/* do_mounts_dm.c
* Copyright (C) 2010 The Chromium OS Authors <chromium-os-dev@chromium.org>
* All Rights Reserved.
* Based on do_mounts_md.c
*
* This file is released under the GPL.
*/
#include <linux/async.h>
#include <linux/ctype.h>
#include <linux/device-mapper.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/delay.h>
#include "do_mounts.h"
#define DM_MAX_DEVICES 256
#define DM_MAX_TARGETS 256
#define DM_MAX_NAME 32
#define DM_MAX_UUID 129
#define DM_NO_UUID "none"
#define DM_MSG_PREFIX "init"
/* Separators used for parsing the dm= argument. */
#define DM_FIELD_SEP " "
#define DM_LINE_SEP ","
#define DM_ANY_SEP DM_FIELD_SEP DM_LINE_SEP
/*
* When the device-mapper and any targets are compiled into the kernel
* (not a module), one or more device-mappers may be created and used
* as the root device at boot time with the parameters given with the
* boot line dm=...
*
* Multiple device-mappers can be stacked specifing the number of
* devices. A device can have multiple targets if the the number of
* targets is specified.
*
* TODO(taysom:defect 32847)
* In the future, the <num> field will be mandatory.
*
* <device> ::= [<num>] <device-mapper>+
* <device-mapper> ::= <head> "," <target>+
* <head> ::= <name> <uuid> <mode> [<num>]
* <target> ::= <start> <length> <type> <options> ","
* <mode> ::= "ro" | "rw"
* <uuid> ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "none"
* <type> ::= "verity" | "bootcache" | ...
*
* Example:
* 2 vboot none ro 1,
* 0 1768000 bootcache
* device=aa55b119-2a47-8c45-946a-5ac57765011f+1
* signature=76e9be054b15884a9fa85973e9cb274c93afadb6
* cache_start=1768000 max_blocks=100000 size_limit=23 max_trace=20000,
* vroot none ro 1,
* 0 1740800 verity payload=254:0 hashtree=254:0 hashstart=1740800 alg=sha1
* root_hexdigest=76e9be054b15884a9fa85973e9cb274c93afadb6
* salt=5b3549d54d6c7a3837b9b81ed72e49463a64c03680c47835bef94d768e5646fe
*
* Notes:
* 1. uuid is a label for the device and we set it to "none".
* 2. The <num> field will be optional initially and assumed to be 1.
* Once all the scripts that set these fields have been set, it will
* be made mandatory.
*/
struct dm_setup_target {
sector_t begin;
sector_t length;
char *type;
char *params;
/* simple singly linked list */
struct dm_setup_target *next;
};
struct dm_device {
int minor;
int ro;
char name[DM_MAX_NAME];
char uuid[DM_MAX_UUID];
unsigned long num_targets;
struct dm_setup_target *target;
int target_count;
struct dm_device *next;
};
struct dm_option {
char *start;
char *next;
size_t len;
char delim;
};
static struct {
unsigned long num_devices;
char *str;
} dm_setup_args __initdata;
static __initdata int dm_early_setup;
static int __init get_dm_option(struct dm_option *opt, const char *accept)
{
char *str = opt->next;
char *endp;
if (!str)
return 0;
str = skip_spaces(str);
opt->start = str;
endp = strpbrk(str, accept);
if (!endp) { /* act like strchrnul */
opt->len = strlen(str);
endp = str + opt->len;
} else {
opt->len = endp - str;
}
opt->delim = *endp;
if (*endp == 0) {
/* Don't advance past the nul. */
opt->next = endp;
} else {
opt->next = endp + 1;
}
return opt->len != 0;
}
static int __init dm_setup_cleanup(struct dm_device *devices)
{
struct dm_device *dev = devices;
while (dev) {
struct dm_device *old_dev = dev;
struct dm_setup_target *target = dev->target;
while (target) {
struct dm_setup_target *old_target = target;
kfree(target->type);
kfree(target->params);
target = target->next;
kfree(old_target);
dev->target_count--;
}
BUG_ON(dev->target_count);
dev = dev->next;
kfree(old_dev);
}
return 0;
}
static char * __init dm_parse_device(struct dm_device *dev, char *str)
{
struct dm_option opt;
size_t len;
/* Grab the logical name of the device to be exported to udev */
opt.next = str;
if (!get_dm_option(&opt, DM_FIELD_SEP)) {
DMERR("failed to parse device name");
goto parse_fail;
}
len = min(opt.len + 1, sizeof(dev->name));
strlcpy(dev->name, opt.start, len); /* includes nul */
/* Grab the UUID value or "none" */
if (!get_dm_option(&opt, DM_FIELD_SEP)) {
DMERR("failed to parse device uuid");
goto parse_fail;
}
len = min(opt.len + 1, sizeof(dev->uuid));
strlcpy(dev->uuid, opt.start, len);
/* Determine if the table/device will be read only or read-write */
get_dm_option(&opt, DM_ANY_SEP);
if (!strncmp("ro", opt.start, opt.len)) {
dev->ro = 1;
} else if (!strncmp("rw", opt.start, opt.len)) {
dev->ro = 0;
} else {
DMERR("failed to parse table mode");
goto parse_fail;
}
/* Optional number field */
/* XXX: The <num> field will be mandatory in the next round */
if (opt.delim == DM_FIELD_SEP[0]) {
if (!get_dm_option(&opt, DM_LINE_SEP))
return NULL;
dev->num_targets = simple_strtoul(opt.start, NULL, 10);
} else {
dev->num_targets = 1;
}
if (dev->num_targets > DM_MAX_TARGETS) {
DMERR("too many targets %lu > %d",
dev->num_targets, DM_MAX_TARGETS);
}
return opt.next;
parse_fail:
return NULL;
}
static char * __init dm_parse_targets(struct dm_device *dev, char *str)
{
struct dm_option opt;
struct dm_setup_target **target = &dev->target;
unsigned long num_targets = dev->num_targets;
unsigned long i;
/* Targets are defined as per the table format but with a
* comma as a newline separator. */
opt.next = str;
for (i = 0; i < num_targets; i++) {
*target = kzalloc(sizeof(struct dm_setup_target), GFP_KERNEL);
if (!*target) {
DMERR("failed to allocate memory for target %s<%ld>",
dev->name, i);
goto parse_fail;
}
dev->target_count++;
if (!get_dm_option(&opt, DM_FIELD_SEP)) {
DMERR("failed to parse starting sector"
" for target %s<%ld>", dev->name, i);
goto parse_fail;
}
(*target)->begin = simple_strtoull(opt.start, NULL, 10);
if (!get_dm_option(&opt, DM_FIELD_SEP)) {
DMERR("failed to parse length for target %s<%ld>",
dev->name, i);
goto parse_fail;
}
(*target)->length = simple_strtoull(opt.start, NULL, 10);
if (get_dm_option(&opt, DM_FIELD_SEP))
(*target)->type = kstrndup(opt.start, opt.len,
GFP_KERNEL);
if (!((*target)->type)) {
DMERR("failed to parse type for target %s<%ld>",
dev->name, i);
goto parse_fail;
}
if (get_dm_option(&opt, DM_LINE_SEP))
(*target)->params = kstrndup(opt.start, opt.len,
GFP_KERNEL);
if (!((*target)->params)) {
DMERR("failed to parse params for target %s<%ld>",
dev->name, i);
goto parse_fail;
}
target = &((*target)->next);
}
DMDEBUG("parsed %d targets", dev->target_count);
return opt.next;
parse_fail:
return NULL;
}
static struct dm_device * __init dm_parse_args(void)
{
struct dm_device *devices = NULL;
struct dm_device **tail = &devices;
struct dm_device *dev;
char *str = dm_setup_args.str;
unsigned long num_devices = dm_setup_args.num_devices;
unsigned long i;
if (!str)
return NULL;
for (i = 0; i < num_devices; i++) {
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
DMERR("failed to allocated memory for dev");
goto error;
}
*tail = dev;
tail = &dev->next;
/*
* devices are given minor numbers 0 - n-1
* in the order they are found in the arg
* string.
*/
dev->minor = i;
str = dm_parse_device(dev, str);
if (!str) /* NULL indicates error in parsing, bail */
goto error;
str = dm_parse_targets(dev, str);
if (!str)
goto error;
}
return devices;
error:
dm_setup_cleanup(devices);
return NULL;
}
/*
* Parse the command-line parameters given our kernel, but do not
* actually try to invoke the DM device now; that is handled by
* dm_setup_drives after the low-level disk drivers have initialised.
* dm format is described at the top of the file.
*
* Because dm minor numbers are assigned in assending order starting with 0,
* You can assume the first device is /dev/dm-0, the next device is /dev/dm-1,
* and so forth.
*/
static int __init dm_setup(char *str)
{
struct dm_option opt;
unsigned long num_devices;
if (!str) {
DMDEBUG("str is NULL");
goto parse_fail;
}
opt.next = str;
if (!get_dm_option(&opt, DM_FIELD_SEP))
goto parse_fail;
if (isdigit(opt.start[0])) { /* XXX: Optional number field */
num_devices = simple_strtoul(opt.start, NULL, 10);
str = opt.next;
} else {
num_devices = 1;
/* Don't advance str */
}
if (num_devices > DM_MAX_DEVICES) {
DMDEBUG("too many devices %lu > %d",
num_devices, DM_MAX_DEVICES);
}
dm_setup_args.str = str;
dm_setup_args.num_devices = num_devices;
DMINFO("will configure %lu devices", num_devices);
dm_early_setup = 1;
return 1;
parse_fail:
DMWARN("Invalid arguments supplied to dm=.");
return 0;
}
static void __init dm_setup_drives(void)
{
struct mapped_device *md = NULL;
struct dm_table *table = NULL;
struct dm_setup_target *target;
struct dm_device *dev;
char *uuid;
fmode_t fmode = FMODE_READ;
struct dm_device *devices;
devices = dm_parse_args();
for (dev = devices; dev; dev = dev->next) {
if (dm_create(dev->minor, &md)) {
DMDEBUG("failed to create the device");
goto dm_create_fail;
}
DMDEBUG("created device '%s'", dm_device_name(md));
/*
* In addition to flagging the table below, the disk must be
* set explicitly ro/rw.
*/
set_disk_ro(dm_disk(md), dev->ro);
if (!dev->ro)
fmode |= FMODE_WRITE;
if (dm_table_create(&table, fmode, dev->target_count, md)) {
DMDEBUG("failed to create the table");
goto dm_table_create_fail;
}
dm_lock_md_type(md);
for (target = dev->target; target; target = target->next) {
DMINFO("adding target '%llu %llu %s %s'",
(unsigned long long) target->begin,
(unsigned long long) target->length,
target->type, target->params);
if (dm_table_add_target(table, target->type,
target->begin,
target->length,
target->params)) {
DMDEBUG("failed to add the target"
" to the table");
goto add_target_fail;
}
}
if (dm_table_complete(table)) {
DMDEBUG("failed to complete the table");
goto table_complete_fail;
}
/* Suspend the device so that we can bind it to the table. */
if (dm_suspend(md, 0)) {
DMDEBUG("failed to suspend the device pre-bind");
goto suspend_fail;
}
/* Initial table load: acquire type of table. */
dm_set_md_type(md, dm_table_get_type(table));
/* Setup md->queue to reflect md's type. */
if (dm_setup_md_queue(md)) {
DMWARN("unable to set up device queue for new table.");
goto setup_md_queue_fail;
}
/*
* Bind the table to the device. This is the only way
* to associate md->map with the table and set the disk
* capacity directly.
*/
if (dm_swap_table(md, table)) { /* should return NULL. */
DMDEBUG("failed to bind the device to the table");
goto table_bind_fail;
}
/* Finally, resume and the device should be ready. */
if (dm_resume(md)) {
DMDEBUG("failed to resume the device");
goto resume_fail;
}
/* Export the dm device via the ioctl interface */
if (!strcmp(DM_NO_UUID, dev->uuid))
uuid = NULL;
if (dm_ioctl_export(md, dev->name, uuid)) {
DMDEBUG("failed to export device with given"
" name and uuid");
goto export_fail;
}
dm_unlock_md_type(md);
DMINFO("dm-%d is ready", dev->minor);
}
dm_setup_cleanup(devices);
return;
export_fail:
resume_fail:
table_bind_fail:
setup_md_queue_fail:
suspend_fail:
table_complete_fail:
add_target_fail:
dm_unlock_md_type(md);
dm_table_create_fail:
dm_put(md);
dm_create_fail:
DMWARN("starting dm-%d (%s) failed",
dev->minor, dev->name);
dm_setup_cleanup(devices);
}
__setup("dm=", dm_setup);
void __init dm_run_setup(void)
{
if (!dm_early_setup)
return;
DMINFO("attempting early device configuration.");
dm_setup_drives();
}