,   \
                    priority);                                          \
        }                                                               \
        SYSINIT(name ## _evh_init, SI_SUB_CONFIGURE, SI_ORDER_ANY,      \
            name ## _evh_init, arg);                                    \
        struct __hack

#define EVENTHANDLER_INVOKE(name, ...)                                  \
do {                                                                    \
        struct eventhandler_list *_el;                                  \
                                                                        \
        if ((_el = eventhandler_find_list(#name)) != NULL)              \
                _EVENTHANDLER_INVOKE(name, _el , ## __VA_ARGS__);       \
} while (0)

#define EVENTHANDLER_REGISTER(name, func, arg, priority)                \
        eventhandler_register(NULL, #name, func, arg, priority)

#define EVENTHANDLER_DEREGISTER(name, tag)                              \
do {                                                                    \
        struct eventhandler_list *_el;                                  \
                                                                        \
        if ((_el = eventhandler_find_list(#name)) != NULL)              \
                eventhandler_deregister(_el, tag);                      \
} while (0)

#define EVENTHANDLER_DEREGISTER_NOWAIT(name, tag)                       \
do {                                                                    \
        struct eventhandler_list *_el;                                  \
                                                                        \
        if ((_el = eventhandler_find_list(#name)) != NULL)              \
                eventhandler_deregister_nowait(_el, tag);               \
} while (0)

eventhandler_tag eventhandler_register(struct eventhandler_list *list, 
            const char *name, void *func, void *arg, int priority);
void    eventhandler_deregister(struct eventhandler_list *list,
            eventhandler_tag tag);
void    eventhandler_deregister_nowait(struct eventhandler_list *list,
            eventhandler_tag tag);
struct eventhandler_list *eventhandler_find_list(const char *name);
void    eventhandler_prune_list(struct eventhandler_list *list);
struct eventhandler_list *eventhandler_create_list(const char *name);

#ifdef VIMAGE
typedef void (*vimage_iterator_func_t)(void *, ...);

eventhandler_tag vimage_eventhandler_register(struct eventhandler_list *list,
            const char *name, void *func, void *arg, int priority,
            vimage_iterator_func_t);
#endif

/*
 * Standard system event queues.
 */

/* Generic priority levels */
#define EVENTHANDLER_PRI_FIRST  0
#define EVENTHANDLER_PRI_ANY    10000
#define EVENTHANDLER_PRI_LAST   20000

/*
 * Successive shutdown events invoked by kern_reboot(9).
 *
 * Handlers will receive the 'howto' value as their second argument.
 *
 * All handlers must be prepared to be executed from a panic/debugger context;
 * see the man page for details.
 */
typedef void (*shutdown_fn)(void *, int);

#define SHUTDOWN_PRI_FIRST      EVENTHANDLER_PRI_FIRST
#define SHUTDOWN_PRI_DEFAULT    EVENTHANDLER_PRI_ANY
#define SHUTDOWN_PRI_LAST       EVENTHANDLER_PRI_LAST

EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn);   /* before fs sync */
EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);  /* after fs sync */
EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);

/* Power state change events */
typedef void (*power_change_fn)(void *, enum power_stype stype);
EVENTHANDLER_DECLARE(power_resume, power_change_fn);
EVENTHANDLER_DECLARE(power_suspend, power_change_fn);
EVENTHANDLER_DECLARE(power_suspend_early, power_change_fn);

/* Low memory event */
typedef void (*vm_lowmem_handler_t)(void *, int);
#define LOWMEM_PRI_DEFAULT      EVENTHANDLER_PRI_FIRST
EVENTHANDLER_DECLARE(vm_lowmem, vm_lowmem_handler_t);
/* Some of mbuf(9) zones reached maximum */
EVENTHANDLER_DECLARE(mbuf_lowmem, vm_lowmem_handler_t);

/* Root mounted event */
typedef void (*mountroot_handler_t)(void *);
EVENTHANDLER_DECLARE(mountroot, mountroot_handler_t);

/* File system mount events */
struct mount;
struct vnode;
struct thread;
typedef void (*vfs_mounted_notify_fn)(void *, struct mount *, struct vnode *,
    struct thread *);
typedef void (*vfs_unmounted_notify_fn)(void *, struct mount *,
    struct thread *);
EVENTHANDLER_DECLARE(vfs_mounted, vfs_mounted_notify_fn);
EVENTHANDLER_DECLARE(vfs_unmounted, vfs_unmounted_notify_fn);

/*
 * Process events
 * process_fork and exit handlers are called without Giant.
 * exec handlers are called with Giant, but that is by accident.
 */
struct proc;
struct image_params;

typedef void (*exitlist_fn)(void *, struct proc *);
typedef void (*forklist_fn)(void *, struct proc *, struct proc *, int);
typedef void (*execlist_fn)(void *, struct proc *, struct image_params *);
typedef void (*proc_ctor_fn)(void *, struct proc *);
typedef void (*proc_dtor_fn)(void *, struct proc *);
typedef void (*proc_init_fn)(void *, struct proc *);
typedef void (*proc_fini_fn)(void *, struct proc *);
EVENTHANDLER_DECLARE(process_ctor, proc_ctor_fn);
EVENTHANDLER_DECLARE(process_dtor, proc_dtor_fn);
EVENTHANDLER_DECLARE(process_init, proc_init_fn);
EVENTHANDLER_DECLARE(process_fini, proc_fini_fn);
EVENTHANDLER_DECLARE(process_exit, exitlist_fn);
EVENTHANDLER_DECLARE(process_fork, forklist_fn);
EVENTHANDLER_DECLARE(process_exec, execlist_fn);

/*
 * application dump event
 */
typedef void (*app_coredump_start_fn)(void *, struct thread *, char *name);
typedef void (*app_coredump_progress_fn)(void *, struct thread *td, int byte_count);
typedef void (*app_coredump_finish_fn)(void *, struct thread *td);
typedef void (*app_coredump_error_fn)(void *, struct thread *td, char *msg, ...);

EVENTHANDLER_DECLARE(app_coredump_start, app_coredump_start_fn);
EVENTHANDLER_DECLARE(app_coredump_progress, app_coredump_progress_fn);
EVENTHANDLER_DECLARE(app_coredump_finish, app_coredump_finish_fn);
EVENTHANDLER_DECLARE(app_coredump_error, app_coredump_error_fn);

typedef void (*thread_ctor_fn)(void *, struct thread *);
typedef void (*thread_dtor_fn)(void *, struct thread *);
typedef void (*thread_fini_fn)(void *, struct thread *);
typedef void (*thread_init_fn)(void *, struct thread *);
EVENTHANDLER_DECLARE(thread_ctor, thread_ctor_fn);
EVENTHANDLER_DECLARE(thread_dtor, thread_dtor_fn);
EVENTHANDLER_DECLARE(thread_init, thread_init_fn);
EVENTHANDLER_DECLARE(thread_fini, thread_fini_fn);

typedef void (*uma_zone_chfn)(void *);
EVENTHANDLER_DECLARE(nmbclusters_change, uma_zone_chfn);
EVENTHANDLER_DECLARE(nmbufs_change, uma_zone_chfn);
EVENTHANDLER_DECLARE(maxsockets_change, uma_zone_chfn);

/* Kernel linker file load and unload events */
struct linker_file;
typedef void (*kld_load_fn)(void *, struct linker_file *);
typedef void (*kld_unload_fn)(void *, const char *, caddr_t, size_t);
typedef void (*kld_unload_try_fn)(void *, struct linker_file *, int *);
EVENTHANDLER_DECLARE(kld_load, kld_load_fn);
EVENTHANDLER_DECLARE(kld_unload, kld_unload_fn);
EVENTHANDLER_DECLARE(kld_unload_try, kld_unload_try_fn);

/* Generic graphics framebuffer interface */
struct fb_info;
typedef void (*register_framebuffer_fn)(void *, struct fb_info *);
typedef void (*unregister_framebuffer_fn)(void *, struct fb_info *);
EVENTHANDLER_DECLARE(register_framebuffer, register_framebuffer_fn);
EVENTHANDLER_DECLARE(unregister_framebuffer, unregister_framebuffer_fn);

/* Veto ada attachment */
struct cam_path;
struct ata_params;
typedef void (*ada_probe_veto_fn)(void *, struct cam_path *,
    struct ata_params *, int *);
EVENTHANDLER_DECLARE(ada_probe_veto, ada_probe_veto_fn);

/* Swap device events */
struct swdevt;
typedef void (*swapon_fn)(void *, struct swdevt *);
typedef void (*swapoff_fn)(void *, struct swdevt *);
EVENTHANDLER_DECLARE(swapon, swapon_fn);
EVENTHANDLER_DECLARE(swapoff, swapoff_fn);

/* newbus device events */
enum evhdev_detach {
        EVHDEV_DETACH_BEGIN,    /* Before detach() is called */
        EVHDEV_DETACH_COMPLETE, /* After detach() returns 0 */
        EVHDEV_DETACH_FAILED    /* After detach() returns err */
};
typedef void (*device_attach_fn)(void *, device_t);
typedef void (*device_detach_fn)(void *, device_t, enum evhdev_detach);
typedef void (*device_nomatch_fn)(void *, device_t);
EVENTHANDLER_DECLARE(device_attach, device_attach_fn);
EVENTHANDLER_DECLARE(device_detach, device_detach_fn);
EVENTHANDLER_DECLARE(device_nomatch, device_nomatch_fn);

/* Interface address addition and removal event */
struct ifaddr;
typedef void (*rt_addrmsg_fn)(void *, struct ifaddr *, int);
EVENTHANDLER_DECLARE(rt_addrmsg, rt_addrmsg_fn);

/* Kernel environment variable change event */
typedef void (*env_change_fn)(void *, const char *);
EVENTHANDLER_DECLARE(setenv, env_change_fn);
EVENTHANDLER_DECLARE(unsetenv, env_change_fn);

#endif /* _SYS_EVENTHANDLER_H_ */