| // SPDX-License-Identifier: GPL-2.0 |
| |
| /* |
| * dm-init.c |
| * Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org> |
| * |
| * This file is released under the GPLv2. |
| */ |
| |
| #include <linux/ctype.h> |
| #include <linux/device.h> |
| #include <linux/device-mapper.h> |
| #include <linux/init.h> |
| #include <linux/list.h> |
| #include <linux/moduleparam.h> |
| |
| #define DM_MSG_PREFIX "init" |
| #define DM_MAX_DEVICES 256 |
| #define DM_MAX_TARGETS 256 |
| #define DM_MAX_STR_SIZE 4096 |
| |
| static char *create; |
| |
| /* |
| * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] |
| * Table format: <start_sector> <num_sectors> <target_type> <target_args> |
| * |
| * See Documentation/device-mapper/dm-init.txt for dm-mod.create="..." format |
| * details. |
| */ |
| |
| struct dm_device { |
| struct dm_ioctl dmi; |
| struct dm_target_spec *table[DM_MAX_TARGETS]; |
| char *target_args_array[DM_MAX_TARGETS]; |
| struct list_head list; |
| }; |
| |
| const char * const dm_allowed_targets[] __initconst = { |
| "crypt", |
| "delay", |
| "linear", |
| "snapshot-origin", |
| "striped", |
| "verity", |
| }; |
| |
| static int __init dm_verify_target_type(const char *target) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) { |
| if (!strcmp(dm_allowed_targets[i], target)) |
| return 0; |
| } |
| return -EINVAL; |
| } |
| |
| static void __init dm_setup_cleanup(struct list_head *devices) |
| { |
| struct dm_device *dev, *tmp; |
| unsigned int i; |
| |
| list_for_each_entry_safe(dev, tmp, devices, list) { |
| list_del(&dev->list); |
| for (i = 0; i < dev->dmi.target_count; i++) { |
| kfree(dev->table[i]); |
| kfree(dev->target_args_array[i]); |
| } |
| kfree(dev); |
| } |
| } |
| |
| /** |
| * str_field_delimit - delimit a string based on a separator char. |
| * @str: the pointer to the string to delimit. |
| * @separator: char that delimits the field |
| * |
| * Find a @separator and replace it by '\0'. |
| * Remove leading and trailing spaces. |
| * Return the remainder string after the @separator. |
| */ |
| static char __init *str_field_delimit(char **str, char separator) |
| { |
| char *s; |
| |
| /* TODO: add support for escaped characters */ |
| *str = skip_spaces(*str); |
| s = strchr(*str, separator); |
| /* Delimit the field and remove trailing spaces */ |
| if (s) |
| *s = '\0'; |
| *str = strim(*str); |
| return s ? ++s : NULL; |
| } |
| |
| /** |
| * dm_parse_table_entry - parse a table entry |
| * @dev: device to store the parsed information. |
| * @str: the pointer to a string with the format: |
| * <start_sector> <num_sectors> <target_type> <target_args>[, ...] |
| * |
| * Return the remainder string after the table entry, i.e, after the comma which |
| * delimits the entry or NULL if reached the end of the string. |
| */ |
| static char __init *dm_parse_table_entry(struct dm_device *dev, char *str) |
| { |
| const unsigned int n = dev->dmi.target_count - 1; |
| struct dm_target_spec *sp; |
| unsigned int i; |
| /* fields: */ |
| char *field[4]; |
| char *next; |
| |
| field[0] = str; |
| /* Delimit first 3 fields that are separated by space */ |
| for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { |
| field[i + 1] = str_field_delimit(&field[i], ' '); |
| if (!field[i + 1]) |
| return ERR_PTR(-EINVAL); |
| } |
| /* Delimit last field that can be terminated by comma */ |
| next = str_field_delimit(&field[i], ','); |
| |
| sp = kzalloc(sizeof(*sp), GFP_KERNEL); |
| if (!sp) |
| return ERR_PTR(-ENOMEM); |
| dev->table[n] = sp; |
| |
| /* start_sector */ |
| if (kstrtoull(field[0], 0, &sp->sector_start)) |
| return ERR_PTR(-EINVAL); |
| /* num_sector */ |
| if (kstrtoull(field[1], 0, &sp->length)) |
| return ERR_PTR(-EINVAL); |
| /* target_type */ |
| strscpy(sp->target_type, field[2], sizeof(sp->target_type)); |
| if (dm_verify_target_type(sp->target_type)) { |
| DMERR("invalid type \"%s\"", sp->target_type); |
| return ERR_PTR(-EINVAL); |
| } |
| /* target_args */ |
| dev->target_args_array[n] = kstrndup(field[3], GFP_KERNEL, |
| DM_MAX_STR_SIZE); |
| if (!dev->target_args_array[n]) |
| return ERR_PTR(-ENOMEM); |
| |
| return next; |
| } |
| |
| /** |
| * dm_parse_table - parse "dm-mod.create=" table field |
| * @dev: device to store the parsed information. |
| * @str: the pointer to a string with the format: |
| * <table>[,<table>+] |
| */ |
| static int __init dm_parse_table(struct dm_device *dev, char *str) |
| { |
| char *table_entry = str; |
| |
| while (table_entry) { |
| DMDEBUG("parsing table \"%s\"", str); |
| if (++dev->dmi.target_count >= DM_MAX_TARGETS) { |
| DMERR("too many targets %u > %d", |
| dev->dmi.target_count, DM_MAX_TARGETS); |
| return -EINVAL; |
| } |
| table_entry = dm_parse_table_entry(dev, table_entry); |
| if (IS_ERR(table_entry)) { |
| DMERR("couldn't parse table"); |
| return PTR_ERR(table_entry); |
| } |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * dm_parse_device_entry - parse a device entry |
| * @dev: device to store the parsed information. |
| * @str: the pointer to a string with the format: |
| * name,uuid,minor,flags,table[; ...] |
| * |
| * Return the remainder string after the table entry, i.e, after the semi-colon |
| * which delimits the entry or NULL if reached the end of the string. |
| */ |
| static char __init *dm_parse_device_entry(struct dm_device *dev, char *str) |
| { |
| /* There are 5 fields: name,uuid,minor,flags,table; */ |
| char *field[5]; |
| unsigned int i; |
| char *next; |
| |
| field[0] = str; |
| /* Delimit first 4 fields that are separated by comma */ |
| for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { |
| field[i+1] = str_field_delimit(&field[i], ','); |
| if (!field[i+1]) |
| return ERR_PTR(-EINVAL); |
| } |
| /* Delimit last field that can be delimited by semi-colon */ |
| next = str_field_delimit(&field[i], ';'); |
| |
| /* name */ |
| strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name)); |
| /* uuid */ |
| strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid)); |
| /* minor */ |
| if (strlen(field[2])) { |
| if (kstrtoull(field[2], 0, &dev->dmi.dev)) |
| return ERR_PTR(-EINVAL); |
| dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG; |
| } |
| /* flags */ |
| if (!strcmp(field[3], "ro")) |
| dev->dmi.flags |= DM_READONLY_FLAG; |
| else if (strcmp(field[3], "rw")) |
| return ERR_PTR(-EINVAL); |
| /* table */ |
| if (dm_parse_table(dev, field[4])) |
| return ERR_PTR(-EINVAL); |
| |
| return next; |
| } |
| |
| /** |
| * dm_parse_devices - parse "dm-mod.create=" argument |
| * @devices: list of struct dm_device to store the parsed information. |
| * @str: the pointer to a string with the format: |
| * <device>[;<device>+] |
| */ |
| static int __init dm_parse_devices(struct list_head *devices, char *str) |
| { |
| unsigned long ndev = 0; |
| struct dm_device *dev; |
| char *device = str; |
| |
| DMDEBUG("parsing \"%s\"", str); |
| while (device) { |
| dev = kzalloc(sizeof(*dev), GFP_KERNEL); |
| if (!dev) |
| return -ENOMEM; |
| list_add_tail(&dev->list, devices); |
| |
| if (++ndev >= DM_MAX_DEVICES) { |
| DMERR("too many targets %u > %d", |
| dev->dmi.target_count, DM_MAX_TARGETS); |
| return -EINVAL; |
| } |
| |
| device = dm_parse_device_entry(dev, device); |
| if (IS_ERR(device)) { |
| DMERR("couldn't parse device"); |
| return PTR_ERR(device); |
| } |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * dm_init_init - parse "dm-mod.create=" argument and configure drivers |
| */ |
| static int __init dm_init_init(void) |
| { |
| struct dm_device *dev; |
| LIST_HEAD(devices); |
| char *str; |
| int r; |
| |
| if (!create) |
| return 0; |
| |
| if (strlen(create) >= DM_MAX_STR_SIZE) { |
| DMERR("Argument is too big. Limit is %d\n", DM_MAX_STR_SIZE); |
| return -EINVAL; |
| } |
| str = kstrndup(create, GFP_KERNEL, DM_MAX_STR_SIZE); |
| if (!str) |
| return -ENOMEM; |
| |
| r = dm_parse_devices(&devices, str); |
| if (r) |
| goto out; |
| |
| DMINFO("waiting for all devices to be available before creating mapped devices\n"); |
| wait_for_device_probe(); |
| |
| list_for_each_entry(dev, &devices, list) { |
| if (dm_early_create(&dev->dmi, dev->table, |
| dev->target_args_array)) |
| break; |
| } |
| out: |
| kfree(str); |
| dm_setup_cleanup(&devices); |
| return r; |
| } |
| |
| late_initcall(dm_init_init); |
| |
| module_param(create, charp, 0); |
| MODULE_PARM_DESC(create, "Create a mapped device in early boot"); |