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  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25  */
26 
27 #ifdef _KERNEL
28 #include <sys/systm.h>
29 #else
30 #include <errno.h>
31 #include <string.h>
32 #endif
33 #include <sys/debug.h>
34 #include <sys/fs/zfs.h>
35 #include <sys/inttypes.h>
36 #include <sys/types.h>
37 #include "zfeature_common.h"
38 
39 /*
40  * Set to disable all feature checks while opening pools, allowing pools with
41  * unsupported features to be opened. Set for testing only.
42  */
43 boolean_t zfeature_checks_disable = B_FALSE;
44 
45 zfeature_info_t spa_feature_table[SPA_FEATURES];
46 
47 /*
48  * Valid characters for feature guids. This list is mainly for aesthetic
49  * purposes and could be expanded in the future. There are different allowed
50  * characters in the guids reverse dns portion (before the colon) and its
51  * short name (after the colon).
52  */
53 static int
54 valid_char(char c, boolean_t after_colon)
55 {
56 	return ((c >= 'a' && c <= 'z') ||
57 	    (c >= '0' && c <= '9') ||
58 	    c == (after_colon ? '_' : '.'));
59 }
60 
61 /*
62  * Every feature guid must contain exactly one colon which separates a reverse
63  * dns organization name from the feature's "short" name (e.g.
64  * "com.company:feature_name").
65  */
66 boolean_t
67 zfeature_is_valid_guid(const char *name)
68 {
69 	int i;
70 	boolean_t has_colon = B_FALSE;
71 
72 	i = 0;
73 	while (name[i] != '\0') {
74 		char c = name[i++];
75 		if (c == ':') {
76 			if (has_colon)
77 				return (B_FALSE);
78 			has_colon = B_TRUE;
79 			continue;
80 		}
81 		if (!valid_char(c, has_colon))
82 			return (B_FALSE);
83 	}
84 
85 	return (has_colon);
86 }
87 
88 boolean_t
89 zfeature_is_supported(const char *guid)
90 {
91 	if (zfeature_checks_disable)
92 		return (B_TRUE);
93 
94 	return (0 == zfeature_lookup_guid(guid, NULL));
95 }
96 
97 int
98 zfeature_lookup_guid(const char *guid, zfeature_info_t **res)
99 {
100 	for (int i = 0; i < SPA_FEATURES; i++) {
101 		zfeature_info_t *feature = &spa_feature_table[i];
102 		if (strcmp(guid, feature->fi_guid) == 0) {
103 			if (res != NULL)
104 				*res = feature;
105 			return (0);
106 		}
107 	}
108 
109 	return (ENOENT);
110 }
111 
112 int
113 zfeature_lookup_name(const char *name, zfeature_info_t **res)
114 {
115 	for (int i = 0; i < SPA_FEATURES; i++) {
116 		zfeature_info_t *feature = &spa_feature_table[i];
117 		if (strcmp(name, feature->fi_uname) == 0) {
118 			if (res != NULL)
119 				*res = feature;
120 			return (0);
121 		}
122 	}
123 
124 	return (ENOENT);
125 }
126 
127 static void
128 zfeature_register(int fid, const char *guid, const char *name, const char *desc,
129     boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
130 {
131 	zfeature_info_t *feature = &spa_feature_table[fid];
132 	static zfeature_info_t *nodeps[] = { NULL };
133 
134 	ASSERT(name != NULL);
135 	ASSERT(desc != NULL);
136 	ASSERT(!readonly || !mos);
137 	ASSERT3U(fid, <, SPA_FEATURES);
138 	ASSERT(zfeature_is_valid_guid(guid));
139 
140 	if (deps == NULL)
141 		deps = nodeps;
142 
143 	feature->fi_guid = guid;
144 	feature->fi_uname = name;
145 	feature->fi_desc = desc;
146 	feature->fi_can_readonly = readonly;
147 	feature->fi_mos = mos;
148 	feature->fi_depends = deps;
149 }
150 
151 void
152 zpool_feature_init(void)
153 {
154 	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
155 	    "com.delphix:async_destroy", "async_destroy",
156 	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
157 	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
158 	    "com.delphix:empty_bpobj", "empty_bpobj",
159 	    "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
160 	zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
161 	    "org.illumos:lz4_compress", "lz4_compress",
162 	    "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
163 }
164