97 lines
2.1 KiB
C
97 lines
2.1 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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typedef uint8_t u8;
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static u8 *memsearch(u8 *startPos, const void *pattern, int size, int patternSize)
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{
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const u8 *patternc = (const u8 *)pattern;
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int table[256];
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//Preprocessing
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int i;
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for(i = 0; i < 256; i++)
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table[i] = patternSize;
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for(i = 0; i < patternSize - 1; i++)
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table[patternc[i]] = patternSize - i - 1;
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//Searching
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int j = 0;
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while(j <= size - patternSize)
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{
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u8 c = startPos[j + patternSize - 1];
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if(patternc[patternSize - 1] == c && memcmp(pattern, startPos + j, patternSize - 1) == 0)
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return startPos + j;
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j += table[c];
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}
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return NULL;
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}
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static int fsize(FILE *fp)
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{
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fseek(fp, 0, SEEK_END);
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int size = ftell(fp);
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rewind(fp);
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return size;
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}
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static void error(FILE *payload, const char *message)
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{
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fclose(payload);
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printf("%s, are you sure you're using a Luma3DS payload?\n", message);
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exit(0);
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}
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int main(int argc, char **argv)
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{
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if(argc == 1)
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{
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printf("Usage: %s <Luma3DS payload path>\n", argv[0]);
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exit(0);
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}
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FILE *payload;
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size_t size;
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payload = fopen(argv[1], "rb+");
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size = fsize(payload);
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if(size > 0x20000)
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error(payload, "The input file is too large");
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u8 *buffer = (u8 *)malloc(size);
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fread(buffer, 1, size, payload);
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u8 pattern[] = {'s', 0, 'd', 0, 'm', 0, 'c', 0, ':', 0, '/', 0};
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u8 *found = memsearch(buffer, pattern, size, sizeof(pattern));
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if(found == NULL)
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{
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free(buffer);
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error(payload, "Pattern not found");
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}
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u8 input[38] = {0};
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u8 payloadname[2 * (sizeof(input) - 1)] = {0};
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printf("Enter the payload's path (37 characters max): ");
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scanf("%37s", input);
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unsigned int i;
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for (i = 0; i < sizeof(input) - 1; i++)
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payloadname[2 * i] = input[i];
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memcpy(found + 12, payloadname, sizeof(payloadname));
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rewind(payload);
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fwrite(buffer, 1, size, payload);
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free(buffer);
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fclose(payload);
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exit(0);
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} |