/*
 * Many of the syscalls used in this file expect some of the arguments
 * to be __user pointers not __kernel pointers.  To limit the sparse
 * noise, turn off sparse checking for this file.
 */
#ifdef __CHECKER__
#undef __CHECKER__
#warning "Sparse checking disabled for this file"
#endif

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/fd.h>
#include <linux/tty.h>
#include <linux/suspend.h>
#include <linux/root_dev.h>
#include <linux/security.h>
#include <linux/delay.h>
#include <linux/genhd.h>
#include <linux/mount.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/initrd.h>
#include <linux/async.h>
#include <linux/fs_struct.h>
#include <linux/slab.h>

#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_mount.h>

#include "do_mounts.h"

int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */

int root_mountflags = MS_RDONLY | MS_SILENT;
static char * __initdata root_device_name;
static char __initdata saved_root_name[64];
static int root_wait;

dev_t ROOT_DEV;

static int __init load_ramdisk(char *str)
{
	rd_doload = simple_strtol(str,NULL,0) & 3;
	return 1;
}
__setup("load_ramdisk=", load_ramdisk);

static int __init readonly(char *str)
{
	if (*str)
		return 0;
	root_mountflags |= MS_RDONLY;
	return 1;
}

static int __init readwrite(char *str)
{
	if (*str)
		return 0;
	root_mountflags &= ~MS_RDONLY;
	return 1;
}

__setup("ro", readonly);
__setup("rw", readwrite);

#ifdef CONFIG_BLOCK
struct uuidcmp {
	const char *uuid;
	int len;
};

/**
 * match_dev_by_uuid - callback for finding a partition using its uuid
 * @dev:	device passed in by the caller
 * @data:	opaque pointer to the desired struct uuidcmp to match
 *
 * Returns 1 if the device matches, and 0 otherwise.
 */
static int match_dev_by_uuid(struct device *dev, const void *data)
{
	const struct uuidcmp *cmp = data;
	struct hd_struct *part = dev_to_part(dev);

	if (!part->info)
		goto no_match;

	if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
		goto no_match;

	return 1;
no_match:
	return 0;
}


/**
 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
 * @uuid:	char array containing ascii UUID
 *
 * The function will return the first partition which contains a matching
 * UUID value in its partition_meta_info struct.  This does not search
 * by filesystem UUIDs.
 *
 * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
 * extracted and used as an offset from the partition identified by the UUID.
 *
 * Returns the matching dev_t on success or 0 on failure.
 */
static dev_t devt_from_partuuid(const char *uuid_str)
{
	dev_t res = 0;
	struct uuidcmp cmp;
	struct device *dev = NULL;
	struct gendisk *disk;
	struct hd_struct *part;
	int offset = 0;
	bool clear_root_wait = false;
	char *slash;

	cmp.uuid = uuid_str;

	slash = strchr(uuid_str, '/');
	/* Check for optional partition number offset attributes. */
	if (slash) {
		char c = 0;
		/* Explicitly fail on poor PARTUUID syntax. */
		if (sscanf(slash + 1,
			   "PARTNROFF=%d%c", &offset, &c) != 1) {
			clear_root_wait = true;
			goto done;
		}
		cmp.len = slash - uuid_str;
	} else {
		cmp.len = strlen(uuid_str);
	}

	if (!cmp.len) {
		clear_root_wait = true;
		goto done;
	}

	dev = class_find_device(&block_class, NULL, &cmp,
				&match_dev_by_uuid);
	if (!dev)
		goto done;

	res = dev->devt;

	/* Attempt to find the partition by offset. */
	if (!offset)
		goto no_offset;

	res = 0;
	disk = part_to_disk(dev_to_part(dev));
	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
	if (part) {
		res = part_devt(part);
		put_device(part_to_dev(part));
	}

no_offset:
	put_device(dev);
done:
	if (clear_root_wait) {
		pr_err("VFS: PARTUUID= is invalid.\n"
		       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
		if (root_wait)
			pr_err("Disabling rootwait; root= is invalid.\n");
		root_wait = 0;
	}
	return res;
}
#endif

/*
 *	Convert a name into device number.  We accept the following variants:
 *
 *	1) device number in hexadecimal	represents itself
 *	2) /dev/nfs represents Root_NFS (0xff)
 *	3) /dev/<disk_name> represents the device number of disk
 *	4) /dev/<disk_name><decimal> represents the device number
 *         of partition - device number of disk plus the partition number
 *	5) /dev/<disk_name>p<decimal> - same as the above, that form is
 *	   used when disk name of partitioned disk ends on a digit.
 *	6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 *	   unique id of a partition if the partition table provides it.
 *	   The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
 *	   partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
 *	   filled hex representation of the 32-bit "NT disk signature", and PP
 *	   is a zero-filled hex representation of the 1-based partition number.
 *	7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 *	   a partition with a known unique id.
 *
 *	If name doesn't have fall into the categories above, we return (0,0).
 *	block_class is used to check if something is a disk name. If the disk
 *	name contains slashes, the device name has them replaced with
 *	bangs.
 */

dev_t name_to_dev_t(char *name)
{
	char s[32];
	char *p;
	dev_t res = 0;
	int part;

#ifdef CONFIG_BLOCK
	if (strncmp(name, "PARTUUID=", 9) == 0) {
		name += 9;
		res = devt_from_partuuid(name);
		if (!res)
			goto fail;
		goto done;
	}
#endif

	if (strncmp(name, "/dev/", 5) != 0) {
		unsigned maj, min;

		if (sscanf(name, "%u:%u", &maj, &min) == 2) {
			res = MKDEV(maj, min);
			if (maj != MAJOR(res) || min != MINOR(res))
				goto fail;
		} else {
			res = new_decode_dev(simple_strtoul(name, &p, 16));
			if (*p)
				goto fail;
		}
		goto done;
	}

	name += 5;
	res = Root_NFS;
	if (strcmp(name, "nfs") == 0)
		goto done;
	res = Root_RAM0;
	if (strcmp(name, "ram") == 0)
		goto done;

	if (strlen(name) > 31)
		goto fail;
	strcpy(s, name);
	for (p = s; *p; p++)
		if (*p == '/')
			*p = '!';
	res = blk_lookup_devt(s, 0);
	if (res)
		goto done;

	/*
	 * try non-existent, but valid partition, which may only exist
	 * after revalidating the disk, like partitioned md devices
	 */
	while (p > s && isdigit(p[-1]))
		p--;
	if (p == s || !*p || *p == '0')
		goto fail;

	/* try disk name without <part number> */
	part = simple_strtoul(p, NULL, 10);
	*p = '\0';
	res = blk_lookup_devt(s, part);
	if (res)
		goto done;

	/* try disk name without p<part number> */
	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
		goto fail;
	p[-1] = '\0';
	res = blk_lookup_devt(s, part);
	if (res)
		goto done;

fail:
	return 0;
done:
	return res;
}

static int __init root_dev_setup(char *line)
{
	strlcpy(saved_root_name, line, sizeof(saved_root_name));
	return 1;
}

__setup("root=", root_dev_setup);

static int __init rootwait_setup(char *str)
{
	if (*str)
		return 0;
	root_wait = 1;
	return 1;
}

__setup("rootwait", rootwait_setup);

static char * __initdata root_mount_data;
static int __init root_data_setup(char *str)
{
	root_mount_data = str;
	return 1;
}

static char * __initdata root_fs_names;