kernel/fs/zfs/zcp_get.c

   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 "lua.h"
  21 #include "lualib.h"
  22 #include "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/zfs_ioctl.h>
  38 #include <sys/zfs_znode.h>
  39 #include <sys/zvol.h>
  40
  41 #ifdef _KERNEL
  42 #include <sys/zfs_vfsops.h>
  43 #endif
  44
  45 static int
  46 get_objset_type(dsl_dataset_t *ds, zfs_type_t *type)
  47 {
  48         int error;
  49         objset_t *os;
  50         error = dmu_objset_from_ds(ds, &os);
  51         if (error != 0)
  52                 return (error);
  53         if (ds->ds_is_snapshot) {
  54                 *type = ZFS_TYPE_SNAPSHOT;
  55         } else {
  56                 switch (os->os_phys->os_type) {
  57                 case DMU_OST_ZFS:
  58                         *type = ZFS_TYPE_FILESYSTEM;
  59                         break;
  60                 case DMU_OST_ZVOL:
  61                         *type = ZFS_TYPE_VOLUME;
  62                         break;
  63                 default:
  64                         return (EINVAL);
  65                 }
  66         }
  67         return (0);
  68 }
  69
  70 /*
  71  * Returns the string name of ds's type in str (a buffer which should be
  72  * at least 12 bytes long).
  73  */
  74 static int
  75 get_objset_type_name(dsl_dataset_t *ds, char *str)
  76 {
  77         int error;
  78         zfs_type_t type;
  79         error = get_objset_type(ds, &type);
  80         if (error != 0)
  81                 return (error);
  82         switch (type) {
  83         case ZFS_TYPE_SNAPSHOT:
  84                 (void) strcpy(str, "snapshot");
  85                 break;
  86         case ZFS_TYPE_FILESYSTEM:
  87                 (void) strcpy(str, "filesystem");
  88                 break;
  89         case ZFS_TYPE_VOLUME:
  90                 (void) strcpy(str, "volume");
  91                 break;
  92         default:
  93                 return (EINVAL);
  94         }
  95         return (0);
  96 }
  97
  98 /*
  99  * Determines the source of a property given its setpoint and
 100  * property type. It pushes the source to the lua stack.
 101  */
 102 static void
 103 get_prop_src(lua_State *state, const char *setpoint, zfs_prop_t prop)
 104 {
 105         if (zfs_prop_readonly(prop) || (prop == ZFS_PROP_VERSION)) {
 106                 lua_pushnil(state);
 107         } else {
 108                 const char *src;
 109                 if (strcmp("", setpoint) == 0) {
 110                         src = "default";
 111                 } else {
 112                         src = setpoint;
 113                 }
 114                 (void) lua_pushstring(state, src);
 115         }
 116 }
 117
 118 /*
 119  * Given an error encountered while getting properties, either longjmp's for
 120  * a fatal error or pushes nothing to the stack for a non fatal one.
 121  */
 122 static int
 123 zcp_handle_error(lua_State *state, const char *dataset_name,
 124     const char *property_name, int error)
 125 {
 126         ASSERT3S(error, !=, 0);
 127         if (error == ENOENT) {
 128                 return (0);
 129         } else if (error == EINVAL) {
 130                 return (luaL_error(state,
 131                     "property '%s' is not a valid property on dataset '%s'",
 132                     property_name, dataset_name));
 133         } else if (error == EIO) {
 134                 return (luaL_error(state,
 135                     "I/O error while retrieving property '%s' on dataset '%s'",
 136                     property_name, dataset_name));
 137         } else {
 138                 return (luaL_error(state, "unexpected error %d while "
 139                     "retrieving property '%s' on dataset '%s'",
 140                     error, property_name, dataset_name));
 141         }
 142 }
 143
 144 /*
 145  * Look up a user defined property in the zap object. If it exists, push it
 146  * and the setpoint onto the stack, otherwise don't push anything.
 147  */
 148 static int
 149 zcp_get_user_prop(lua_State *state, dsl_pool_t *dp, const char *dataset_name,
 150     const char *property_name)
 151 {
 152         int error;
 153         char *buf;
 154         char setpoint[ZFS_MAX_DATASET_NAME_LEN];
 155         /*
 156          * zcp_dataset_hold will either successfully return the requested
 157          * dataset or throw a lua error and longjmp out of the zfs.get_prop call
 158          * without returning.
 159          */
 160         dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
 161         if (ds == NULL)
 162                 return (1); /* not reached; zcp_dataset_hold() longjmp'd */
 163
 164         buf = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
 165         error = dsl_prop_get_ds(ds, property_name, 1, ZAP_MAXVALUELEN,
 166             buf, setpoint);
 167         dsl_dataset_rele(ds, FTAG);
 168
 169         if (error != 0) {
 170                 kmem_free(buf, ZAP_MAXVALUELEN);
 171                 return (zcp_handle_error(state, dataset_name, property_name,
 172                     error));
 173         }
 174         (void) lua_pushstring(state, buf);
 175         (void) lua_pushstring(state, setpoint);
 176         kmem_free(buf, ZAP_MAXVALUELEN);
 177         return (2);
 178 }
 179
 180 /*
 181  * Check if the property we're looking for is stored in the ds_dir. If so,
 182  * return it in the 'val' argument. Return 0 on success and ENOENT and if
 183  * the property is not present.
 184  */
 185 static int
 186 get_dsl_dir_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop,
 187     uint64_t *val)
 188 {
 189         dsl_dir_t *dd = ds->ds_dir;
 190         mutex_enter(&dd->dd_lock);
 191         switch (zfs_prop) {
 192         case ZFS_PROP_USEDSNAP:
 193                 *val = dsl_dir_get_usedsnap(dd);
 194                 break;
 195         case ZFS_PROP_USEDCHILD:
 196                 *val = dsl_dir_get_usedchild(dd);
 197                 break;
 198         case ZFS_PROP_USEDDS:
 199                 *val = dsl_dir_get_usedds(dd);
 200                 break;
 201         case ZFS_PROP_USEDREFRESERV:
 202                 *val = dsl_dir_get_usedrefreserv(dd);
 203                 break;
 204         case ZFS_PROP_LOGICALUSED:
 205                 *val = dsl_dir_get_logicalused(dd);
 206                 break;
 207         default:
 208                 mutex_exit(&dd->dd_lock);
 209                 return (ENOENT);
 210         }
 211         mutex_exit(&dd->dd_lock);
 212         return (0);
 213 }
 214
 215 /*
 216  * Takes a dataset, a property, a value and that value's setpoint as
 217  * found in the ZAP. Checks if the property has been changed in the vfs.
 218  * If so, val and setpoint will be overwritten with updated content.
 219  * Otherwise, they are left unchanged.
 220  */
 221 static int
 222 get_temporary_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop, uint64_t *val,
 223     char *setpoint)
 224 {
 225 #ifndef _KERNEL
 226         return (0);
 227 #else
 228         int error;
 229         zfsvfs_t *zfvp;
 230         vfs_t *vfsp;
 231         objset_t *os;
 232         uint64_t tmp = *val;
 233
 234         error = dmu_objset_from_ds(ds, &os);
 235         if (error != 0)
 236                 return (error);
 237
 238         error = getzfsvfs_impl(os, &zfvp);
 239         if (error != 0)
 240                 return (error);
 241
 242         vfsp = zfvp->z_vfs;
 243
 244         switch (zfs_prop) {
 245         case ZFS_PROP_ATIME:
 246                 if (vfs_optionisset(vfsp, MNTOPT_NOATIME, NULL))
 247                         tmp = 0;
 248                 if (vfs_optionisset(vfsp, MNTOPT_ATIME, NULL))
 249                         tmp = 1;
 250                 break;
 251         case ZFS_PROP_DEVICES:
 252                 if (vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL))
 253                         tmp = 0;
 254                 if (vfs_optionisset(vfsp, MNTOPT_DEVICES, NULL))
 255                         tmp = 1;
 256                 break;
 257         case ZFS_PROP_EXEC:
 258                 if (vfs_optionisset(vfsp, MNTOPT_NOEXEC, NULL))
 259                         tmp = 0;
 260                 if (vfs_optionisset(vfsp, MNTOPT_EXEC, NULL))
 261                         tmp = 1;
 262                 break;
 263         case ZFS_PROP_SETUID:
 264                 if (vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL))
 265                         tmp = 0;
 266                 if (vfs_optionisset(vfsp, MNTOPT_SETUID, NULL))
 267                         tmp = 1;
 268                 break;
 269         case ZFS_PROP_READONLY:
 270                 if (vfs_optionisset(vfsp, MNTOPT_RW, NULL))
 271                         tmp = 0;
 272                 if (vfs_optionisset(vfsp, MNTOPT_RO, NULL))
 273                         tmp = 1;
 274                 break;
 275         case ZFS_PROP_XATTR:
 276                 if (vfs_optionisset(vfsp, MNTOPT_NOXATTR, NULL))
 277                         tmp = 0;
 278                 if (vfs_optionisset(vfsp, MNTOPT_XATTR, NULL))
 279                         tmp = 1;
 280                 break;
 281         case ZFS_PROP_NBMAND:
 282                 if (vfs_optionisset(vfsp, MNTOPT_NONBMAND, NULL))
 283                         tmp = 0;
 284                 if (vfs_optionisset(vfsp, MNTOPT_NBMAND, NULL))
 285                         tmp = 1;
 286                 break;
 287         default:
 288                 VFS_RELE(vfsp);
 289                 return (ENOENT);
 290         }
 291
 292         VFS_RELE(vfsp);
 293         if (tmp != *val) {
 294                 (void) strcpy(setpoint, "temporary");
 295                 *val = tmp;
 296         }
 297         return (0);
 298 #endif
 299 }
 300
 301 /*
 302  * Check if the property we're looking for is stored at the dsl_dataset or
 303  * dsl_dir level. If so, push the property value and source onto the lua stack
 304  * and return 0. If it is not present or a failure occurs in lookup, return a
 305  * non-zero error value.
 306  */
 307 static int
 308 get_special_prop(lua_State *state, dsl_dataset_t *ds, const char *dsname,
 309     zfs_prop_t zfs_prop)
 310 {
 311         int error = 0;
 312         objset_t *os;
 313         uint64_t numval;
 314         char *strval = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
 315         char setpoint[ZFS_MAX_DATASET_NAME_LEN] =
 316             "Internal error - setpoint not determined";
 317         zfs_type_t ds_type;
 318         zprop_type_t prop_type = zfs_prop_get_type(zfs_prop);
 319         (void) get_objset_type(ds, &ds_type);
 320
 321         switch (zfs_prop) {
 322         case ZFS_PROP_REFRATIO:
 323                 numval = dsl_get_refratio(ds);
 324                 break;
 325         case ZFS_PROP_USED:
 326                 numval = dsl_get_used(ds);
 327                 break;
 328         case ZFS_PROP_CLONES: {
 329                 nvlist_t *clones = fnvlist_alloc();
 330                 error = get_clones_stat_impl(ds, clones);
 331                 if (error == 0) {
 332                         /* push list to lua stack */
 333                         VERIFY0(zcp_nvlist_to_lua(state, clones, NULL, 0));
 334                         /* source */
 335                         (void) lua_pushnil(state);
 336                 }
 337                 nvlist_free(clones);
 338                 kmem_free(strval, ZAP_MAXVALUELEN);
 339                 return (error);
 340         }
 341         case ZFS_PROP_COMPRESSRATIO:
 342                 numval = dsl_get_compressratio(ds);
 343                 break;
 344         case ZFS_PROP_CREATION:
 345                 numval = dsl_get_creation(ds);
 346                 break;
 347         case ZFS_PROP_REFERENCED:
 348                 numval = dsl_get_referenced(ds);
 349                 break;
 350         case ZFS_PROP_AVAILABLE:
 351                 numval = dsl_get_available(ds);
 352                 break;
 353         case ZFS_PROP_LOGICALREFERENCED:
 354                 numval = dsl_get_logicalreferenced(ds);
 355                 break;
 356         case ZFS_PROP_CREATETXG:
 357                 numval = dsl_get_creationtxg(ds);
 358                 break;
 359         case ZFS_PROP_GUID:
 360                 numval = dsl_get_guid(ds);
 361                 break;
 362         case ZFS_PROP_UNIQUE:
 363                 numval = dsl_get_unique(ds);
 364                 break;
 365         case ZFS_PROP_OBJSETID:
 366                 numval = dsl_get_objsetid(ds);
 367                 break;
 368         case ZFS_PROP_ORIGIN:
 369                 dsl_dir_get_origin(ds->ds_dir, strval);
 370                 break;
 371         case ZFS_PROP_USERACCOUNTING:
 372                 error = dmu_objset_from_ds(ds, &os);
 373                 if (error == 0)
 374                         numval = dmu_objset_userspace_present(os);
 375                 break;
 376         case ZFS_PROP_WRITTEN:
 377                 error = dsl_get_written(ds, &numval);
 378                 break;
 379         case ZFS_PROP_TYPE:
 380                 error = get_objset_type_name(ds, strval);
 381                 break;
 382         case ZFS_PROP_PREV_SNAP:
 383                 error = dsl_get_prev_snap(ds, strval);
 384                 break;
 385         case ZFS_PROP_NAME:
 386                 dsl_dataset_name(ds, strval);
 387                 break;
 388         case ZFS_PROP_MOUNTPOINT:
 389                 error = dsl_get_mountpoint(ds, dsname, strval, setpoint);
 390                 break;
 391         case ZFS_PROP_VERSION:
 392                 /* should be a snapshot or filesystem */
 393                 ASSERT(ds_type != ZFS_TYPE_VOLUME);
 394                 error = dmu_objset_from_ds(ds, &os);
 395                 /* look in the master node for the version */
 396                 if (error == 0) {
 397                         error = zap_lookup(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
 398                             sizeof (numval), 1, &numval);
 399                 }
 400                 break;
 401         case ZFS_PROP_DEFER_DESTROY:
 402                 numval = dsl_get_defer_destroy(ds);
 403                 break;
 404         case ZFS_PROP_USERREFS:
 405                 numval = dsl_get_userrefs(ds);
 406                 break;
 407         case ZFS_PROP_FILESYSTEM_COUNT:
 408                 error = dsl_dir_get_filesystem_count(ds->ds_dir, &numval);
 409                 (void) strcpy(setpoint, "");
 410                 break;
 411         case ZFS_PROP_SNAPSHOT_COUNT:
 412                 error = dsl_dir_get_snapshot_count(ds->ds_dir, &numval);
 413                 (void) strcpy(setpoint, "");
 414                 break;
 415         case ZFS_PROP_NUMCLONES:
 416                 numval = dsl_get_numclones(ds);
 417                 break;
 418         case ZFS_PROP_INCONSISTENT:
 419                 numval = dsl_get_inconsistent(ds);
 420                 break;
 421         case ZFS_PROP_RECEIVE_RESUME_TOKEN:
 422                 VERIFY3U(strlcpy(strval, get_receive_resume_stats_impl(ds),
 423                     ZAP_MAXVALUELEN), <, ZAP_MAXVALUELEN);
 424                 if (strcmp(strval, "") == 0) {
 425                         VERIFY3U(strlcpy(strval, get_child_receive_stats(ds),
 426                             ZAP_MAXVALUELEN), <, ZAP_MAXVALUELEN);
 427                         if (strcmp(strval, "") == 0)
 428                                 error = ENOENT;
 429                 }
 430                 break;
 431         case ZFS_PROP_VOLSIZE:
 432                 ASSERT(ds_type == ZFS_TYPE_VOLUME);
 433                 error = dmu_objset_from_ds(ds, &os);
 434                 if (error == 0) {
 435                         error = zap_lookup(os, ZVOL_ZAP_OBJ, "size",
 436                             sizeof (numval), 1, &numval);
 437                 }
 438                 if (error == 0)
 439                         (void) strcpy(setpoint, dsname);
 440
 441                 break;
 442         case ZFS_PROP_VOLBLOCKSIZE: {
 443                 ASSERT(ds_type == ZFS_TYPE_VOLUME);
 444                 dmu_object_info_t doi;
 445                 error = dmu_objset_from_ds(ds, &os);
 446                 if (error == 0) {
 447                         error = dmu_object_info(os, ZVOL_OBJ, &doi);
 448                         if (error == 0)
 449                                 numval = doi.doi_data_block_size;
 450                 }
 451                 break;
 452         }
 453         default:
 454                 /* Did not match these props, check in the dsl_dir */
 455                 error = get_dsl_dir_prop(ds, zfs_prop, &numval);
 456         }
 457         if (error != 0) {
 458                 kmem_free(strval, ZAP_MAXVALUELEN);
 459                 return (error);
 460         }
 461
 462         switch (prop_type) {
 463         case PROP_TYPE_NUMBER: {
 464                 (void) lua_pushnumber(state, numval);
 465                 break;
 466         }
 467         case PROP_TYPE_STRING: {
 468                 (void) lua_pushstring(state, strval);
 469                 break;
 470         }
 471         case PROP_TYPE_INDEX: {
 472                 const char *propval;
 473                 error = zfs_prop_index_to_string(zfs_prop, numval, &propval);
 474                 if (error != 0) {
 475                         kmem_free(strval, ZAP_MAXVALUELEN);
 476                         return (error);
 477                 }
 478                 (void) lua_pushstring(state, propval);
 479                 break;
 480         }
 481         }
 482         kmem_free(strval, ZAP_MAXVALUELEN);
 483
 484         /* Push the source to the stack */
 485         get_prop_src(state, setpoint, zfs_prop);
 486         return (0);
 487 }
 488
 489 /*
 490  * Look up a property and its source in the zap object. If the value is
 491  * present and successfully retrieved, push the value and source on the
 492  * lua stack and return 0. On failure, return a non-zero error value.
 493  */
 494 static int
 495 get_zap_prop(lua_State *state, dsl_dataset_t *ds, zfs_prop_t zfs_prop)
 496 {
 497         int error = 0;
 498         char setpoint[ZFS_MAX_DATASET_NAME_LEN];
 499         char *strval = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
 500         uint64_t numval;
 501         const char *prop_name = zfs_prop_to_name(zfs_prop);
 502         zprop_type_t prop_type = zfs_prop_get_type(zfs_prop);
 503
 504         if (prop_type == PROP_TYPE_STRING) {
 505                 /* Push value to lua stack */
 506                 error = dsl_prop_get_ds(ds, prop_name, 1,
 507                     ZAP_MAXVALUELEN, strval, setpoint);
 508                 if (error == 0)
 509                         (void) lua_pushstring(state, strval);
 510         } else {
 511                 error = dsl_prop_get_ds(ds, prop_name, sizeof (numval),
 512                     1, &numval, setpoint);
 513
 514                 /* Fill in temorary value for prop, if applicable */
 515                 (void) get_temporary_prop(ds, zfs_prop, &numval, setpoint);
 516
 517                 /* Push value to lua stack */
 518                 if (prop_type == PROP_TYPE_INDEX) {
 519                         const char *propval;
 520                         error = zfs_prop_index_to_string(zfs_prop, numval,
 521                             &propval);
 522                         if (error == 0)
 523                                 (void) lua_pushstring(state, propval);
 524                 } else {
 525                         if (error == 0)
 526                                 (void) lua_pushnumber(state, numval);
 527                 }
 528         }
 529         kmem_free(strval, ZAP_MAXVALUELEN);
 530         if (error == 0)
 531                 get_prop_src(state, setpoint, zfs_prop);
 532         return (error);
 533 }
 534
 535 /*
 536  * Determine whether property is valid for a given dataset
 537  */
 538 boolean_t
 539 prop_valid_for_ds(dsl_dataset_t *ds, zfs_prop_t zfs_prop)
 540 {
 541         int error;
 542         zfs_type_t zfs_type;
 543
 544         /* properties not supported */
 545         if ((zfs_prop == ZFS_PROP_ISCSIOPTIONS) ||
 546             (zfs_prop == ZFS_PROP_MOUNTED))
 547                 return (B_FALSE);
 548
 549         /* if we want the origin prop, ds must be a clone */
 550         if ((zfs_prop == ZFS_PROP_ORIGIN) && (!dsl_dir_is_clone(ds->ds_dir)))
 551                 return (B_FALSE);
 552
 553         error = get_objset_type(ds, &zfs_type);
 554         if (error != 0)
 555                 return (B_FALSE);
 556         return (zfs_prop_valid_for_type(zfs_prop, zfs_type));
 557 }
 558
 559 /*
 560  * Look up a given dataset property. On success return 2, the number of
 561  * values pushed to the lua stack (property value and source). On a fatal
 562  * error, longjmp. On a non fatal error push nothing.
 563  */
 564 static int
 565 zcp_get_system_prop(lua_State *state, dsl_pool_t *dp, const char *dataset_name,
 566     zfs_prop_t zfs_prop)
 567 {
 568         int error;
 569         /*
 570          * zcp_dataset_hold will either successfully return the requested
 571          * dataset or throw a lua error and longjmp out of the zfs.get_prop call
 572          * without returning.
 573          */
 574         dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
 575         if (ds == NULL)
 576                 return (1); /* not reached; zcp_dataset_hold() longjmp'd */
 577
 578         /* Check that the property is valid for the given dataset */
 579         const char *prop_name = zfs_prop_to_name(zfs_prop);
 580         if (!prop_valid_for_ds(ds, zfs_prop)) {
 581                 dsl_dataset_rele(ds, FTAG);
 582                 return (0);
 583         }
 584
 585         /* Check if the property can be accessed directly */
 586         error = get_special_prop(state, ds, dataset_name, zfs_prop);
 587         if (error == 0) {
 588                 dsl_dataset_rele(ds, FTAG);
 589                 /* The value and source have been pushed by get_special_prop */
 590                 return (2);
 591         }
 592         if (error != ENOENT) {
 593                 dsl_dataset_rele(ds, FTAG);
 594                 return (zcp_handle_error(state, dataset_name,
 595                     prop_name, error));
 596         }
 597
 598         /* If we were unable to find it, look in the zap object */
 599         error = get_zap_prop(state, ds, zfs_prop);
 600         dsl_dataset_rele(ds, FTAG);
 601         if (error != 0) {
 602                 return (zcp_handle_error(state, dataset_name,
 603                     prop_name, error));
 604         }
 605         /* The value and source have been pushed by get_zap_prop */
 606         return (2);
 607 }
 608
 609 static zfs_userquota_prop_t
 610 get_userquota_prop(const char *prop_name)
 611 {
 612         zfs_userquota_prop_t type;
 613         /* Figure out the property type ({user|group}{quota|used}) */
 614         for (type = 0; type < ZFS_NUM_USERQUOTA_PROPS; type++) {
 615                 if (strncmp(prop_name, zfs_userquota_prop_prefixes[type],
 616                     strlen(zfs_userquota_prop_prefixes[type])) == 0)
 617                         break;
 618         }
 619         return (type);
 620 }
 621
 622 #ifdef _KERNEL
 623 /*
 624  * Given the name of a zfs_userquota_prop, this function determines the
 625  * prop type as well as the numeric group/user ids based on the string
 626  * following the '@' in the property name. On success, returns 0. On failure,
 627  * returns a non-zero error.
 628  * 'domain' must be free'd by caller using strfree()
 629  */
 630 static int
 631 parse_userquota_prop(const char *prop_name, zfs_userquota_prop_t *type,
 632     char **domain, uint64_t *rid)
 633 {
 634         char *cp, *end, *domain_val;
 635
 636         *type = get_userquota_prop(prop_name);
 637         if (*type >= ZFS_NUM_USERQUOTA_PROPS)
 638                 return (EINVAL);
 639
 640         *rid = 0;
 641         cp = strchr(prop_name, '@') + 1;
 642         if (strncmp(cp, "S-1-", 4) == 0) {
 643                 /*
 644                  * It's a numeric SID (eg "S-1-234-567-89") and we want to
 645                  * seperate the domain id and the rid
 646                  */
 647                 int domain_len = strrchr(cp, '-') - cp;
 648                 domain_val = kmem_alloc(domain_len + 1, KM_SLEEP);
 649                 (void) strncpy(domain_val, cp, domain_len);
 650                 domain_val[domain_len] = '\0';
 651                 cp += domain_len + 1;
 652
 653                 (void) ddi_strtoll(cp, &end, 10, (longlong_t *)rid);
 654                 if (*end != '\0') {
 655                         strfree(domain_val);
 656                         return (EINVAL);
 657                 }
 658         } else {
 659                 /* It's only a user/group ID (eg "12345"), just get the rid */
 660                 domain_val = NULL;
 661                 (void) ddi_strtoll(cp, &end, 10, (longlong_t *)rid);
 662                 if (*end != '\0')
 663                         return (EINVAL);
 664         }
 665         *domain = domain_val;
 666         return (0);
 667 }
 668
 669 /*
 670  * Look up {user|group}{quota|used} property for given dataset. On success
 671  * push the value (quota or used amount) and the setpoint. On failure, push
 672  * a lua error.
 673  */
 674 static int
 675 zcp_get_userquota_prop(lua_State *state, dsl_pool_t *dp,
 676     const char *dataset_name, const char *prop_name)
 677 {
 678         zfsvfs_t *zfvp;
 679         zfsvfs_t *zfsvfs;
 680         int error;
 681         zfs_userquota_prop_t type;
 682         char *domain;
 683         uint64_t rid, value;
 684         objset_t *os;
 685
 686         dsl_dataset_t *ds = zcp_dataset_hold(state, dp, dataset_name, FTAG);
 687         if (ds == NULL)
 688                 return (1); /* not reached; zcp_dataset_hold() longjmp'd */
 689
 690         error = parse_userquota_prop(prop_name, &type, &domain, &rid);
 691         if (error == 0) {
 692                 error = dmu_objset_from_ds(ds, &os);
 693                 if (error == 0) {
 694                         zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
 695                         error = zfsvfs_create_impl(&zfvp, zfsvfs, os);
 696                         if (error == 0) {
 697                                 error = zfs_userspace_one(zfvp, type, domain,
 698                                     rid, &value);
 699                                 zfsvfs_free(zfvp);
 700                         }
 701                 }
 702                 if (domain != NULL)
 703                         strfree(domain);
 704         }
 705         dsl_dataset_rele(ds, FTAG);
 706
 707         if ((value == 0) && ((type == ZFS_PROP_USERQUOTA) ||
 708             (type == ZFS_PROP_GROUPQUOTA)))
 709                 error = ENOENT;
 710         if (error != 0) {
 711                 return (zcp_handle_error(state, dataset_name,
 712                     prop_name, error));
 713         }
 714
 715         (void) lua_pushnumber(state, value);
 716         (void) lua_pushstring(state, dataset_name);
 717         return (2);
 718 }
 719 #endif
 720
 721 /*
 722  * Determines the name of the snapshot referenced in the written property
 723  * name. Returns snapshot name in snap_name, a buffer that must be at least
 724  * as large as ZFS_MAX_DATASET_NAME_LEN
 725  */
 726 static void
 727 parse_written_prop(const char *dataset_name, const char *prop_name,
 728     char *snap_name)
 729 {
 730         ASSERT(zfs_prop_written(prop_name));
 731         const char *name = prop_name + ZFS_WRITTEN_PROP_PREFIX_LEN;
 732         if (strchr(name, '@') == NULL) {
 733                 (void) sprintf(snap_name, "%s@%s", dataset_name, name);
 734         } else {
 735                 (void) strcpy(snap_name, name);
 736         }
 737 }
 738
 739 /*
 740  * Look up written@ property for given dataset. On success
 741  * push the value and the setpoint. If error is fatal, we will
 742  * longjmp, otherwise push nothing.
 743  */
 744 static int
 745 zcp_get_written_prop(lua_State *state, dsl_pool_t *dp,
 746     const char *dataset_name, const char *prop_name)
 747 {
 748         char snap_name[ZFS_MAX_DATASET_NAME_LEN];
 749         uint64_t used, comp, uncomp;
 750         dsl_dataset_t *old;
 751         int error = 0;
 752
 753         parse_written_prop(dataset_name, prop_name, snap_name);
 754         dsl_dataset_t *new = zcp_dataset_hold(state, dp, dataset_name, FTAG);
 755         if (new == NULL)
 756                 return (1); /* not reached; zcp_dataset_hold() longjmp'd */
 757
 758         error = dsl_dataset_hold(dp, snap_name, FTAG, &old);
 759         if (error != 0) {
 760                 dsl_dataset_rele(new, FTAG);
 761                 return (zcp_dataset_hold_error(state, dp, snap_name,
 762                     error));
 763         }
 764         error = dsl_dataset_space_written(old, new,
 765             &used, &comp, &uncomp);
 766
 767         dsl_dataset_rele(old, FTAG);
 768         dsl_dataset_rele(new, FTAG);
 769
 770         if (error != 0) {
 771                 return (zcp_handle_error(state, dataset_name,
 772                     snap_name, error));
 773         }
 774         (void) lua_pushnumber(state, used);
 775         (void) lua_pushstring(state, dataset_name);
 776         return (2);
 777 }
 778
 779 static int zcp_get_prop(lua_State *state);
 780 static zcp_lib_info_t zcp_get_prop_info = {
 781         .name = "get_prop",
 782         .func = zcp_get_prop,
 783         .pargs = {
 784             { .za_name = "dataset", .za_lua_type = LUA_TSTRING},
 785             { .za_name = "property", .za_lua_type =  LUA_TSTRING},
 786             {NULL, 0}
 787         },
 788         .kwargs = {
 789             {NULL, 0}
 790         }
 791 };
 792
 793 static int
 794 zcp_get_prop(lua_State *state)
 795 {
 796         const char *dataset_name;
 797         const char *property_name;
 798         dsl_pool_t *dp = zcp_run_info(state)->zri_pool;
 799         zcp_lib_info_t *libinfo = &zcp_get_prop_info;
 800
 801         zcp_parse_args(state, libinfo->name, libinfo->pargs, libinfo->kwargs);
 802
 803         dataset_name = lua_tostring(state, 1);
 804         property_name = lua_tostring(state, 2);
 805
 806         /* User defined property */
 807         if (zfs_prop_user(property_name)) {
 808                 return (zcp_get_user_prop(state, dp,
 809                     dataset_name, property_name));
 810         }
 811         /* userspace property */
 812         if (zfs_prop_userquota(property_name)) {
 813 #ifdef _KERNEL
 814                 return (zcp_get_userquota_prop(state, dp,
 815                     dataset_name, property_name));
 816 #else
 817                 return (luaL_error(state,
 818                     "user quota properties only supported in kernel mode",
 819                     property_name));
 820 #endif
 821         }
 822         /* written@ property */
 823         if (zfs_prop_written(property_name)) {
 824                 return (zcp_get_written_prop(state, dp,
 825                     dataset_name, property_name));
 826         }
 827
 828         zfs_prop_t zfs_prop = zfs_name_to_prop(property_name);
 829         /* Valid system property */
 830         if (zfs_prop != ZPROP_INVAL) {
 831                 return (zcp_get_system_prop(state, dp, dataset_name,
 832                     zfs_prop));
 833         }
 834
 835         /* Invalid property name */
 836         return (luaL_error(state,
 837             "'%s' is not a valid property", property_name));
 838 }
 839
 840 int
 841 zcp_load_get_lib(lua_State *state)
 842 {
 843         lua_pushcclosure(state, zcp_get_prop_info.func, 0);
 844         lua_setfield(state, -2, zcp_get_prop_info.name);
 845
 846         return (1);
 847 }