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