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/*
* Copyright (C) 2009-2013 Felix Fietkau <nbd@nbd.name>
* Copyright (C) 2009-2013 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2012 Jonas Gorski <jogo@openwrt.org>
* Copyright (C) 2013 Hauke Mehrtens <hauke@hauke-m.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#define pr_fmt(fmt) "mtdsplit: " fmt
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/magic.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/byteorder/generic.h>
#include "mtdsplit.h"
#define UBI_EC_MAGIC 0x55424923 /* UBI# */
struct squashfs_super_block {
__le32 s_magic;
__le32 pad0[9];
__le64 bytes_used;
};
int mtd_get_squashfs_len(struct mtd_info *master,
size_t offset,
size_t *squashfs_len)
{
struct squashfs_super_block sb;
size_t retlen;
int err;
err = mtd_read(master, offset, sizeof(sb), &retlen, (void *)&sb);
if (err || (retlen != sizeof(sb))) {
pr_alert("error occured while reading from \"%s\"\n",
master->name);
return -EIO;
}
if (le32_to_cpu(sb.s_magic) != SQUASHFS_MAGIC) {
pr_alert("no squashfs found in \"%s\"\n", master->name);
return -EINVAL;
}
retlen = le64_to_cpu(sb.bytes_used);
if (retlen <= 0) {
pr_alert("squashfs is empty in \"%s\"\n", master->name);
return -ENODEV;
}
if (offset + retlen > master->size) {
pr_alert("squashfs has invalid size in \"%s\"\n",
master->name);
return -EINVAL;
}
*squashfs_len = retlen;
return 0;
}
EXPORT_SYMBOL_GPL(mtd_get_squashfs_len);
static ssize_t mtd_next_eb(struct mtd_info *mtd, size_t offset)
{
return mtd_rounddown_to_eb(offset, mtd) + mtd->erasesize;
}
int mtd_check_rootfs_magic(struct mtd_info *mtd, size_t offset,
enum mtdsplit_part_type *type)
{
u32 magic;
size_t retlen;
int ret;
ret = mtd_read(mtd, offset, sizeof(magic), &retlen,
(unsigned char *) &magic);
if (ret)
return ret;
if (retlen != sizeof(magic))
return -EIO;
if (le32_to_cpu(magic) == SQUASHFS_MAGIC) {
if (type)
*type = MTDSPLIT_PART_TYPE_SQUASHFS;
return 0;
} else if (magic == 0x19852003) {
if (type)
*type = MTDSPLIT_PART_TYPE_JFFS2;
return 0;
} else if (be32_to_cpu(magic) == UBI_EC_MAGIC) {
if (type)
*type = MTDSPLIT_PART_TYPE_UBI;
return 0;
}
return -EINVAL;
}
EXPORT_SYMBOL_GPL(mtd_check_rootfs_magic);
int mtd_find_rootfs_from(struct mtd_info *mtd,
size_t from,
size_t limit,
size_t *ret_offset,
enum mtdsplit_part_type *type)
{
size_t offset;
int err;
for (offset = from; offset < limit;
offset = mtd_next_eb(mtd, offset)) {
err = mtd_check_rootfs_magic(mtd, offset, type);
if (err)
continue;
*ret_offset = offset;
return 0;
}
return -ENODEV;
}
EXPORT_SYMBOL_GPL(mtd_find_rootfs_from);
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