u-boot/cmd/mbr.c
Joshua Watt 55a4244372 cmd: mbr: Force DOS driver to be used for verify
Forces the DOS partition type driver to be used when verifying the MBR.
This is particularly useful when using a hybrid MBR & GPT layout as
otherwise MBR verification would mostly likely fail since the GPT
partitions will be returned, even if the MBR is actually valid.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2023-07-17 16:20:08 -04:00

315 lines
6.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* cmd_mbr.c -- MBR (Master Boot Record) handling command
*
* Copyright (C) 2020 Samsung Electronics
* author: Marek Szyprowski <m.szyprowski@samsung.com>
*
* based on the gpt command.
*/
#include <common.h>
#include <blk.h>
#include <command.h>
#include <malloc.h>
#include <part.h>
/**
* extract_val() - Extract a value from the key=value pair list
* @str: pointer to string with key=values pairs
* @key: pointer to the key to search for
*
* The list of parameters is come separated, only a value for
* the given key is returend.
*
* Function allocates memory for the value, remember to free!
*
* Return: Pointer to allocated string with the value.
*/
static char *extract_val(const char *str, const char *key)
{
char *v, *k;
char *s, *strcopy;
char *new = NULL;
strcopy = strdup(str);
if (strcopy == NULL)
return NULL;
s = strcopy;
while (s) {
v = strsep(&s, ",");
if (!v)
break;
k = strsep(&v, "=");
if (!k)
break;
if (strcmp(k, key) == 0) {
new = strdup(v);
break;
}
}
free(strcopy);
return new;
}
/**
* found_key() - Search for a key without a value in the parameter list
* @str: pointer to string with key
* @key: pointer to the key to search for
*
* The list of parameters is come separated.
*
* Return: True if key has been found.
*/
static bool found_key(const char *str, const char *key)
{
char *k;
char *s, *strcopy;
bool result = false;
strcopy = strdup(str);
if (!strcopy)
return NULL;
s = strcopy;
while (s) {
k = strsep(&s, ",");
if (!k)
break;
if (strcmp(k, key) == 0) {
result = true;
break;
}
}
free(strcopy);
return result;
}
static int str_to_partitions(const char *str_part, int blksz,
unsigned long *disk_uuid, struct disk_partition **partitions,
int *parts_count)
{
char *tok, *str, *s;
int i;
char *val, *p;
int p_count;
struct disk_partition *parts;
int errno = 0;
uint64_t size_ll, start_ll;
if (str_part == NULL)
return -1;
str = strdup(str_part);
if (str == NULL)
return -ENOMEM;
/* extract disk guid */
s = str;
val = extract_val(str, "uuid_disk");
if (val) {
val = strsep(&val, ";");
p = val;
*disk_uuid = ustrtoull(p, &p, 0);
free(val);
/* Move s to first partition */
strsep(&s, ";");
}
if (s == NULL) {
printf("Error: is the partitions string NULL-terminated?\n");
return -EINVAL;
}
/* remove the optional semicolon at the end of the string */
i = strlen(s) - 1;
if (s[i] == ';')
s[i] = '\0';
/* calculate expected number of partitions */
p_count = 1;
p = s;
while (*p) {
if (*p++ == ';')
p_count++;
}
/* allocate memory for partitions */
parts = calloc(sizeof(struct disk_partition), p_count);
if (parts == NULL)
return -ENOMEM;
/* retrieve partitions data from string */
for (i = 0; i < p_count; i++) {
tok = strsep(&s, ";");
if (tok == NULL)
break;
/* size */
val = extract_val(tok, "size");
if (!val) { /* 'size' is mandatory */
errno = -4;
goto err;
}
p = val;
if ((strcmp(p, "-") == 0)) {
/* auto extend the size */
parts[i].size = 0;
} else {
size_ll = ustrtoull(p, &p, 0);
parts[i].size = size_ll / blksz;
}
free(val);
/* start address */
val = extract_val(tok, "start");
if (val) { /* start address is optional */
p = val;
start_ll = ustrtoull(p, &p, 0);
parts[i].start = start_ll / blksz;
free(val);
}
/* system id */
val = extract_val(tok, "id");
if (!val) { /* '' is mandatory */
errno = -4;
goto err;
}
p = val;
parts[i].sys_ind = ustrtoul(p, &p, 0);
free(val);
/* bootable */
if (found_key(tok, "bootable"))
parts[i].bootable = PART_BOOTABLE;
}
*parts_count = p_count;
*partitions = parts;
free(str);
return 0;
err:
free(str);
free(parts);
return errno;
}
static int do_write_mbr(struct blk_desc *dev, const char *str)
{
unsigned long disk_uuid = 0;
struct disk_partition *partitions;
int blksz = dev->blksz;
int count;
if (str_to_partitions(str, blksz, &disk_uuid, &partitions, &count)) {
printf("MBR: failed to setup partitions from \"%s\"\n", str);
return -1;
}
if (layout_mbr_partitions(partitions, count, dev->lba)) {
printf("MBR: failed to layout partitions on the device\n");
free(partitions);
return -1;
}
if (write_mbr_partitions(dev, partitions, count, disk_uuid)) {
printf("MBR: failed to write partitions to the device\n");
free(partitions);
return -1;
}
return 0;
}
static int do_verify_mbr(struct blk_desc *dev, const char *str)
{
unsigned long disk_uuid = 0;
struct disk_partition *partitions;
int blksz = dev->blksz;
int count, i, ret = 1;
if (str_to_partitions(str, blksz, &disk_uuid, &partitions, &count)) {
printf("MBR: failed to setup partitions from \"%s\"\n", str);
return -1;
}
for (i = 0; i < count; i++) {
struct disk_partition p;
if (part_get_info_by_type(dev, i + 1, PART_TYPE_DOS, &p))
goto fail;
if ((partitions[i].size && p.size != partitions[i].size) ||
(partitions[i].start && p.start != partitions[i].start) ||
p.sys_ind != partitions[i].sys_ind)
goto fail;
}
ret = 0;
fail:
free(partitions);
return ret;
}
static int do_mbr(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
const char *parts = NULL;
int ret = CMD_RET_SUCCESS;
int dev = 0;
char *ep;
struct blk_desc *blk_dev_desc = NULL;
if (argc != 4 && argc != 5)
return CMD_RET_USAGE;
dev = (int)dectoul(argv[3], &ep);
if (!ep || ep[0] != '\0') {
printf("'%s' is not a number\n", argv[3]);
return CMD_RET_USAGE;
}
blk_dev_desc = blk_get_dev(argv[2], dev);
if (!blk_dev_desc) {
printf("%s: %s dev %d NOT available\n",
__func__, argv[2], dev);
return CMD_RET_FAILURE;
}
if ((strcmp(argv[1], "write") == 0)) {
parts = (argc == 5) ? argv[4] : env_get("mbr_parts");
printf("MBR: write ");
ret = do_write_mbr(blk_dev_desc, parts);
} else if ((strcmp(argv[1], "verify") == 0)) {
printf("MBR: verify ");
parts = (argc == 5) ? argv[4] : env_get("mbr_parts");
ret = do_verify_mbr(blk_dev_desc, parts);
} else {
return CMD_RET_USAGE;
}
if (ret) {
printf("error!\n");
return CMD_RET_FAILURE;
}
printf("success!\n");
return CMD_RET_SUCCESS;
}
U_BOOT_CMD(mbr, CONFIG_SYS_MAXARGS, 1, do_mbr,
"MBR (Master Boot Record)",
"<command> <interface> <dev> <partitions_list>\n"
" - MBR partition table restoration utility\n"
" Restore or check partition information on a device connected\n"
" to the given block interface\n"
" Example usage:\n"
" mbr write mmc 0 [\"${mbr_parts}\"]\n"
" mbr verify mmc 0 [\"${partitions}\"]\n"
);