forked from len0rd/rockbox
6ffd42548b
Instead of verifying the CRC before every access of the boot data, verify the CRC once at startup and set a flag to indicate the boot data is valid. Also add a framework to support multiple boot protocol versions. Firmware declares the maximum supported protocol version using a version byte in the boot data header. The bootloader chooses the highest version supported by it and the firmware when deciding what boot protocol to use. Change-Id: I810194625dc0833f026d2a23b8d64ed467fa6aca
126 lines
4.6 KiB
C
126 lines
4.6 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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*
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* Copyright (C) 2017, 2020 by William Wilgus
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "system.h"
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#include "bootdata.h"
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#include "crc32.h"
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#include "loader_strerror.h"
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#include "file.h"
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#include <string.h>
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#include <stdio.h>
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static void write_bootdata_v0(struct boot_data_t *data, unsigned int boot_volume)
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{
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memset(data->payload, data->length, 0);
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data->boot_volume = boot_volume;
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data->version = 0;
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}
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/* Write bootdata into location in FIRMWARE marked by magic header
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* Assumes buffer is already loaded with the firmware image
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* We just need to find the location and write data into the
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* payload region along with the crc for later verification and use.
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* Returns payload len on success,
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* On error returns false
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*/
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bool write_bootdata(unsigned char* buf, int len, unsigned int boot_volume)
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{
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int search_len = MIN(len, BOOT_DATA_SEARCH_SIZE) - sizeof(struct boot_data_t);
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/* search for boot data header prior to search_len */
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for(int i = 0; i < search_len; i++)
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{
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struct boot_data_t *data = (struct boot_data_t *)&buf[i];
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if (data->magic[0] != BOOT_DATA_MAGIC0 ||
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data->magic[1] != BOOT_DATA_MAGIC1)
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continue;
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/* Ignore it if the length extends past the end of the buffer. */
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int data_len = offsetof(struct boot_data_t, payload) + data->length;
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if (i + data_len > len)
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continue;
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/* Determine the maximum supported boot protocol version.
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* Version 0 firmware may use 0 or 0xff, all other versions
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* declare the highest supported version in the version byte. */
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int proto_version = 0;
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if (data->version < 0xff)
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proto_version = MIN(BOOT_DATA_VERSION, data->version);
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/* Write boot data according to the selected protocol */
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if (proto_version == 0)
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write_bootdata_v0(data, boot_volume);
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else
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break;
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/* Calculate payload CRC, used by all protocol versions. */
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data->crc = crc_32(data->payload, data->length, 0xffffffff);
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return true;
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}
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return false;
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}
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#ifdef HAVE_MULTIBOOT
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/* Check in root of this <volume> for rockbox_main.<playername>
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* if this file empty or there is a single slash '/'
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* buf = '<volume#>/<rootdir>/<firmware(name)>\0'
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* If instead '/<*DIRECTORY*>' is supplied
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* addpath will be set to this DIRECTORY buf =
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* '/<volume#>/addpath/<rootdir>/<firmware(name)>\0'
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* On error returns Negative number or 0
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* On success returns bytes from snprintf
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* and generated path will be placed in buf
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* note: if supplied buffer is too small return will be
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* the number of bytes that would have been written
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*/
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int get_redirect_dir(char* buf, int buffer_size, int volume,
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const char* rootdir, const char* firmware)
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{
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int fd;
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size_t f_offset;
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char add_path[MAX_PATH];
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/* Check in root of volume for rockbox_main.<playername> redirect */
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snprintf(add_path, sizeof(add_path), "/<%d>/"BOOT_REDIR, volume);
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fd = open(add_path, O_RDONLY);
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if (fd < 0)
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return EFILE_NOT_FOUND;
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/*clear add_path for re-use*/
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memset(add_path, 0, sizeof(add_path));
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f_offset = read(fd, add_path,sizeof(add_path));
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close(fd);
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for(size_t i = f_offset - 1; i < f_offset; i--)
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{
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/* strip control chars < SPACE or all if path doesn't start with '/' */
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if (add_path[i] < 0x20 || add_path[0] != '/')
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add_path[i] = '\0';
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}
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/* if '/add_path' is specified in rockbox_main.<playername>
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path is /<vol#>/add_path/rootdir/firmwarename
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if add_path is empty or '/' is missing from beginning
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path is /<vol#>/rootdir/firmwarename
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*/
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return snprintf(buf, buffer_size, "/<%d>%s/%s/%s", volume, add_path,
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rootdir, firmware);
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}
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#endif
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