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
22static 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
32struct 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
39const char *dm_allowed_targets[] __initconst = {
40 "crypt",
41 "delay",
42 "linear",
43 "snapshot-origin",
44 "striped",
45 "verity",
46};
47
48static 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
59static 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 */
83static 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 */
106static 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 */
157static 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 */
187static 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 */
232static 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 */
264static 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 }
294out:
295 kfree(str);
296 dm_setup_cleanup(&devices);
297 return r;
298}
299
300late_initcall(dm_init_init);
301
302module_param(create, charp, 0);
303MODULE_PARM_DESC(create, "Create a mapped device in early boot");
304