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156 lines
3.6 KiB
156 lines
3.6 KiB
// 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 <[email protected]> |
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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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