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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2013 HUAWEI
- * Author: Cai Zhiyong <[email protected]>
- *
- * 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/blkdev.h>
- #include <linux/fs.h>
- #include <linux/slab.h>
- #include "check.h"
- /* partition flags */
- #define PF_RDONLY 0x01 /* Device is read only */
- #define PF_POWERUP_LOCK 0x02 /* Always locked after reset */
- struct cmdline_subpart {
- char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */
- sector_t from;
- sector_t size;
- int flags;
- struct cmdline_subpart *next_subpart;
- };
- struct cmdline_parts {
- char name[BDEVNAME_SIZE]; /* block device, such as 'mmcblk0' */
- unsigned int nr_subparts;
- struct cmdline_subpart *subpart;
- struct cmdline_parts *next_parts;
- };
- static int parse_subpart(struct cmdline_subpart **subpart, char *partdef)
- {
- int ret = 0;
- struct cmdline_subpart *new_subpart;
- *subpart = NULL;
- new_subpart = kzalloc(sizeof(struct cmdline_subpart), GFP_KERNEL);
- if (!new_subpart)
- return -ENOMEM;
- if (*partdef == '-') {
- new_subpart->size = (sector_t)(~0ULL);
- partdef++;
- } else {
- new_subpart->size = (sector_t)memparse(partdef, &partdef);
- if (new_subpart->size < (sector_t)PAGE_SIZE) {
- pr_warn("cmdline partition size is invalid.");
- ret = -EINVAL;
- goto fail;
- }
- }
- if (*partdef == '@') {
- partdef++;
- new_subpart->from = (sector_t)memparse(partdef, &partdef);
- } else {
- new_subpart->from = (sector_t)(~0ULL);
- }
- if (*partdef == '(') {
- int length;
- char *next = strchr(++partdef, ')');
- if (!next) {
- pr_warn("cmdline partition format is invalid.");
- ret = -EINVAL;
- goto fail;
- }
- length = min_t(int, next - partdef,
- sizeof(new_subpart->name) - 1);
- strncpy(new_subpart->name, partdef, length);
- new_subpart->name[length] = '\0';
- partdef = ++next;
- } else
- new_subpart->name[0] = '\0';
- new_subpart->flags = 0;
- if (!strncmp(partdef, "ro", 2)) {
- new_subpart->flags |= PF_RDONLY;
- partdef += 2;
- }
- if (!strncmp(partdef, "lk", 2)) {
- new_subpart->flags |= PF_POWERUP_LOCK;
- partdef += 2;
- }
- *subpart = new_subpart;
- return 0;
- fail:
- kfree(new_subpart);
- return ret;
- }
- static void free_subpart(struct cmdline_parts *parts)
- {
- struct cmdline_subpart *subpart;
- while (parts->subpart) {
- subpart = parts->subpart;
- parts->subpart = subpart->next_subpart;
- kfree(subpart);
- }
- }
- static int parse_parts(struct cmdline_parts **parts, const char *bdevdef)
- {
- int ret = -EINVAL;
- char *next;
- int length;
- struct cmdline_subpart **next_subpart;
- struct cmdline_parts *newparts;
- char buf[BDEVNAME_SIZE + 32 + 4];
- *parts = NULL;
- newparts = kzalloc(sizeof(struct cmdline_parts), GFP_KERNEL);
- if (!newparts)
- return -ENOMEM;
- next = strchr(bdevdef, ':');
- if (!next) {
- pr_warn("cmdline partition has no block device.");
- goto fail;
- }
- length = min_t(int, next - bdevdef, sizeof(newparts->name) - 1);
- strncpy(newparts->name, bdevdef, length);
- newparts->name[length] = '\0';
- newparts->nr_subparts = 0;
- next_subpart = &newparts->subpart;
- while (next && *(++next)) {
- bdevdef = next;
- next = strchr(bdevdef, ',');
- length = (!next) ? (sizeof(buf) - 1) :
- min_t(int, next - bdevdef, sizeof(buf) - 1);
- strncpy(buf, bdevdef, length);
- buf[length] = '\0';
- ret = parse_subpart(next_subpart, buf);
- if (ret)
- goto fail;
- newparts->nr_subparts++;
- next_subpart = &(*next_subpart)->next_subpart;
- }
- if (!newparts->subpart) {
- pr_warn("cmdline partition has no valid partition.");
- ret = -EINVAL;
- goto fail;
- }
- *parts = newparts;
- return 0;
- fail:
- free_subpart(newparts);
- kfree(newparts);
- return ret;
- }
- static void cmdline_parts_free(struct cmdline_parts **parts)
- {
- struct cmdline_parts *next_parts;
- while (*parts) {
- next_parts = (*parts)->next_parts;
- free_subpart(*parts);
- kfree(*parts);
- *parts = next_parts;
- }
- }
- static int cmdline_parts_parse(struct cmdline_parts **parts,
- const char *cmdline)
- {
- int ret;
- char *buf;
- char *pbuf;
- char *next;
- struct cmdline_parts **next_parts;
- *parts = NULL;
- next = pbuf = buf = kstrdup(cmdline, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
- next_parts = parts;
- while (next && *pbuf) {
- next = strchr(pbuf, ';');
- if (next)
- *next = '\0';
- ret = parse_parts(next_parts, pbuf);
- if (ret)
- goto fail;
- if (next)
- pbuf = ++next;
- next_parts = &(*next_parts)->next_parts;
- }
- if (!*parts) {
- pr_warn("cmdline partition has no valid partition.");
- ret = -EINVAL;
- goto fail;
- }
- ret = 0;
- done:
- kfree(buf);
- return ret;
- fail:
- cmdline_parts_free(parts);
- goto done;
- }
- static struct cmdline_parts *cmdline_parts_find(struct cmdline_parts *parts,
- const char *bdev)
- {
- while (parts && strncmp(bdev, parts->name, sizeof(parts->name)))
- parts = parts->next_parts;
- return parts;
- }
- static char *cmdline;
- static struct cmdline_parts *bdev_parts;
- static int add_part(int slot, struct cmdline_subpart *subpart,
- struct parsed_partitions *state)
- {
- int label_min;
- struct partition_meta_info *info;
- char tmp[sizeof(info->volname) + 4];
- 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 cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size,
- struct parsed_partitions *state)
- {
- sector_t from = 0;
- struct cmdline_subpart *subpart;
- int slot = 1;
- for (subpart = parts->subpart; subpart;
- subpart = subpart->next_subpart, slot++) {
- if (subpart->from == (sector_t)(~0ULL))
- subpart->from = from;
- else
- from = subpart->from;
- if (from >= disk_size)
- break;
- if (subpart->size > (disk_size - from))
- subpart->size = disk_size - from;
- from += subpart->size;
- if (add_part(slot, subpart, state))
- break;
- }
- return slot;
- }
- 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;
- 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;
- parts = cmdline_parts_find(bdev_parts, state->disk->disk_name);
- if (!parts)
- return 0;
- disk_size = get_capacity(state->disk) << 9;
- cmdline_parts_set(parts, disk_size, state);
- cmdline_parts_verifier(1, state);
- strlcat(state->pp_buf, "\n", PAGE_SIZE);
- return 1;
- }
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