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		    dev->dmi.dev >= (1 << MINORBITS))
217			return ERR_PTR(-EINVAL);
218		dev->dmi.dev = huge_encode_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(-EINVAL);
226	/* table */
227	if (dm_parse_table(dev, field[4]))
228		return ERR_PTR(-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(&dev->list, 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, device);
259		if (IS_ERR(device)) {
260			DMERR("couldn't parse device");
261			return PTR_ERR(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(create, DM_MAX_STR_SIZE, GFP_KERNEL);
286	if (!str)
287		return -ENOMEM;
288
289	r = dm_parse_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(waitfor[i], &dev))
302				fsleep(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(&dev->dmi, dev->table,
311				    dev->target_args_array))
312			break;
313	}
314out:
315	kfree(str);
316	dm_setup_cleanup(&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");