// SPDX-License-Identifier: GPL-2.0-only
/*
* 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/delay.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
#define DM_MAX_WAITFOR 256
static char *create;
static char *waitfor[DM_MAX_WAITFOR];
/*
* 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>
* Block devices to wait for to become available before setting up tables:
* dm-mod.waitfor=<device1>[,..,<deviceN>]
*
* See Documentation/admin-guide/device-mapper/dm-init.rst 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;
};
static 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], DM_MAX_STR_SIZE,
GFP_KERNEL);
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 devices %lu > %d",
ndev, DM_MAX_DEVICES);
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 i, r;
if (!create)
return 0;
if (strlen(create) >= DM_MAX_STR_SIZE) {
DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE);
return -EINVAL;
}
str = kstrndup(create, DM_MAX_STR_SIZE, GFP_KERNEL);
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");
wait_for_device_probe();
for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
if (waitfor[i]) {
dev_t dev;
DMINFO("waiting for device %s ...", waitfor[i]);
while (early_lookup_bdev(waitfor[i], &dev))
fsleep(5000);
}
}
if (waitfor[0])
DMINFO("all devices available");
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");
module_param_array(waitfor, charp, NULL, 0);
MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables");
