81 lines
2.0 KiB
C
81 lines
2.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <inttypes.h>
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int main(int argc, char *argv[]) {
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FILE *bootloader_file, *device;
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uint8_t *bootloader_img;
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uint8_t orig_mbr[70], timestamp[6];
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uint32_t stage2_sect;
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if (argc < 3) {
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printf("Usage: %s <bootloader image> <device> [stage2 start sector]\n", argv[0]);
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return 1;
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}
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bootloader_file = fopen(argv[1], "rb");
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if (bootloader_file == NULL) {
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perror("Error: ");
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return 1;
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}
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// The bootloader image is 64 sectors (32k)
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bootloader_img = malloc(64 * 512);
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if (bootloader_img == NULL) {
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perror("Error: ");
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fclose(bootloader_file);
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return 1;
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}
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// Load in bootloader image
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fseek(bootloader_file, 0, SEEK_SET);
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fread(bootloader_img, 64, 512, bootloader_file);
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fclose(bootloader_file);
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device = fopen(argv[2], "r+b");
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if (device == NULL) {
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perror("Error: ");
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free(bootloader_img);
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return 1;
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}
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stage2_sect = 1;
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if (argc >= 4)
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sscanf(argv[3], "%" SCNu32, &stage2_sect);
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// Save original timestamp
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fseek(device, 218, SEEK_SET);
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fread(timestamp, 1, 6, device);
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// Save the original partition table of the device
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fseek(device, 440, SEEK_SET);
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fread(orig_mbr, 1, 70, device);
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// Write the bootsector from the bootloader to the device
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fseek(device, 0, SEEK_SET);
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fwrite(&bootloader_img[0], 1, 512, device);
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// Write the rest of stage 2 to the device
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fseek(device, stage2_sect * 512, SEEK_SET);
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fwrite(&bootloader_img[512], 63, 512, device);
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// Hardcode in the bootsector the location of stage 2
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fseek(device, 0x1b0, SEEK_SET);
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fwrite(&stage2_sect, 1, sizeof(uint32_t), device);
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// Write back timestamp
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fseek(device, 218, SEEK_SET);
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fwrite(timestamp, 1, 6, device);
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// Write back the saved partition table to the device
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fseek(device, 440, SEEK_SET);
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fwrite(orig_mbr, 1, 70, device);
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fclose(device);
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free(bootloader_img);
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return 0;
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}
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