xref: /freebsd/sys/contrib/openzfs/module/zfs/zcp_iter.c (revision 7a7741af18d6c8a804cc643cb7ecda9d730c6aa6)
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
zcp_clones_iter(lua_State * state)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 	za = zap_attribute_alloc();
79 	err = zap_cursor_retrieve(&zc, za);
80 	if (err != 0) {
81 		zap_cursor_fini(&zc);
82 		zap_attribute_free(za);
83 		if (err != ENOENT) {
84 			return (luaL_error(state,
85 			    "unexpected error %d from zap_cursor_retrieve()",
86 			    err));
87 		}
88 		return (0);
89 	}
90 	zap_cursor_advance(&zc);
91 	cursor = zap_cursor_serialize(&zc);
92 	zap_cursor_fini(&zc);
93 
94 	err = dsl_dataset_hold_obj(dp, za->za_first_integer, FTAG, &clone);
95 	zap_attribute_free(za);
96 	if (err != 0) {
97 		return (luaL_error(state,
98 		    "unexpected error %d from "
99 		    "dsl_dataset_hold_obj(za_first_integer)", err));
100 	}
101 
102 	dsl_dir_name(clone->ds_dir, clonename);
103 	dsl_dataset_rele(clone, FTAG);
104 
105 	lua_pushnumber(state, cursor);
106 	lua_replace(state, lua_upvalueindex(2));
107 
108 	(void) lua_pushstring(state, clonename);
109 	return (1);
110 }
111 
112 static int zcp_clones_list(lua_State *);
113 static const zcp_list_info_t zcp_clones_list_info = {
114 	.name = "clones",
115 	.func = zcp_clones_list,
116 	.gc = NULL,
117 	.pargs = {
118 	    { .za_name = "snapshot", .za_lua_type = LUA_TSTRING },
119 	    {NULL, 0}
120 	},
121 	.kwargs = {
122 	    {NULL, 0}
123 	}
124 };
125 
126 static int
zcp_clones_list(lua_State * state)127 zcp_clones_list(lua_State *state)
128 {
129 	const char *snapname = lua_tostring(state, 1);
130 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
131 
132 	/*
133 	 * zcp_dataset_hold will either successfully return the requested
134 	 * dataset or throw a lua error and longjmp out of the zfs.list.clones
135 	 * call without returning.
136 	 */
137 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, snapname, FTAG);
138 	if (ds == NULL)
139 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
140 	boolean_t issnap = ds->ds_is_snapshot;
141 	uint64_t cursor = 0;
142 	uint64_t dsobj = ds->ds_object;
143 	dsl_dataset_rele(ds, FTAG);
144 
145 	if (!issnap) {
146 		return (zcp_argerror(state, 1, "%s is not a snapshot",
147 		    snapname));
148 	}
149 
150 	lua_pushnumber(state, dsobj);
151 	lua_pushnumber(state, cursor);
152 	lua_pushcclosure(state, &zcp_clones_iter, 2);
153 	return (1);
154 }
155 
156 static int
zcp_snapshots_iter(lua_State * state)157 zcp_snapshots_iter(lua_State *state)
158 {
159 	int err;
160 	char snapname[ZFS_MAX_DATASET_NAME_LEN];
161 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
162 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
163 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
164 	dsl_dataset_t *ds;
165 	objset_t *os;
166 	char *p;
167 
168 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
169 	if (err != 0) {
170 		return (luaL_error(state,
171 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
172 		    err));
173 	}
174 
175 	dsl_dataset_name(ds, snapname);
176 	VERIFY3U(sizeof (snapname), >,
177 	    strlcat(snapname, "@", sizeof (snapname)));
178 
179 	p = strchr(snapname, '\0');
180 	VERIFY0(dmu_objset_from_ds(ds, &os));
181 	err = dmu_snapshot_list_next(os,
182 	    sizeof (snapname) - (p - snapname), p, NULL, &cursor, NULL);
183 	dsl_dataset_rele(ds, FTAG);
184 
185 	if (err == ENOENT) {
186 		return (0);
187 	} else if (err != 0) {
188 		return (luaL_error(state,
189 		    "unexpected error %d from dmu_snapshot_list_next()", err));
190 	}
191 
192 	lua_pushnumber(state, cursor);
193 	lua_replace(state, lua_upvalueindex(2));
194 
195 	(void) lua_pushstring(state, snapname);
196 	return (1);
197 }
198 
199 static int zcp_snapshots_list(lua_State *);
200 static const zcp_list_info_t zcp_snapshots_list_info = {
201 	.name = "snapshots",
202 	.func = zcp_snapshots_list,
203 	.gc = NULL,
204 	.pargs = {
205 	    { .za_name = "filesystem | volume", .za_lua_type = LUA_TSTRING },
206 	    {NULL, 0}
207 	},
208 	.kwargs = {
209 	    {NULL, 0}
210 	}
211 };
212 
213 static int
zcp_snapshots_list(lua_State * state)214 zcp_snapshots_list(lua_State *state)
215 {
216 	const char *fsname = lua_tostring(state, 1);
217 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
218 	boolean_t issnap;
219 	uint64_t dsobj;
220 
221 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, fsname, FTAG);
222 	if (ds == NULL)
223 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
224 	issnap = ds->ds_is_snapshot;
225 	dsobj = ds->ds_object;
226 	dsl_dataset_rele(ds, FTAG);
227 
228 	if (issnap) {
229 		return (zcp_argerror(state, 1,
230 		    "argument %s cannot be a snapshot", fsname));
231 	}
232 
233 	lua_pushnumber(state, dsobj);
234 	lua_pushnumber(state, 0);
235 	lua_pushcclosure(state, &zcp_snapshots_iter, 2);
236 	return (1);
237 }
238 
239 static int
zcp_children_iter(lua_State * state)240 zcp_children_iter(lua_State *state)
241 {
242 	int err;
243 	char childname[ZFS_MAX_DATASET_NAME_LEN];
244 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
245 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
246 	zcp_run_info_t *ri = zcp_run_info(state);
247 	dsl_pool_t *dp = ri->zri_pool;
248 	dsl_dataset_t *ds;
249 	objset_t *os;
250 	char *p;
251 
252 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
253 	if (err != 0) {
254 		return (luaL_error(state,
255 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
256 		    err));
257 	}
258 
259 	dsl_dataset_name(ds, childname);
260 	VERIFY3U(sizeof (childname), >,
261 	    strlcat(childname, "/", sizeof (childname)));
262 	p = strchr(childname, '\0');
263 
264 	VERIFY0(dmu_objset_from_ds(ds, &os));
265 	do {
266 		err = dmu_dir_list_next(os,
267 		    sizeof (childname) - (p - childname), p, NULL, &cursor);
268 	} while (err == 0 && zfs_dataset_name_hidden(childname));
269 	dsl_dataset_rele(ds, FTAG);
270 
271 	if (err == ENOENT) {
272 		return (0);
273 	} else if (err != 0) {
274 		return (luaL_error(state,
275 		    "unexpected error %d from dmu_dir_list_next()",
276 		    err));
277 	}
278 
279 	lua_pushnumber(state, cursor);
280 	lua_replace(state, lua_upvalueindex(2));
281 
282 	(void) lua_pushstring(state, childname);
283 	return (1);
284 }
285 
286 static int zcp_children_list(lua_State *);
287 static const zcp_list_info_t zcp_children_list_info = {
288 	.name = "children",
289 	.func = zcp_children_list,
290 	.gc = NULL,
291 	.pargs = {
292 	    { .za_name = "filesystem | volume", .za_lua_type = LUA_TSTRING },
293 	    {NULL, 0}
294 	},
295 	.kwargs = {
296 	    {NULL, 0}
297 	}
298 };
299 
300 static int
zcp_children_list(lua_State * state)301 zcp_children_list(lua_State *state)
302 {
303 	const char *fsname = lua_tostring(state, 1);
304 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
305 	boolean_t issnap;
306 	uint64_t dsobj;
307 
308 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, fsname, FTAG);
309 	if (ds == NULL)
310 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
311 
312 	issnap = ds->ds_is_snapshot;
313 	dsobj = ds->ds_object;
314 	dsl_dataset_rele(ds, FTAG);
315 
316 	if (issnap) {
317 		return (zcp_argerror(state, 1,
318 		    "argument %s cannot be a snapshot", fsname));
319 	}
320 
321 	lua_pushnumber(state, dsobj);
322 	lua_pushnumber(state, 0);
323 	lua_pushcclosure(state, &zcp_children_iter, 2);
324 	return (1);
325 }
326 
327 static int
zcp_user_props_list_gc(lua_State * state)328 zcp_user_props_list_gc(lua_State *state)
329 {
330 	nvlist_t **props = lua_touserdata(state, 1);
331 	if (*props != NULL)
332 		fnvlist_free(*props);
333 	return (0);
334 }
335 
336 static int
zcp_user_props_iter(lua_State * state)337 zcp_user_props_iter(lua_State *state)
338 {
339 	const char *source, *val;
340 	nvlist_t *nvprop;
341 	nvlist_t **props = lua_touserdata(state, lua_upvalueindex(1));
342 	nvpair_t *pair = lua_touserdata(state, lua_upvalueindex(2));
343 
344 	do {
345 		pair = nvlist_next_nvpair(*props, pair);
346 		if (pair == NULL) {
347 			fnvlist_free(*props);
348 			*props = NULL;
349 			return (0);
350 		}
351 	} while (!zfs_prop_user(nvpair_name(pair)));
352 
353 	lua_pushlightuserdata(state, pair);
354 	lua_replace(state, lua_upvalueindex(2));
355 
356 	nvprop = fnvpair_value_nvlist(pair);
357 	val = fnvlist_lookup_string(nvprop, ZPROP_VALUE);
358 	source = fnvlist_lookup_string(nvprop, ZPROP_SOURCE);
359 
360 	(void) lua_pushstring(state, nvpair_name(pair));
361 	(void) lua_pushstring(state, val);
362 	(void) lua_pushstring(state, source);
363 	return (3);
364 }
365 
366 static int zcp_user_props_list(lua_State *);
367 static const zcp_list_info_t zcp_user_props_list_info = {
368 	.name = "user_properties",
369 	.func = zcp_user_props_list,
370 	.gc = zcp_user_props_list_gc,
371 	.pargs = {
372 	    { .za_name = "filesystem | snapshot | volume",
373 	    .za_lua_type = LUA_TSTRING },
374 	    {NULL, 0}
375 	},
376 	.kwargs = {
377 	    {NULL, 0}
378 	}
379 };
380 
381 /*
382  * 'properties' was the initial name for 'user_properties' seen
383  * above. 'user_properties' is a better name as it distinguishes
384  * these properties from 'system_properties' which are different.
385  * In order to avoid breaking compatibility between different
386  * versions of ZFS, we declare 'properties' as an alias for
387  * 'user_properties'.
388  */
389 static const zcp_list_info_t zcp_props_list_info = {
390 	.name = "properties",
391 	.func = zcp_user_props_list,
392 	.gc = zcp_user_props_list_gc,
393 	.pargs = {
394 	    { .za_name = "filesystem | snapshot | volume",
395 	    .za_lua_type = LUA_TSTRING },
396 	    {NULL, 0}
397 	},
398 	.kwargs = {
399 	    {NULL, 0}
400 	}
401 };
402 
403 static int
zcp_user_props_list(lua_State * state)404 zcp_user_props_list(lua_State *state)
405 {
406 	const char *dsname = lua_tostring(state, 1);
407 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
408 	objset_t *os;
409 	nvlist_t **props = lua_newuserdata(state, sizeof (nvlist_t *));
410 
411 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dsname, FTAG);
412 	if (ds == NULL)
413 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
414 	VERIFY0(dmu_objset_from_ds(ds, &os));
415 	VERIFY0(dsl_prop_get_all(os, props));
416 	dsl_dataset_rele(ds, FTAG);
417 
418 	/*
419 	 * Set the metatable for the properties list to free it on
420 	 * completion.
421 	 */
422 	luaL_getmetatable(state, zcp_user_props_list_info.name);
423 	(void) lua_setmetatable(state, -2);
424 
425 	lua_pushlightuserdata(state, NULL);
426 	lua_pushcclosure(state, &zcp_user_props_iter, 2);
427 	return (1);
428 }
429 
430 
431 /*
432  * Populate nv with all valid system properties and their values for the given
433  * dataset.
434  */
435 static void
zcp_dataset_system_props(dsl_dataset_t * ds,nvlist_t * nv)436 zcp_dataset_system_props(dsl_dataset_t *ds, nvlist_t *nv)
437 {
438 	for (int prop = ZFS_PROP_TYPE; prop < ZFS_NUM_PROPS; prop++) {
439 		/* Do not display hidden props */
440 		if (!zfs_prop_visible(prop))
441 			continue;
442 		/* Do not display props not valid for this dataset */
443 		if (!prop_valid_for_ds(ds, prop))
444 			continue;
445 		fnvlist_add_boolean(nv, zfs_prop_to_name(prop));
446 	}
447 }
448 
449 static int zcp_system_props_list(lua_State *);
450 static const zcp_list_info_t zcp_system_props_list_info = {
451 	.name = "system_properties",
452 	.func = zcp_system_props_list,
453 	.pargs = {
454 	    { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
455 	    {NULL, 0}
456 	},
457 	.kwargs = {
458 	    {NULL, 0}
459 	}
460 };
461 
462 /*
463  * Get a list of all visible system properties and their values for a given
464  * dataset. Returned on the stack as a Lua table.
465  */
466 static int
zcp_system_props_list(lua_State * state)467 zcp_system_props_list(lua_State *state)
468 {
469 	int error;
470 	char errbuf[128];
471 	const char *dataset_name;
472 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
473 	const zcp_list_info_t *libinfo = &zcp_system_props_list_info;
474 	zcp_parse_args(state, libinfo->name, libinfo->pargs, libinfo->kwargs);
475 	dataset_name = lua_tostring(state, 1);
476 	nvlist_t *nv = fnvlist_alloc();
477 
478 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
479 	if (ds == NULL)
480 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
481 
482 	/* Get the names of all valid system properties for this dataset */
483 	zcp_dataset_system_props(ds, nv);
484 	dsl_dataset_rele(ds, FTAG);
485 
486 	/* push list as lua table */
487 	error = zcp_nvlist_to_lua(state, nv, errbuf, sizeof (errbuf));
488 	nvlist_free(nv);
489 	if (error != 0) {
490 		return (luaL_error(state,
491 		    "Error returning nvlist: %s", errbuf));
492 	}
493 	return (1);
494 }
495 
496 static int
zcp_bookmarks_iter(lua_State * state)497 zcp_bookmarks_iter(lua_State *state)
498 {
499 	char ds_name[ZFS_MAX_DATASET_NAME_LEN];
500 	char bookmark_name[ZFS_MAX_DATASET_NAME_LEN];
501 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
502 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
503 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
504 	dsl_dataset_t *ds;
505 	zap_attribute_t *za;
506 	zap_cursor_t zc;
507 
508 	int err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
509 	if (err == ENOENT) {
510 		return (0);
511 	} else if (err != 0) {
512 		return (luaL_error(state,
513 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
514 		    err));
515 	}
516 
517 	if (!dsl_dataset_is_zapified(ds)) {
518 		dsl_dataset_rele(ds, FTAG);
519 		return (0);
520 	}
521 
522 	err = zap_lookup(dp->dp_meta_objset, ds->ds_object,
523 	    DS_FIELD_BOOKMARK_NAMES, sizeof (ds->ds_bookmarks_obj), 1,
524 	    &ds->ds_bookmarks_obj);
525 	if (err != 0 && err != ENOENT) {
526 		dsl_dataset_rele(ds, FTAG);
527 		return (luaL_error(state,
528 		    "unexpected error %d from zap_lookup()", err));
529 	}
530 	if (ds->ds_bookmarks_obj == 0) {
531 		dsl_dataset_rele(ds, FTAG);
532 		return (0);
533 	}
534 
535 	/* Store the dataset's name so we can append the bookmark's name */
536 	dsl_dataset_name(ds, ds_name);
537 
538 	zap_cursor_init_serialized(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
539 	    ds->ds_bookmarks_obj, cursor);
540 	dsl_dataset_rele(ds, FTAG);
541 
542 	za = zap_attribute_alloc();
543 	err = zap_cursor_retrieve(&zc, za);
544 	if (err != 0) {
545 		zap_cursor_fini(&zc);
546 		zap_attribute_free(za);
547 		if (err != ENOENT) {
548 			return (luaL_error(state,
549 			    "unexpected error %d from zap_cursor_retrieve()",
550 			    err));
551 		}
552 		return (0);
553 	}
554 	zap_cursor_advance(&zc);
555 	cursor = zap_cursor_serialize(&zc);
556 	zap_cursor_fini(&zc);
557 
558 	/* Create the full "pool/fs#bookmark" string to return */
559 	int n = snprintf(bookmark_name, ZFS_MAX_DATASET_NAME_LEN, "%s#%s",
560 	    ds_name, za->za_name);
561 	zap_attribute_free(za);
562 	if (n >= ZFS_MAX_DATASET_NAME_LEN) {
563 		return (luaL_error(state,
564 		    "unexpected error %d from snprintf()", ENAMETOOLONG));
565 	}
566 
567 	lua_pushnumber(state, cursor);
568 	lua_replace(state, lua_upvalueindex(2));
569 
570 	(void) lua_pushstring(state, bookmark_name);
571 	return (1);
572 }
573 
574 static int zcp_bookmarks_list(lua_State *);
575 static const zcp_list_info_t zcp_bookmarks_list_info = {
576 	.name = "bookmarks",
577 	.func = zcp_bookmarks_list,
578 	.pargs = {
579 	    { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
580 	    {NULL, 0}
581 	},
582 	.kwargs = {
583 	    {NULL, 0}
584 	}
585 };
586 
587 static int
zcp_bookmarks_list(lua_State * state)588 zcp_bookmarks_list(lua_State *state)
589 {
590 	const char *dsname = lua_tostring(state, 1);
591 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
592 
593 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dsname, FTAG);
594 	if (ds == NULL)
595 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
596 
597 	boolean_t issnap = ds->ds_is_snapshot;
598 	uint64_t dsobj = ds->ds_object;
599 	uint64_t cursor = 0;
600 	dsl_dataset_rele(ds, FTAG);
601 
602 	if (issnap) {
603 		return (zcp_argerror(state, 1, "%s is a snapshot", dsname));
604 	}
605 
606 	lua_pushnumber(state, dsobj);
607 	lua_pushnumber(state, cursor);
608 	lua_pushcclosure(state, &zcp_bookmarks_iter, 2);
609 	return (1);
610 }
611 
612 static int
zcp_holds_iter(lua_State * state)613 zcp_holds_iter(lua_State *state)
614 {
615 	uint64_t dsobj = lua_tonumber(state, lua_upvalueindex(1));
616 	uint64_t cursor = lua_tonumber(state, lua_upvalueindex(2));
617 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
618 	dsl_dataset_t *ds;
619 	zap_attribute_t *za;
620 	zap_cursor_t zc;
621 
622 	int err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
623 	if (err == ENOENT) {
624 		return (0);
625 	} else if (err != 0) {
626 		return (luaL_error(state,
627 		    "unexpected error %d from dsl_dataset_hold_obj(dsobj)",
628 		    err));
629 	}
630 
631 	if (dsl_dataset_phys(ds)->ds_userrefs_obj == 0) {
632 		dsl_dataset_rele(ds, FTAG);
633 		return (0);
634 	}
635 
636 	zap_cursor_init_serialized(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
637 	    dsl_dataset_phys(ds)->ds_userrefs_obj, cursor);
638 	dsl_dataset_rele(ds, FTAG);
639 
640 	za = zap_attribute_alloc();
641 	err = zap_cursor_retrieve(&zc, za);
642 	if (err != 0) {
643 		zap_cursor_fini(&zc);
644 		zap_attribute_free(za);
645 		if (err != ENOENT) {
646 			return (luaL_error(state,
647 			    "unexpected error %d from zap_cursor_retrieve()",
648 			    err));
649 		}
650 		return (0);
651 	}
652 	zap_cursor_advance(&zc);
653 	cursor = zap_cursor_serialize(&zc);
654 	zap_cursor_fini(&zc);
655 
656 	lua_pushnumber(state, cursor);
657 	lua_replace(state, lua_upvalueindex(2));
658 
659 	(void) lua_pushstring(state, za->za_name);
660 	(void) lua_pushnumber(state, za->za_first_integer);
661 	zap_attribute_free(za);
662 	return (2);
663 }
664 
665 static int zcp_holds_list(lua_State *);
666 static const zcp_list_info_t zcp_holds_list_info = {
667 	.name = "holds",
668 	.func = zcp_holds_list,
669 	.gc = NULL,
670 	.pargs = {
671 	    { .za_name = "snapshot", .za_lua_type = LUA_TSTRING },
672 	    {NULL, 0}
673 	},
674 	.kwargs = {
675 	    {NULL, 0}
676 	}
677 };
678 
679 /*
680  * Iterate over all the holds for a given dataset. Each iteration returns
681  * a hold's tag and its timestamp as an integer.
682  */
683 static int
zcp_holds_list(lua_State * state)684 zcp_holds_list(lua_State *state)
685 {
686 	const char *snapname = lua_tostring(state, 1);
687 	dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
688 
689 	dsl_dataset_t *ds = zcp_dataset_hold(state, dp, snapname, FTAG);
690 	if (ds == NULL)
691 		return (1); /* not reached; zcp_dataset_hold() longjmp'd */
692 
693 	boolean_t issnap = ds->ds_is_snapshot;
694 	uint64_t dsobj = ds->ds_object;
695 	uint64_t cursor = 0;
696 	dsl_dataset_rele(ds, FTAG);
697 
698 	if (!issnap) {
699 		return (zcp_argerror(state, 1, "%s is not a snapshot",
700 		    snapname));
701 	}
702 
703 	lua_pushnumber(state, dsobj);
704 	lua_pushnumber(state, cursor);
705 	lua_pushcclosure(state, &zcp_holds_iter, 2);
706 	return (1);
707 }
708 
709 static int
zcp_list_func(lua_State * state)710 zcp_list_func(lua_State *state)
711 {
712 	zcp_list_info_t *info = lua_touserdata(state, lua_upvalueindex(1));
713 
714 	zcp_parse_args(state, info->name, info->pargs, info->kwargs);
715 
716 	return (info->func(state));
717 }
718 
719 int
zcp_load_list_lib(lua_State * state)720 zcp_load_list_lib(lua_State *state)
721 {
722 	const zcp_list_info_t *zcp_list_funcs[] = {
723 		&zcp_children_list_info,
724 		&zcp_snapshots_list_info,
725 		&zcp_user_props_list_info,
726 		&zcp_props_list_info,
727 		&zcp_clones_list_info,
728 		&zcp_system_props_list_info,
729 		&zcp_bookmarks_list_info,
730 		&zcp_holds_list_info,
731 		NULL
732 	};
733 
734 	lua_newtable(state);
735 
736 	for (int i = 0; zcp_list_funcs[i] != NULL; i++) {
737 		const zcp_list_info_t *info = zcp_list_funcs[i];
738 
739 		if (info->gc != NULL) {
740 			/*
741 			 * If the function requires garbage collection, create
742 			 * a metatable with its name and register the __gc
743 			 * function.
744 			 */
745 			(void) luaL_newmetatable(state, info->name);
746 			(void) lua_pushstring(state, "__gc");
747 			lua_pushcfunction(state, info->gc);
748 			lua_settable(state, -3);
749 			lua_pop(state, 1);
750 		}
751 
752 		lua_pushlightuserdata(state, (void *)(uintptr_t)info);
753 		lua_pushcclosure(state, &zcp_list_func, 1);
754 		lua_setfield(state, -2, info->name);
755 	}
756 
757 	return (1);
758 }
759