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
23static char *create;
24
25static 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
37struct 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
44static const char * const dm_allowed_targets[] __initconst = {
45 "crypt",
46 "delay",
47 "linear",
48 "snapshot-origin",
49 "striped",
50 "verity",
51};
52
53static 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
64static 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 */
88static 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 */
111static 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(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(sp->target_type, field[2], 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 */
162static 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 */
192static 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(dev->dmi.name, field[0], sizeof(dev->dmi.name));
211 /* uuid */
212 strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid));
213 /* minor */
214 if (strlen(field[2])) {
215 if (kstrtoull(s: field[2], base: 0, res: &dev->dmi.dev) ||
216 dev->dmi.dev >= (1 << MINORBITS))
217 return ERR_PTR(error: -EINVAL);
218 dev->dmi.dev = huge_encode_dev(dev: (dev_t)dev->dmi.dev);
219 dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG;
220 }
221 /* flags */
222 if (!strcmp(field[3], "ro"))
223 dev->dmi.flags |= DM_READONLY_FLAG;
224 else if (strcmp(field[3], "rw"))
225 return ERR_PTR(error: -EINVAL);
226 /* table */
227 if (dm_parse_table(dev, str: field[4]))
228 return ERR_PTR(error: -EINVAL);
229
230 return next;
231}
232
233/**
234 * dm_parse_devices - parse "dm-mod.create=" argument
235 * @devices: list of struct dm_device to store the parsed information.
236 * @str: the pointer to a string with the format:
237 * <device>[;<device>+]
238 */
239static int __init dm_parse_devices(struct list_head *devices, char *str)
240{
241 unsigned long ndev = 0;
242 struct dm_device *dev;
243 char *device = str;
244
245 DMDEBUG("parsing \"%s\"", str);
246 while (device) {
247 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
248 if (!dev)
249 return -ENOMEM;
250 list_add_tail(new: &dev->list, head: devices);
251
252 if (++ndev > DM_MAX_DEVICES) {
253 DMERR("too many devices %lu > %d",
254 ndev, DM_MAX_DEVICES);
255 return -EINVAL;
256 }
257
258 device = dm_parse_device_entry(dev, str: device);
259 if (IS_ERR(ptr: device)) {
260 DMERR("couldn't parse device");
261 return PTR_ERR(ptr: device);
262 }
263 }
264
265 return 0;
266}
267
268/**
269 * dm_init_init - parse "dm-mod.create=" argument and configure drivers
270 */
271static int __init dm_init_init(void)
272{
273 struct dm_device *dev;
274 LIST_HEAD(devices);
275 char *str;
276 int i, r;
277
278 if (!create)
279 return 0;
280
281 if (strlen(create) >= DM_MAX_STR_SIZE) {
282 DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE);
283 return -EINVAL;
284 }
285 str = kstrndup(s: create, DM_MAX_STR_SIZE, GFP_KERNEL);
286 if (!str)
287 return -ENOMEM;
288
289 r = dm_parse_devices(devices: &devices, str);
290 if (r)
291 goto out;
292
293 DMINFO("waiting for all devices to be available before creating mapped devices");
294 wait_for_device_probe();
295
296 for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
297 if (waitfor[i]) {
298 dev_t dev;
299
300 DMINFO("waiting for device %s ...", waitfor[i]);
301 while (early_lookup_bdev(pathname: waitfor[i], dev: &dev))
302 fsleep(usecs: 5000);
303 }
304 }
305
306 if (waitfor[0])
307 DMINFO("all devices available");
308
309 list_for_each_entry(dev, &devices, list) {
310 if (dm_early_create(dmi: &dev->dmi, spec_array: dev->table,
311 target_params_array: dev->target_args_array))
312 break;
313 }
314out:
315 kfree(objp: str);
316 dm_setup_cleanup(devices: &devices);
317 return r;
318}
319
320late_initcall(dm_init_init);
321
322module_param(create, charp, 0);
323MODULE_PARM_DESC(create, "Create a mapped device in early boot");
324
325module_param_array(waitfor, charp, NULL, 0);
326MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables");
327

source code of linux/drivers/md/dm-init.c