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411 lines
8.5 KiB
411 lines
8.5 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/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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strlcat(state->pp_buf, "\n", PAGE_SIZE); |
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return 1; |
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}
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