xref: /freebsd/sys/contrib/openzfs/module/zfs/zcp_iter.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
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, 2018 by Delphix. All rights reserved.
18  */
19 
20 #include <sys/lua/lua.h>
21 #include <sys/lua/lauxlib.h>
22 
23 #include <sys/dmu.h>
24 #include <sys/dsl_prop.h>
25 #include <sys/dsl_synctask.h>
26 #include <sys/dsl_bookmark.h>
27 #include <sys/dsl_dataset.h>
28 #include <sys/dsl_pool.h>
29 #include <sys/dmu_tx.h>
30 #include <sys/dmu_objset.h>
31 #include <sys/zap.h>
32 #include <sys/dsl_dir.h>
33 #include <sys/zcp_prop.h>
34 
35 #include <sys/zcp.h>
36 
37 #include "zfs_comutil.h"
38 
39 typedef int (zcp_list_func_t)(lua_State *);
40 typedef struct zcp_list_info {
41 	const char *name;
42 	zcp_list_func_t *func;
43 	zcp_list_func_t *gc;
44 	const zcp_arg_t pargs[4];
45 	const zcp_arg_t kwargs[2];
46 } zcp_list_info_t;
47 
48 static int
49 zcp_clones_iter(lua_State *state)
50 {
51 	int err;
52 	char clonename[ZFS_MAX_DATASET_NAME_LEN];
53 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
54 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
55 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
56 	dsl_dataset_t *ds, *clone;
57 	zap_attribute_t za;
58 	zap_cursor_t zc;
59 
60 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
61 	if (err == ENOENT) {
62 		return (0);
63 	} else if (err != 0) {
64 		return (luaL_error(state,
65 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
66 		    err));
67 	}
68 
69 	if (dsl_dataset_phys(ds)->ds_next_clones_obj == 0) {
70 		dsl_dataset_rele(ds, FTAG);
71 		return (0);
72 	}
73 
74 	zap_cursor_init_serialized(&zc, dp->dp_meta_objset,
75 	    dsl_dataset_phys(ds)->ds_next_clones_obj, cursor);
76 	dsl_dataset_rele(ds, FTAG);
77 
78 	err = zap_cursor_retrieve(&zc, &za);
79 	if (err != 0) {
80 		zap_cursor_fini(&zc);
81 		if (err != ENOENT) {
82 			return (luaL_error(state,
83 			    "unexpected error %d from zap_cursor_retrieve()",
84 			    err));
85 		}
86 		return (0);
87 	}
88 	zap_cursor_advance(&zc);
89 	cursor = zap_cursor_serialize(&zc);
90 	zap_cursor_fini(&zc);
91 
92 	err = dsl_dataset_hold_obj(dp, za.za_first_integer, FTAG, &clone);
93 	if (err != 0) {
94 		return (luaL_error(state,
95 		    "unexpected error %d from "
96 		    "dsl_dataset_hold_obj(za_first_integer)", err));
97 	}
98 
99 	dsl_dir_name(clone->ds_dir, clonename);
100 	dsl_dataset_rele(clone, FTAG);
101 
102 	lua_pushnumber(state, cursor);
103 	lua_replace(state, lua_upvalueindex(2));
104 
105 	(void) lua_pushstring(state, clonename);
106 	return (1);
107 }
108 
109 static int zcp_clones_list(lua_State *);
110 static const zcp_list_info_t zcp_clones_list_info = {
111 	.name = "clones",
112 	.func = zcp_clones_list,
113 	.gc = NULL,
114 	.pargs = {
115 	    { .za_name = "snapshot", .za_lua_type = LUA_TSTRING },
116 	    {NULL, 0}
117 	},
118 	.kwargs = {
119 	    {NULL, 0}
120 	}
121 };
122 
123 static int
124 zcp_clones_list(lua_State *state)
125 {
126 	const char *snapname = lua_tostring(state, 1);
127 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
128 
129 	/*
130 	 * zcp_dataset_hold will either successfully return the requested
131 	 * dataset or throw a lua error and longjmp out of the zfs.list.clones
132 	 * call without returning.
133 	 */
134 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, snapname, FTAG);
135 	if (ds == NULL)
136 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
137 	boolean_t issnap = ds->ds_is_snapshot;
138 	uint64_t cursor = 0;
139 	uint64_t dsobj = ds->ds_object;
140 	dsl_dataset_rele(ds, FTAG);
141 
142 	if (!issnap) {
143 		return (zcp_argerror(state, 1, "%s is not a snapshot",
144 		    snapname));
145 	}
146 
147 	lua_pushnumber(state, dsobj);
148 	lua_pushnumber(state, cursor);
149 	lua_pushcclosure(state, &zcp_clones_iter, 2);
150 	return (1);
151 }
152 
153 static int
154 zcp_snapshots_iter(lua_State *state)
155 {
156 	int err;
157 	char snapname[ZFS_MAX_DATASET_NAME_LEN];
158 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
159 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
160 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
161 	dsl_dataset_t *ds;
162 	objset_t *os;
163 	char *p;
164 
165 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
166 	if (err != 0) {
167 		return (luaL_error(state,
168 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
169 		    err));
170 	}
171 
172 	dsl_dataset_name(ds, snapname);
173 	VERIFY3U(sizeof (snapname), >,
174 	    strlcat(snapname, "@", sizeof (snapname)));
175 
176 	p = strchr(snapname, '\0');
177 	VERIFY0(dmu_objset_from_ds(ds, &os));
178 	err = dmu_snapshot_list_next(os,
179 	    sizeof (snapname) - (p - snapname), p, NULL, &cursor, NULL);
180 	dsl_dataset_rele(ds, FTAG);
181 
182 	if (err == ENOENT) {
183 		return (0);
184 	} else if (err != 0) {
185 		return (luaL_error(state,
186 		    "unexpected error %d from dmu_snapshot_list_next()", err));
187 	}
188 
189 	lua_pushnumber(state, cursor);
190 	lua_replace(state, lua_upvalueindex(2));
191 
192 	(void) lua_pushstring(state, snapname);
193 	return (1);
194 }
195 
196 static int zcp_snapshots_list(lua_State *);
197 static const zcp_list_info_t zcp_snapshots_list_info = {
198 	.name = "snapshots",
199 	.func = zcp_snapshots_list,
200 	.gc = NULL,
201 	.pargs = {
202 	    { .za_name = "filesystem | volume", .za_lua_type = LUA_TSTRING },
203 	    {NULL, 0}
204 	},
205 	.kwargs = {
206 	    {NULL, 0}
207 	}
208 };
209 
210 static int
211 zcp_snapshots_list(lua_State *state)
212 {
213 	const char *fsname = lua_tostring(state, 1);
214 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
215 	boolean_t issnap;
216 	uint64_t dsobj;
217 
218 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, fsname, FTAG);
219 	if (ds == NULL)
220 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
221 	issnap = ds->ds_is_snapshot;
222 	dsobj = ds->ds_object;
223 	dsl_dataset_rele(ds, FTAG);
224 
225 	if (issnap) {
226 		return (zcp_argerror(state, 1,
227 		    "argument %s cannot be a snapshot", fsname));
228 	}
229 
230 	lua_pushnumber(state, dsobj);
231 	lua_pushnumber(state, 0);
232 	lua_pushcclosure(state, &zcp_snapshots_iter, 2);
233 	return (1);
234 }
235 
236 static int
237 zcp_children_iter(lua_State *state)
238 {
239 	int err;
240 	char childname[ZFS_MAX_DATASET_NAME_LEN];
241 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
242 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
243 	zcp_run_info_t *ri = zcp_run_info(state);
244 	dsl_pool_t *dp = ri->zri_pool;
245 	dsl_dataset_t *ds;
246 	objset_t *os;
247 	char *p;
248 
249 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
250 	if (err != 0) {
251 		return (luaL_error(state,
252 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
253 		    err));
254 	}
255 
256 	dsl_dataset_name(ds, childname);
257 	VERIFY3U(sizeof (childname), >,
258 	    strlcat(childname, "/", sizeof (childname)));
259 	p = strchr(childname, '\0');
260 
261 	VERIFY0(dmu_objset_from_ds(ds, &os));
262 	do {
263 		err = dmu_dir_list_next(os,
264 		    sizeof (childname) - (p - childname), p, NULL, &cursor);
265 	} while (err == 0 && zfs_dataset_name_hidden(childname));
266 	dsl_dataset_rele(ds, FTAG);
267 
268 	if (err == ENOENT) {
269 		return (0);
270 	} else if (err != 0) {
271 		return (luaL_error(state,
272 		    "unexpected error %d from dmu_dir_list_next()",
273 		    err));
274 	}
275 
276 	lua_pushnumber(state, cursor);
277 	lua_replace(state, lua_upvalueindex(2));
278 
279 	(void) lua_pushstring(state, childname);
280 	return (1);
281 }
282 
283 static int zcp_children_list(lua_State *);
284 static const zcp_list_info_t zcp_children_list_info = {
285 	.name = "children",
286 	.func = zcp_children_list,
287 	.gc = NULL,
288 	.pargs = {
289 	    { .za_name = "filesystem | volume", .za_lua_type = LUA_TSTRING },
290 	    {NULL, 0}
291 	},
292 	.kwargs = {
293 	    {NULL, 0}
294 	}
295 };
296 
297 static int
298 zcp_children_list(lua_State *state)
299 {
300 	const char *fsname = lua_tostring(state, 1);
301 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
302 	boolean_t issnap;
303 	uint64_t dsobj;
304 
305 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, fsname, FTAG);
306 	if (ds == NULL)
307 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
308 
309 	issnap = ds->ds_is_snapshot;
310 	dsobj = ds->ds_object;
311 	dsl_dataset_rele(ds, FTAG);
312 
313 	if (issnap) {
314 		return (zcp_argerror(state, 1,
315 		    "argument %s cannot be a snapshot", fsname));
316 	}
317 
318 	lua_pushnumber(state, dsobj);
319 	lua_pushnumber(state, 0);
320 	lua_pushcclosure(state, &zcp_children_iter, 2);
321 	return (1);
322 }
323 
324 static int
325 zcp_user_props_list_gc(lua_State *state)
326 {
327 	nvlist_t **props = lua_touserdata(state, 1);
328 	if (*props != NULL)
329 		fnvlist_free(*props);
330 	return (0);
331 }
332 
333 static int
334 zcp_user_props_iter(lua_State *state)
335 {
336 	const char *source, *val;
337 	nvlist_t *nvprop;
338 	nvlist_t **props = lua_touserdata(state, lua_upvalueindex(1));
339 	nvpair_t *pair = lua_touserdata(state, lua_upvalueindex(2));
340 
341 	do {
342 		pair = nvlist_next_nvpair(*props, pair);
343 		if (pair == NULL) {
344 			fnvlist_free(*props);
345 			*props = NULL;
346 			return (0);
347 		}
348 	} while (!zfs_prop_user(nvpair_name(pair)));
349 
350 	lua_pushlightuserdata(state, pair);
351 	lua_replace(state, lua_upvalueindex(2));
352 
353 	nvprop = fnvpair_value_nvlist(pair);
354 	val = fnvlist_lookup_string(nvprop, ZPROP_VALUE);
355 	source = fnvlist_lookup_string(nvprop, ZPROP_SOURCE);
356 
357 	(void) lua_pushstring(state, nvpair_name(pair));
358 	(void) lua_pushstring(state, val);
359 	(void) lua_pushstring(state, source);
360 	return (3);
361 }
362 
363 static int zcp_user_props_list(lua_State *);
364 static const zcp_list_info_t zcp_user_props_list_info = {
365 	.name = "user_properties",
366 	.func = zcp_user_props_list,
367 	.gc = zcp_user_props_list_gc,
368 	.pargs = {
369 	    { .za_name = "filesystem | snapshot | volume",
370 	    .za_lua_type = LUA_TSTRING },
371 	    {NULL, 0}
372 	},
373 	.kwargs = {
374 	    {NULL, 0}
375 	}
376 };
377 
378 /*
379  * 'properties' was the initial name for 'user_properties' seen
380  * above. 'user_properties' is a better name as it distinguishes
381  * these properties from 'system_properties' which are different.
382  * In order to avoid breaking compatibility between different
383  * versions of ZFS, we declare 'properties' as an alias for
384  * 'user_properties'.
385  */
386 static const zcp_list_info_t zcp_props_list_info = {
387 	.name = "properties",
388 	.func = zcp_user_props_list,
389 	.gc = zcp_user_props_list_gc,
390 	.pargs = {
391 	    { .za_name = "filesystem | snapshot | volume",
392 	    .za_lua_type = LUA_TSTRING },
393 	    {NULL, 0}
394 	},
395 	.kwargs = {
396 	    {NULL, 0}
397 	}
398 };
399 
400 static int
401 zcp_user_props_list(lua_State *state)
402 {
403 	const char *dsname = lua_tostring(state, 1);
404 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
405 	objset_t *os;
406 	nvlist_t **props = lua_newuserdata(state, sizeof (nvlist_t *));
407 
408 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dsname, FTAG);
409 	if (ds == NULL)
410 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
411 	VERIFY0(dmu_objset_from_ds(ds, &os));
412 	VERIFY0(dsl_prop_get_all(os, props));
413 	dsl_dataset_rele(ds, FTAG);
414 
415 	/*
416 	 * Set the metatable for the properties list to free it on
417 	 * completion.
418 	 */
419 	luaL_getmetatable(state, zcp_user_props_list_info.name);
420 	(void) lua_setmetatable(state, -2);
421 
422 	lua_pushlightuserdata(state, NULL);
423 	lua_pushcclosure(state, &zcp_user_props_iter, 2);
424 	return (1);
425 }
426 
427 
428 /*
429  * Populate nv with all valid system properties and their values for the given
430  * dataset.
431  */
432 static void
433 zcp_dataset_system_props(dsl_dataset_t *ds, nvlist_t *nv)
434 {
435 	for (int prop = ZFS_PROP_TYPE; prop < ZFS_NUM_PROPS; prop++) {
436 		/* Do not display hidden props */
437 		if (!zfs_prop_visible(prop))
438 			continue;
439 		/* Do not display props not valid for this dataset */
440 		if (!prop_valid_for_ds(ds, prop))
441 			continue;
442 		fnvlist_add_boolean(nv, zfs_prop_to_name(prop));
443 	}
444 }
445 
446 static int zcp_system_props_list(lua_State *);
447 static const zcp_list_info_t zcp_system_props_list_info = {
448 	.name = "system_properties",
449 	.func = zcp_system_props_list,
450 	.pargs = {
451 	    { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
452 	    {NULL, 0}
453 	},
454 	.kwargs = {
455 	    {NULL, 0}
456 	}
457 };
458 
459 /*
460  * Get a list of all visible system properties and their values for a given
461  * dataset. Returned on the stack as a Lua table.
462  */
463 static int
464 zcp_system_props_list(lua_State *state)
465 {
466 	int error;
467 	char errbuf[128];
468 	const char *dataset_name;
469 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
470 	const zcp_list_info_t *libinfo = &zcp_system_props_list_info;
471 	zcp_parse_args(state, libinfo->name, libinfo->pargs, libinfo->kwargs);
472 	dataset_name = lua_tostring(state, 1);
473 	nvlist_t *nv = fnvlist_alloc();
474 
475 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
476 	if (ds == NULL)
477 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
478 
479 	/* Get the names of all valid system properties for this dataset */
480 	zcp_dataset_system_props(ds, nv);
481 	dsl_dataset_rele(ds, FTAG);
482 
483 	/* push list as lua table */
484 	error = zcp_nvlist_to_lua(state, nv, errbuf, sizeof (errbuf));
485 	nvlist_free(nv);
486 	if (error != 0) {
487 		return (luaL_error(state,
488 		    "Error returning nvlist: %s", errbuf));
489 	}
490 	return (1);
491 }
492 
493 static int
494 zcp_bookmarks_iter(lua_State *state)
495 {
496 	char ds_name[ZFS_MAX_DATASET_NAME_LEN];
497 	char bookmark_name[ZFS_MAX_DATASET_NAME_LEN];
498 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
499 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
500 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
501 	dsl_dataset_t *ds;
502 	zap_attribute_t za;
503 	zap_cursor_t zc;
504 
505 	int err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
506 	if (err == ENOENT) {
507 		return (0);
508 	} else if (err != 0) {
509 		return (luaL_error(state,
510 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
511 		    err));
512 	}
513 
514 	if (!dsl_dataset_is_zapified(ds)) {
515 		dsl_dataset_rele(ds, FTAG);
516 		return (0);
517 	}
518 
519 	err = zap_lookup(dp->dp_meta_objset, ds->ds_object,
520 	    DS_FIELD_BOOKMARK_NAMES, sizeof (ds->ds_bookmarks_obj), 1,
521 	    &ds->ds_bookmarks_obj);
522 	if (err != 0 && err != ENOENT) {
523 		dsl_dataset_rele(ds, FTAG);
524 		return (luaL_error(state,
525 		    "unexpected error %d from zap_lookup()", err));
526 	}
527 	if (ds->ds_bookmarks_obj == 0) {
528 		dsl_dataset_rele(ds, FTAG);
529 		return (0);
530 	}
531 
532 	/* Store the dataset's name so we can append the bookmark's name */
533 	dsl_dataset_name(ds, ds_name);
534 
535 	zap_cursor_init_serialized(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
536 	    ds->ds_bookmarks_obj, cursor);
537 	dsl_dataset_rele(ds, FTAG);
538 
539 	err = zap_cursor_retrieve(&zc, &za);
540 	if (err != 0) {
541 		zap_cursor_fini(&zc);
542 		if (err != ENOENT) {
543 			return (luaL_error(state,
544 			    "unexpected error %d from zap_cursor_retrieve()",
545 			    err));
546 		}
547 		return (0);
548 	}
549 	zap_cursor_advance(&zc);
550 	cursor = zap_cursor_serialize(&zc);
551 	zap_cursor_fini(&zc);
552 
553 	/* Create the full "pool/fs#bookmark" string to return */
554 	int n = snprintf(bookmark_name, ZFS_MAX_DATASET_NAME_LEN, "%s#%s",
555 	    ds_name, za.za_name);
556 	if (n >= ZFS_MAX_DATASET_NAME_LEN) {
557 		return (luaL_error(state,
558 		    "unexpected error %d from snprintf()", ENAMETOOLONG));
559 	}
560 
561 	lua_pushnumber(state, cursor);
562 	lua_replace(state, lua_upvalueindex(2));
563 
564 	(void) lua_pushstring(state, bookmark_name);
565 	return (1);
566 }
567 
568 static int zcp_bookmarks_list(lua_State *);
569 static const zcp_list_info_t zcp_bookmarks_list_info = {
570 	.name = "bookmarks",
571 	.func = zcp_bookmarks_list,
572 	.pargs = {
573 	    { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
574 	    {NULL, 0}
575 	},
576 	.kwargs = {
577 	    {NULL, 0}
578 	}
579 };
580 
581 static int
582 zcp_bookmarks_list(lua_State *state)
583 {
584 	const char *dsname = lua_tostring(state, 1);
585 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
586 
587 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dsname, FTAG);
588 	if (ds == NULL)
589 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
590 
591 	boolean_t issnap = ds->ds_is_snapshot;
592 	uint64_t dsobj = ds->ds_object;
593 	uint64_t cursor = 0;
594 	dsl_dataset_rele(ds, FTAG);
595 
596 	if (issnap) {
597 		return (zcp_argerror(state, 1, "%s is a snapshot", dsname));
598 	}
599 
600 	lua_pushnumber(state, dsobj);
601 	lua_pushnumber(state, cursor);
602 	lua_pushcclosure(state, &zcp_bookmarks_iter, 2);
603 	return (1);
604 }
605 
606 static int
607 zcp_holds_iter(lua_State *state)
608 {
609 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
610 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
611 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
612 	dsl_dataset_t *ds;
613 	zap_attribute_t za;
614 	zap_cursor_t zc;
615 
616 	int err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
617 	if (err == ENOENT) {
618 		return (0);
619 	} else if (err != 0) {
620 		return (luaL_error(state,
621 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
622 		    err));
623 	}
624 
625 	if (dsl_dataset_phys(ds)->ds_userrefs_obj == 0) {
626 		dsl_dataset_rele(ds, FTAG);
627 		return (0);
628 	}
629 
630 	zap_cursor_init_serialized(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
631 	    dsl_dataset_phys(ds)->ds_userrefs_obj, cursor);
632 	dsl_dataset_rele(ds, FTAG);
633 
634 	err = zap_cursor_retrieve(&zc, &za);
635 	if (err != 0) {
636 		zap_cursor_fini(&zc);
637 		if (err != ENOENT) {
638 			return (luaL_error(state,
639 			    "unexpected error %d from zap_cursor_retrieve()",
640 			    err));
641 		}
642 		return (0);
643 	}
644 	zap_cursor_advance(&zc);
645 	cursor = zap_cursor_serialize(&zc);
646 	zap_cursor_fini(&zc);
647 
648 	lua_pushnumber(state, cursor);
649 	lua_replace(state, lua_upvalueindex(2));
650 
651 	(void) lua_pushstring(state, za.za_name);
652 	(void) lua_pushnumber(state, za.za_first_integer);
653 	return (2);
654 }
655 
656 static int zcp_holds_list(lua_State *);
657 static const zcp_list_info_t zcp_holds_list_info = {
658 	.name = "holds",
659 	.func = zcp_holds_list,
660 	.gc = NULL,
661 	.pargs = {
662 	    { .za_name = "snapshot", .za_lua_type = LUA_TSTRING },
663 	    {NULL, 0}
664 	},
665 	.kwargs = {
666 	    {NULL, 0}
667 	}
668 };
669 
670 /*
671  * Iterate over all the holds for a given dataset. Each iteration returns
672  * a hold's tag and its timestamp as an integer.
673  */
674 static int
675 zcp_holds_list(lua_State *state)
676 {
677 	const char *snapname = lua_tostring(state, 1);
678 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
679 
680 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, snapname, FTAG);
681 	if (ds == NULL)
682 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
683 
684 	boolean_t issnap = ds->ds_is_snapshot;
685 	uint64_t dsobj = ds->ds_object;
686 	uint64_t cursor = 0;
687 	dsl_dataset_rele(ds, FTAG);
688 
689 	if (!issnap) {
690 		return (zcp_argerror(state, 1, "%s is not a snapshot",
691 		    snapname));
692 	}
693 
694 	lua_pushnumber(state, dsobj);
695 	lua_pushnumber(state, cursor);
696 	lua_pushcclosure(state, &zcp_holds_iter, 2);
697 	return (1);
698 }
699 
700 static int
701 zcp_list_func(lua_State *state)
702 {
703 	zcp_list_info_t *info = lua_touserdata(state, lua_upvalueindex(1));
704 
705 	zcp_parse_args(state, info->name, info->pargs, info->kwargs);
706 
707 	return (info->func(state));
708 }
709 
710 int
711 zcp_load_list_lib(lua_State *state)
712 {
713 	const zcp_list_info_t *zcp_list_funcs[] = {
714 		&zcp_children_list_info,
715 		&zcp_snapshots_list_info,
716 		&zcp_user_props_list_info,
717 		&zcp_props_list_info,
718 		&zcp_clones_list_info,
719 		&zcp_system_props_list_info,
720 		&zcp_bookmarks_list_info,
721 		&zcp_holds_list_info,
722 		NULL
723 	};
724 
725 	lua_newtable(state);
726 
727 	for (int i = 0; zcp_list_funcs[i] != NULL; i++) {
728 		const zcp_list_info_t *info = zcp_list_funcs[i];
729 
730 		if (info->gc != NULL) {
731 			/*
732 			 * If the function requires garbage collection, create
733 			 * a metatable with its name and register the __gc
734 			 * function.
735 			 */
736 			(void) luaL_newmetatable(state, info->name);
737 			(void) lua_pushstring(state, "__gc");
738 			lua_pushcfunction(state, info->gc);
739 			lua_settable(state, -3);
740 			lua_pop(state, 1);
741 		}
742 
743 		lua_pushlightuserdata(state, (void *)(uintptr_t)info);
744 		lua_pushcclosure(state, &zcp_list_func, 1);
745 		lua_setfield(state, -2, info->name);
746 	}
747 
748 	return (1);
749 }
750