diff options
Diffstat (limited to 'block/partitions/cmdline.c')
-rw-r--r-- | block/partitions/cmdline.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/block/partitions/cmdline.c b/block/partitions/cmdline.c new file mode 100644 index 000000000..8f545c36c --- /dev/null +++ b/block/partitions/cmdline.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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.rst" + * + */ + +#include <linux/cmdline-parser.h> + +#include "check.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); + +static bool has_overlaps(sector_t from, sector_t size, + sector_t from2, sector_t size2) +{ + sector_t end = from + size; + sector_t end2 = from2 + size2; + + if (from >= from2 && from < end2) + return true; + + if (end > from2 && end <= end2) + return true; + + if (from2 >= from && from2 < end) + return true; + + if (end2 > from && end2 <= end) + return true; + + return false; +} + +static inline void overlaps_warns_header(void) +{ + pr_warn("Overlapping partitions are used in command line partitions."); + pr_warn("Don't use filesystems on overlapping partitions:"); +} + +static void cmdline_parts_verifier(int slot, struct parsed_partitions *state) +{ + int i; + bool header = true; + + for (; slot < state->limit && state->parts[slot].has_info; slot++) { + for (i = slot+1; i < state->limit && state->parts[i].has_info; + i++) { + if (has_overlaps(state->parts[slot].from, + state->parts[slot].size, + state->parts[i].from, + state->parts[i].size)) { + if (header) { + header = false; + overlaps_warns_header(); + } + pr_warn("%s[%llu,%llu] overlaps with " + "%s[%llu,%llu].", + state->parts[slot].info.volname, + (u64)state->parts[slot].from << 9, + (u64)state->parts[slot].size << 9, + state->parts[i].info.volname, + (u64)state->parts[i].from << 9, + (u64)state->parts[i].size << 9); + } + } + } +} + +/* + * 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); + cmdline_parts_verifier(1, state); + + strlcat(state->pp_buf, "\n", PAGE_SIZE); + + return 1; +} |