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