android_bootable_recovery/kernel_module_loader.cpp

#include "kernel_module_loader.hpp"
#include "common.h"

const std::vector<std::string> kernel_modules_requested = TWFunc::split_string(EXPAND(TW_LOAD_VENDOR_MODULES), ' ', true);

bool KernelModuleLoader::Load_Vendor_Modules() {
	// check /lib/modules (ramdisk vendor_boot)
	// check /lib/modules/N.N (ramdisk vendor_boot)
	// check /lib/modules/N.N-gki (ramdisk vendor_boot)
	// check /vendor/lib/modules (ramdisk)
	// check /vendor/lib/modules/1.1 (ramdisk prebuilt modules)
	// check /vendor/lib/modules/N.N (vendor mounted)
	// check /vendor/lib/modules/N.N-gki (vendor mounted)
	int modules_loaded = 0;

	LOGINFO("Attempting to load modules\n");
	std::string vendor_base_dir(VENDOR_MODULE_DIR);
	std::string base_dir(VENDOR_BOOT_MODULE_DIR);
	std::vector<std::string> module_dirs;
	std::vector<std::string> vendor_module_dirs;

	TWPartition* ven = PartitionManager.Find_Partition_By_Path("/vendor");
	vendor_module_dirs.push_back(VENDOR_MODULE_DIR);
	vendor_module_dirs.push_back(vendor_base_dir + "/1.1");

	module_dirs.push_back(base_dir);

	struct utsname uts;
	if (uname(&uts)) {
		LOGERR("Unable to query kernel for version info\n");
	}

	std::string rls(uts.release);
	std::vector<std::string> release = TWFunc::split_string(rls, '.', true);
	int expected_module_count = kernel_modules_requested.size();
	module_dirs.push_back(base_dir + "/" + release[0] + "." + release[1]);
	std::string gki = "/" + release[0] + "." + release[1] + "-gki";
	module_dirs.push_back(base_dir + gki);
	vendor_module_dirs.push_back(vendor_base_dir + gki);

	for (auto&& module_dir:module_dirs) {
		modules_loaded += Try_And_Load_Modules(module_dir, false);
		if (modules_loaded >= expected_module_count) goto exit;
	}

	for (auto&& module_dir:vendor_module_dirs) {
		modules_loaded += Try_And_Load_Modules(module_dir, false);
		if (modules_loaded >= expected_module_count) goto exit;
	}

	if (ven) {
		LOGINFO("Checking mounted /vendor\n");
		ven->Mount(true);
	}

	for (auto&& module_dir:vendor_module_dirs) {
		modules_loaded += Try_And_Load_Modules(module_dir, true);
		if (modules_loaded >= expected_module_count) goto exit;
	}

exit:
	if (ven)
		ven->UnMount(false);

	android::base::SetProperty("twrp.modules.loaded", "true");

	TWFunc::Wait_For_Battery(3s);

	return true;
}

int KernelModuleLoader::Try_And_Load_Modules(std::string module_dir, bool vendor_is_mounted) {
		LOGINFO("Checking directory: %s\n", module_dir.c_str());
		int modules_loaded = 0;
		std::string dest_module_dir;
		dest_module_dir = "/tmp" + module_dir;
		TWFunc::Recursive_Mkdir(dest_module_dir);
		Copy_Modules_To_Tmpfs(module_dir);
		if (!Write_Module_List(dest_module_dir))
			return kernel_modules_requested.size();
		if (!vendor_is_mounted && module_dir == "/vendor/lib/modules") {
			module_dir = "/lib/modules";
		}
		LOGINFO("mounting %s on %s\n", dest_module_dir.c_str(), module_dir.c_str());
		if (mount(dest_module_dir.c_str(), module_dir.c_str(), "", MS_BIND, NULL) == 0) {
			Modprobe m({module_dir}, "modules.load.twrp");
			m.EnableVerbose(true);
			m.LoadListedModules(false);
			modules_loaded = m.GetModuleCount();
			umount2(module_dir.c_str(), MNT_DETACH);
			LOGINFO("Modules Loaded: %d\n", modules_loaded);
		}
		return modules_loaded;
}

std::vector<string> KernelModuleLoader::Skip_Loaded_Kernel_Modules() {
	std::vector<string> kernel_modules = kernel_modules_requested;
	std::vector<string> loaded_modules;
	std::string kernel_module_file = "/proc/modules";
	if (TWFunc::read_file(kernel_module_file, loaded_modules) < 0)
		LOGINFO("failed to get loaded kernel modules\n");
	LOGINFO("number of modules loaded by init: %zu\n", loaded_modules.size());
	if (loaded_modules.size() == 0)
		return kernel_modules;
	for (auto&& module_line:loaded_modules) {
		auto module = TWFunc::Split_String(module_line, " ")[0];
		std::string full_module_name = module + ".ko";
		auto found = std::find(kernel_modules.begin(), kernel_modules.end(), full_module_name);
		if (found != kernel_modules.end()) {
			LOGINFO("found module to dedupe: %s\n", (*found).c_str());
			kernel_modules.erase(found);
		}
	}
	return kernel_modules;
}

bool KernelModuleLoader::Write_Module_List(std::string module_dir) {
	DIR* d;
	struct dirent* de;
	std::vector<std::string> kernel_modules;
	d = opendir(module_dir.c_str());
	auto deduped_modules = Skip_Loaded_Kernel_Modules();
	if (deduped_modules.size() == 0) {
		LOGINFO("Requested modules are loaded\n");
		return false;
	}
	if (d != nullptr) {
		while ((de = readdir(d)) != nullptr) {
			std::string kernel_module = de->d_name;
			if (de->d_type == DT_REG) {
				if (android::base::EndsWith(kernel_module, ".ko")) {
					for (auto&& requested:kernel_modules_requested) {
						if (kernel_module == requested) {
							kernel_modules.push_back(kernel_module);
							continue;
						}
					}
					continue;
				}
			}
		}
		std::string module_file = module_dir + "/modules.load.twrp";
		TWFunc::write_to_file(module_file, kernel_modules);
		closedir(d);
	}
	return true;
}

bool KernelModuleLoader::Copy_Modules_To_Tmpfs(std::string module_dir) {
	std::string ramdisk_dir = "/tmp" + module_dir;
	DIR* d;
	struct dirent* de;
	d = opendir(module_dir.c_str());
	if (d != nullptr) {
		while ((de = readdir(d)) != nullptr) {
			std::string kernel_module = de->d_name;
			if (de->d_type == DT_REG) {
				std::string src =  module_dir + "/" + de->d_name;
				std::string dest = ramdisk_dir + "/" + de->d_name;
				if (TWFunc::copy_file(src, dest, 0700, false) != 0) {
					return false;
				}
			}
		}
		closedir(d);
	} else {
		LOGINFO("Unable to open module directory: %s. Skipping\n", module_dir.c_str());
		return false;
	}
	return true;
}