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/*
extract_fw.c - extract the main firmware image from a Sansa V2 (AMS) firmware
file
Copyright (C) Dave Chapman 2008
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
/* Win32 compatibility */
#ifndef O_BINARY
#define O_BINARY 0
#endif
static off_t filesize(int fd) {
struct stat buf;
if (fstat(fd,&buf) < 0) {
perror("[ERR] Checking filesize of input file");
return -1;
} else {
return(buf.st_size);
}
}
static uint32_t get_uint32le(unsigned char* p)
{
return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
}
void usage(void)
{
printf("Usage: extract_fw <firmware file> <output file>\n");
exit(1);
}
int main(int argc, char* argv[])
{
char *infile, *outfile;
int fdin, fdout;
off_t len;
uint32_t n;
unsigned char* buf;
uint32_t firmware_size;
if(argc != 3) {
usage();
}
infile = argv[1];
outfile = argv[2];
/* Open the firmware file */
fdin = open(infile,O_RDONLY|O_BINARY);
if (fdin < 0) {
fprintf(stderr,"[ERR] Could not open %s for reading\n",infile);
return 1;
}
if ((len = filesize(fdin)) < 0)
return 1;
/* We will need no more memory than the total size plus the bootloader size
padded to a boundary */
if ((buf = malloc(len)) == NULL) {
fprintf(stderr,"[ERR] Could not allocate buffer for input file (%d bytes)\n",(int)len);
return 1;
}
n = read(fdin, buf, len);
if (n != (uint32_t)len) {
fprintf(stderr,"[ERR] Could not read firmware file\n");
return 1;
}
close(fdin);
/* Get the firmware size */
if (get_uint32le(&buf[0x04])==0x0000f000)
firmware_size = get_uint32le(&buf[0x10]); /* v2 format */
else
firmware_size = get_uint32le(&buf[0x0c]); /* v1 format */
fdout = open(outfile, O_CREAT|O_TRUNC|O_WRONLY|O_BINARY,0666);
if (fdout < 0) {
fprintf(stderr,"[ERR] Could not open %s for writing\n",outfile);
return 1;
}
n = write(fdout, buf + 0x400, firmware_size);
if (n != (uint32_t)firmware_size) {
fprintf(stderr,"[ERR] Could not write firmware block\n");
return 1;
}
/* Clean up */
close(fdout);
free(buf);
return 0;
}
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