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/*
* Linksys boot counter reset code for mtd
*
* Copyright (C) 2013 Jonas Gorski <jogo@openwrt.org>
* Portions Copyright (c) 2019, Jeff Kletsky
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License v2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <endian.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
#include <syslog.h>
#include <sys/ioctl.h>
#include <mtd/mtd-user.h>
#include "mtd.h"
#define BOOTCOUNT_MAGIC 0x20110811
/*
* EA6350v3, and potentially other NOR-boot devices,
* use an offset increment of 16 between records,
* not mtd_info_user.writesize (often 1 on NOR devices).
*/
#define BC_OFFSET_INCREMENT_MIN 16
#define DLOG_OPEN()
#define DLOG_ERR(...) do { \
fprintf(stderr, "ERROR: " __VA_ARGS__); fprintf(stderr, "\n"); \
} while (0)
#define DLOG_NOTICE(...) do { \
fprintf(stderr, __VA_ARGS__); fprintf(stderr, "\n"); \
} while (0)
#define DLOG_DEBUG(...)
struct bootcounter {
uint32_t magic;
uint32_t count;
uint32_t checksum;
};
static char page[2048];
int mtd_resetbc(const char *mtd)
{
struct mtd_info_user mtd_info;
struct bootcounter *curr = (struct bootcounter *)page;
unsigned int i;
unsigned int bc_offset_increment;
int last_count = 0;
int num_bc;
int fd;
int ret;
int retval = 0;
DLOG_OPEN();
fd = mtd_check_open(mtd);
if (ioctl(fd, MEMGETINFO, &mtd_info) < 0) {
DLOG_ERR("Unable to obtain mtd_info for given partition name.");
retval = -1;
goto out;
}
/* Detect need to override increment (for EA6350v3) */
if (mtd_info.writesize < BC_OFFSET_INCREMENT_MIN) {
bc_offset_increment = BC_OFFSET_INCREMENT_MIN;
DLOG_DEBUG("Offset increment set to %i for writesize of %i",
bc_offset_increment, mtd_info.writesize);
} else {
bc_offset_increment = mtd_info.writesize;
}
num_bc = mtd_info.size / bc_offset_increment;
for (i = 0; i < num_bc; i++) {
pread(fd, curr, sizeof(*curr), i * bc_offset_increment);
/* Existing code assumes erase is to 0xff; left as-is (2019) */
if (curr->magic != BOOTCOUNT_MAGIC &&
curr->magic != 0xffffffff) {
DLOG_ERR("Unexpected magic %08x at offset %08x; aborting.",
curr->magic, i * bc_offset_increment);
retval = -2;
goto out;
}
if (curr->magic == 0xffffffff)
break;
last_count = curr->count;
}
if (last_count == 0) { /* bootcount is already 0 */
retval = 0;
goto out;
}
if (i == num_bc) {
DLOG_NOTICE("Boot-count log full with %i entries; erasing (expected occasionally).",
i);
struct erase_info_user erase_info;
erase_info.start = 0;
erase_info.length = mtd_info.size;
ret = ioctl(fd, MEMERASE, &erase_info);
if (ret < 0) {
DLOG_ERR("Failed to erase boot-count log MTD; ioctl() MEMERASE returned %i",
ret);
retval = -3;
goto out;
}
i = 0;
}
memset(curr, 0xff, bc_offset_increment);
curr->magic = BOOTCOUNT_MAGIC;
curr->count = 0;
curr->checksum = BOOTCOUNT_MAGIC;
/* Assumes bc_offset_increment is a multiple of mtd_info.writesize */
ret = pwrite(fd, curr, bc_offset_increment, i * bc_offset_increment);
if (ret < 0) {
DLOG_ERR("Failed to write boot-count log entry; pwrite() returned %i",
errno);
retval = -4;
goto out;
} else {
sync();
DLOG_NOTICE("Boot count sucessfully reset to zero.");
retval = 0;
goto out;
}
out:
close(fd);
return retval;
}
|
