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(&dev->list);
71		for (i = 0; i < dev->dmi.target_count; i++) {
72			kfree(dev->table[i]);
73			kfree(dev->target_args_array[i]);
74		}
75		kfree(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(&field[i], ' ');
124		if (!field[i + 1])
125			return ERR_PTR(-EINVAL);
126	}
127	/* Delimit last field that can be terminated by comma */
128	next = str_field_delimit(&field[i], ',');
129
130	sp = kzalloc(sizeof(*sp), GFP_KERNEL);
131	if (!sp)
132		return ERR_PTR(-ENOMEM);
133	dev->table[n] = sp;
134
135	/* start_sector */
136	if (kstrtoull(field[0], 0, &sp->sector_start))
137		return ERR_PTR(-EINVAL);
138	/* num_sector */
139	if (kstrtoull(field[1], 0, &sp->length))
140		return ERR_PTR(-EINVAL);
141	/* target_type */
142	strscpy(sp->target_type, field[2], sizeof(sp->target_type));
143	if (dm_verify_target_type(sp->target_type)) {
144		DMERR("invalid type \"%s\"", sp->target_type);
145		return ERR_PTR(-EINVAL);
146	}
147	/* target_args */
148	dev->target_args_array[n] = kstrndup(field[3], DM_MAX_STR_SIZE,
149					     GFP_KERNEL);
150	if (!dev->target_args_array[n])
151		return ERR_PTR(-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, table_entry);
174		if (IS_ERR(table_entry)) {
175			DMERR("couldn't parse table");
176			return PTR_ERR(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(&field[i], ',');
203		if (!field[i+1])
204			return ERR_PTR(-EINVAL);
205	}
206	/* Delimit last field that can be delimited by semi-colon */
207	next = str_field_delimit(&field[i], ';');
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(field[2], 0, &dev->dmi.dev))
216			return ERR_PTR(-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(-EINVAL);
224	/* table */
225	if (dm_parse_table(dev, field[4]))
226		return ERR_PTR(-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 */
237static 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(sizeof(*dev), GFP_KERNEL);
246		if (!dev)
247			return -ENOMEM;
248		list_add_tail(&dev->list, 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, device);
257		if (IS_ERR(device)) {
258			DMERR("couldn't parse device");
259			return PTR_ERR(device);
260		}
261	}
262
263	return 0;
264}
265
266/**
267 * dm_init_init - parse "dm-mod.create=" argument and configure drivers
268 */
269static 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(create, DM_MAX_STR_SIZE, GFP_KERNEL);
284	if (!str)
285		return -ENOMEM;
286
287	r = dm_parse_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(waitfor[i], &dev))
300				fsleep(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(&dev->dmi, dev->table,
309				    dev->target_args_array))
310			break;
311	}
312out:
313	kfree(str);
314	dm_setup_cleanup(&devices);
315	return r;
316}
317
318late_initcall(dm_init_init);
319
320module_param(create, charp, 0);
321MODULE_PARM_DESC(create, "Create a mapped device in early boot");
322
323module_param_array(waitfor, charp, NULL, 0);
324MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables");
325