1/*-
2 * Copyright (c) 2010,2013 Lawrence Stewart <lstewart@freebsd.org>
3 * Copyright (c) 2010 The FreeBSD Foundation
4 * All rights reserved.
5 *
6 * This software was developed by Lawrence Stewart while studying at the Centre
7 * for Advanced Internet Architectures, Swinburne University of Technology,
8 * made possible in part by grants from the FreeBSD Foundation and Cisco
9 * University Research Program Fund at Community Foundation Silicon Valley.
10 *
11 * Portions of this software were developed at the Centre for Advanced
12 * Internet Architectures, Swinburne University of Technology, Melbourne,
13 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD$");
39
40#include <sys/param.h>
41#include <sys/kernel.h>
42#include <sys/hhook.h>
43#include <sys/khelp.h>
44#include <sys/lock.h>
45#include <sys/malloc.h>
46#include <sys/module.h>
47#include <sys/module_khelp.h>
48#include <sys/osd.h>
49#include <sys/queue.h>
50#include <sys/refcount.h>
51#include <sys/rwlock.h>
52#include <sys/systm.h>
53
54static struct rwlock khelp_list_lock;
55RW_SYSINIT(khelplistlock, &khelp_list_lock, "helper list lock");
56
57static TAILQ_HEAD(helper_head, helper) helpers = TAILQ_HEAD_INITIALIZER(helpers);
58
59/* Private function prototypes. */
60static inline void khelp_remove_osd(struct helper *h, struct osd *hosd);
61void khelp_new_hhook_registered(struct hhook_head *hhh, uint32_t flags);
62
63#define	KHELP_LIST_WLOCK() rw_wlock(&khelp_list_lock)
64#define	KHELP_LIST_WUNLOCK() rw_wunlock(&khelp_list_lock)
65#define	KHELP_LIST_RLOCK() rw_rlock(&khelp_list_lock)
66#define	KHELP_LIST_RUNLOCK() rw_runlock(&khelp_list_lock)
67#define	KHELP_LIST_LOCK_ASSERT() rw_assert(&khelp_list_lock, RA_LOCKED)
68
69int
70khelp_register_helper(struct helper *h)
71{
72	struct helper *tmph;
73	int error, i, inserted;
74
75	error = inserted = 0;
76	refcount_init(&h->h_refcount, 0);
77	h->h_id = osd_register(OSD_KHELP, NULL, NULL);
78
79	/* It's only safe to add the hooks after osd_register(). */
80	for (i = 0; i < h->h_nhooks && !error; i++) {
81		/* We don't require the module to assign hook_helper. */
82		h->h_hooks[i].hook_helper = h;
83		error = hhook_add_hook_lookup(&h->h_hooks[i], HHOOK_WAITOK);
84		if (error)
85			printf("%s: \"%s\" khelp module unable to "
86			    "hook type %d id %d due to error %d\n", __func__,
87			    h->h_name, h->h_hooks[i].hook_type,
88			    h->h_hooks[i].hook_id, error);
89	}
90
91	if (error) {
92		for (i--; i >= 0; i--)
93			hhook_remove_hook_lookup(&h->h_hooks[i]);
94		osd_deregister(OSD_KHELP, h->h_id);
95	} else {
96		KHELP_LIST_WLOCK();
97		/*
98		 * Keep list of helpers sorted in descending h_id order. Due to
99		 * the way osd_set() works, a sorted list ensures
100		 * khelp_init_osd() will operate with improved efficiency.
101		 */
102		TAILQ_FOREACH(tmph, &helpers, h_next) {
103			if (tmph->h_id < h->h_id) {
104				TAILQ_INSERT_BEFORE(tmph, h, h_next);
105				inserted = 1;
106				break;
107			}
108		}
109
110		if (!inserted)
111			TAILQ_INSERT_TAIL(&helpers, h, h_next);
112		KHELP_LIST_WUNLOCK();
113	}
114
115	return (error);
116}
117
118int
119khelp_deregister_helper(struct helper *h)
120{
121	struct helper *tmph;
122	int error, i;
123
124	KHELP_LIST_WLOCK();
125	if (h->h_refcount > 0)
126		error = EBUSY;
127	else {
128		error = ENOENT;
129		TAILQ_FOREACH(tmph, &helpers, h_next) {
130			if (tmph == h) {
131				TAILQ_REMOVE(&helpers, h, h_next);
132				error = 0;
133				break;
134			}
135		}
136	}
137	KHELP_LIST_WUNLOCK();
138
139	if (!error) {
140		for (i = 0; i < h->h_nhooks; i++)
141			hhook_remove_hook_lookup(&h->h_hooks[i]);
142		osd_deregister(OSD_KHELP, h->h_id);
143	}
144
145	return (error);
146}
147
148int
149khelp_init_osd(uint32_t classes, struct osd *hosd)
150{
151	struct helper *h;
152	void *hdata;
153	int error;
154
155	KASSERT(hosd != NULL, ("struct osd not initialised!"));
156
157	error = 0;
158
159	KHELP_LIST_RLOCK();
160	TAILQ_FOREACH(h, &helpers, h_next) {
161		/* If helper is correct class and needs to store OSD... */
162		if (h->h_classes & classes && h->h_flags & HELPER_NEEDS_OSD) {
163			hdata = uma_zalloc(h->h_zone, M_NOWAIT);
164			if (hdata == NULL) {
165				error = ENOMEM;
166				break;
167			}
168			osd_set(OSD_KHELP, hosd, h->h_id, hdata);
169			refcount_acquire(&h->h_refcount);
170		}
171	}
172
173	if (error) {
174		/* Delete OSD that was assigned prior to the error. */
175		TAILQ_FOREACH(h, &helpers, h_next) {
176			if (h->h_classes & classes)
177				khelp_remove_osd(h, hosd);
178		}
179	}
180	KHELP_LIST_RUNLOCK();
181
182	return (error);
183}
184
185int
186khelp_destroy_osd(struct osd *hosd)
187{
188	struct helper *h;
189	int error;
190
191	KASSERT(hosd != NULL, ("struct osd not initialised!"));
192
193	error = 0;
194
195	KHELP_LIST_RLOCK();
196	/*
197	 * Clean up all khelp related OSD.
198	 *
199	 * XXXLAS: Would be nice to use something like osd_exit() here but it
200	 * doesn't have the right semantics for this purpose.
201	 */
202	TAILQ_FOREACH(h, &helpers, h_next)
203		khelp_remove_osd(h, hosd);
204	KHELP_LIST_RUNLOCK();
205
206	return (error);
207}
208
209static inline void
210khelp_remove_osd(struct helper *h, struct osd *hosd)
211{
212	void *hdata;
213
214	if (h->h_flags & HELPER_NEEDS_OSD) {
215		/*
216		 * If the current helper uses OSD and calling osd_get()
217		 * on the helper's h_id returns non-NULL, the helper has
218		 * OSD attached to 'hosd' which needs to be cleaned up.
219		 */
220		hdata = osd_get(OSD_KHELP, hosd, h->h_id);
221		if (hdata != NULL) {
222			uma_zfree(h->h_zone, hdata);
223			osd_del(OSD_KHELP, hosd, h->h_id);
224			refcount_release(&h->h_refcount);
225		}
226	}
227}
228
229void *
230khelp_get_osd(struct osd *hosd, int32_t id)
231{
232
233	return (osd_get(OSD_KHELP, hosd, id));
234}
235
236int32_t
237khelp_get_id(char *hname)
238{
239	struct helper *h;
240	int32_t id;
241
242	id = -1;
243
244	KHELP_LIST_RLOCK();
245	TAILQ_FOREACH(h, &helpers, h_next) {
246		if (strncmp(h->h_name, hname, HELPER_NAME_MAXLEN) == 0) {
247			id = h->h_id;
248			break;
249		}
250	}
251	KHELP_LIST_RUNLOCK();
252
253	return (id);
254}
255
256int
257khelp_add_hhook(struct hookinfo *hki, uint32_t flags)
258{
259	int error;
260
261	/*
262	 * XXXLAS: Should probably include the functionality to update the
263	 * helper's h_hooks struct member.
264	 */
265	error = hhook_add_hook_lookup(hki, flags);
266
267	return (error);
268}
269
270int
271khelp_remove_hhook(struct hookinfo *hki)
272{
273	int error;
274
275	/*
276	 * XXXLAS: Should probably include the functionality to update the
277	 * helper's h_hooks struct member.
278	 */
279	error = hhook_remove_hook_lookup(hki);
280
281	return (error);
282}
283
284/*
285 * Private KPI between hhook and khelp that allows khelp modules to insert hook
286 * functions into hhook points which register after the modules were loaded.
287 */
288void
289khelp_new_hhook_registered(struct hhook_head *hhh, uint32_t flags)
290{
291	struct helper *h;
292	int error, i;
293
294	KHELP_LIST_RLOCK();
295	TAILQ_FOREACH(h, &helpers, h_next) {
296		for (i = 0; i < h->h_nhooks; i++) {
297			if (hhh->hhh_type != h->h_hooks[i].hook_type ||
298			    hhh->hhh_id != h->h_hooks[i].hook_id)
299				continue;
300			error = hhook_add_hook(hhh, &h->h_hooks[i], flags);
301			if (error) {
302				printf("%s: \"%s\" khelp module unable to "
303				    "hook type %d id %d due to error %d\n",
304				    __func__, h->h_name,
305				    h->h_hooks[i].hook_type,
306				    h->h_hooks[i].hook_id, error);
307				error = 0;
308			}
309		}
310	}
311	KHELP_LIST_RUNLOCK();
312}
313
314int
315khelp_modevent(module_t mod, int event_type, void *data)
316{
317	struct khelp_modevent_data *kmd;
318	int error;
319
320	kmd = (struct khelp_modevent_data *)data;
321	error = 0;
322
323	switch(event_type) {
324	case MOD_LOAD:
325		if (kmd->helper->h_flags & HELPER_NEEDS_OSD) {
326			if (kmd->uma_zsize <= 0) {
327				printf("Use KHELP_DECLARE_MOD_UMA() instead!\n");
328				error = EDOOFUS;
329				break;
330			}
331			kmd->helper->h_zone = uma_zcreate(kmd->name,
332			    kmd->uma_zsize, kmd->umactor, kmd->umadtor, NULL,
333			    NULL, 0, 0);
334			if (kmd->helper->h_zone == NULL) {
335				error = ENOMEM;
336				break;
337			}
338		}
339		strlcpy(kmd->helper->h_name, kmd->name, HELPER_NAME_MAXLEN);
340		kmd->helper->h_hooks = kmd->hooks;
341		kmd->helper->h_nhooks = kmd->nhooks;
342		if (kmd->helper->mod_init != NULL)
343			error = kmd->helper->mod_init();
344		if (!error)
345			error = khelp_register_helper(kmd->helper);
346		break;
347
348	case MOD_QUIESCE:
349	case MOD_SHUTDOWN:
350	case MOD_UNLOAD:
351		error = khelp_deregister_helper(kmd->helper);
352		if (!error) {
353			if (kmd->helper->h_flags & HELPER_NEEDS_OSD)
354				uma_zdestroy(kmd->helper->h_zone);
355			if (kmd->helper->mod_destroy != NULL)
356				kmd->helper->mod_destroy();
357		} else if (error == ENOENT)
358			/* Do nothing and allow unload if helper not in list. */
359			error = 0;
360		else if (error == EBUSY)
361			printf("Khelp module \"%s\" can't unload until its "
362			    "refcount drops from %d to 0.\n", kmd->name,
363			    kmd->helper->h_refcount);
364		break;
365
366	default:
367		error = EINVAL;
368		break;
369	}
370
371	return (error);
372}
373