#include #include #include #include #include #include #include #include #include "core.hpp" using namespace std; #define VLOGD(tag, from, to) LOGD("%-8s: %s <- %s\n", tag, to, from) #define TYPE_MIRROR (1 << 0) /* mount from mirror */ #define TYPE_INTER (1 << 1) /* intermediate node */ #define TYPE_TMPFS (1 << 2) /* replace with tmpfs */ #define TYPE_MODULE (1 << 3) /* mount from module */ #define TYPE_ROOT (1 << 4) /* partition root */ #define TYPE_CUSTOM (1 << 5) /* custom node type overrides all */ #define TYPE_DIR (TYPE_INTER|TYPE_TMPFS|TYPE_ROOT) class node_entry; class dir_node; class inter_node; class mirror_node; class tmpfs_node; class module_node; class root_node; template static bool isa(node_entry *node); static int bind_mount(const char *from, const char *to) { int ret = xmount(from, to, nullptr, MS_BIND, nullptr); if (ret == 0) VLOGD("bind_mnt", from, to); return ret; } template uint8_t type_id() { return TYPE_CUSTOM; } template<> uint8_t type_id() { return TYPE_DIR; } template<> uint8_t type_id() { return TYPE_INTER; } template<> uint8_t type_id() { return TYPE_MIRROR; } template<> uint8_t type_id() { return TYPE_TMPFS; } template<> uint8_t type_id() { return TYPE_MODULE; } template<> uint8_t type_id() { return TYPE_ROOT; } class node_entry { public: virtual ~node_entry() = default; // Node info bool is_dir() { return file_type() == DT_DIR; } bool is_lnk() { return file_type() == DT_LNK; } bool is_reg() { return file_type() == DT_REG; } uint8_t type() { return node_type; } const string &name() { return _name; } const string &node_path(); string mirror_path() { return mirror_dir + node_path(); } // Tree methods dir_node *parent() { return _parent; } void merge(node_entry *other); virtual void mount() = 0; static string module_mnt; static string mirror_dir; protected: template node_entry(const char *name, uint8_t file_type, T*) : _name(name), _file_type(file_type), node_type(type_id()) {} template explicit node_entry(T*) : _file_type(0), node_type(type_id()) {} void create_and_mount(const string &src); // Use top bit of _file_type for node exist status bool exist() { return static_cast(_file_type & (1 << 7)); } void set_exist(bool b) { if (b) _file_type |= (1 << 7); else _file_type &= ~(1 << 7); } uint8_t file_type() { return static_cast(_file_type & ~(1 << 7)); } private: friend class dir_node; static bool should_be_tmpfs(node_entry *child); // Node properties string _name; uint8_t _file_type; uint8_t node_type; dir_node *_parent = nullptr; // Cache string _node_path; }; class dir_node : public node_entry { public: friend void node_entry::merge(node_entry *other); using map_type = map; using iterator = map_type::iterator; ~dir_node() override { for (auto &it : children) delete it.second; children.clear(); } // Return false to indicate need to upgrade to module bool collect_files(const char *module, int dfd); // Return false to indicate need to upgrade to skeleton bool prepare(); // Default directory mount logic void mount() override { for (auto &pair : children) pair.second->mount(); } /*************** * Tree Methods ***************/ bool is_empty() { return children.empty(); } template T *child(string_view name) { return iterator_to_node(children.find(name)); } // Lazy val root_node *root() { if (!_root) _root = _parent->root(); return _root; } // Return child with name or nullptr node_entry *extract(string_view name); // Return false if rejected bool insert(node_entry *node) { auto fn = [=](auto) { return node; }; return node && iterator_to_node(insert(node->_name, node->node_type, fn)); } // Return inserted node or null if rejected template T *emplace(string_view name, Args &&...args) { auto fn = [&](auto) { return new T(std::forward(args)...); }; return iterator_to_node(insert(name, type_id(), fn)); } // Return inserted node, existing node with same rank, or null if rejected template T *emplace_or_get(string_view name, Args &&...args) { auto fn = [&](auto) { return new T(std::forward(args)...); }; return iterator_to_node(insert(name, type_id(), fn, true)); } // Return upgraded node or null if rejected template T *upgrade(string_view name, Args &...args) { return iterator_to_node(upgrade(children.find(name), args...)); } protected: template dir_node(const char *name, uint8_t file_type, T *self) : node_entry(name, file_type, self) { if constexpr (std::is_same_v) _root = self; } template dir_node(node_entry *node, T *self) : node_entry(self) { merge(node); if constexpr (std::is_same_v) _root = self; } template dir_node(const char *name, T *self) : dir_node(name, DT_DIR, self) {} template T *iterator_to_node(iterator it) { return static_cast(it == children.end() ? nullptr : it->second); } // Emplace insert a new node, or upgrade if the requested type has a higher rank. // Return iterator to new node or end() if insertion is rejected. // If get_same is true and a node with the same rank exists, it will return that node instead. // fn is the node construction callback. Signature: (node_ent *&) -> node_ent * // fn gets a reference to the existing node pointer and returns a new node object. // Input is null when there is no existing node. If returns null, the insertion is rejected. // If fn consumes the input, it should set the reference to null. template iterator insert(iterator it, uint8_t type, const Func &fn, bool get_same); template iterator insert(string_view name, uint8_t type, const Func &fn, bool get_same = false) { return insert(children.find(name), type, fn, get_same); } template iterator upgrade(iterator it, Args &&...args); // dir nodes host children map_type children; // Root node lookup cache root_node *_root = nullptr; }; class root_node : public dir_node { public: explicit root_node(const char *name) : dir_node(name, this), prefix("") {} explicit root_node(node_entry *node) : dir_node(node, this), prefix("/system") {} const char * const prefix; }; class inter_node : public dir_node { public: inter_node(const char *name, const char *module) : dir_node(name, this), module(module) {} private: const char *module; friend class module_node; }; class module_node : public node_entry { public: module_node(const char *module, dirent *entry) : node_entry(entry->d_name, entry->d_type, this), module(module) {} module_node(node_entry *node, const char *module) : node_entry(this), module(module) { merge(node); } explicit module_node(inter_node *node) : module_node(node, node->module) {} void mount() override; private: const char *module; }; class mirror_node : public node_entry { public: explicit mirror_node(dirent *entry) : node_entry(entry->d_name, entry->d_type, this) {} void mount() override { create_and_mount(mirror_path()); } }; class tmpfs_node : public dir_node { public: explicit tmpfs_node(node_entry *node); void mount() override; }; // Poor man's dynamic cast without RTTI template static bool isa(node_entry *node) { return node && (node->type() & type_id()); } template static T *dyn_cast(node_entry *node) { return isa(node) ? static_cast(node) : nullptr; } string node_entry::module_mnt; string node_entry::mirror_dir; // other will be deleted void node_entry::merge(node_entry *other) { _name.swap(other->_name); _file_type = other->_file_type; _parent = other->_parent; // Merge children if both is dir if (auto a = dyn_cast(this)) { if (auto b = dyn_cast(other)) { a->children.merge(b->children); for (auto &pair : a->children) pair.second->_parent = a; } } delete other; } const string &node_entry::node_path() { if (_parent && _node_path.empty()) _node_path = _parent->node_path() + '/' + _name; return _node_path; } /************************* * Node Tree Construction *************************/ template dir_node::iterator dir_node::insert(iterator it, uint8_t type, const Func &fn, bool get_same) { node_entry *node = nullptr; if (it != children.end()) { // Upgrade existing node only if higher rank if (it->second->node_type < type) { node = fn(it->second); if (!node) return children.end(); if (it->second) node->merge(it->second); it = children.erase(it); // Minor optimization to make insert O(1) by using hint if (it == children.begin()) it = children.emplace(node->_name, node).first; else it = children.emplace_hint(--it, node->_name, node); } else { if (get_same && it->second->node_type != type) return children.end(); return it; } } else { node = fn(node); if (!node) return children.end(); node->_parent = this; it = children.emplace(node->_name, node).first; } return it; } template dir_node::iterator dir_node::upgrade(iterator it, Args &&... args) { return insert(it, type_id(), [&](node_entry *&ex) -> node_entry * { if (!ex) return nullptr; if constexpr (!std::is_same_v) { // Type check if type is specified if (!isa(ex)) return nullptr; } auto node = new To(static_cast(ex), std::forward(args)...); ex = nullptr; return node; }, false); } node_entry* dir_node::extract(string_view name) { auto it = children.find(name); if (it != children.end()) { auto ret = it->second; children.erase(it); return ret; } return nullptr; } tmpfs_node::tmpfs_node(node_entry *node) : dir_node(node, this) { string mirror = mirror_path(); if (auto dir = open_dir(mirror.data())) { set_exist(true); for (dirent *entry; (entry = xreaddir(dir.get()));) { // Insert mirror nodes emplace(entry->d_name, entry); } } else { // It is actually possible that mirror does not exist (nested mount points) // Set self to non exist so this node will be ignored at mount set_exist(false); return; } for (auto it = children.begin(); it != children.end(); ++it) { // Need to upgrade all inter_node children to tmpfs_node if (isa(it->second)) it = upgrade(it); } } // We need to upgrade to tmpfs node if any child: // - Target does not exist // - Source or target is a symlink bool node_entry::should_be_tmpfs(node_entry *child) { struct stat st; if (lstat(child->node_path().data(), &st) != 0) { return true; } else { child->set_exist(true); if (child->is_lnk() || S_ISLNK(st.st_mode)) return true; } return false; } bool dir_node::prepare() { bool to_tmpfs = false; for (auto it = children.begin(); it != children.end();) { if (should_be_tmpfs(it->second)) { if (node_type > type_id()) { // Upgrade will fail, remove the unsupported child node delete it->second; it = children.erase(it); continue; } // Tell parent to upgrade self to tmpfs to_tmpfs = true; // If child is inter_node, upgrade to module if (auto nit = upgrade(it); nit != children.end()) { it = nit; goto next_node; } } if (auto dn = dyn_cast(it->second); dn && dn->is_dir() && !dn->prepare()) { // Upgrade child to tmpfs it = upgrade(it); } next_node: ++it; } return !to_tmpfs; } bool dir_node::collect_files(const char *module, int dfd) { auto dir = xopen_dir(xopenat(dfd, _name.data(), O_RDONLY | O_CLOEXEC)); if (!dir) return true; for (dirent *entry; (entry = xreaddir(dir.get()));) { if (entry->d_name == ".replace"sv) { // Stop traversing and tell parent to upgrade self to module return false; } if (entry->d_type == DT_DIR) { dir_node *dn; if (auto it = children.find(entry->d_name); it == children.end()) { dn = emplace(entry->d_name, entry->d_name, module); } else { dn = iterator_to_node(upgrade(it)); dn->set_exist(true); } if (dn && !dn->collect_files(module, dirfd(dir.get()))) { upgrade(dn->name(), module); } } else { emplace(entry->d_name, module, entry); } } return true; } /************************ * Mount Implementations ************************/ void node_entry::create_and_mount(const string &src) { const string &dest = node_path(); if (is_lnk()) { VLOGD("cp_link", src.data(), dest.data()); cp_afc(src.data(), dest.data()); } else { if (is_dir()) xmkdir(dest.data(), 0); else if (is_reg()) close(xopen(dest.data(), O_RDONLY | O_CREAT | O_CLOEXEC, 0)); else return; bind_mount(src.data(), dest.data()); } } void module_node::mount() { string src = module_mnt + module + parent()->root()->prefix + node_path(); if (exist()) clone_attr(mirror_path().data(), src.data()); if (isa(parent())) create_and_mount(src); else if (is_dir() || is_reg()) bind_mount(src.data(), node_path().data()); } void tmpfs_node::mount() { if (!exist()) return; string src = mirror_path(); const string &dest = node_path(); file_attr a{}; if (access(src.data(), F_OK) == 0) getattr(src.data(), &a); else getattr(parent()->node_path().data(), &a); mkdir(dest.data(), 0); if (!isa(parent())) { // We don't need another layer of tmpfs if parent is skel xmount("tmpfs", dest.data(), "tmpfs", 0, nullptr); VLOGD("mnt_tmp", "tmpfs", dest.data()); } setattr(dest.data(), &a); dir_node::mount(); } /**************** * Magisk Stuffs ****************/ class magisk_node : public node_entry { public: explicit magisk_node(const char *name) : node_entry(name, DT_REG, this) {} void mount() override { const string &dir_name = parent()->node_path(); if (name() == "magisk") { for (int i = 0; applet_names[i]; ++i) { string dest = dir_name + "/" + applet_names[i]; VLOGD("create", "./magisk", dest.data()); xsymlink("./magisk", dest.data()); } } else { string dest = dir_name + "/supolicy"; VLOGD("create", "./magiskpolicy", dest.data()); xsymlink("./magiskpolicy", dest.data()); } create_and_mount(MAGISKTMP + "/" + name()); } }; static void inject_magisk_bins(root_node *system) { auto bin = system->child("bin"); if (!bin) { bin = new inter_node("bin", ""); system->insert(bin); } // Insert binaries bin->insert(new magisk_node("magisk")); bin->insert(new magisk_node("magiskpolicy")); // Also delete all applets to make sure no modules can override it for (int i = 0; applet_names[i]; ++i) delete bin->extract(applet_names[i]); delete bin->extract("supolicy"); } vector *module_list; int app_process_32 = -1; int app_process_64 = -1; #define mount_zygisk(bit) \ if (access("/system/bin/app_process" #bit, F_OK) == 0) { \ app_process_##bit = xopen("/system/bin/app_process" #bit, O_RDONLY | O_CLOEXEC); \ string zbin = zygisk_bin + "/app_process" #bit; \ string mbin = MAGISKTMP + "/magisk" #bit; \ int src = xopen(mbin.data(), O_RDONLY | O_CLOEXEC); \ int out = xopen(zbin.data(), O_CREAT | O_WRONLY | O_CLOEXEC, 0); \ xsendfile(out, src, nullptr, INT_MAX); \ close(src); \ close(out); \ clone_attr("/system/bin/app_process" #bit, zbin.data()); \ bind_mount(zbin.data(), "/system/bin/app_process" #bit); \ } void magic_mount() { node_entry::mirror_dir = MAGISKTMP + "/" MIRRDIR; node_entry::module_mnt = MAGISKTMP + "/" MODULEMNT "/"; auto root = make_unique(""); auto system = new root_node("system"); root->insert(system); char buf[4096]; LOGI("* Loading modules\n"); if (module_list) { for (const auto &m : *module_list) { const char *module = m.name.data(); char *b = buf + sprintf(buf, "%s/" MODULEMNT "/%s/", MAGISKTMP.data(), module); // Read props strcpy(b, "system.prop"); if (access(buf, F_OK) == 0) { LOGI("%s: loading [system.prop]\n", module); load_prop_file(buf, false); } // Check whether skip mounting strcpy(b, "skip_mount"); if (access(buf, F_OK) == 0) continue; // Double check whether the system folder exists strcpy(b, "system"); if (access(buf, F_OK) != 0) continue; LOGI("%s: loading mount files\n", module); b[-1] = '\0'; int fd = xopen(buf, O_RDONLY | O_CLOEXEC); system->collect_files(module, fd); close(fd); } } if (MAGISKTMP != "/sbin") { // Need to inject our binaries into /system/bin inject_magisk_bins(system); } if (!system->is_empty()) { // Handle special read-only partitions for (const char *part : { "/vendor", "/product", "/system_ext" }) { struct stat st; if (lstat(part, &st) == 0 && S_ISDIR(st.st_mode)) { if (auto old = system->extract(part + 1)) { auto new_node = new root_node(old); root->insert(new_node); } } } root->prepare(); root->mount(); } // Mount on top of modules to enable zygisk if (zygisk_enabled) { string zygisk_bin = MAGISKTMP + "/" ZYGISKBIN; mkdir(zygisk_bin.data(), 0); mount_zygisk(32) mount_zygisk(64) } } static void prepare_modules() { // Upgrade modules if (auto dir = open_dir(MODULEUPGRADE); dir) { int ufd = dirfd(dir.get()); int mfd = xopen(MODULEROOT, O_RDONLY | O_CLOEXEC); for (dirent *entry; (entry = xreaddir(dir.get()));) { if (entry->d_type == DT_DIR) { // Cleanup old module if exists if (faccessat(mfd, entry->d_name, F_OK, 0) == 0) { int modfd = xopenat(mfd, entry->d_name, O_RDONLY | O_CLOEXEC); if (faccessat(modfd, "disable", F_OK, 0) == 0) { auto disable = entry->d_name + "/disable"s; close(xopenat(ufd, disable.data(), O_RDONLY | O_CREAT | O_CLOEXEC, 0)); } frm_rf(modfd); unlinkat(mfd, entry->d_name, AT_REMOVEDIR); } LOGI("Upgrade / New module: %s\n", entry->d_name); renameat(ufd, entry->d_name, mfd, entry->d_name); } } close(mfd); rm_rf(MODULEUPGRADE); } // Setup module mount (workaround nosuid selabel issue) auto src = MAGISKTMP + "/" MIRRDIR MODULEROOT; auto dest = MAGISKTMP + "/" MODULEMNT; xmkdir(dest.data(), 0755); bind_mount(src.data(), dest.data()); restorecon(); chmod(SECURE_DIR, 0700); } template static void foreach_module(Func fn) { auto dir = open_dir(MODULEROOT); if (!dir) return; int dfd = dirfd(dir.get()); for (dirent *entry; (entry = xreaddir(dir.get()));) { if (entry->d_type == DT_DIR && entry->d_name != ".core"sv) { int modfd = xopenat(dfd, entry->d_name, O_RDONLY | O_CLOEXEC); fn(dfd, entry, modfd); close(modfd); } } } static void collect_modules(bool open_zygisk) { foreach_module([=](int dfd, dirent *entry, int modfd) { if (faccessat(modfd, "remove", F_OK, 0) == 0) { LOGI("%s: remove\n", entry->d_name); auto uninstaller = MODULEROOT + "/"s + entry->d_name + "/uninstall.sh"; if (access(uninstaller.data(), F_OK) == 0) exec_script(uninstaller.data()); frm_rf(xdup(modfd)); unlinkat(dfd, entry->d_name, AT_REMOVEDIR); return; } unlinkat(modfd, "update", 0); if (faccessat(modfd, "disable", F_OK, 0) == 0) return; module_info info; if (zygisk_enabled) { // Riru and its modules are not compatible with zygisk if (entry->d_name == "riru-core"sv || faccessat(modfd, "riru", F_OK, 0) == 0) { LOGI("%s: ignore\n", entry->d_name); return; } if (open_zygisk) { #if defined(__arm__) info.z32 = openat(modfd, "zygisk/armeabi-v7a.so", O_RDONLY | O_CLOEXEC); #elif defined(__aarch64__) info.z32 = openat(modfd, "zygisk/armeabi-v7a.so", O_RDONLY | O_CLOEXEC); info.z64 = openat(modfd, "zygisk/arm64-v8a.so", O_RDONLY | O_CLOEXEC); #elif defined(__i386__) info.z32 = openat(modfd, "zygisk/x86.so", O_RDONLY | O_CLOEXEC); #elif defined(__x86_64__) info.z32 = openat(modfd, "zygisk/x86.so", O_RDONLY | O_CLOEXEC); info.z64 = openat(modfd, "zygisk/x86_64.so", O_RDONLY | O_CLOEXEC); #else #error Unsupported ABI #endif unlinkat(modfd, "zygisk/unloaded", 0); } } else { // Ignore zygisk modules when zygisk is not enabled if (faccessat(modfd, "zygisk", F_OK, 0) == 0) { LOGI("%s: ignore\n", entry->d_name); return; } } info.name = entry->d_name; module_list->push_back(info); }); if (zygisk_enabled) { bool use_memfd = true; auto convert_to_memfd = [&](int fd) -> int { if (fd < 0) return -1; if (use_memfd) { int memfd = syscall(__NR_memfd_create, "jit-cache", MFD_CLOEXEC); if (memfd >= 0) { xsendfile(memfd, fd, nullptr, INT_MAX); close(fd); return memfd; } else { // memfd_create failed, just use what we had use_memfd = false; } } return fd; }; std::for_each(module_list->begin(), module_list->end(), [&](module_info &info) { info.z32 = convert_to_memfd(info.z32); #if defined(__LP64__) info.z64 = convert_to_memfd(info.z64); #endif }); } } void handle_modules() { default_new(module_list); prepare_modules(); collect_modules(false); exec_module_scripts("post-fs-data"); // Recollect modules (module scripts could remove itself) module_list->clear(); collect_modules(true); } void disable_modules() { foreach_module([](int, auto, int modfd) { close(xopenat(modfd, "disable", O_RDONLY | O_CREAT | O_CLOEXEC, 0)); }); } void remove_modules() { foreach_module([](int, dirent *entry, int) { auto uninstaller = MODULEROOT + "/"s + entry->d_name + "/uninstall.sh"; if (access(uninstaller.data(), F_OK) == 0) exec_script(uninstaller.data()); }); rm_rf(MODULEROOT); } void exec_module_scripts(const char *stage) { vector module_names; std::transform(module_list->begin(), module_list->end(), std::back_inserter(module_names), [](const module_info &info) -> string_view { return info.name; }); exec_module_scripts(stage, module_names); }