1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright (c) 2012 by Delphix. All rights reserved.
  24  */
  25 
  26 #ifdef _KERNEL
  27 #include <sys/systm.h>
  28 #else
  29 #include <errno.h>
  30 #include <string.h>
  31 #endif
  32 #include <sys/debug.h>
  33 #include <sys/fs/zfs.h>
  34 #include <sys/inttypes.h>
  35 #include <sys/types.h>
  36 #include "zfeature_common.h"
  37 
  38 /*
  39  * Set to disable all feature checks while opening pools, allowing pools with
  40  * unsupported features to be opened. Set for testing only.
  41  */
  42 boolean_t zfeature_checks_disable = B_FALSE;
  43 
  44 zfeature_info_t spa_feature_table[SPA_FEATURES];
  45 
  46 /*
  47  * Valid characters for feature guids. This list is mainly for aesthetic
  48  * purposes and could be expanded in the future. There are different allowed
  49  * characters in the guids reverse dns portion (before the colon) and its
  50  * short name (after the colon).
  51  */
  52 static int
  53 valid_char(char c, boolean_t after_colon)
  54 {
  55         return ((c >= 'a' && c <= 'z') ||
  56             (c >= '0' && c <= '9') ||
  57             c == (after_colon ? '_' : '.'));
  58 }
  59 
  60 /*
  61  * Every feature guid must contain exactly one colon which separates a reverse
  62  * dns organization name from the feature's "short" name (e.g.
  63  * "com.company:feature_name").
  64  */
  65 boolean_t
  66 zfeature_is_valid_guid(const char *name)
  67 {
  68         int i;
  69         boolean_t has_colon = B_FALSE;
  70 
  71         i = 0;
  72         while (name[i] != '\0') {
  73                 char c = name[i++];
  74                 if (c == ':') {
  75                         if (has_colon)
  76                                 return (B_FALSE);
  77                         has_colon = B_TRUE;
  78                         continue;
  79                 }
  80                 if (!valid_char(c, has_colon))
  81                         return (B_FALSE);
  82         }
  83 
  84         return (has_colon);
  85 }
  86 
  87 boolean_t
  88 zfeature_is_supported(const char *guid)
  89 {
  90         if (zfeature_checks_disable)
  91                 return (B_TRUE);
  92 
  93         return (0 == zfeature_lookup_guid(guid, NULL));
  94 }
  95 
  96 int
  97 zfeature_lookup_guid(const char *guid, zfeature_info_t **res)
  98 {
  99         for (int i = 0; i < SPA_FEATURES; i++) {
 100                 zfeature_info_t *feature = &spa_feature_table[i];
 101                 if (strcmp(guid, feature->fi_guid) == 0) {
 102                         if (res != NULL)
 103                                 *res = feature;
 104                         return (0);
 105                 }
 106         }
 107 
 108         return (ENOENT);
 109 }
 110 
 111 int
 112 zfeature_lookup_name(const char *name, zfeature_info_t **res)
 113 {
 114         for (int i = 0; i < SPA_FEATURES; i++) {
 115                 zfeature_info_t *feature = &spa_feature_table[i];
 116                 if (strcmp(name, feature->fi_uname) == 0) {
 117                         if (res != NULL)
 118                                 *res = feature;
 119                         return (0);
 120                 }
 121         }
 122 
 123         return (ENOENT);
 124 }
 125 
 126 static void
 127 zfeature_register(int fid, const char *guid, const char *name, const char *desc,
 128     boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
 129 {
 130         zfeature_info_t *feature = &spa_feature_table[fid];
 131         static zfeature_info_t *nodeps[] = { NULL };
 132 
 133         ASSERT(name != NULL);
 134         ASSERT(desc != NULL);
 135         ASSERT(!readonly || !mos);
 136         ASSERT3U(fid, <, SPA_FEATURES);
 137         ASSERT(zfeature_is_valid_guid(guid));
 138 
 139         if (deps == NULL)
 140                 deps = nodeps;
 141 
 142         feature->fi_guid = guid;
 143         feature->fi_uname = name;
 144         feature->fi_desc = desc;
 145         feature->fi_can_readonly = readonly;
 146         feature->fi_mos = mos;
 147         feature->fi_depends = deps;
 148 }
 149 
 150 void
 151 zpool_feature_init(void)
 152 {
 153         zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
 154             "com.delphix:async_destroy", "async_destroy",
 155             "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
 156 }