Commit | Line | Data |
---|---|---|
6bbc923d HK |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | /* | |
4 | * dm-init.c | |
5 | * Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org> | |
6 | * | |
7 | * This file is released under the GPLv2. | |
8 | */ | |
9 | ||
10 | #include <linux/ctype.h> | |
11 | #include <linux/device.h> | |
12 | #include <linux/device-mapper.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/list.h> | |
15 | #include <linux/moduleparam.h> | |
16 | ||
17 | #define DM_MSG_PREFIX "init" | |
18 | #define DM_MAX_DEVICES 256 | |
19 | #define DM_MAX_TARGETS 256 | |
20 | #define DM_MAX_STR_SIZE 4096 | |
21 | ||
22 | static char *create; | |
23 | ||
24 | /* | |
25 | * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] | |
26 | * Table format: <start_sector> <num_sectors> <target_type> <target_args> | |
27 | * | |
28 | * See Documentation/device-mapper/dm-init.txt for dm-mod.create="..." format | |
29 | * details. | |
30 | */ | |
31 | ||
32 | struct dm_device { | |
33 | struct dm_ioctl dmi; | |
34 | struct dm_target_spec *table[DM_MAX_TARGETS]; | |
35 | char *target_args_array[DM_MAX_TARGETS]; | |
36 | struct list_head list; | |
37 | }; | |
38 | ||
93fc9167 | 39 | const char * const dm_allowed_targets[] __initconst = { |
6bbc923d HK |
40 | "crypt", |
41 | "delay", | |
42 | "linear", | |
43 | "snapshot-origin", | |
44 | "striped", | |
45 | "verity", | |
46 | }; | |
47 | ||
48 | static int __init dm_verify_target_type(const char *target) | |
49 | { | |
50 | unsigned int i; | |
51 | ||
52 | for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) { | |
53 | if (!strcmp(dm_allowed_targets[i], target)) | |
54 | return 0; | |
55 | } | |
56 | return -EINVAL; | |
57 | } | |
58 | ||
59 | static void __init dm_setup_cleanup(struct list_head *devices) | |
60 | { | |
61 | struct dm_device *dev, *tmp; | |
62 | unsigned int i; | |
63 | ||
64 | list_for_each_entry_safe(dev, tmp, devices, list) { | |
65 | list_del(&dev->list); | |
66 | for (i = 0; i < dev->dmi.target_count; i++) { | |
67 | kfree(dev->table[i]); | |
68 | kfree(dev->target_args_array[i]); | |
69 | } | |
70 | kfree(dev); | |
71 | } | |
72 | } | |
73 | ||
74 | /** | |
75 | * str_field_delimit - delimit a string based on a separator char. | |
76 | * @str: the pointer to the string to delimit. | |
77 | * @separator: char that delimits the field | |
78 | * | |
79 | * Find a @separator and replace it by '\0'. | |
80 | * Remove leading and trailing spaces. | |
81 | * Return the remainder string after the @separator. | |
82 | */ | |
83 | static char __init *str_field_delimit(char **str, char separator) | |
84 | { | |
85 | char *s; | |
86 | ||
87 | /* TODO: add support for escaped characters */ | |
88 | *str = skip_spaces(*str); | |
89 | s = strchr(*str, separator); | |
90 | /* Delimit the field and remove trailing spaces */ | |
91 | if (s) | |
92 | *s = '\0'; | |
93 | *str = strim(*str); | |
94 | return s ? ++s : NULL; | |
95 | } | |
96 | ||
97 | /** | |
98 | * dm_parse_table_entry - parse a table entry | |
99 | * @dev: device to store the parsed information. | |
100 | * @str: the pointer to a string with the format: | |
101 | * <start_sector> <num_sectors> <target_type> <target_args>[, ...] | |
102 | * | |
103 | * Return the remainder string after the table entry, i.e, after the comma which | |
104 | * delimits the entry or NULL if reached the end of the string. | |
105 | */ | |
106 | static char __init *dm_parse_table_entry(struct dm_device *dev, char *str) | |
107 | { | |
108 | const unsigned int n = dev->dmi.target_count - 1; | |
109 | struct dm_target_spec *sp; | |
110 | unsigned int i; | |
111 | /* fields: */ | |
112 | char *field[4]; | |
113 | char *next; | |
114 | ||
115 | field[0] = str; | |
116 | /* Delimit first 3 fields that are separated by space */ | |
117 | for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { | |
118 | field[i + 1] = str_field_delimit(&field[i], ' '); | |
119 | if (!field[i + 1]) | |
120 | return ERR_PTR(-EINVAL); | |
121 | } | |
122 | /* Delimit last field that can be terminated by comma */ | |
123 | next = str_field_delimit(&field[i], ','); | |
124 | ||
125 | sp = kzalloc(sizeof(*sp), GFP_KERNEL); | |
126 | if (!sp) | |
127 | return ERR_PTR(-ENOMEM); | |
128 | dev->table[n] = sp; | |
129 | ||
130 | /* start_sector */ | |
131 | if (kstrtoull(field[0], 0, &sp->sector_start)) | |
132 | return ERR_PTR(-EINVAL); | |
133 | /* num_sector */ | |
134 | if (kstrtoull(field[1], 0, &sp->length)) | |
135 | return ERR_PTR(-EINVAL); | |
136 | /* target_type */ | |
137 | strscpy(sp->target_type, field[2], sizeof(sp->target_type)); | |
138 | if (dm_verify_target_type(sp->target_type)) { | |
139 | DMERR("invalid type \"%s\"", sp->target_type); | |
140 | return ERR_PTR(-EINVAL); | |
141 | } | |
142 | /* target_args */ | |
143 | dev->target_args_array[n] = kstrndup(field[3], GFP_KERNEL, | |
144 | DM_MAX_STR_SIZE); | |
145 | if (!dev->target_args_array[n]) | |
146 | return ERR_PTR(-ENOMEM); | |
147 | ||
148 | return next; | |
149 | } | |
150 | ||
151 | /** | |
152 | * dm_parse_table - parse "dm-mod.create=" table field | |
153 | * @dev: device to store the parsed information. | |
154 | * @str: the pointer to a string with the format: | |
155 | * <table>[,<table>+] | |
156 | */ | |
157 | static int __init dm_parse_table(struct dm_device *dev, char *str) | |
158 | { | |
159 | char *table_entry = str; | |
160 | ||
161 | while (table_entry) { | |
162 | DMDEBUG("parsing table \"%s\"", str); | |
163 | if (++dev->dmi.target_count >= DM_MAX_TARGETS) { | |
164 | DMERR("too many targets %u > %d", | |
165 | dev->dmi.target_count, DM_MAX_TARGETS); | |
166 | return -EINVAL; | |
167 | } | |
168 | table_entry = dm_parse_table_entry(dev, table_entry); | |
169 | if (IS_ERR(table_entry)) { | |
170 | DMERR("couldn't parse table"); | |
171 | return PTR_ERR(table_entry); | |
172 | } | |
173 | } | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | /** | |
179 | * dm_parse_device_entry - parse a device entry | |
180 | * @dev: device to store the parsed information. | |
181 | * @str: the pointer to a string with the format: | |
182 | * name,uuid,minor,flags,table[; ...] | |
183 | * | |
184 | * Return the remainder string after the table entry, i.e, after the semi-colon | |
185 | * which delimits the entry or NULL if reached the end of the string. | |
186 | */ | |
187 | static char __init *dm_parse_device_entry(struct dm_device *dev, char *str) | |
188 | { | |
189 | /* There are 5 fields: name,uuid,minor,flags,table; */ | |
190 | char *field[5]; | |
191 | unsigned int i; | |
192 | char *next; | |
193 | ||
194 | field[0] = str; | |
195 | /* Delimit first 4 fields that are separated by comma */ | |
196 | for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { | |
197 | field[i+1] = str_field_delimit(&field[i], ','); | |
198 | if (!field[i+1]) | |
199 | return ERR_PTR(-EINVAL); | |
200 | } | |
201 | /* Delimit last field that can be delimited by semi-colon */ | |
202 | next = str_field_delimit(&field[i], ';'); | |
203 | ||
204 | /* name */ | |
205 | strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name)); | |
206 | /* uuid */ | |
207 | strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid)); | |
208 | /* minor */ | |
209 | if (strlen(field[2])) { | |
210 | if (kstrtoull(field[2], 0, &dev->dmi.dev)) | |
211 | return ERR_PTR(-EINVAL); | |
212 | dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG; | |
213 | } | |
214 | /* flags */ | |
215 | if (!strcmp(field[3], "ro")) | |
216 | dev->dmi.flags |= DM_READONLY_FLAG; | |
217 | else if (strcmp(field[3], "rw")) | |
218 | return ERR_PTR(-EINVAL); | |
219 | /* table */ | |
220 | if (dm_parse_table(dev, field[4])) | |
221 | return ERR_PTR(-EINVAL); | |
222 | ||
223 | return next; | |
224 | } | |
225 | ||
226 | /** | |
227 | * dm_parse_devices - parse "dm-mod.create=" argument | |
228 | * @devices: list of struct dm_device to store the parsed information. | |
229 | * @str: the pointer to a string with the format: | |
230 | * <device>[;<device>+] | |
231 | */ | |
232 | static int __init dm_parse_devices(struct list_head *devices, char *str) | |
233 | { | |
234 | unsigned long ndev = 0; | |
235 | struct dm_device *dev; | |
236 | char *device = str; | |
237 | ||
238 | DMDEBUG("parsing \"%s\"", str); | |
239 | while (device) { | |
240 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
241 | if (!dev) | |
242 | return -ENOMEM; | |
243 | list_add_tail(&dev->list, devices); | |
244 | ||
245 | if (++ndev >= DM_MAX_DEVICES) { | |
246 | DMERR("too many targets %u > %d", | |
247 | dev->dmi.target_count, DM_MAX_TARGETS); | |
248 | return -EINVAL; | |
249 | } | |
250 | ||
251 | device = dm_parse_device_entry(dev, device); | |
252 | if (IS_ERR(device)) { | |
253 | DMERR("couldn't parse device"); | |
254 | return PTR_ERR(device); | |
255 | } | |
256 | } | |
257 | ||
258 | return 0; | |
259 | } | |
260 | ||
261 | /** | |
262 | * dm_init_init - parse "dm-mod.create=" argument and configure drivers | |
263 | */ | |
264 | static int __init dm_init_init(void) | |
265 | { | |
266 | struct dm_device *dev; | |
267 | LIST_HEAD(devices); | |
268 | char *str; | |
269 | int r; | |
270 | ||
271 | if (!create) | |
272 | return 0; | |
273 | ||
274 | if (strlen(create) >= DM_MAX_STR_SIZE) { | |
275 | DMERR("Argument is too big. Limit is %d\n", DM_MAX_STR_SIZE); | |
276 | return -EINVAL; | |
277 | } | |
278 | str = kstrndup(create, GFP_KERNEL, DM_MAX_STR_SIZE); | |
279 | if (!str) | |
280 | return -ENOMEM; | |
281 | ||
282 | r = dm_parse_devices(&devices, str); | |
283 | if (r) | |
284 | goto out; | |
285 | ||
286 | DMINFO("waiting for all devices to be available before creating mapped devices\n"); | |
287 | wait_for_device_probe(); | |
288 | ||
289 | list_for_each_entry(dev, &devices, list) { | |
290 | if (dm_early_create(&dev->dmi, dev->table, | |
291 | dev->target_args_array)) | |
292 | break; | |
293 | } | |
294 | out: | |
295 | kfree(str); | |
296 | dm_setup_cleanup(&devices); | |
297 | return r; | |
298 | } | |
299 | ||
300 | late_initcall(dm_init_init); | |
301 | ||
302 | module_param(create, charp, 0); | |
303 | MODULE_PARM_DESC(create, "Create a mapped device in early boot"); |