Magisk/core/jni/magiskboot/hexpatch.c
2017-12-21 03:36:18 +08:00

39 lines
1.1 KiB
C

#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <sys/mman.h>
#include "magiskboot.h"
#include "utils.h"
static void hex2byte(const char *hex, unsigned char *str) {
char high, low;
for (int i = 0, length = strlen(hex); i < length; i += 2) {
high = toupper(hex[i]) - '0';
low = toupper(hex[i + 1]) - '0';
str[i / 2] = ((high > 9 ? high - 7 : high) << 4) + (low > 9 ? low - 7 : low);
}
}
void hexpatch(const char *image, const char *from, const char *to) {
int patternsize = strlen(from) / 2, patchsize = strlen(to) / 2;
size_t filesize;
void *file, *pattern, *patch;
mmap_rw(image, &file, &filesize);
pattern = xmalloc(patternsize);
patch = xmalloc(patchsize);
hex2byte(from, pattern);
hex2byte(to, patch);
for (size_t i = 0; filesize > 0 && i < filesize - patternsize; ++i) {
if (memcmp(file + i, pattern, patternsize) == 0) {
fprintf(stderr, "Patch @ %08X [%s]->[%s]\n", (unsigned) i, from, to);
memset(file + i, 0, patternsize);
memcpy(file + i, patch, patchsize);
i += patternsize - 1;
}
}
munmap(file, filesize);
free(pattern);
free(patch);
}