1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | |
3 | /* |
4 | * Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org> |
5 | * |
6 | * This file is released under the GPLv2. |
7 | */ |
8 | |
9 | #include <linux/ctype.h> |
10 | #include <linux/delay.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 | #define DM_MAX_WAITFOR 256 |
22 | |
23 | static char *create; |
24 | |
25 | static char *waitfor[DM_MAX_WAITFOR]; |
26 | |
27 | /* |
28 | * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] |
29 | * Table format: <start_sector> <num_sectors> <target_type> <target_args> |
30 | * Block devices to wait for to become available before setting up tables: |
31 | * dm-mod.waitfor=<device1>[,..,<deviceN>] |
32 | * |
33 | * See Documentation/admin-guide/device-mapper/dm-init.rst for dm-mod.create="..." format |
34 | * details. |
35 | */ |
36 | |
37 | struct dm_device { |
38 | struct dm_ioctl dmi; |
39 | struct dm_target_spec *table[DM_MAX_TARGETS]; |
40 | char *target_args_array[DM_MAX_TARGETS]; |
41 | struct list_head list; |
42 | }; |
43 | |
44 | static const char * const dm_allowed_targets[] __initconst = { |
45 | "crypt" , |
46 | "delay" , |
47 | "linear" , |
48 | "snapshot-origin" , |
49 | "striped" , |
50 | "verity" , |
51 | }; |
52 | |
53 | static int __init dm_verify_target_type(const char *target) |
54 | { |
55 | unsigned int i; |
56 | |
57 | for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) { |
58 | if (!strcmp(dm_allowed_targets[i], target)) |
59 | return 0; |
60 | } |
61 | return -EINVAL; |
62 | } |
63 | |
64 | static void __init dm_setup_cleanup(struct list_head *devices) |
65 | { |
66 | struct dm_device *dev, *tmp; |
67 | unsigned int i; |
68 | |
69 | list_for_each_entry_safe(dev, tmp, devices, list) { |
70 | list_del(entry: &dev->list); |
71 | for (i = 0; i < dev->dmi.target_count; i++) { |
72 | kfree(objp: dev->table[i]); |
73 | kfree(objp: dev->target_args_array[i]); |
74 | } |
75 | kfree(objp: dev); |
76 | } |
77 | } |
78 | |
79 | /** |
80 | * str_field_delimit - delimit a string based on a separator char. |
81 | * @str: the pointer to the string to delimit. |
82 | * @separator: char that delimits the field |
83 | * |
84 | * Find a @separator and replace it by '\0'. |
85 | * Remove leading and trailing spaces. |
86 | * Return the remainder string after the @separator. |
87 | */ |
88 | static char __init *str_field_delimit(char **str, char separator) |
89 | { |
90 | char *s; |
91 | |
92 | /* TODO: add support for escaped characters */ |
93 | *str = skip_spaces(*str); |
94 | s = strchr(*str, separator); |
95 | /* Delimit the field and remove trailing spaces */ |
96 | if (s) |
97 | *s = '\0'; |
98 | *str = strim(*str); |
99 | return s ? ++s : NULL; |
100 | } |
101 | |
102 | /** |
103 | * dm_parse_table_entry - parse a table entry |
104 | * @dev: device to store the parsed information. |
105 | * @str: the pointer to a string with the format: |
106 | * <start_sector> <num_sectors> <target_type> <target_args>[, ...] |
107 | * |
108 | * Return the remainder string after the table entry, i.e, after the comma which |
109 | * delimits the entry or NULL if reached the end of the string. |
110 | */ |
111 | static char __init *dm_parse_table_entry(struct dm_device *dev, char *str) |
112 | { |
113 | const unsigned int n = dev->dmi.target_count - 1; |
114 | struct dm_target_spec *sp; |
115 | unsigned int i; |
116 | /* fields: */ |
117 | char *field[4]; |
118 | char *next; |
119 | |
120 | field[0] = str; |
121 | /* Delimit first 3 fields that are separated by space */ |
122 | for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { |
123 | field[i + 1] = str_field_delimit(str: &field[i], separator: ' '); |
124 | if (!field[i + 1]) |
125 | return ERR_PTR(error: -EINVAL); |
126 | } |
127 | /* Delimit last field that can be terminated by comma */ |
128 | next = str_field_delimit(str: &field[i], separator: ','); |
129 | |
130 | sp = kzalloc(size: sizeof(*sp), GFP_KERNEL); |
131 | if (!sp) |
132 | return ERR_PTR(error: -ENOMEM); |
133 | dev->table[n] = sp; |
134 | |
135 | /* start_sector */ |
136 | if (kstrtoull(s: field[0], base: 0, res: &sp->sector_start)) |
137 | return ERR_PTR(error: -EINVAL); |
138 | /* num_sector */ |
139 | if (kstrtoull(s: field[1], base: 0, res: &sp->length)) |
140 | return ERR_PTR(error: -EINVAL); |
141 | /* target_type */ |
142 | strscpy(p: sp->target_type, q: field[2], size: sizeof(sp->target_type)); |
143 | if (dm_verify_target_type(target: sp->target_type)) { |
144 | DMERR("invalid type \"%s\"" , sp->target_type); |
145 | return ERR_PTR(error: -EINVAL); |
146 | } |
147 | /* target_args */ |
148 | dev->target_args_array[n] = kstrndup(s: field[3], DM_MAX_STR_SIZE, |
149 | GFP_KERNEL); |
150 | if (!dev->target_args_array[n]) |
151 | return ERR_PTR(error: -ENOMEM); |
152 | |
153 | return next; |
154 | } |
155 | |
156 | /** |
157 | * dm_parse_table - parse "dm-mod.create=" table field |
158 | * @dev: device to store the parsed information. |
159 | * @str: the pointer to a string with the format: |
160 | * <table>[,<table>+] |
161 | */ |
162 | static int __init dm_parse_table(struct dm_device *dev, char *str) |
163 | { |
164 | char *table_entry = str; |
165 | |
166 | while (table_entry) { |
167 | DMDEBUG("parsing table \"%s\"" , str); |
168 | if (++dev->dmi.target_count > DM_MAX_TARGETS) { |
169 | DMERR("too many targets %u > %d" , |
170 | dev->dmi.target_count, DM_MAX_TARGETS); |
171 | return -EINVAL; |
172 | } |
173 | table_entry = dm_parse_table_entry(dev, str: table_entry); |
174 | if (IS_ERR(ptr: table_entry)) { |
175 | DMERR("couldn't parse table" ); |
176 | return PTR_ERR(ptr: table_entry); |
177 | } |
178 | } |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | /** |
184 | * dm_parse_device_entry - parse a device entry |
185 | * @dev: device to store the parsed information. |
186 | * @str: the pointer to a string with the format: |
187 | * name,uuid,minor,flags,table[; ...] |
188 | * |
189 | * Return the remainder string after the table entry, i.e, after the semi-colon |
190 | * which delimits the entry or NULL if reached the end of the string. |
191 | */ |
192 | static char __init *dm_parse_device_entry(struct dm_device *dev, char *str) |
193 | { |
194 | /* There are 5 fields: name,uuid,minor,flags,table; */ |
195 | char *field[5]; |
196 | unsigned int i; |
197 | char *next; |
198 | |
199 | field[0] = str; |
200 | /* Delimit first 4 fields that are separated by comma */ |
201 | for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { |
202 | field[i+1] = str_field_delimit(str: &field[i], separator: ','); |
203 | if (!field[i+1]) |
204 | return ERR_PTR(error: -EINVAL); |
205 | } |
206 | /* Delimit last field that can be delimited by semi-colon */ |
207 | next = str_field_delimit(str: &field[i], separator: ';'); |
208 | |
209 | /* name */ |
210 | strscpy(p: dev->dmi.name, q: field[0], size: sizeof(dev->dmi.name)); |
211 | /* uuid */ |
212 | strscpy(p: dev->dmi.uuid, q: field[1], size: sizeof(dev->dmi.uuid)); |
213 | /* minor */ |
214 | if (strlen(field[2])) { |
215 | if (kstrtoull(s: field[2], base: 0, res: &dev->dmi.dev)) |
216 | return ERR_PTR(error: -EINVAL); |
217 | dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG; |
218 | } |
219 | /* flags */ |
220 | if (!strcmp(field[3], "ro" )) |
221 | dev->dmi.flags |= DM_READONLY_FLAG; |
222 | else if (strcmp(field[3], "rw" )) |
223 | return ERR_PTR(error: -EINVAL); |
224 | /* table */ |
225 | if (dm_parse_table(dev, str: field[4])) |
226 | return ERR_PTR(error: -EINVAL); |
227 | |
228 | return next; |
229 | } |
230 | |
231 | /** |
232 | * dm_parse_devices - parse "dm-mod.create=" argument |
233 | * @devices: list of struct dm_device to store the parsed information. |
234 | * @str: the pointer to a string with the format: |
235 | * <device>[;<device>+] |
236 | */ |
237 | static int __init dm_parse_devices(struct list_head *devices, char *str) |
238 | { |
239 | unsigned long ndev = 0; |
240 | struct dm_device *dev; |
241 | char *device = str; |
242 | |
243 | DMDEBUG("parsing \"%s\"" , str); |
244 | while (device) { |
245 | dev = kzalloc(size: sizeof(*dev), GFP_KERNEL); |
246 | if (!dev) |
247 | return -ENOMEM; |
248 | list_add_tail(new: &dev->list, head: devices); |
249 | |
250 | if (++ndev > DM_MAX_DEVICES) { |
251 | DMERR("too many devices %lu > %d" , |
252 | ndev, DM_MAX_DEVICES); |
253 | return -EINVAL; |
254 | } |
255 | |
256 | device = dm_parse_device_entry(dev, str: device); |
257 | if (IS_ERR(ptr: device)) { |
258 | DMERR("couldn't parse device" ); |
259 | return PTR_ERR(ptr: device); |
260 | } |
261 | } |
262 | |
263 | return 0; |
264 | } |
265 | |
266 | /** |
267 | * dm_init_init - parse "dm-mod.create=" argument and configure drivers |
268 | */ |
269 | static int __init dm_init_init(void) |
270 | { |
271 | struct dm_device *dev; |
272 | LIST_HEAD(devices); |
273 | char *str; |
274 | int i, r; |
275 | |
276 | if (!create) |
277 | return 0; |
278 | |
279 | if (strlen(create) >= DM_MAX_STR_SIZE) { |
280 | DMERR("Argument is too big. Limit is %d" , DM_MAX_STR_SIZE); |
281 | return -EINVAL; |
282 | } |
283 | str = kstrndup(s: create, DM_MAX_STR_SIZE, GFP_KERNEL); |
284 | if (!str) |
285 | return -ENOMEM; |
286 | |
287 | r = dm_parse_devices(devices: &devices, str); |
288 | if (r) |
289 | goto out; |
290 | |
291 | DMINFO("waiting for all devices to be available before creating mapped devices" ); |
292 | wait_for_device_probe(); |
293 | |
294 | for (i = 0; i < ARRAY_SIZE(waitfor); i++) { |
295 | if (waitfor[i]) { |
296 | dev_t dev; |
297 | |
298 | DMINFO("waiting for device %s ..." , waitfor[i]); |
299 | while (early_lookup_bdev(pathname: waitfor[i], dev: &dev)) |
300 | fsleep(usecs: 5000); |
301 | } |
302 | } |
303 | |
304 | if (waitfor[0]) |
305 | DMINFO("all devices available" ); |
306 | |
307 | list_for_each_entry(dev, &devices, list) { |
308 | if (dm_early_create(dmi: &dev->dmi, spec_array: dev->table, |
309 | target_params_array: dev->target_args_array)) |
310 | break; |
311 | } |
312 | out: |
313 | kfree(objp: str); |
314 | dm_setup_cleanup(devices: &devices); |
315 | return r; |
316 | } |
317 | |
318 | late_initcall(dm_init_init); |
319 | |
320 | module_param(create, charp, 0); |
321 | MODULE_PARM_DESC(create, "Create a mapped device in early boot" ); |
322 | |
323 | module_param_array(waitfor, charp, NULL, 0); |
324 | MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables" ); |
325 | |