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- /*
- * mkbrnimg.c - partially based on OpenWrt's wndr3700.c
- *
- * Copyright (C) 2011 Tobias Diedrich <ranma+openwrt@tdiedrich.de>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License,
- * version 2 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 <errno.h>
- #include <fcntl.h>
- #include <sys/mman.h>
- #include <string.h>
- #include <netinet/in.h>
- #include <inttypes.h>
- #define BPB 8 /* bits/byte */
- static uint32_t crc32[1<<BPB];
- static void init_crc32()
- {
- const uint32_t poly = ntohl(0x2083b8ed);
- int n;
- for (n = 0; n < 1<<BPB; n++) {
- uint32_t crc = n;
- int bit;
- for (bit = 0; bit < BPB; bit++)
- crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1);
- crc32[n] = crc;
- }
- }
- static uint32_t crc32buf(unsigned char *buf, size_t len)
- {
- uint32_t crc = 0xFFFFFFFF;
- for (; len; len--, buf++)
- crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB);
- return ~crc;
- }
- static void usage(const char *) __attribute__ (( __noreturn__ ));
- static void usage(const char *mess)
- {
- fprintf(stderr, "Error: %s\n", mess);
- fprintf(stderr, "Usage: mkbrnimg [-o output_file] [-m magic] [-s signature] kernel_file [additional files]\n");
- fprintf(stderr, "\n");
- exit(1);
- }
- static char *output_file = "default-brnImage";
- static uint32_t magic = 0x12345678;
- static char *signature = "BRNDTW502";
- static void parseopts(int *argc, char ***argv)
- {
- char *endptr;
- int res;
- while ((res = getopt(*argc, *argv, "o:m:s:")) != -1) {
- switch (res) {
- default:
- usage("Unknown option");
- break;
- case 'o':
- output_file = optarg;
- break;
- case 'm':
- magic = strtoul(optarg, &endptr, 0);
- if (endptr == optarg || *endptr != 0)
- usage("magic must be a decimal or hexadecimal 32-bit value");
- break;
- case 's':
- signature = optarg;
- break;
- }
- }
- *argc -= optind;
- *argv += optind;
- }
- static void appendfile(int outfd, char *path, int kernel) {
- int fd;
- size_t len, padded_len;
- char *input_file;
- uint32_t crc;
- char padding[0x400];
- char footer[12];
- memset(padding, 0xff, sizeof(padding));
- // mmap input_file
- if ((fd = open(path, O_RDONLY)) < 0
- || (len = lseek(fd, 0, SEEK_END)) < 0
- || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1)
- || close(fd) < 0)
- {
- fprintf(stderr, "Error mapping file '%s': %s\n", path, strerror(errno));
- exit(1);
- }
- // kernel should be lzma compressed image, not uImage
- if (kernel &&
- (input_file[0] != (char)0x5d ||
- input_file[1] != (char)0x00 ||
- input_file[2] != (char)0x00 ||
- input_file[3] != (char)0x80)) {
- fprintf(stderr, "lzma signature not found on kernel image.\n");
- exit(1);
- }
- init_crc32();
- crc = crc32buf(input_file, len);
- fprintf(stderr, "crc32 for '%s' is %08x.\n", path, crc);
- // write the file
- write(outfd, input_file, len);
- // write padding
- padded_len = ((len + sizeof(footer) + sizeof(padding) - 1) & ~(sizeof(padding) - 1)) - sizeof(footer);
- fprintf(stderr, "len=%08x padded_len=%08x\n", len, padded_len);
- write(outfd, padding, padded_len - len);
- // write footer
- footer[0] = (len >> 0) & 0xff;
- footer[1] = (len >> 8) & 0xff;
- footer[2] = (len >> 16) & 0xff;
- footer[3] = (len >> 24) & 0xff;
- footer[4] = (magic >> 0) & 0xff;
- footer[5] = (magic >> 8) & 0xff;
- footer[6] = (magic >> 16) & 0xff;
- footer[7] = (magic >> 24) & 0xff;
- footer[8] = (crc >> 0) & 0xff;
- footer[9] = (crc >> 8) & 0xff;
- footer[10] = (crc >> 16) & 0xff;
- footer[11] = (crc >> 24) & 0xff;
- write(outfd, footer, sizeof(footer));
- munmap(input_file, len);
- }
- int main(int argc, char **argv)
- {
- int outfd;
- int i;
- parseopts(&argc, &argv);
- if (argc < 1)
- usage("wrong number of arguments");
- if ((outfd = open(output_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
- {
- fprintf(stderr, "Error opening '%s' for writing: %s\n", output_file, strerror(errno));
- exit(1);
- }
- for (i=0; i<argc; i++) {
- appendfile(outfd, argv[i], i == 0);
- }
- write(outfd, signature, strlen(signature)+1);
- close(outfd);
- return 0;
- }
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