FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_khelp.c
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: releng/11.2/sys/kern/kern_khelp.c 251778 2013-06-15 06:45:17Z lstewart $");
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
54 static struct rwlock khelp_list_lock;
55 RW_SYSINIT(khelplistlock, &khelp_list_lock, "helper list lock");
56
57 static TAILQ_HEAD(helper_head, helper) helpers = TAILQ_HEAD_INITIALIZER(helpers);
58
59 /* Private function prototypes. */
60 static inline void khelp_remove_osd(struct helper *h, struct osd *hosd);
61 void 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
69 int
70 khelp_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
118 int
119 khelp_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
148 int
149 khelp_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
185 int
186 khelp_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
209 static inline void
210 khelp_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
229 void *
230 khelp_get_osd(struct osd *hosd, int32_t id)
231 {
232
233 return (osd_get(OSD_KHELP, hosd, id));
234 }
235
236 int32_t
237 khelp_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
256 int
257 khelp_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
270 int
271 khelp_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 */
288 void
289 khelp_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
314 int
315 khelp_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 }
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