Magisk/native/jni/magiskboot/hexpatch.cpp
2021-02-28 14:37:12 -08:00

45 lines
1.2 KiB
C++

#include <sys/mman.h>
#include <utils.hpp>
#include "magiskboot.hpp"
using namespace std;
static void hex2byte(const char *hex, uint8_t *buf) {
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';
buf[i / 2] = ((high > 9 ? high - 7 : high) << 4) + (low > 9 ? low - 7 : low);
}
}
int hexpatch(const char *image, const char *from, const char *to) {
int patched = 1;
uint8_t *buf;
size_t sz;
mmap_rw(image, buf, sz);
run_finally f([=]{ munmap(buf, sz); });
vector<uint8_t> pattern(strlen(from) / 2);
vector<uint8_t> patch(strlen(to) / 2);
hex2byte(from, pattern.data());
hex2byte(to, patch.data());
uint8_t * const end = buf + sz;
for (uint8_t *curr = buf; curr < end; curr += pattern.size()) {
curr = static_cast<uint8_t*>(memmem(curr, end - curr, pattern.data(), pattern.size()));
if (curr == nullptr)
return patched;
fprintf(stderr, "Patch @ %08X [%s] -> [%s]\n", curr - buf, from, to);
memset(curr, 0, pattern.size());
memcpy(curr, patch.data(), patch.size());
patched = 0;
}
return patched;
}