cmdline.c
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/*
* Copyright (C) 2013 HUAWEI
* Author: Cai Zhiyong <caizhiyong@huawei.com>
*
* Read block device partition table from the command line.
* Typically used for fixed block (eMMC) embedded devices.
* It has no MBR, so saves storage space. Bootloader can be easily accessed
* by absolute address of data on the block device.
* Users can easily change the partition.
*
* The format for the command line is just like mtdparts.
*
* For further information, see "Documentation/block/cmdline-partition.txt"
*
*/
#include <linux/cmdline-parser.h>
#include "check.h"
#include "cmdline.h"
static char *cmdline;
static struct cmdline_parts *bdev_parts;
static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
{
int label_min;
struct partition_meta_info *info;
char tmp[sizeof(info->volname) + 4];
struct parsed_partitions *state = (struct parsed_partitions *)param;
if (slot >= state->limit)
return 1;
put_partition(state, slot, subpart->from >> 9,
subpart->size >> 9);
info = &state->parts[slot].info;
label_min = min_t(int, sizeof(info->volname) - 1,
sizeof(subpart->name));
strncpy(info->volname, subpart->name, label_min);
info->volname[label_min] = '\0';
snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
state->parts[slot].has_info = true;
return 0;
}
static int __init cmdline_parts_setup(char *s)
{
cmdline = s;
return 1;
}
__setup("blkdevparts=", cmdline_parts_setup);
/*
* Purpose: allocate cmdline partitions.
* Returns:
* -1 if unable to read the partition table
* 0 if this isn't our partition table
* 1 if successful
*/
int cmdline_partition(struct parsed_partitions *state)
{
sector_t disk_size;
char bdev[BDEVNAME_SIZE];
struct cmdline_parts *parts;
if (cmdline) {
if (bdev_parts)
cmdline_parts_free(&bdev_parts);
if (cmdline_parts_parse(&bdev_parts, cmdline)) {
cmdline = NULL;
return -1;
}
cmdline = NULL;
}
if (!bdev_parts)
return 0;
bdevname(state->bdev, bdev);
parts = cmdline_parts_find(bdev_parts, bdev);
if (!parts)
return 0;
disk_size = get_capacity(state->bdev->bd_disk) << 9;
cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
strlcat(state->pp_buf, "\n", PAGE_SIZE);
return 1;
}