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opnsense-src/sys/sys/eventhandler.h
Ian Lepore 7f92689427 Add eventhandler notifications for newbus device attach/detach. 
The detach case is slightly complicated by the fact that some in-kernel
consumers may want to know before a device detaches (so they can release
related resources, stop using the device, etc), but the detach can fail. So
there are pre- and post-detach notifications for those consumers who need to
handle all cases.

A couple salient comments from the review, they amount to some helpful
documentation about these events, but there's currently no good place for
such documentation...

Note that in the current newbus locking model, DETACH_BEGIN and
DETACH_COMPLETE/FAILED sequence of event handler invocation might interweave
with other attach/detach events arbitrarily. The handlers should be prepared
for such situations.

Also should note that detach may be called after the parent bus knows the
hardware has left the building. In-kernel consumers have to be prepared to
cope with this race.

Differential Revision:	https://reviews.freebsd.org/D12557
2017-10-08 17:33:49 +00:00

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/*-
* 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.
*
* $FreeBSD$
*/
#ifndef _SYS_EVENTHANDLER_H_
#define _SYS_EVENTHANDLER_H_
#include <sys/lock.h>
#include <sys/ktr.h>
#include <sys/mutex.h>
#include <sys/queue.h>
struct eventhandler_entry {
TAILQ_ENTRY(eventhandler_entry) ee_link;
int ee_priority;
#define EHE_DEAD_PRIORITY (-1)
void *ee_arg;
};
#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;
int el_flags;
#define EHL_INITTED (1<<0)
u_int el_runcount;
struct mtx el_lock;
TAILQ_ENTRY(eventhandler_list) el_link;
TAILQ_HEAD(,eventhandler_entry) el_entries;
};
typedef struct eventhandler_entry *eventhandler_tag;
#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; \
\
KASSERT((list)->el_flags & EHL_INITTED, \
("eventhandler_invoke: running non-inited list")); \
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) \
eventhandler_prune_list(list); \
EHL_UNLOCK((list)); \
} while (0)
/*
* Slow handlers are entirely dynamic; lists are created
* when entries are added to them, and thus have no concept of "owner",
*
* Slow handlers need to be declared, but do not need to be defined. The
* declaration must be in scope wherever the handler is to be invoked.
*/
#define EVENTHANDLER_DECLARE(name, type) \
struct eventhandler_entry_ ## name \
{ \
struct eventhandler_entry ee; \
type eh_func; \
}; \
struct __hack
#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);
#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
/* Shutdown events */
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 *);
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);
/* 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);
EVENTHANDLER_DECLARE(device_attach, device_attach_fn);
EVENTHANDLER_DECLARE(device_detach, device_detach_fn);
#endif /* _SYS_EVENTHANDLER_H_ */
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