xref: /titanic_41/usr/src/uts/common/io/kstat.c (revision 5bbb4db2c3f208d12bf0fd11769728f9e5ba66a2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 
27 /*
28  * kernel statistics driver
29  */
30 
31 #include <sys/types.h>
32 #include <sys/time.h>
33 #include <sys/param.h>
34 #include <sys/sysmacros.h>
35 #include <sys/file.h>
36 #include <sys/cmn_err.h>
37 #include <sys/t_lock.h>
38 #include <sys/proc.h>
39 #include <sys/fcntl.h>
40 #include <sys/uio.h>
41 #include <sys/kmem.h>
42 #include <sys/cred.h>
43 #include <sys/mman.h>
44 #include <sys/errno.h>
45 #include <sys/ioccom.h>
46 #include <sys/cpuvar.h>
47 #include <sys/stat.h>
48 #include <sys/conf.h>
49 #include <sys/ddi.h>
50 #include <sys/sunddi.h>
51 #include <sys/modctl.h>
52 #include <sys/kobj.h>
53 #include <sys/kstat.h>
54 #include <sys/atomic.h>
55 #include <sys/policy.h>
56 #include <sys/zone.h>
57 
58 static dev_info_t *kstat_devi;
59 
60 static int
61 read_kstat_data(int *rvalp, void *user_ksp, int flag)
62 {
63 	kstat_t user_kstat, *ksp;
64 #ifdef _MULTI_DATAMODEL
65 	kstat32_t user_kstat32;
66 #endif
67 	void *kbuf = NULL;
68 	size_t kbufsize, ubufsize, copysize;
69 	int error = 0;
70 	uint_t model;
71 
72 	switch (model = ddi_model_convert_from(flag & FMODELS)) {
73 #ifdef _MULTI_DATAMODEL
74 	case DDI_MODEL_ILP32:
75 		if (copyin(user_ksp, &user_kstat32, sizeof (kstat32_t)) != 0)
76 			return (EFAULT);
77 		user_kstat.ks_kid = user_kstat32.ks_kid;
78 		user_kstat.ks_data = (void *)(uintptr_t)user_kstat32.ks_data;
79 		user_kstat.ks_data_size = (size_t)user_kstat32.ks_data_size;
80 		break;
81 #endif
82 	default:
83 	case DDI_MODEL_NONE:
84 		if (copyin(user_ksp, &user_kstat, sizeof (kstat_t)) != 0)
85 			return (EFAULT);
86 	}
87 
88 	ksp = kstat_hold_bykid(user_kstat.ks_kid, getzoneid());
89 	if (ksp == NULL) {
90 		/*
91 		 * There is no kstat with the specified KID
92 		 */
93 		return (ENXIO);
94 	}
95 	if (ksp->ks_flags & KSTAT_FLAG_INVALID) {
96 		/*
97 		 * The kstat exists, but is momentarily in some
98 		 * indeterminate state (e.g. the data section is not
99 		 * yet initialized).  Try again in a few milliseconds.
100 		 */
101 		kstat_rele(ksp);
102 		return (EAGAIN);
103 	}
104 
105 	/*
106 	 * If it's a fixed-size kstat, allocate the buffer now, so we
107 	 * don't have to do it under the kstat's data lock.  (If it's a
108 	 * var-size kstat, we don't know the size until after the update
109 	 * routine is called, so we can't do this optimization.)
110 	 * The allocator relies on this behavior to prevent recursive
111 	 * mutex_enter in its (fixed-size) kstat update routine.
112 	 * It's a zalloc to prevent unintentional exposure of random
113 	 * juicy morsels of (old) kernel data.
114 	 */
115 	if (!(ksp->ks_flags & KSTAT_FLAG_VAR_SIZE)) {
116 		kbufsize = ksp->ks_data_size;
117 		kbuf = kmem_zalloc(kbufsize + 1, KM_NOSLEEP);
118 		if (kbuf == NULL) {
119 			kstat_rele(ksp);
120 			return (EAGAIN);
121 		}
122 	}
123 	KSTAT_ENTER(ksp);
124 	if ((error = KSTAT_UPDATE(ksp, KSTAT_READ)) != 0) {
125 		KSTAT_EXIT(ksp);
126 		kstat_rele(ksp);
127 		if (kbuf != NULL)
128 			kmem_free(kbuf, kbufsize + 1);
129 		return (error);
130 	}
131 
132 	kbufsize = ksp->ks_data_size;
133 	ubufsize = user_kstat.ks_data_size;
134 
135 	if (ubufsize < kbufsize) {
136 		error = ENOMEM;
137 	} else {
138 		if (kbuf == NULL)
139 			kbuf = kmem_zalloc(kbufsize + 1, KM_NOSLEEP);
140 		if (kbuf == NULL) {
141 			error = EAGAIN;
142 		} else {
143 			error = KSTAT_SNAPSHOT(ksp, kbuf, KSTAT_READ);
144 		}
145 	}
146 
147 	/*
148 	 * The following info must be returned to user level,
149 	 * even if the the update or snapshot failed.  This allows
150 	 * kstat readers to get a handle on variable-size kstats,
151 	 * detect dormant kstats, etc.
152 	 */
153 	user_kstat.ks_ndata	= ksp->ks_ndata;
154 	user_kstat.ks_data_size	= kbufsize;
155 	user_kstat.ks_flags	= ksp->ks_flags;
156 	user_kstat.ks_snaptime	= ksp->ks_snaptime;
157 
158 	*rvalp = kstat_chain_id;
159 	KSTAT_EXIT(ksp);
160 	kstat_rele(ksp);
161 
162 	/*
163 	 * Copy the buffer containing the kstat back to userland.
164 	 */
165 	copysize = kbufsize;
166 	if (kbuf != NULL) {
167 #ifdef _MULTI_DATAMODEL
168 		kstat32_t *k32;
169 		kstat_t *k;
170 #endif
171 		int i;
172 
173 		switch (model) {
174 #ifdef _MULTI_DATAMODEL
175 		case DDI_MODEL_ILP32:
176 
177 			if (ksp->ks_type == KSTAT_TYPE_NAMED) {
178 				kstat_named_t *kn = kbuf;
179 
180 				for (i = 0; i < user_kstat.ks_ndata; kn++, i++)
181 					switch (kn->data_type) {
182 					/*
183 					 * Named statistics have fields of type
184 					 * 'long'.  For a 32-bit application
185 					 * looking at a 64-bit kernel,
186 					 * forcibly truncate these 64-bit
187 					 * quantities to 32-bit values.
188 					 */
189 					case KSTAT_DATA_LONG:
190 						kn->value.i32 =
191 						    (int32_t)kn->value.l;
192 						kn->data_type =
193 						    KSTAT_DATA_INT32;
194 						break;
195 					case KSTAT_DATA_ULONG:
196 						kn->value.ui32 =
197 						    (uint32_t)kn->value.ul;
198 						kn->data_type =
199 						    KSTAT_DATA_UINT32;
200 						break;
201 					/*
202 					 * Long strings must be massaged before
203 					 * being copied out to userland.  Do
204 					 * that here.
205 					 */
206 					case KSTAT_DATA_STRING:
207 						if (KSTAT_NAMED_STR_PTR(kn)
208 						    == NULL)
209 							break;
210 						/*
211 						 * The offsets within the
212 						 * buffers are the same, so add
213 						 * the offset to the beginning
214 						 * of the new buffer to fix the
215 						 * pointer.
216 						 */
217 						KSTAT_NAMED_STR_PTR(kn) =
218 						    (char *)user_kstat.ks_data +
219 						    (KSTAT_NAMED_STR_PTR(kn) -
220 						    (char *)kbuf);
221 						/*
222 						 * Make sure the string pointer
223 						 * lies within the allocated
224 						 * buffer.
225 						 */
226 						ASSERT(KSTAT_NAMED_STR_PTR(kn) +
227 						    KSTAT_NAMED_STR_BUFLEN(kn)
228 						    <=
229 						    ((char *)
230 						    user_kstat.ks_data +
231 						    ubufsize));
232 						ASSERT(KSTAT_NAMED_STR_PTR(kn)
233 						    >=
234 						    (char *)
235 						    ((kstat_named_t *)
236 						    user_kstat.ks_data +
237 						    user_kstat.ks_ndata));
238 						/*
239 						 * Cast 64-bit ptr to 32-bit.
240 						 */
241 						kn->value.str.addr.ptr32 =
242 						    (caddr32_t)(uintptr_t)
243 						    KSTAT_NAMED_STR_PTR(kn);
244 						break;
245 					default:
246 						break;
247 					}
248 			}
249 
250 			if (user_kstat.ks_kid != 0)
251 				break;
252 
253 			/*
254 			 * This is the special case of the kstat header
255 			 * list for the entire system.  Reshape the
256 			 * array in place, then copy it out.
257 			 */
258 			k32 = kbuf;
259 			k = kbuf;
260 			for (i = 0; i < user_kstat.ks_ndata; k32++, k++, i++) {
261 				k32->ks_crtime		= k->ks_crtime;
262 				k32->ks_next		= 0;
263 				k32->ks_kid		= k->ks_kid;
264 				(void) strcpy(k32->ks_module, k->ks_module);
265 				k32->ks_resv		= k->ks_resv;
266 				k32->ks_instance	= k->ks_instance;
267 				(void) strcpy(k32->ks_name, k->ks_name);
268 				k32->ks_type		= k->ks_type;
269 				(void) strcpy(k32->ks_class, k->ks_class);
270 				k32->ks_flags		= k->ks_flags;
271 				k32->ks_data		= 0;
272 				k32->ks_ndata		= k->ks_ndata;
273 				if (k->ks_data_size > UINT32_MAX) {
274 					error = EOVERFLOW;
275 					break;
276 				}
277 				k32->ks_data_size = (size32_t)k->ks_data_size;
278 				k32->ks_snaptime	= k->ks_snaptime;
279 			}
280 
281 			/*
282 			 * XXX	In this case we copy less data than is
283 			 *	claimed in the header.
284 			 */
285 			copysize = user_kstat.ks_ndata * sizeof (kstat32_t);
286 			break;
287 #endif	/* _MULTI_DATAMODEL */
288 		default:
289 		case DDI_MODEL_NONE:
290 			if (ksp->ks_type == KSTAT_TYPE_NAMED) {
291 				kstat_named_t *kn = kbuf;
292 
293 				for (i = 0; i < user_kstat.ks_ndata; kn++, i++)
294 					switch (kn->data_type) {
295 #ifdef _LP64
296 					case KSTAT_DATA_LONG:
297 						kn->data_type =
298 						    KSTAT_DATA_INT64;
299 						break;
300 					case KSTAT_DATA_ULONG:
301 						kn->data_type =
302 						    KSTAT_DATA_UINT64;
303 						break;
304 #endif	/* _LP64 */
305 					case KSTAT_DATA_STRING:
306 						if (KSTAT_NAMED_STR_PTR(kn)
307 						    == NULL)
308 							break;
309 						KSTAT_NAMED_STR_PTR(kn) =
310 						    (char *)user_kstat.ks_data +
311 						    (KSTAT_NAMED_STR_PTR(kn) -
312 						    (char *)kbuf);
313 						ASSERT(KSTAT_NAMED_STR_PTR(kn) +
314 						    KSTAT_NAMED_STR_BUFLEN(kn)
315 						    <=
316 						    ((char *)
317 						    user_kstat.ks_data +
318 						    ubufsize));
319 						ASSERT(KSTAT_NAMED_STR_PTR(kn)
320 						    >=
321 						    (char *)
322 						    ((kstat_named_t *)
323 						    user_kstat.ks_data +
324 						    user_kstat.ks_ndata));
325 						break;
326 					default:
327 						break;
328 					}
329 			}
330 			break;
331 		}
332 
333 		if (error == 0 &&
334 		    copyout(kbuf, user_kstat.ks_data, copysize))
335 			error = EFAULT;
336 		kmem_free(kbuf, kbufsize + 1);
337 	}
338 
339 	/*
340 	 * We have modified the ks_ndata, ks_data_size, ks_flags, and
341 	 * ks_snaptime fields of the user kstat; now copy it back to userland.
342 	 */
343 	switch (model) {
344 #ifdef _MULTI_DATAMODEL
345 	case DDI_MODEL_ILP32:
346 		if (kbufsize > UINT32_MAX) {
347 			error = EOVERFLOW;
348 			break;
349 		}
350 		user_kstat32.ks_ndata		= user_kstat.ks_ndata;
351 		user_kstat32.ks_data_size	= (size32_t)kbufsize;
352 		user_kstat32.ks_flags		= user_kstat.ks_flags;
353 		user_kstat32.ks_snaptime	= user_kstat.ks_snaptime;
354 		if (copyout(&user_kstat32, user_ksp, sizeof (kstat32_t)) &&
355 		    error == 0)
356 			error = EFAULT;
357 		break;
358 #endif
359 	default:
360 	case DDI_MODEL_NONE:
361 		if (copyout(&user_kstat, user_ksp, sizeof (kstat_t)) &&
362 		    error == 0)
363 			error = EFAULT;
364 		break;
365 	}
366 
367 	return (error);
368 }
369 
370 static int
371 write_kstat_data(int *rvalp, void *user_ksp, int flag, cred_t *cred)
372 {
373 	kstat_t user_kstat, *ksp;
374 	void *buf = NULL;
375 	size_t bufsize;
376 	int error = 0;
377 
378 	if (secpolicy_sys_config(cred, B_FALSE) != 0)
379 		return (EPERM);
380 
381 	switch (ddi_model_convert_from(flag & FMODELS)) {
382 #ifdef _MULTI_DATAMODEL
383 		kstat32_t user_kstat32;
384 
385 	case DDI_MODEL_ILP32:
386 		if (copyin(user_ksp, &user_kstat32, sizeof (kstat32_t)))
387 			return (EFAULT);
388 		/*
389 		 * These are the only fields we actually look at.
390 		 */
391 		user_kstat.ks_kid = user_kstat32.ks_kid;
392 		user_kstat.ks_data = (void *)(uintptr_t)user_kstat32.ks_data;
393 		user_kstat.ks_data_size = (size_t)user_kstat32.ks_data_size;
394 		user_kstat.ks_ndata = user_kstat32.ks_ndata;
395 		break;
396 #endif
397 	default:
398 	case DDI_MODEL_NONE:
399 		if (copyin(user_ksp, &user_kstat, sizeof (kstat_t)))
400 			return (EFAULT);
401 	}
402 
403 	bufsize = user_kstat.ks_data_size;
404 	buf = kmem_alloc(bufsize + 1, KM_NOSLEEP);
405 	if (buf == NULL)
406 		return (EAGAIN);
407 
408 	if (copyin(user_kstat.ks_data, buf, bufsize)) {
409 		kmem_free(buf, bufsize + 1);
410 		return (EFAULT);
411 	}
412 
413 	ksp = kstat_hold_bykid(user_kstat.ks_kid, getzoneid());
414 	if (ksp == NULL) {
415 		kmem_free(buf, bufsize + 1);
416 		return (ENXIO);
417 	}
418 	if (ksp->ks_flags & KSTAT_FLAG_INVALID) {
419 		kstat_rele(ksp);
420 		kmem_free(buf, bufsize + 1);
421 		return (EAGAIN);
422 	}
423 	if (!(ksp->ks_flags & KSTAT_FLAG_WRITABLE)) {
424 		kstat_rele(ksp);
425 		kmem_free(buf, bufsize + 1);
426 		return (EACCES);
427 	}
428 
429 	/*
430 	 * With KSTAT_FLAG_VARIABLE, one must call the kstat's update callback
431 	 * routine to ensure ks_data_size is up to date.
432 	 * In this case it makes sense to do it anyhow, as it will be shortly
433 	 * followed by a KSTAT_SNAPSHOT().
434 	 */
435 	KSTAT_ENTER(ksp);
436 	error = KSTAT_UPDATE(ksp, KSTAT_READ);
437 	if (error || user_kstat.ks_data_size != ksp->ks_data_size ||
438 	    user_kstat.ks_ndata != ksp->ks_ndata) {
439 		KSTAT_EXIT(ksp);
440 		kstat_rele(ksp);
441 		kmem_free(buf, bufsize + 1);
442 		return (error ? error : EINVAL);
443 	}
444 
445 	/*
446 	 * We have to ensure that we don't accidentally change the type of
447 	 * existing kstat_named statistics when writing over them.
448 	 * Since read_kstat_data() modifies some of the types on their way
449 	 * out, we need to be sure to handle these types seperately.
450 	 */
451 	if (ksp->ks_type == KSTAT_TYPE_NAMED) {
452 		void *kbuf;
453 		kstat_named_t *kold;
454 		kstat_named_t *knew = buf;
455 		int i;
456 
457 #ifdef	_MULTI_DATAMODEL
458 		int model = ddi_model_convert_from(flag & FMODELS);
459 #endif
460 
461 		/*
462 		 * Since ksp->ks_data may be NULL, we need to take a snapshot
463 		 * of the published data to look at the types.
464 		 */
465 		kbuf = kmem_alloc(bufsize + 1, KM_NOSLEEP);
466 		if (kbuf == NULL) {
467 			KSTAT_EXIT(ksp);
468 			kstat_rele(ksp);
469 			kmem_free(buf, bufsize + 1);
470 			return (EAGAIN);
471 		}
472 		error = KSTAT_SNAPSHOT(ksp, kbuf, KSTAT_READ);
473 		if (error) {
474 			KSTAT_EXIT(ksp);
475 			kstat_rele(ksp);
476 			kmem_free(kbuf, bufsize + 1);
477 			kmem_free(buf, bufsize + 1);
478 			return (error);
479 		}
480 		kold = kbuf;
481 
482 		/*
483 		 * read_kstat_data() changes the types of
484 		 * KSTAT_DATA_LONG / KSTAT_DATA_ULONG, so we need to
485 		 * make sure that these (modified) types are considered
486 		 * valid.
487 		 */
488 		for (i = 0; i < ksp->ks_ndata; i++, kold++, knew++) {
489 			switch (kold->data_type) {
490 #ifdef	_MULTI_DATAMODEL
491 			case KSTAT_DATA_LONG:
492 				switch (model) {
493 				case DDI_MODEL_ILP32:
494 					if (knew->data_type ==
495 					    KSTAT_DATA_INT32) {
496 						knew->value.l =
497 						    (long)knew->value.i32;
498 						knew->data_type =
499 						    KSTAT_DATA_LONG;
500 					}
501 					break;
502 				default:
503 				case DDI_MODEL_NONE:
504 #ifdef _LP64
505 					if (knew->data_type ==
506 					    KSTAT_DATA_INT64) {
507 						knew->value.l =
508 						    (long)knew->value.i64;
509 						knew->data_type =
510 						    KSTAT_DATA_LONG;
511 					}
512 #endif /* _LP64 */
513 					break;
514 				}
515 				break;
516 			case KSTAT_DATA_ULONG:
517 				switch (model) {
518 				case DDI_MODEL_ILP32:
519 					if (knew->data_type ==
520 					    KSTAT_DATA_UINT32) {
521 						knew->value.ul =
522 						    (ulong_t)knew->value.ui32;
523 						knew->data_type =
524 						    KSTAT_DATA_ULONG;
525 					}
526 					break;
527 				default:
528 				case DDI_MODEL_NONE:
529 #ifdef _LP64
530 					if (knew->data_type ==
531 					    KSTAT_DATA_UINT64) {
532 						knew->value.ul =
533 						    (ulong_t)knew->value.ui64;
534 						knew->data_type =
535 						    KSTAT_DATA_ULONG;
536 					}
537 #endif /* _LP64 */
538 					break;
539 				}
540 				break;
541 #endif /* _MULTI_DATAMODEL */
542 			case KSTAT_DATA_STRING:
543 				if (knew->data_type != KSTAT_DATA_STRING) {
544 					KSTAT_EXIT(ksp);
545 					kstat_rele(ksp);
546 					kmem_free(kbuf, bufsize + 1);
547 					kmem_free(buf, bufsize + 1);
548 					return (EINVAL);
549 				}
550 
551 #ifdef _MULTI_DATAMODEL
552 				if (model == DDI_MODEL_ILP32)
553 					KSTAT_NAMED_STR_PTR(knew) =
554 					    (char *)(uintptr_t)
555 						knew->value.str.addr.ptr32;
556 #endif
557 				/*
558 				 * Nothing special for NULL
559 				 */
560 				if (KSTAT_NAMED_STR_PTR(knew) == NULL)
561 					break;
562 
563 				/*
564 				 * Check to see that the pointers all point
565 				 * to within the buffer and after the array
566 				 * of kstat_named_t's.
567 				 */
568 				if (KSTAT_NAMED_STR_PTR(knew) <
569 				    (char *)
570 				    ((kstat_named_t *)user_kstat.ks_data +
571 				    ksp->ks_ndata)) {
572 					KSTAT_EXIT(ksp);
573 					kstat_rele(ksp);
574 					kmem_free(kbuf, bufsize + 1);
575 					kmem_free(buf, bufsize + 1);
576 					return (EINVAL);
577 				}
578 				if (KSTAT_NAMED_STR_PTR(knew) +
579 				    KSTAT_NAMED_STR_BUFLEN(knew) >
580 				    ((char *)user_kstat.ks_data +
581 				    ksp->ks_data_size)) {
582 					KSTAT_EXIT(ksp);
583 					kstat_rele(ksp);
584 					kmem_free(kbuf, bufsize + 1);
585 					kmem_free(buf, bufsize + 1);
586 					return (EINVAL);
587 				}
588 
589 				/*
590 				 * Update the pointers within the buffer
591 				 */
592 				KSTAT_NAMED_STR_PTR(knew) =
593 				    (char *)buf +
594 				    (KSTAT_NAMED_STR_PTR(knew) -
595 				    (char *)user_kstat.ks_data);
596 				break;
597 			default:
598 				break;
599 			}
600 		}
601 
602 		kold = kbuf;
603 		knew = buf;
604 
605 		/*
606 		 * Now make sure the types are what we expected them to be.
607 		 */
608 		for (i = 0; i < ksp->ks_ndata; i++, kold++, knew++)
609 			if (kold->data_type != knew->data_type) {
610 				KSTAT_EXIT(ksp);
611 				kstat_rele(ksp);
612 				kmem_free(kbuf, bufsize + 1);
613 				kmem_free(buf, bufsize + 1);
614 				return (EINVAL);
615 			}
616 
617 		kmem_free(kbuf, bufsize + 1);
618 	}
619 
620 	error = KSTAT_SNAPSHOT(ksp, buf, KSTAT_WRITE);
621 	if (!error)
622 		error = KSTAT_UPDATE(ksp, KSTAT_WRITE);
623 	*rvalp = kstat_chain_id;
624 	KSTAT_EXIT(ksp);
625 	kstat_rele(ksp);
626 	kmem_free(buf, bufsize + 1);
627 	return (error);
628 }
629 
630 /*ARGSUSED*/
631 static int
632 kstat_ioctl(dev_t dev, int cmd, intptr_t data, int flag, cred_t *cr, int *rvalp)
633 {
634 	int rc = 0;
635 
636 	switch (cmd) {
637 
638 	case KSTAT_IOC_CHAIN_ID:
639 		*rvalp = kstat_chain_id;
640 		break;
641 
642 	case KSTAT_IOC_READ:
643 		rc = read_kstat_data(rvalp, (void *)data, flag);
644 		break;
645 
646 	case KSTAT_IOC_WRITE:
647 		rc = write_kstat_data(rvalp, (void *)data, flag, cr);
648 		break;
649 
650 	default:
651 		/* invalid request */
652 		rc = EINVAL;
653 	}
654 	return (rc);
655 }
656 
657 /* ARGSUSED */
658 static int
659 kstat_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
660 	void **result)
661 {
662 	switch (infocmd) {
663 	case DDI_INFO_DEVT2DEVINFO:
664 		*result = kstat_devi;
665 		return (DDI_SUCCESS);
666 	case DDI_INFO_DEVT2INSTANCE:
667 		*result = NULL;
668 		return (DDI_SUCCESS);
669 	}
670 	return (DDI_FAILURE);
671 }
672 
673 static int
674 kstat_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
675 {
676 	if (cmd != DDI_ATTACH)
677 		return (DDI_FAILURE);
678 
679 	if (ddi_create_minor_node(devi, "kstat", S_IFCHR,
680 	    0, DDI_PSEUDO, NULL) == DDI_FAILURE) {
681 		ddi_remove_minor_node(devi, NULL);
682 		return (DDI_FAILURE);
683 	}
684 	kstat_devi = devi;
685 	return (DDI_SUCCESS);
686 }
687 
688 static int
689 kstat_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
690 {
691 	if (cmd != DDI_DETACH)
692 		return (DDI_FAILURE);
693 
694 	ddi_remove_minor_node(devi, NULL);
695 	return (DDI_SUCCESS);
696 }
697 
698 static struct cb_ops kstat_cb_ops = {
699 	nulldev,		/* open */
700 	nulldev,		/* close */
701 	nodev,			/* strategy */
702 	nodev,			/* print */
703 	nodev,			/* dump */
704 	nodev,			/* read */
705 	nodev,			/* write */
706 	kstat_ioctl,		/* ioctl */
707 	nodev,			/* devmap */
708 	nodev,			/* mmap */
709 	nodev,			/* segmap */
710 	nochpoll,		/* poll */
711 	ddi_prop_op,		/* prop_op */
712 	0,			/* streamtab  */
713 	D_NEW | D_MP		/* Driver compatibility flag */
714 };
715 
716 static struct dev_ops kstat_ops = {
717 	DEVO_REV,		/* devo_rev, */
718 	0,			/* refcnt  */
719 	kstat_info,		/* get_dev_info */
720 	nulldev,		/* identify */
721 	nulldev,		/* probe */
722 	kstat_attach,		/* attach */
723 	kstat_detach,		/* detach */
724 	nodev,			/* reset */
725 	&kstat_cb_ops,		/* driver operations */
726 	(struct bus_ops *)0,	/* no bus operations */
727 	NULL,			/* power */
728 	ddi_quiesce_not_needed,		/* quiesce */
729 };
730 
731 static struct modldrv modldrv = {
732 	&mod_driverops, "kernel statistics driver", &kstat_ops,
733 };
734 
735 static struct modlinkage modlinkage = {
736 	MODREV_1, &modldrv, NULL
737 };
738 
739 int
740 _init(void)
741 {
742 	return (mod_install(&modlinkage));
743 }
744 
745 int
746 _fini(void)
747 {
748 	return (mod_remove(&modlinkage));
749 }
750 
751 int
752 _info(struct modinfo *modinfop)
753 {
754 	return (mod_info(&modlinkage, modinfop));
755 }
756