mirror of
https://github.com/kavishdevar/librepods.git
synced 2026-05-02 10:59:19 +00:00
325 lines
8.3 KiB
C++
325 lines
8.3 KiB
C++
/*
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LibrePods - AirPods liberated from Apple’s ecosystem
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Copyright (C) 2025 LibrePods contributors
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <android/log.h>
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#include <cstring>
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#include <string>
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#include <vector>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <elf.h>
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#include "l2c_fcr_hook.h"
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extern "C" {
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#include "xz.h"
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}
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#define LOG_TAG "LibrePods"
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#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)
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#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__)
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static HookFunType hook_func = nullptr;
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static uint8_t (*original_l2c_fcr_chk_chan_modes)(void*) = nullptr;
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static tBTA_STATUS (*original_BTA_DmSetLocalDiRecord)(
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tSDP_DI_RECORD*, uint32_t*) = nullptr;
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uint8_t fake_l2c_fcr_chk_chan_modes(void* p_ccb) {
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LOGI("l2c_fcr_chk_chan_modes hooked");
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uint8_t orig = 0;
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if (original_l2c_fcr_chk_chan_modes)
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orig = original_l2c_fcr_chk_chan_modes(p_ccb);
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LOGI("Original returned %d, forcing 1", orig);
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return 1;
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}
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tBTA_STATUS fake_BTA_DmSetLocalDiRecord(
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tSDP_DI_RECORD* p_device_info,
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uint32_t* p_handle) {
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LOGI("BTA_DmSetLocalDiRecord hooked");
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if (p_device_info) {
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p_device_info->vendor = 0x004C;
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p_device_info->vendor_id_source = 0x0001;
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}
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if (original_BTA_DmSetLocalDiRecord)
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return original_BTA_DmSetLocalDiRecord(p_device_info, p_handle);
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return BTA_FAILURE;
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}
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static bool decompressXZ(
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const uint8_t* input,
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size_t input_size,
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std::vector<uint8_t>& output) {
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xz_crc32_init();
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#ifdef XZ_USE_CRC64
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xz_crc64_init();
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#endif
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struct xz_dec* dec = xz_dec_init(XZ_DYNALLOC, 64U << 20);
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if (!dec) return false;
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struct xz_buf buf{};
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buf.in = input;
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buf.in_pos = 0;
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buf.in_size = input_size;
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output.resize(input_size * 8);
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buf.out = output.data();
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buf.out_pos = 0;
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buf.out_size = output.size();
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while (true) {
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enum xz_ret ret = xz_dec_run(dec, &buf);
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if (ret == XZ_STREAM_END)
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break;
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if (ret != XZ_OK) {
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xz_dec_end(dec);
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return false;
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}
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if (buf.out_pos == buf.out_size) {
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size_t old = output.size();
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output.resize(old * 2);
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buf.out = output.data();
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buf.out_size = output.size();
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}
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}
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output.resize(buf.out_pos);
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xz_dec_end(dec);
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return true;
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}
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static bool getLibraryPath(const char* name, std::string& out) {
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FILE* fp = fopen("/proc/self/maps", "r");
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if (!fp) return false;
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char line[1024];
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while (fgets(line, sizeof(line), fp)) {
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if (strstr(line, name)) {
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char* path = strchr(line, '/');
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if (path) {
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out = path;
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out.erase(out.find('\n'));
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fclose(fp);
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return true;
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}
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}
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}
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fclose(fp);
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return false;
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}
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static uintptr_t getModuleBase(const char* name) {
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FILE* fp = fopen("/proc/self/maps", "r");
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if (!fp) return 0;
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char line[1024];
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uintptr_t base = 0;
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while (fgets(line, sizeof(line), fp)) {
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if (strstr(line, name)) {
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base = strtoull(line, nullptr, 16);
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break;
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}
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}
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fclose(fp);
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return base;
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}
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static uint64_t findSymbolOffset(
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const std::vector<uint8_t>& elf,
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const char* symbol_substring) {
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auto* eh = reinterpret_cast<const Elf64_Ehdr*>(elf.data());
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auto* shdr = reinterpret_cast<const Elf64_Shdr*>(
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elf.data() + eh->e_shoff);
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const char* shstr =
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reinterpret_cast<const char*>(
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elf.data() + shdr[eh->e_shstrndx].sh_offset);
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const Elf64_Shdr* symtab = nullptr;
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const Elf64_Shdr* strtab = nullptr;
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for (int i = 0; i < eh->e_shnum; ++i) {
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const char* secname = shstr + shdr[i].sh_name;
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if (!strcmp(secname, ".symtab"))
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symtab = &shdr[i];
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if (!strcmp(secname, ".strtab"))
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strtab = &shdr[i];
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}
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if (!symtab || !strtab)
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return 0;
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auto* symbols = reinterpret_cast<const Elf64_Sym*>(
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elf.data() + symtab->sh_offset);
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const char* strings =
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reinterpret_cast<const char*>(
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elf.data() + strtab->sh_offset);
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size_t count = symtab->sh_size / sizeof(Elf64_Sym);
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for (size_t i = 0; i < count; ++i) {
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const char* name = strings + symbols[i].st_name;
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if (strstr(name, symbol_substring) &&
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ELF64_ST_TYPE(symbols[i].st_info) == STT_FUNC) {
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LOGI("Resolved %s at 0x%lx",
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name,
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(unsigned long)symbols[i].st_value);
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return symbols[i].st_value;
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}
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}
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return 0;
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}
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static bool hookLibrary(const char* libname) {
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if (!hook_func) {
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LOGE("hook_func not initialized");
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return false;
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}
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std::string path;
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if (!getLibraryPath(libname, path)) {
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LOGE("Failed to locate %s", libname);
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return false;
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}
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int fd = open(path.c_str(), O_RDONLY);
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if (fd < 0) return false;
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struct stat st{};
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if (fstat(fd, &st) != 0) {
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close(fd);
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return false;
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}
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std::vector<uint8_t> file(st.st_size);
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read(fd, file.data(), st.st_size);
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close(fd);
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auto* eh = reinterpret_cast<Elf64_Ehdr*>(file.data());
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auto* shdr = reinterpret_cast<Elf64_Shdr*>(
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file.data() + eh->e_shoff);
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const char* shstr =
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reinterpret_cast<const char*>(
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file.data() + shdr[eh->e_shstrndx].sh_offset);
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for (int i = 0; i < eh->e_shnum; ++i) {
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if (!strcmp(shstr + shdr[i].sh_name, ".gnu_debugdata")) {
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std::vector<uint8_t> compressed(
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file.begin() + shdr[i].sh_offset,
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file.begin() + shdr[i].sh_offset + shdr[i].sh_size);
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std::vector<uint8_t> decompressed;
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if (!decompressXZ(
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compressed.data(),
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compressed.size(),
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decompressed))
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return false;
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uintptr_t base = getModuleBase(libname);
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if (!base) return false;
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uint64_t chk_offset =
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findSymbolOffset(decompressed,
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"l2c_fcr_chk_chan_modes");
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uint64_t sdp_offset =
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findSymbolOffset(decompressed,
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"BTA_DmSetLocalDiRecord");
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if (chk_offset) {
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void* target =
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reinterpret_cast<void*>(base + chk_offset);
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hook_func(target,
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(void*)fake_l2c_fcr_chk_chan_modes,
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(void**)&original_l2c_fcr_chk_chan_modes);
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LOGI("Hooked l2c_fcr_chk_chan_modes");
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}
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if (sdp_offset) {
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void* target =
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reinterpret_cast<void*>(base + sdp_offset);
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hook_func(target,
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(void*)fake_BTA_DmSetLocalDiRecord,
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(void**)&original_BTA_DmSetLocalDiRecord);
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LOGI("Hooked BTA_DmSetLocalDiRecord");
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}
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return true;
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}
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}
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return false;
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}
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static void on_library_loaded(const char* name, void*) {
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if (strstr(name, "libbluetooth_jni.so")) {
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LOGI("Bluetooth JNI loaded");
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hookLibrary("libbluetooth_jni.so");
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}
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if (strstr(name, "libbluetooth_qti.so")) {
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LOGI("Bluetooth QTI loaded");
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hookLibrary("libbluetooth_qti.so");
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}
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}
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extern "C"
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[[gnu::visibility("default")]]
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[[gnu::used]]
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NativeOnModuleLoaded native_init(const NativeAPIEntries* entries) {
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LOGI("LibrePods initialized");
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hook_func = (HookFunType)entries->hook_func;
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return on_library_loaded;
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}
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