323 lines
8.0 KiB
C
323 lines
8.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org>
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/ctype.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/device-mapper.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/moduleparam.h>
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#define DM_MSG_PREFIX "init"
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#define DM_MAX_DEVICES 256
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#define DM_MAX_TARGETS 256
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#define DM_MAX_STR_SIZE 4096
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#define DM_MAX_WAITFOR 256
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static char *create;
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static char *waitfor[DM_MAX_WAITFOR];
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/*
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* Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+]
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* Table format: <start_sector> <num_sectors> <target_type> <target_args>
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* Block devices to wait for to become available before setting up tables:
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* dm-mod.waitfor=<device1>[,..,<deviceN>]
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*
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* See Documentation/admin-guide/device-mapper/dm-init.rst for dm-mod.create="..." format
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* details.
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*/
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struct dm_device {
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struct dm_ioctl dmi;
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struct dm_target_spec *table[DM_MAX_TARGETS];
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char *target_args_array[DM_MAX_TARGETS];
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struct list_head list;
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};
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static const char * const dm_allowed_targets[] __initconst = {
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"crypt",
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"delay",
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"linear",
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"snapshot-origin",
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"striped",
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"verity",
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};
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static int __init dm_verify_target_type(const char *target)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) {
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if (!strcmp(dm_allowed_targets[i], target))
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return 0;
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}
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return -EINVAL;
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}
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static void __init dm_setup_cleanup(struct list_head *devices)
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{
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struct dm_device *dev, *tmp;
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unsigned int i;
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list_for_each_entry_safe(dev, tmp, devices, list) {
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list_del(&dev->list);
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for (i = 0; i < dev->dmi.target_count; i++) {
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kfree(dev->table[i]);
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kfree(dev->target_args_array[i]);
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}
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kfree(dev);
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}
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}
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/**
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* str_field_delimit - delimit a string based on a separator char.
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* @str: the pointer to the string to delimit.
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* @separator: char that delimits the field
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*
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* Find a @separator and replace it by '\0'.
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* Remove leading and trailing spaces.
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* Return the remainder string after the @separator.
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*/
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static char __init *str_field_delimit(char **str, char separator)
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{
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char *s;
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/* TODO: add support for escaped characters */
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*str = skip_spaces(*str);
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s = strchr(*str, separator);
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/* Delimit the field and remove trailing spaces */
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if (s)
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*s = '\0';
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*str = strim(*str);
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return s ? ++s : NULL;
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}
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/**
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* dm_parse_table_entry - parse a table entry
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* @dev: device to store the parsed information.
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* @str: the pointer to a string with the format:
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* <start_sector> <num_sectors> <target_type> <target_args>[, ...]
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*
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* Return the remainder string after the table entry, i.e, after the comma which
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* delimits the entry or NULL if reached the end of the string.
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*/
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static char __init *dm_parse_table_entry(struct dm_device *dev, char *str)
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{
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const unsigned int n = dev->dmi.target_count - 1;
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struct dm_target_spec *sp;
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unsigned int i;
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/* fields: */
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char *field[4];
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char *next;
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field[0] = str;
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/* Delimit first 3 fields that are separated by space */
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for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
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field[i + 1] = str_field_delimit(&field[i], ' ');
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if (!field[i + 1])
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return ERR_PTR(-EINVAL);
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}
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/* Delimit last field that can be terminated by comma */
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next = str_field_delimit(&field[i], ',');
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sp = kzalloc(sizeof(*sp), GFP_KERNEL);
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if (!sp)
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return ERR_PTR(-ENOMEM);
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dev->table[n] = sp;
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/* start_sector */
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if (kstrtoull(field[0], 0, &sp->sector_start))
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return ERR_PTR(-EINVAL);
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/* num_sector */
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if (kstrtoull(field[1], 0, &sp->length))
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return ERR_PTR(-EINVAL);
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/* target_type */
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strscpy(sp->target_type, field[2], sizeof(sp->target_type));
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if (dm_verify_target_type(sp->target_type)) {
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DMERR("invalid type \"%s\"", sp->target_type);
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return ERR_PTR(-EINVAL);
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}
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/* target_args */
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dev->target_args_array[n] = kstrndup(field[3], DM_MAX_STR_SIZE,
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GFP_KERNEL);
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if (!dev->target_args_array[n])
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return ERR_PTR(-ENOMEM);
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return next;
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}
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/**
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* dm_parse_table - parse "dm-mod.create=" table field
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* @dev: device to store the parsed information.
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* @str: the pointer to a string with the format:
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* <table>[,<table>+]
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*/
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static int __init dm_parse_table(struct dm_device *dev, char *str)
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{
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char *table_entry = str;
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while (table_entry) {
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DMDEBUG("parsing table \"%s\"", str);
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if (++dev->dmi.target_count > DM_MAX_TARGETS) {
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DMERR("too many targets %u > %d",
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dev->dmi.target_count, DM_MAX_TARGETS);
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return -EINVAL;
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}
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table_entry = dm_parse_table_entry(dev, table_entry);
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if (IS_ERR(table_entry)) {
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DMERR("couldn't parse table");
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return PTR_ERR(table_entry);
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}
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}
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return 0;
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}
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/**
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* dm_parse_device_entry - parse a device entry
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* @dev: device to store the parsed information.
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* @str: the pointer to a string with the format:
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* name,uuid,minor,flags,table[; ...]
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*
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* Return the remainder string after the table entry, i.e, after the semi-colon
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* which delimits the entry or NULL if reached the end of the string.
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*/
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static char __init *dm_parse_device_entry(struct dm_device *dev, char *str)
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{
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/* There are 5 fields: name,uuid,minor,flags,table; */
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char *field[5];
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unsigned int i;
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char *next;
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field[0] = str;
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/* Delimit first 4 fields that are separated by comma */
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for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
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field[i+1] = str_field_delimit(&field[i], ',');
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if (!field[i+1])
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return ERR_PTR(-EINVAL);
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}
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/* Delimit last field that can be delimited by semi-colon */
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next = str_field_delimit(&field[i], ';');
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/* name */
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strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name));
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/* uuid */
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strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid));
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/* minor */
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if (strlen(field[2])) {
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if (kstrtoull(field[2], 0, &dev->dmi.dev))
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return ERR_PTR(-EINVAL);
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dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG;
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}
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/* flags */
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if (!strcmp(field[3], "ro"))
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dev->dmi.flags |= DM_READONLY_FLAG;
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else if (strcmp(field[3], "rw"))
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return ERR_PTR(-EINVAL);
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/* table */
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if (dm_parse_table(dev, field[4]))
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return ERR_PTR(-EINVAL);
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return next;
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}
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/**
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* dm_parse_devices - parse "dm-mod.create=" argument
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* @devices: list of struct dm_device to store the parsed information.
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* @str: the pointer to a string with the format:
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* <device>[;<device>+]
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*/
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static int __init dm_parse_devices(struct list_head *devices, char *str)
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{
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unsigned long ndev = 0;
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struct dm_device *dev;
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char *device = str;
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DMDEBUG("parsing \"%s\"", str);
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while (device) {
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev)
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return -ENOMEM;
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list_add_tail(&dev->list, devices);
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if (++ndev > DM_MAX_DEVICES) {
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DMERR("too many devices %lu > %d",
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ndev, DM_MAX_DEVICES);
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return -EINVAL;
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}
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device = dm_parse_device_entry(dev, device);
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if (IS_ERR(device)) {
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DMERR("couldn't parse device");
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return PTR_ERR(device);
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}
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}
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return 0;
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}
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/**
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* dm_init_init - parse "dm-mod.create=" argument and configure drivers
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*/
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static int __init dm_init_init(void)
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{
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struct dm_device *dev;
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LIST_HEAD(devices);
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char *str;
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int i, r;
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if (!create)
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return 0;
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if (strlen(create) >= DM_MAX_STR_SIZE) {
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DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE);
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return -EINVAL;
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}
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str = kstrndup(create, DM_MAX_STR_SIZE, GFP_KERNEL);
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if (!str)
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return -ENOMEM;
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r = dm_parse_devices(&devices, str);
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if (r)
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goto out;
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DMINFO("waiting for all devices to be available before creating mapped devices");
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wait_for_device_probe();
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for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
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if (waitfor[i]) {
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DMINFO("waiting for device %s ...", waitfor[i]);
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while (!dm_get_dev_t(waitfor[i]))
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fsleep(5000);
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}
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}
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if (waitfor[0])
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DMINFO("all devices available");
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list_for_each_entry(dev, &devices, list) {
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if (dm_early_create(&dev->dmi, dev->table,
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dev->target_args_array))
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break;
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}
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out:
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kfree(str);
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dm_setup_cleanup(&devices);
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return r;
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}
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late_initcall(dm_init_init);
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module_param(create, charp, 0);
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MODULE_PARM_DESC(create, "Create a mapped device in early boot");
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module_param_array(waitfor, charp, NULL, 0);
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MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables");
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