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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
*/
#include <byteswap.h>
#include <endian.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if !defined(__BYTE_ORDER)
#error "Unknown byte order"
#endif
#if __BYTE_ORDER == __BIG_ENDIAN
#define cpu_to_le32(x) bswap_32(x)
#define le32_to_cpu(x) bswap_32(x)
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#define cpu_to_le32(x) (x)
#define le32_to_cpu(x) (x)
#else
#error "Unsupported endianness"
#endif
struct bcm4908kernel_header {
uint32_t unk1;
uint32_t unk2;
uint32_t length;
uint8_t magic[4];
uint32_t unused;
};
static void usage() {
printf("Usage:\n");
printf("\n");
printf("\t-i pathname\t\t\tinput kernel filepath\n");
printf("\t-o pathname\t\t\toutput kernel filepath\n");
}
int main(int argc, char **argv) {
struct bcm4908kernel_header header;
uint8_t buf[1024];
FILE *out = NULL;
FILE *in = NULL;
size_t length;
size_t bytes;
int err = 0;
char c;
if (argc >= 2 && !strcmp(argv[1], "-h")) {
usage();
return 0;
}
while ((c = getopt(argc, argv, "i:o:")) != -1) {
switch (c) {
case 'i':
in = fopen(optarg, "r");
break;
case 'o':
out = fopen(optarg, "w+");
break;
}
}
if (!in || !out) {
fprintf(stderr, "Failed to open input and/or output file\n");
usage();
return -EINVAL;
}
if (fread(&header, 1, sizeof(header), in) != sizeof(header)) {
fprintf(stderr, "Failed to read %zu bytes from input file\n", sizeof(header));
err = -EIO;
goto err_close;
}
if (!memcmp(header.magic, "BRCM", 4)) {
fprintf(stderr, "Input file already contains BCM4908 kernel header\n");
err = -EIO;
goto err_close;
}
err = fseek(out, sizeof(header), SEEK_SET);
if (err) {
err = -errno;
fprintf(stderr, "Failed to fseek(): %d\n", err);
goto err_close;
}
length = 0;
rewind(in);
while ((bytes = fread(buf, 1, sizeof(buf), in)) > 0) {
if (fwrite(buf, 1, bytes, out) != bytes) {
fprintf(stderr, "Failed to write %zu B to the output file\n", bytes);
err = -EIO;
goto err_close;
}
length += bytes;
}
header.unk1 = cpu_to_le32(0x00080000);
header.unk2 = cpu_to_le32(0x00080000);
header.length = cpu_to_le32(length);
header.magic[0] = 'B';
header.magic[1] = 'R';
header.magic[2] = 'C';
header.magic[3] = 'M';
header.unused = 0;
fseek(out, 0, SEEK_SET);
if (fwrite(&header, 1, sizeof(header), out) != sizeof(header)) {
fprintf(stderr, "Failed to write header to the output file\n");
err = -EIO;
goto err_close;
}
err_close:
fclose(out);
fclose(in);
return err;
}
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