xref: /freebsd/sys/contrib/openzfs/module/zfs/zcp_get.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*
2  * CDDL HEADER START
3  *
4  * This file and its contents are supplied under the terms of the
5  * Common Development and Distribution License ("CDDL"), version 1.0.
6  * You may only use this file in accordance with the terms of version
7  * 1.0 of the CDDL.
8  *
9  * A full copy of the text of the CDDL should have accompanied this
10  * source.  A copy of the CDDL is also available via the Internet at
11  * http://www.illumos.org/license/CDDL.
12  *
13  * CDDL HEADER END
14  */
15 
16 /*
17  * Copyright (c) 2016 by Delphix. All rights reserved.
18  */
19 
20 #include <sys/lua/lua.h>
21 #include <sys/lua/lualib.h>
22 #include <sys/lua/lauxlib.h>
23 
24 #include <zfs_prop.h>
25 
26 #include <sys/dsl_prop.h>
27 #include <sys/dsl_synctask.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_dir.h>
30 #include <sys/dmu_objset.h>
31 #include <sys/mntent.h>
32 #include <sys/sunddi.h>
33 #include <sys/zap.h>
34 #include <sys/zcp.h>
35 #include <sys/zcp_iter.h>
36 #include <sys/zcp_global.h>
37 #include <sys/zcp_prop.h>
38 #include <sys/zfs_ioctl.h>
39 #include <sys/zfs_znode.h>
40 #include <sys/zvol.h>
41 
42 #ifdef _KERNEL
43 #include <sys/zfs_quota.h>
44 #include <sys/zfs_vfsops.h>
45 #endif
46 
47 static int
48 get_objset_type(dsl_dataset_t *ds, zfs_type_t *type)
49 {
50 	int error;
51 	objset_t *os;
52 	error = dmu_objset_from_ds(ds, &os);
53 	if (error != 0)
54 		return (error);
55 	if (ds->ds_is_snapshot) {
56 		*type = ZFS_TYPE_SNAPSHOT;
57 	} else {
58 		switch (os->os_phys->os_type) {
59 		case DMU_OST_ZFS:
60 			*type = ZFS_TYPE_FILESYSTEM;
61 			break;
62 		case DMU_OST_ZVOL:
63 			*type = ZFS_TYPE_VOLUME;
64 			break;
65 		default:
66 			return (EINVAL);
67 		}
68 	}
69 	return (0);
70 }
71 
72 /*
73  * Returns the string name of ds's type in str (a buffer which should be
74  * at least 12 bytes long).
75  */
76 static int
77 get_objset_type_name(dsl_dataset_t *ds, char *str)
78 {
79 	int error;
80 	zfs_type_t type;
81 	error = get_objset_type(ds, &type);
82 	if (error != 0)
83 		return (error);
84 	switch (type) {
85 	case ZFS_TYPE_SNAPSHOT:
86 		(void) strlcpy(str, "snapshot", ZAP_MAXVALUELEN);
87 		break;
88 	case ZFS_TYPE_FILESYSTEM:
89 		(void) strlcpy(str, "filesystem", ZAP_MAXVALUELEN);
90 		break;
91 	case ZFS_TYPE_VOLUME:
92 		(void) strlcpy(str, "volume", ZAP_MAXVALUELEN);
93 		break;
94 	default:
95 		return (EINVAL);
96 	}
97 	return (0);
98 }
99 
100 /*
101  * Determines the source of a property given its setpoint and
102  * property type. It pushes the source to the lua stack.
103  */
104 static void
105 get_prop_src(lua_State *state, const char *setpoint, zfs_prop_t prop)
106 {
107 	if (zfs_prop_readonly(prop) || (prop == ZFS_PROP_VERSION)) {
108 		lua_pushnil(state);
109 	} else {
110 		const char *src;
111 		if (strcmp("", setpoint) == 0) {
112 			src = "default";
113 		} else {
114 			src = setpoint;
115 		}
116 		(void) lua_pushstring(state, src);
117 	}
118 }
119 
120 /*
121  * Given an error encountered while getting properties, either longjmp's for
122  * a fatal error or pushes nothing to the stack for a non fatal one.
123  */
124 static int
125 zcp_handle_error(lua_State *state, const char *dataset_name,
126     const char *property_name, int error)
127 {
128 	ASSERT3S(error, !=, 0);
129 	if (error == ENOENT) {
130 		return (0);
131 	} else if (error == EINVAL) {
132 		return (luaL_error(state,
133 		    "property '%s' is not a valid property on dataset '%s'",
134 		    property_name, dataset_name));
135 	} else if (error == EIO) {
136 		return (luaL_error(state,
137 		    "I/O error while retrieving property '%s' on dataset '%s'",
138 		    property_name, dataset_name));
139 	} else {
140 		return (luaL_error(state, "unexpected error %d while "
141 		    "retrieving property '%s' on dataset '%s'",
142 		    error, property_name, dataset_name));
143 	}
144 }
145 
146 /*
147  * Look up a user defined property in the zap object. If it exists, push it
148  * and the setpoint onto the stack, otherwise don't push anything.
149  */
150 static int
151 zcp_get_user_prop(lua_State *state, dsl_pool_t *dp, const char *dataset_name,
152     const char *property_name)
153 {
154 	int error;
155 	char *buf;
156 	char setpoint[ZFS_MAX_DATASET_NAME_LEN];
157 	/*
158 	 * zcp_dataset_hold will either successfully return the requested
159 	 * dataset or throw a lua error and longjmp out of the zfs.get_prop call
160 	 * without returning.
161 	 */
162 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
163 	if (ds == NULL)
164 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
165 
166 	buf = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
167 	error = dsl_prop_get_ds(ds, property_name, 1, ZAP_MAXVALUELEN,
168 	    buf, setpoint);
169 	dsl_dataset_rele(ds, FTAG);
170 
171 	if (error != 0) {
172 		kmem_free(buf, ZAP_MAXVALUELEN);
173 		return (zcp_handle_error(state, dataset_name, property_name,
174 		    error));
175 	}
176 	(void) lua_pushstring(state, buf);
177 	(void) lua_pushstring(state, setpoint);
178 	kmem_free(buf, ZAP_MAXVALUELEN);
179 	return (2);
180 }
181 
182 /*
183  * Check if the property we're looking for is stored in the ds_dir. If so,
184  * return it in the 'val' argument. Return 0 on success and ENOENT and if
185  * the property is not present.
186  */
187 static int
188 get_dsl_dir_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop,
189     uint64_t *val)
190 {
191 	dsl_dir_t *dd = ds->ds_dir;
192 	mutex_enter(&dd->dd_lock);
193 	switch (zfs_prop) {
194 	case ZFS_PROP_USEDSNAP:
195 		*val = dsl_dir_get_usedsnap(dd);
196 		break;
197 	case ZFS_PROP_USEDCHILD:
198 		*val = dsl_dir_get_usedchild(dd);
199 		break;
200 	case ZFS_PROP_USEDDS:
201 		*val = dsl_dir_get_usedds(dd);
202 		break;
203 	case ZFS_PROP_USEDREFRESERV:
204 		*val = dsl_dir_get_usedrefreserv(dd);
205 		break;
206 	case ZFS_PROP_LOGICALUSED:
207 		*val = dsl_dir_get_logicalused(dd);
208 		break;
209 	default:
210 		mutex_exit(&dd->dd_lock);
211 		return (SET_ERROR(ENOENT));
212 	}
213 	mutex_exit(&dd->dd_lock);
214 	return (0);
215 }
216 
217 /*
218  * Check if the property we're looking for is stored at the dsl_dataset or
219  * dsl_dir level. If so, push the property value and source onto the lua stack
220  * and return 0. If it is not present or a failure occurs in lookup, return a
221  * non-zero error value.
222  */
223 static int
224 get_special_prop(lua_State *state, dsl_dataset_t *ds, const char *dsname,
225     zfs_prop_t zfs_prop)
226 {
227 	int error = 0;
228 	objset_t *os;
229 	uint64_t numval = 0;
230 	char *strval = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
231 	char setpoint[ZFS_MAX_DATASET_NAME_LEN] =
232 	    "Internal error - setpoint not determined";
233 	zfs_type_t ds_type;
234 	zprop_type_t prop_type = zfs_prop_get_type(zfs_prop);
235 	(void) get_objset_type(ds, &ds_type);
236 
237 	switch (zfs_prop) {
238 	case ZFS_PROP_REFRATIO:
239 		numval = dsl_get_refratio(ds);
240 		break;
241 	case ZFS_PROP_USED:
242 		numval = dsl_get_used(ds);
243 		break;
244 	case ZFS_PROP_CLONES: {
245 		nvlist_t *clones = fnvlist_alloc();
246 		error = get_clones_stat_impl(ds, clones);
247 		if (error == 0) {
248 			/* push list to lua stack */
249 			VERIFY0(zcp_nvlist_to_lua(state, clones, NULL, 0ULL));
250 			/* source */
251 			(void) lua_pushnil(state);
252 		}
253 		nvlist_free(clones);
254 		kmem_free(strval, ZAP_MAXVALUELEN);
255 		return (error);
256 	}
257 	case ZFS_PROP_COMPRESSRATIO:
258 		numval = dsl_get_compressratio(ds);
259 		break;
260 	case ZFS_PROP_CREATION:
261 		numval = dsl_get_creation(ds);
262 		break;
263 	case ZFS_PROP_REFERENCED:
264 		numval = dsl_get_referenced(ds);
265 		break;
266 	case ZFS_PROP_AVAILABLE:
267 		numval = dsl_get_available(ds);
268 		break;
269 	case ZFS_PROP_LOGICALREFERENCED:
270 		numval = dsl_get_logicalreferenced(ds);
271 		break;
272 	case ZFS_PROP_CREATETXG:
273 		numval = dsl_get_creationtxg(ds);
274 		break;
275 	case ZFS_PROP_GUID:
276 		numval = dsl_get_guid(ds);
277 		break;
278 	case ZFS_PROP_UNIQUE:
279 		numval = dsl_get_unique(ds);
280 		break;
281 	case ZFS_PROP_OBJSETID:
282 		numval = dsl_get_objsetid(ds);
283 		break;
284 	case ZFS_PROP_ORIGIN:
285 		dsl_dir_get_origin(ds->ds_dir, strval);
286 		break;
287 	case ZFS_PROP_USERACCOUNTING:
288 		error = dmu_objset_from_ds(ds, &os);
289 		if (error == 0)
290 			numval = dmu_objset_userspace_present(os);
291 		break;
292 	case ZFS_PROP_WRITTEN:
293 		error = dsl_get_written(ds, &numval);
294 		break;
295 	case ZFS_PROP_TYPE:
296 		error = get_objset_type_name(ds, strval);
297 		break;
298 	case ZFS_PROP_PREV_SNAP:
299 		error = dsl_get_prev_snap(ds, strval);
300 		break;
301 	case ZFS_PROP_NAME:
302 		dsl_dataset_name(ds, strval);
303 		break;
304 	case ZFS_PROP_MOUNTPOINT:
305 		error = dsl_get_mountpoint(ds, dsname, strval, setpoint);
306 		break;
307 	case ZFS_PROP_VERSION:
308 		/* should be a snapshot or filesystem */
309 		ASSERT(ds_type != ZFS_TYPE_VOLUME);
310 		error = dmu_objset_from_ds(ds, &os);
311 		/* look in the master node for the version */
312 		if (error == 0) {
313 			error = zap_lookup(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
314 			    sizeof (numval), 1, &numval);
315 		}
316 		break;
317 	case ZFS_PROP_DEFER_DESTROY:
318 		numval = dsl_get_defer_destroy(ds);
319 		break;
320 	case ZFS_PROP_USERREFS:
321 		numval = dsl_get_userrefs(ds);
322 		break;
323 	case ZFS_PROP_FILESYSTEM_COUNT:
324 		error = dsl_dir_get_filesystem_count(ds->ds_dir, &numval);
325 		(void) strlcpy(setpoint, "", ZFS_MAX_DATASET_NAME_LEN);
326 		break;
327 	case ZFS_PROP_SNAPSHOT_COUNT:
328 		error = dsl_dir_get_snapshot_count(ds->ds_dir, &numval);
329 		(void) strlcpy(setpoint, "", ZFS_MAX_DATASET_NAME_LEN);
330 		break;
331 	case ZFS_PROP_NUMCLONES:
332 		numval = dsl_get_numclones(ds);
333 		break;
334 	case ZFS_PROP_INCONSISTENT:
335 		numval = dsl_get_inconsistent(ds);
336 		break;
337 	case ZFS_PROP_IVSET_GUID:
338 		if (dsl_dataset_is_zapified(ds)) {
339 			error = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
340 			    ds->ds_object, DS_FIELD_IVSET_GUID,
341 			    sizeof (numval), 1, &numval);
342 		} else {
343 			error = ENOENT;
344 		}
345 		break;
346 	case ZFS_PROP_RECEIVE_RESUME_TOKEN: {
347 		char *token = get_receive_resume_stats_impl(ds);
348 
349 		(void) strlcpy(strval, token, ZAP_MAXVALUELEN);
350 		if (strcmp(strval, "") == 0) {
351 			char *childval = get_child_receive_stats(ds);
352 
353 			(void) strlcpy(strval, childval, ZAP_MAXVALUELEN);
354 			if (strcmp(strval, "") == 0)
355 				error = ENOENT;
356 
357 			kmem_strfree(childval);
358 		}
359 		kmem_strfree(token);
360 		break;
361 	}
362 	case ZFS_PROP_VOLSIZE:
363 		ASSERT(ds_type == ZFS_TYPE_VOLUME ||
364 		    ds_type == ZFS_TYPE_SNAPSHOT);
365 		error = dmu_objset_from_ds(ds, &os);
366 		if (error == 0) {
367 			error = zap_lookup(os, ZVOL_ZAP_OBJ, "size",
368 			    sizeof (numval), 1, &numval);
369 		}
370 		if (error == 0)
371 			(void) strlcpy(setpoint, dsname,
372 			    ZFS_MAX_DATASET_NAME_LEN);
373 
374 		break;
375 	case ZFS_PROP_VOLBLOCKSIZE: {
376 		ASSERT(ds_type == ZFS_TYPE_VOLUME);
377 		dmu_object_info_t doi;
378 		error = dmu_objset_from_ds(ds, &os);
379 		if (error == 0) {
380 			error = dmu_object_info(os, ZVOL_OBJ, &doi);
381 			if (error == 0)
382 				numval = doi.doi_data_block_size;
383 		}
384 		break;
385 	}
386 
387 	case ZFS_PROP_KEYSTATUS:
388 	case ZFS_PROP_KEYFORMAT: {
389 		/* provide defaults in case no crypto obj exists */
390 		setpoint[0] = '\0';
391 		if (zfs_prop == ZFS_PROP_KEYSTATUS)
392 			numval = ZFS_KEYSTATUS_NONE;
393 		else
394 			numval = ZFS_KEYFORMAT_NONE;
395 
396 		nvlist_t *nvl, *propval;
397 		nvl = fnvlist_alloc();
398 		dsl_dataset_crypt_stats(ds, nvl);
399 		if (nvlist_lookup_nvlist(nvl, zfs_prop_to_name(zfs_prop),
400 		    &propval) == 0) {
401 			char *source;
402 
403 			(void) nvlist_lookup_uint64(propval, ZPROP_VALUE,
404 			    &numval);
405 			if (nvlist_lookup_string(propval, ZPROP_SOURCE,
406 			    &source) == 0)
407 				strlcpy(setpoint, source, sizeof (setpoint));
408 		}
409 		nvlist_free(nvl);
410 		break;
411 	}
412 
413 	default:
414 		/* Did not match these props, check in the dsl_dir */
415 		error = get_dsl_dir_prop(ds, zfs_prop, &numval);
416 	}
417 	if (error != 0) {
418 		kmem_free(strval, ZAP_MAXVALUELEN);
419 		return (error);
420 	}
421 
422 	switch (prop_type) {
423 	case PROP_TYPE_NUMBER: {
424 		(void) lua_pushnumber(state, numval);
425 		break;
426 	}
427 	case PROP_TYPE_STRING: {
428 		(void) lua_pushstring(state, strval);
429 		break;
430 	}
431 	case PROP_TYPE_INDEX: {
432 		const char *propval;
433 		error = zfs_prop_index_to_string(zfs_prop, numval, &propval);
434 		if (error != 0) {
435 			kmem_free(strval, ZAP_MAXVALUELEN);
436 			return (error);
437 		}
438 		(void) lua_pushstring(state, propval);
439 		break;
440 	}
441 	}
442 	kmem_free(strval, ZAP_MAXVALUELEN);
443 
444 	/* Push the source to the stack */
445 	get_prop_src(state, setpoint, zfs_prop);
446 	return (0);
447 }
448 
449 /*
450  * Look up a property and its source in the zap object. If the value is
451  * present and successfully retrieved, push the value and source on the
452  * lua stack and return 0. On failure, return a non-zero error value.
453  */
454 static int
455 get_zap_prop(lua_State *state, dsl_dataset_t *ds, zfs_prop_t zfs_prop)
456 {
457 	int error = 0;
458 	char setpoint[ZFS_MAX_DATASET_NAME_LEN];
459 	char *strval = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
460 	uint64_t numval;
461 	const char *prop_name = zfs_prop_to_name(zfs_prop);
462 	zprop_type_t prop_type = zfs_prop_get_type(zfs_prop);
463 
464 	if (prop_type == PROP_TYPE_STRING) {
465 		/* Push value to lua stack */
466 		error = dsl_prop_get_ds(ds, prop_name, 1,
467 		    ZAP_MAXVALUELEN, strval, setpoint);
468 		if (error == 0)
469 			(void) lua_pushstring(state, strval);
470 	} else {
471 		error = dsl_prop_get_ds(ds, prop_name, sizeof (numval),
472 		    1, &numval, setpoint);
473 
474 #ifdef _KERNEL
475 		/* Fill in temporary value for prop, if applicable */
476 		(void) zfs_get_temporary_prop(ds, zfs_prop, &numval, setpoint);
477 #else
478 		return (luaL_error(state,
479 		    "temporary properties only supported in kernel mode",
480 		    prop_name));
481 #endif
482 		/* Push value to lua stack */
483 		if (prop_type == PROP_TYPE_INDEX) {
484 			const char *propval;
485 			error = zfs_prop_index_to_string(zfs_prop, numval,
486 			    &propval);
487 			if (error == 0)
488 				(void) lua_pushstring(state, propval);
489 		} else {
490 			if (error == 0)
491 				(void) lua_pushnumber(state, numval);
492 		}
493 	}
494 	kmem_free(strval, ZAP_MAXVALUELEN);
495 	if (error == 0)
496 		get_prop_src(state, setpoint, zfs_prop);
497 	return (error);
498 }
499 
500 /*
501  * Determine whether property is valid for a given dataset
502  */
503 boolean_t
504 prop_valid_for_ds(dsl_dataset_t *ds, zfs_prop_t zfs_prop)
505 {
506 	int error;
507 	zfs_type_t zfs_type;
508 
509 	/* properties not supported */
510 	if ((zfs_prop == ZFS_PROP_ISCSIOPTIONS) ||
511 	    (zfs_prop == ZFS_PROP_MOUNTED))
512 		return (B_FALSE);
513 
514 	/* if we want the origin prop, ds must be a clone */
515 	if ((zfs_prop == ZFS_PROP_ORIGIN) && (!dsl_dir_is_clone(ds->ds_dir)))
516 		return (B_FALSE);
517 
518 	error = get_objset_type(ds, &zfs_type);
519 	if (error != 0)
520 		return (B_FALSE);
521 	return (zfs_prop_valid_for_type(zfs_prop, zfs_type, B_FALSE));
522 }
523 
524 /*
525  * Look up a given dataset property. On success return 2, the number of
526  * values pushed to the lua stack (property value and source). On a fatal
527  * error, longjmp. On a non fatal error push nothing.
528  */
529 static int
530 zcp_get_system_prop(lua_State *state, dsl_pool_t *dp, const char *dataset_name,
531     zfs_prop_t zfs_prop)
532 {
533 	int error;
534 	/*
535 	 * zcp_dataset_hold will either successfully return the requested
536 	 * dataset or throw a lua error and longjmp out of the zfs.get_prop call
537 	 * without returning.
538 	 */
539 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
540 	if (ds == NULL)
541 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
542 
543 	/* Check that the property is valid for the given dataset */
544 	const char *prop_name = zfs_prop_to_name(zfs_prop);
545 	if (!prop_valid_for_ds(ds, zfs_prop)) {
546 		dsl_dataset_rele(ds, FTAG);
547 		return (0);
548 	}
549 
550 	/* Check if the property can be accessed directly */
551 	error = get_special_prop(state, ds, dataset_name, zfs_prop);
552 	if (error == 0) {
553 		dsl_dataset_rele(ds, FTAG);
554 		/* The value and source have been pushed by get_special_prop */
555 		return (2);
556 	}
557 	if (error != ENOENT) {
558 		dsl_dataset_rele(ds, FTAG);
559 		return (zcp_handle_error(state, dataset_name,
560 		    prop_name, error));
561 	}
562 
563 	/* If we were unable to find it, look in the zap object */
564 	error = get_zap_prop(state, ds, zfs_prop);
565 	dsl_dataset_rele(ds, FTAG);
566 	if (error != 0) {
567 		return (zcp_handle_error(state, dataset_name,
568 		    prop_name, error));
569 	}
570 	/* The value and source have been pushed by get_zap_prop */
571 	return (2);
572 }
573 
574 #ifdef _KERNEL
575 static zfs_userquota_prop_t
576 get_userquota_prop(const char *prop_name)
577 {
578 	zfs_userquota_prop_t type;
579 	/* Figure out the property type ({user|group}{quota|used}) */
580 	for (type = 0; type < ZFS_NUM_USERQUOTA_PROPS; type++) {
581 		if (strncmp(prop_name, zfs_userquota_prop_prefixes[type],
582 		    strlen(zfs_userquota_prop_prefixes[type])) == 0)
583 			break;
584 	}
585 	return (type);
586 }
587 
588 /*
589  * Given the name of a zfs_userquota_prop, this function determines the
590  * prop type as well as the numeric group/user ids based on the string
591  * following the '@' in the property name. On success, returns 0. On failure,
592  * returns a non-zero error.
593  * 'domain' must be free'd by caller using kmem_strfree()
594  */
595 static int
596 parse_userquota_prop(const char *prop_name, zfs_userquota_prop_t *type,
597     char **domain, uint64_t *rid)
598 {
599 	char *cp, *end, *domain_val;
600 
601 	*type = get_userquota_prop(prop_name);
602 	if (*type >= ZFS_NUM_USERQUOTA_PROPS)
603 		return (EINVAL);
604 
605 	*rid = 0;
606 	cp = strchr(prop_name, '@') + 1;
607 	if (strncmp(cp, "S-1-", 4) == 0) {
608 		/*
609 		 * It's a numeric SID (eg "S-1-234-567-89") and we want to
610 		 * separate the domain id and the rid
611 		 */
612 		int domain_len = strrchr(cp, '-') - cp;
613 		domain_val = kmem_alloc(domain_len + 1, KM_SLEEP);
614 		(void) strncpy(domain_val, cp, domain_len);
615 		domain_val[domain_len] = '\0';
616 		cp += domain_len + 1;
617 
618 		(void) ddi_strtoll(cp, &end, 10, (longlong_t *)rid);
619 		if (*end != '\0') {
620 			kmem_strfree(domain_val);
621 			return (EINVAL);
622 		}
623 	} else {
624 		/* It's only a user/group ID (eg "12345"), just get the rid */
625 		domain_val = NULL;
626 		(void) ddi_strtoll(cp, &end, 10, (longlong_t *)rid);
627 		if (*end != '\0')
628 			return (EINVAL);
629 	}
630 	*domain = domain_val;
631 	return (0);
632 }
633 
634 /*
635  * Look up {user|group}{quota|used} property for given dataset. On success
636  * push the value (quota or used amount) and the setpoint. On failure, push
637  * a lua error.
638  */
639 static int
640 zcp_get_userquota_prop(lua_State *state, dsl_pool_t *dp,
641     const char *dataset_name, const char *prop_name)
642 {
643 	zfsvfs_t *zfvp;
644 	zfsvfs_t *zfsvfs;
645 	int error;
646 	zfs_userquota_prop_t type;
647 	char *domain;
648 	uint64_t rid, value = 0;
649 	objset_t *os;
650 
651 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
652 	if (ds == NULL)
653 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
654 
655 	error = parse_userquota_prop(prop_name, &type, &domain, &rid);
656 	if (error == 0) {
657 		error = dmu_objset_from_ds(ds, &os);
658 		if (error == 0) {
659 			zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
660 			error = zfsvfs_create_impl(&zfvp, zfsvfs, os);
661 			if (error == 0) {
662 				error = zfs_userspace_one(zfvp, type, domain,
663 				    rid, &value);
664 				zfsvfs_free(zfvp);
665 			}
666 		}
667 		if (domain != NULL)
668 			kmem_strfree(domain);
669 	}
670 	dsl_dataset_rele(ds, FTAG);
671 
672 	if ((value == 0) && ((type == ZFS_PROP_USERQUOTA) ||
673 	    (type == ZFS_PROP_GROUPQUOTA)))
674 		error = SET_ERROR(ENOENT);
675 	if (error != 0) {
676 		return (zcp_handle_error(state, dataset_name,
677 		    prop_name, error));
678 	}
679 
680 	(void) lua_pushnumber(state, value);
681 	(void) lua_pushstring(state, dataset_name);
682 	return (2);
683 }
684 #endif
685 
686 /*
687  * Determines the name of the snapshot referenced in the written property
688  * name. Returns snapshot name in snap_name, a buffer that must be at least
689  * as large as ZFS_MAX_DATASET_NAME_LEN
690  */
691 static void
692 parse_written_prop(const char *dataset_name, const char *prop_name,
693     char *snap_name)
694 {
695 	ASSERT(zfs_prop_written(prop_name));
696 	const char *name = prop_name + ZFS_WRITTEN_PROP_PREFIX_LEN;
697 	if (strchr(name, '@') == NULL) {
698 		(void) snprintf(snap_name, ZFS_MAX_DATASET_NAME_LEN, "%s@%s",
699 		    dataset_name, name);
700 	} else {
701 		(void) strlcpy(snap_name, name, ZFS_MAX_DATASET_NAME_LEN);
702 	}
703 }
704 
705 /*
706  * Look up written@ property for given dataset. On success
707  * push the value and the setpoint. If error is fatal, we will
708  * longjmp, otherwise push nothing.
709  */
710 static int
711 zcp_get_written_prop(lua_State *state, dsl_pool_t *dp,
712     const char *dataset_name, const char *prop_name)
713 {
714 	char snap_name[ZFS_MAX_DATASET_NAME_LEN];
715 	uint64_t used, comp, uncomp;
716 	dsl_dataset_t *old;
717 	int error = 0;
718 
719 	parse_written_prop(dataset_name, prop_name, snap_name);
720 	dsl_dataset_t *new = zcp_dataset_hold(state, dp, dataset_name, FTAG);
721 	if (new == NULL)
722 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
723 
724 	error = dsl_dataset_hold(dp, snap_name, FTAG, &old);
725 	if (error != 0) {
726 		dsl_dataset_rele(new, FTAG);
727 		return (zcp_dataset_hold_error(state, dp, snap_name,
728 		    error));
729 	}
730 	error = dsl_dataset_space_written(old, new,
731 	    &used, &comp, &uncomp);
732 
733 	dsl_dataset_rele(old, FTAG);
734 	dsl_dataset_rele(new, FTAG);
735 
736 	if (error != 0) {
737 		return (zcp_handle_error(state, dataset_name,
738 		    snap_name, error));
739 	}
740 	(void) lua_pushnumber(state, used);
741 	(void) lua_pushstring(state, dataset_name);
742 	return (2);
743 }
744 
745 static int zcp_get_prop(lua_State *state);
746 static zcp_lib_info_t zcp_get_prop_info = {
747 	.name = "get_prop",
748 	.func = zcp_get_prop,
749 	.pargs = {
750 	    { .za_name = "dataset", .za_lua_type = LUA_TSTRING},
751 	    { .za_name = "property", .za_lua_type =  LUA_TSTRING},
752 	    {NULL, 0}
753 	},
754 	.kwargs = {
755 	    {NULL, 0}
756 	}
757 };
758 
759 static int
760 zcp_get_prop(lua_State *state)
761 {
762 	const char *dataset_name;
763 	const char *property_name;
764 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
765 	zcp_lib_info_t *libinfo = &zcp_get_prop_info;
766 
767 	zcp_parse_args(state, libinfo->name, libinfo->pargs, libinfo->kwargs);
768 
769 	dataset_name = lua_tostring(state, 1);
770 	property_name = lua_tostring(state, 2);
771 
772 	/* User defined property */
773 	if (zfs_prop_user(property_name)) {
774 		return (zcp_get_user_prop(state, dp,
775 		    dataset_name, property_name));
776 	}
777 	/* userspace property */
778 	if (zfs_prop_userquota(property_name)) {
779 #ifdef _KERNEL
780 		return (zcp_get_userquota_prop(state, dp,
781 		    dataset_name, property_name));
782 #else
783 		return (luaL_error(state,
784 		    "user quota properties only supported in kernel mode",
785 		    property_name));
786 #endif
787 	}
788 	/* written@ property */
789 	if (zfs_prop_written(property_name)) {
790 		return (zcp_get_written_prop(state, dp,
791 		    dataset_name, property_name));
792 	}
793 
794 	zfs_prop_t zfs_prop = zfs_name_to_prop(property_name);
795 	/* Valid system property */
796 	if (zfs_prop != ZPROP_INVAL) {
797 		return (zcp_get_system_prop(state, dp, dataset_name,
798 		    zfs_prop));
799 	}
800 
801 	/* Invalid property name */
802 	return (luaL_error(state,
803 	    "'%s' is not a valid property", property_name));
804 }
805 
806 int
807 zcp_load_get_lib(lua_State *state)
808 {
809 	lua_pushcclosure(state, zcp_get_prop_info.func, 0);
810 	lua_setfield(state, -2, zcp_get_prop_info.name);
811 
812 	return (1);
813 }
814