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1// SPDX-License-Identifier: GPL-2.0-only2 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 25619#define DM_MAX_TARGETS 25620#define DM_MAX_STR_SIZE 409621#define DM_MAX_WAITFOR 25622 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="..." format34 * 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 field83 *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 entry104 * @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 which109 * 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 field158 * @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 entry185 * @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-colon190 * 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=" argument235 * @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 drivers270 */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");327