157 lines
3.6 KiB
C
157 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2013 HUAWEI
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* Author: Cai Zhiyong <caizhiyong@huawei.com>
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*
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* Read block device partition table from the command line.
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* Typically used for fixed block (eMMC) embedded devices.
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* It has no MBR, so saves storage space. Bootloader can be easily accessed
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* by absolute address of data on the block device.
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* Users can easily change the partition.
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*
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* The format for the command line is just like mtdparts.
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*
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* For further information, see "Documentation/block/cmdline-partition.rst"
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*
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*/
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#include <linux/cmdline-parser.h>
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#include "check.h"
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static char *cmdline;
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static struct cmdline_parts *bdev_parts;
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static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
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{
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int label_min;
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struct partition_meta_info *info;
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char tmp[sizeof(info->volname) + 4];
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struct parsed_partitions *state = (struct parsed_partitions *)param;
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if (slot >= state->limit)
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return 1;
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put_partition(state, slot, subpart->from >> 9,
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subpart->size >> 9);
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info = &state->parts[slot].info;
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label_min = min_t(int, sizeof(info->volname) - 1,
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sizeof(subpart->name));
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strncpy(info->volname, subpart->name, label_min);
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info->volname[label_min] = '\0';
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snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
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strlcat(state->pp_buf, tmp, PAGE_SIZE);
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state->parts[slot].has_info = true;
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return 0;
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}
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static int __init cmdline_parts_setup(char *s)
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{
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cmdline = s;
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return 1;
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}
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__setup("blkdevparts=", cmdline_parts_setup);
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static bool has_overlaps(sector_t from, sector_t size,
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sector_t from2, sector_t size2)
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{
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sector_t end = from + size;
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sector_t end2 = from2 + size2;
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if (from >= from2 && from < end2)
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return true;
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if (end > from2 && end <= end2)
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return true;
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if (from2 >= from && from2 < end)
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return true;
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if (end2 > from && end2 <= end)
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return true;
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return false;
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}
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static inline void overlaps_warns_header(void)
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{
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pr_warn("Overlapping partitions are used in command line partitions.");
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pr_warn("Don't use filesystems on overlapping partitions:");
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}
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static void cmdline_parts_verifier(int slot, struct parsed_partitions *state)
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{
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int i;
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bool header = true;
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for (; slot < state->limit && state->parts[slot].has_info; slot++) {
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for (i = slot+1; i < state->limit && state->parts[i].has_info;
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i++) {
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if (has_overlaps(state->parts[slot].from,
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state->parts[slot].size,
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state->parts[i].from,
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state->parts[i].size)) {
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if (header) {
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header = false;
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overlaps_warns_header();
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}
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pr_warn("%s[%llu,%llu] overlaps with "
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"%s[%llu,%llu].",
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state->parts[slot].info.volname,
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(u64)state->parts[slot].from << 9,
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(u64)state->parts[slot].size << 9,
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state->parts[i].info.volname,
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(u64)state->parts[i].from << 9,
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(u64)state->parts[i].size << 9);
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}
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}
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}
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}
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/*
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* Purpose: allocate cmdline partitions.
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* Returns:
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* -1 if unable to read the partition table
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* 0 if this isn't our partition table
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* 1 if successful
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*/
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int cmdline_partition(struct parsed_partitions *state)
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{
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sector_t disk_size;
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char bdev[BDEVNAME_SIZE];
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struct cmdline_parts *parts;
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if (cmdline) {
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if (bdev_parts)
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cmdline_parts_free(&bdev_parts);
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if (cmdline_parts_parse(&bdev_parts, cmdline)) {
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cmdline = NULL;
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return -1;
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}
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cmdline = NULL;
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}
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if (!bdev_parts)
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return 0;
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bdevname(state->bdev, bdev);
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parts = cmdline_parts_find(bdev_parts, bdev);
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if (!parts)
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return 0;
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disk_size = get_capacity(state->bdev->bd_disk) << 9;
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cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
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cmdline_parts_verifier(1, state);
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strlcat(state->pp_buf, "\n", PAGE_SIZE);
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return 1;
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}
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