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https://github.com/Rockbox/rockbox.git
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5891a38486
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18676 a1c6a512-1295-4272-9138-f99709370657
311 lines
8.6 KiB
C
311 lines
8.6 KiB
C
/*
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mkamsboot.c - a tool for merging bootloader code into an Sansa V2
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(AMS) firmware file
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Copyright (C) Dave Chapman 2008
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
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*/
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/*
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Insert a Rockbox bootloader into an AMS original firmware file.
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We replace the main firmware block (bytes 0x400..padded_firmware_size+0x400)
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with the following:
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Bytes 0..(firmware_size-ucl_size) - Our bootloader code
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Bytes (firmware_size-ucl_size)..firmware_size - UCL compressed OF image
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Bytes firmware_size..padded_firmware_size - UCL decompress function
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mkamsboot writes the following values at offsets into our bootloader code:
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0x20 - Entry point (plus 1 - for thumb mode) of the ucl_unpack function
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0x24 - Location of the UCL compressed version of the original firmware block
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mkamsboot then corrects the length (to include the UCL decompress
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function) and checksum in the main firmware headers (both copies),
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creating a new legal firmware file which can be installed on the
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device.
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Our bootloader first checks for the "dual-boot" keypress, and then either:
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a) Branches to the ucl_unpack function, which will then branch to 0x0 after
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decompressing the OF.
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b) Continues running with our test code
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This method uses no RAM outside the padded area of the original
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firmware block - the UCL compression can happen in-place when the
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compressed image is stored at the end of the destination buffer.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <string.h>
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/* Win32 compatibility */
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#ifndef O_BINARY
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#define O_BINARY 0
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#endif
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#define PAD_TO_BOUNDARY(x) (((x) + 0x1ff) & ~0x1ff)
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static off_t filesize(int fd) {
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struct stat buf;
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if (fstat(fd,&buf) < 0) {
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perror("[ERR] Checking filesize of input file");
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return -1;
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} else {
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return(buf.st_size);
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}
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}
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static uint32_t get_uint32le(unsigned char* p)
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{
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return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
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}
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static void put_uint32le(unsigned char* p, uint32_t x)
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{
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p[0] = x & 0xff;
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p[1] = (x >> 8) & 0xff;
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p[2] = (x >> 16) & 0xff;
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p[3] = (x >> 24) & 0xff;
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}
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static int calc_checksum(unsigned char* buf, uint32_t n)
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{
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uint32_t sum = 0;
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uint32_t i;
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for (i=0;i<n;i+=4)
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sum += get_uint32le(buf + i);
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return sum;
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}
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void usage(void)
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{
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printf("Usage: mkamsboot <firmware file> <ucl image> <boot file> <ucl unpack file> <output file>\n");
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exit(1);
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}
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int main(int argc, char* argv[])
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{
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char *infile, *uclfile, *bootfile, *uclunpackfile, *outfile;
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int fdin, fducl, fdboot, fduclunpack, fdout;
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off_t len;
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uint32_t n;
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unsigned char* buf;
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uint32_t firmware_size;
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uint32_t firmware_paddedsize;
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uint32_t bootloader_size;
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uint32_t ucl_size;
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uint32_t uclunpack_size;
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uint32_t sum,filesum;
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uint32_t i;
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if(argc != 6) {
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usage();
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}
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infile = argv[1];
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uclfile = argv[2];
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bootfile = argv[3];
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uclunpackfile = argv[4];
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outfile = argv[5];
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/* Open the bootloader file */
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fdboot = open(bootfile, O_RDONLY|O_BINARY);
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if (fdboot < 0)
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{
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fprintf(stderr,"[ERR] Could not open %s for reading\n",bootfile);
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return 1;
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}
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bootloader_size = filesize(fdboot);
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/* Open the UCL-compressed image of the firmware block */
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fduclunpack = open(uclunpackfile, O_RDONLY|O_BINARY);
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if (fduclunpack < 0)
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{
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fprintf(stderr,"[ERR] Could not open %s for reading\n",uclunpackfile);
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return 1;
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}
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uclunpack_size = filesize(fduclunpack);
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/* Open the UCL-compressed image of the firmware block */
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fducl = open(uclfile, O_RDONLY|O_BINARY);
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if (fducl < 0)
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{
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fprintf(stderr,"[ERR] Could not open %s for reading\n",uclfile);
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return 1;
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}
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ucl_size = filesize(fducl);
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/* Open the firmware file */
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fdin = open(infile,O_RDONLY|O_BINARY);
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if (fdin < 0) {
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fprintf(stderr,"[ERR] Could not open %s for reading\n",infile);
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return 1;
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}
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if ((len = filesize(fdin)) < 0)
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return 1;
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/* Allocate memory for the OF image - we don't change the size */
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if ((buf = malloc(len)) == NULL) {
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fprintf(stderr,"[ERR] Could not allocate buffer for input file (%d bytes)\n",(int)len);
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return 1;
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}
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n = read(fdin, buf, len);
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if (n != (uint32_t)len) {
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fprintf(stderr,"[ERR] Could not read firmware file\n");
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return 1;
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}
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close(fdin);
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/* Get the firmware size */
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firmware_size = get_uint32le(&buf[0x0c]);
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/* Round size up to next multiple of 0x200 */
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firmware_paddedsize = PAD_TO_BOUNDARY(firmware_size);
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fprintf(stderr,"Original firmware size - %d bytes\n",firmware_size);
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fprintf(stderr,"Padded firmware size - %d bytes\n",firmware_paddedsize);
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fprintf(stderr,"Bootloader size - %d bytes\n",bootloader_size);
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fprintf(stderr,"UCL image size - %d bytes\n",ucl_size);
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fprintf(stderr,"UCL unpack function size - %d bytes\n",uclunpack_size);
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fprintf(stderr,"Original total size of firmware - %d bytes\n",(int)len);
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/* Check we have room for our bootloader - in the future, we could UCL
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pack this image as well if we need to. */
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if (bootloader_size > (firmware_size - ucl_size)) {
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fprintf(stderr,"[ERR] Bootloader too large (%d bytes, %d available)\n",
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bootloader_size, firmware_size - ucl_size);
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return 1;
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}
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/* Check we have enough room for the UCL unpack function. This
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needs to be outside the firmware block, so if we wanted to
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support every firmware version, we could store this function in
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the main firmware block, and then copy it to an unused part of
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RAM. */
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if (uclunpack_size > (firmware_paddedsize - firmware_size)) {
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fprintf(stderr,"[ERR] UCL unpack function too large (%d bytes, %d available)\n",
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uclunpack_size, firmware_paddedsize - firmware_size);
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return 1;
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}
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/* Zero the original firmware area - not needed, but helps debugging */
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memset(buf + 0x400, 0, firmware_size);
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/* Locate our bootloader code at the start of the firmware block */
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n = read(fdboot, buf + 0x400, bootloader_size);
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if (n != bootloader_size) {
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fprintf(stderr,"[ERR] Could not load bootloader file\n");
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return 1;
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}
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close(fdboot);
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/* Locate the compressed image of the original firmware block at the end
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of the firmware block */
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n = read(fducl, buf + 0x400 + firmware_size - ucl_size, ucl_size);
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if (n != ucl_size) {
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fprintf(stderr,"[ERR] Could not load ucl file\n");
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return 1;
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}
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close(fducl);
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/* Locate our UCL unpack function in the padding after the firmware block */
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n = read(fduclunpack, buf + 0x400 + firmware_size, uclunpack_size);
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if (n != uclunpack_size) {
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fprintf(stderr,"[ERR] Could not load uclunpack file\n");
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return 1;
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}
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close(fduclunpack);
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put_uint32le(&buf[0x420], firmware_size + 1); /* UCL unpack entry point */
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put_uint32le(&buf[0x424], firmware_size - ucl_size); /* Location of OF */
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put_uint32le(&buf[0x428], ucl_size); /* Size of UCL image */
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/* Update checksum */
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sum = calc_checksum(buf + 0x400,firmware_size + uclunpack_size);
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put_uint32le(&buf[0x04], sum);
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put_uint32le(&buf[0x204], sum);
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/* Update firmware size */
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put_uint32le(&buf[0x0c], firmware_size + uclunpack_size);
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put_uint32le(&buf[0x20c], firmware_size + uclunpack_size);
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/* Update the whole-file checksum */
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filesum = 0;
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for (i=0;i < (unsigned)len - 4; i+=4)
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filesum += get_uint32le(&buf[i]);
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put_uint32le(buf + len - 4, filesum);
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/* Write the new firmware */
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fdout = open(outfile, O_CREAT|O_TRUNC|O_WRONLY|O_BINARY,0666);
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if (fdout < 0) {
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fprintf(stderr,"[ERR] Could not open %s for writing\n",outfile);
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return 1;
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}
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n = write(fdout, buf, len);
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if (n != (unsigned)len) {
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fprintf(stderr,"[ERR] Could not write firmware file\n");
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return 1;
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}
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close(fdout);
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return 0;
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}
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