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Introduce new module mount implementation

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Rewrite the whole module mounting logic from scratch.
Even the algorithm is different compared to the old one.

This new design focuses on a few key points:
- Modular: Custom nodes can be injected into the mount tree.
  It's the main reason for starting the rewrite (needed for Android 11)
- Efficient: Compared to the existing implementation, this is the most
  efficient (both in terms of computation and memory usage) design I
  currently can come up with.
- Accurate: The old mounting logic relies on handling specifically every
  edge case I can think of. During this rewrite I actually found some
  cases that the old design does not handle properly. This new design is
  architected in a way (node types and its rankings) that it should
  handle edge cases all by itself when constructing mount trees.
This commit is contained in:
topjohnwu 2020-04-18 02:00:48 -07:00
parent ab853e1fcf
commit a73e7e9f99
4 changed files with 631 additions and 429 deletions
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1
native/jni/Android.mk
View File

@ -20,6 +20,7 @@ LOCAL_SRC_FILES := \
core/db.cpp \ core/db.cpp \
core/scripting.cpp \ core/scripting.cpp \
core/restorecon.cpp \ core/restorecon.cpp \
core/module.cpp \
magiskhide/magiskhide.cpp \ magiskhide/magiskhide.cpp \
magiskhide/proc_monitor.cpp \ magiskhide/proc_monitor.cpp \
magiskhide/hide_utils.cpp \ magiskhide/hide_utils.cpp \

439
native/jni/core/bootstages.cpp
View File

@ -16,286 +16,18 @@
#include <daemon.hpp> #include <daemon.hpp>
#include <resetprop.hpp> #include <resetprop.hpp>
#include <selinux.hpp> #include <selinux.hpp>
#include <flags.h>
using namespace std; using namespace std;
static vector<string> module_list; extern vector<string> module_list;
static bool no_secure_dir = false; static bool no_secure_dir = false;
static bool pfs_done = false; static bool pfs_done = false;
static int bind_mount(const char *from, const char *to, bool log = true);
extern void auto_start_magiskhide(); extern void auto_start_magiskhide();
/*************** /*********
* Magic Mount * * Setup *
***************/ *********/
#ifdef MAGISK_DEBUG
#define VLOGI(tag, from, to) LOGI("%s: %s <- %s\n", tag, to, from)
#else
#define VLOGI(tag, from, to) LOGI("%s: %s\n", tag, to)
#endif
// Precedence: MODULE > SKEL > INTER > DUMMY
#define IS_DUMMY 0x01 /* mount from mirror */
#define IS_INTER 0x02 /* intermediate node */
#define IS_SKEL 0x04 /* replace with tmpfs */
#define IS_MODULE 0x08 /* mount from module */
#define IS_DIR(n) ((n)->type == DT_DIR)
#define IS_LNK(n) ((n)->type == DT_LNK)
#define IS_REG(n) ((n)->type == DT_REG)
class node_entry {
public:
explicit node_entry(const char *name, uint8_t type = DT_DIR, uint8_t status = IS_INTER)
: module(nullptr), name(name), type(type), status(status), parent(nullptr) {}
~node_entry();
void create_module_tree(const char *module);
void magic_mount();
node_entry *extract(const char *name);
static bool vendor_root;
static bool product_root;
private:
const char *module; /* Only used when IS_MODULE */
const string name;
uint8_t type;
uint8_t status;
node_entry *parent;
vector<node_entry *> children;
node_entry(node_entry *parent, const char *module, const char *name, uint8_t type)
: module(module), name(name), type(type), status(0), parent(parent) {}
bool is_special();
bool is_root();
string get_path();
void insert(node_entry *&);
void clone_skeleton();
};
bool node_entry::vendor_root = false;
bool node_entry::product_root = false;
node_entry::~node_entry() {
for (auto &node : children)
delete node;
}
#define SPECIAL_NODE (parent->parent ? false : \
((vendor_root && name == "vendor") || (product_root && name == "product")))
bool node_entry::is_special() {
return parent ? SPECIAL_NODE : false;
}
bool node_entry::is_root() {
return parent ? SPECIAL_NODE : true;
}
string node_entry::get_path() {
string path;
if (parent)
path = parent->get_path();
path += "/";
path += name;
return path;
}
void node_entry::insert(node_entry *&node) {
node->parent = this;
for (auto &child : children) {
if (child->name == node->name) {
if (node->status > child->status) {
// The new node has higher precedence
delete child;
child = node;
} else {
delete node;
node = child;
}
return;
}
}
children.push_back(node);
}
void node_entry::create_module_tree(const char *module) {
auto full_path = get_path();
auto cwd = MODULEROOT + "/"s + module + full_path;
auto dir = xopen_dir(cwd.data());
if (!dir)
return;
// Check directory replace
if (faccessat(dirfd(dir.get()), ".replace", F_OK, 0) == 0) {
if (is_root()) {
// Root nodes should not be replaced
rm_rf(cwd.data());
} else if (status < IS_MODULE) {
// Upgrade current node to current module
this->module = module;
status = IS_MODULE;
}
return;
}
for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
// Create new node
auto node = new node_entry(this, module, entry->d_name, entry->d_type);
auto dest = full_path + "/" + entry->d_name;
auto src = cwd + "/" + entry->d_name;
/*
* Clone current directory in one of the following conditions:
* - Target does not exist
* - Module file is a symlink
* - Target file is a symlink (exclude special nodes)
*/
bool clone = false;
if (IS_LNK(node) || access(dest.data(), F_OK) != 0) {
clone = true;
} else if (!node->is_special()) {
struct stat s;
xlstat(dest.data(), &s);
if (S_ISLNK(s.st_mode))
clone = true;
}
if (clone && is_root()) {
// Root nodes should not be cloned
rm_rf(src.data());
delete node;
continue;
}
if (clone) {
// Mark self as a skeleton
status |= IS_SKEL; /* This will not overwrite if parent is module */
node->status = IS_MODULE;
} else if (node->is_special()) {
// Special nodes will be pulled out as root nodes later
node->status = IS_INTER;
} else {
// Clone attributes from real path
clone_attr(dest.data(), src.data());
if (IS_DIR(node)) {
// First mark as an intermediate node
node->status = IS_INTER;
} else if (IS_REG(node)) {
// This is a file, mark as leaf
node->status = IS_MODULE;
}
}
insert(node);
if (IS_DIR(node)) {
// Recursive traverse through everything
node->create_module_tree(module);
}
}
}
void node_entry::clone_skeleton() {
// Clone the structure
auto full_path = get_path();
auto mirror_path = MAGISKTMP + "/" MIRRDIR + full_path;
if (auto dir = xopen_dir(mirror_path.data()); dir) {
for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
// Create dummy node
auto dummy = new node_entry(entry->d_name, entry->d_type, IS_DUMMY);
insert(dummy);
}
} else { return; }
if (status & IS_SKEL) {
file_attr attr;
getattr(full_path.data(), &attr);
LOGI("mnt_tmpfs : %s\n", full_path.data());
xmount("tmpfs", full_path.data(), "tmpfs", 0, nullptr);
setattr(full_path.data(), &attr);
}
for (auto &child : children) {
auto dest = full_path + "/" + child->name;
string src;
// Create the dummy file/directory
if (IS_DIR(child))
xmkdir(dest.data(), 0755);
else if (IS_REG(child))
close(creat(dest.data(), 0644));
// Links will be handled later
if (child->status & IS_MODULE) {
// Mount from module file to dummy file
src = MAGISKTMP + "/" MODULEMNT "/" + child->module + full_path + "/" + child->name;
} else if (child->status & (IS_SKEL | IS_INTER)) {
// It's an intermediate folder, recursive clone
child->clone_skeleton();
continue;
} else if (child->status & IS_DUMMY) {
// Mount from mirror to dummy file
src = MAGISKTMP + "/" MIRRDIR + full_path + "/" + child->name;
}
if (IS_LNK(child)) {
// Copy symlinks directly
cp_afc(src.data(), dest.data());
VLOGI("copy_link ", src.data(), dest.data());
} else {
bind_mount(src.data(), dest.data());
}
}
}
void node_entry::magic_mount() {
if (status & IS_MODULE) {
// Mount module item
auto dest = get_path();
auto src = MAGISKTMP + "/" MODULEMNT "/" + module + dest;
bind_mount(src.data(), dest.data());
} else if (status & IS_SKEL) {
// The node is labeled to be cloned with skeleton, lets do it
clone_skeleton();
} else if (status & IS_INTER) {
// It's an intermediate node, travel deeper
for (auto &child : children)
child->magic_mount();
}
}
node_entry *node_entry::extract(const char *name) {
node_entry *node = nullptr;
// Extract the node out of the tree
for (auto it = children.begin(); it != children.end(); ++it) {
if ((*it)->name == name) {
node = *it;
node->parent = nullptr;
children.erase(it);
break;
}
}
return node;
}
/*****************
* Miscellaneous *
*****************/
static int bind_mount(const char *from, const char *to, bool log) {
int ret = xmount(from, to, nullptr, MS_BIND, nullptr);
if (log) VLOGI("bind_mount", from, to);
return ret;
}
#define DIR_IS(part) (me->mnt_dir == "/" #part ""sv) #define DIR_IS(part) (me->mnt_dir == "/" #part ""sv)
#define SETMIR(b, part) sprintf(b, "%s/" MIRRDIR "/" #part, MAGISKTMP.data()) #define SETMIR(b, part) sprintf(b, "%s/" MIRRDIR "/" #part, MAGISKTMP.data())
@ -308,7 +40,7 @@ static int bind_mount(const char *from, const char *to, bool log) {
mknod(buf2, (st.st_mode & S_IFMT) | 0600, st.st_rdev); \ mknod(buf2, (st.st_mode & S_IFMT) | 0600, st.st_rdev); \
xmkdir(buf1, 0755); \ xmkdir(buf1, 0755); \
xmount(buf2, buf1, me->mnt_type, flag, nullptr); \ xmount(buf2, buf1, me->mnt_type, flag, nullptr); \
VLOGI("mount", buf2, buf1); \ LOGI("mount: %s\n", buf1); \
} }
static bool magisk_env() { static bool magisk_env() {
@ -367,7 +99,7 @@ static bool magisk_env() {
mount_mirror(system_root, MS_RDONLY); mount_mirror(system_root, MS_RDONLY);
SETMIR(buf1, system); SETMIR(buf1, system);
xsymlink("./system_root/system", buf1); xsymlink("./system_root/system", buf1);
VLOGI("link", "./system_root/system", buf1); LOGI("link: %s\n", buf1);
system_as_root = true; system_as_root = true;
} else if (!system_as_root && DIR_IS(system)) { } else if (!system_as_root && DIR_IS(system)) {
mount_mirror(system, MS_RDONLY); mount_mirror(system, MS_RDONLY);
@ -387,17 +119,17 @@ static bool magisk_env() {
if (access(buf1, F_OK) != 0 && access(buf2, F_OK) == 0) { if (access(buf1, F_OK) != 0 && access(buf2, F_OK) == 0) {
// Pre-init mirrors // Pre-init mirrors
xsymlink("./system_root/system", buf1); xsymlink("./system_root/system", buf1);
VLOGI("link", "./system_root/system", buf1); LOGI("link: %s\n", buf1);
} }
SETMIR(buf1, vendor); SETMIR(buf1, vendor);
if (access(buf1, F_OK) != 0) { if (access(buf1, F_OK) != 0) {
xsymlink("./system/vendor", buf1); xsymlink("./system/vendor", buf1);
VLOGI("link", "./system/vendor", buf1); LOGI("link: %s\n", buf1);
} }
SETMIR(buf1, product); SETMIR(buf1, product);
if (access("/system/product", F_OK) == 0 && access(buf1, F_OK) != 0) { if (access("/system/product", F_OK) == 0 && access(buf1, F_OK) != 0) {
xsymlink("./system/product", buf1); xsymlink("./system/product", buf1);
VLOGI("link", "./system/product", buf1); LOGI("link: %s\n", buf1);
} }
// Disable/remove magiskhide, resetprop // Disable/remove magiskhide, resetprop
@ -419,35 +151,6 @@ static bool magisk_env() {
return true; return true;
} }
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) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
// Cleanup old module if exists
if (faccessat(mfd, entry->d_name, F_OK, 0) == 0) {
frm_rf(xopenat(mfd, entry->d_name, O_RDONLY | O_CLOEXEC));
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);
}
auto src = MAGISKTMP + "/" MIRRDIR "/" MODULEROOT;
auto dest = MAGISKTMP + "/" MODULEMNT;
bind_mount(src.data(), dest.data(), false);
restorecon();
chmod(SECURE_DIR, 0700);
}
static void reboot() { static void reboot() {
if (RECOVERY_MODE) if (RECOVERY_MODE)
exec_command_sync("/system/bin/reboot", "recovery"); exec_command_sync("/system/bin/reboot", "recovery");
@ -472,94 +175,6 @@ void remove_modules() {
reboot(); reboot();
} }
static void collect_modules() {
auto dir = xopen_dir(MODULEROOT);
int dfd = dirfd(dir.get());
for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (entry->d_type == DT_DIR) {
if (entry->d_name == "."sv || entry->d_name == ".."sv || entry->d_name == ".core"sv)
continue;
int modfd = xopenat(dfd, entry->d_name, O_RDONLY);
run_finally f([=]{ close(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);
continue;
}
unlinkat(modfd, "update", 0);
if (faccessat(modfd, "disable", F_OK, 0) != 0)
module_list.emplace_back(entry->d_name);
}
}
}
static bool load_modules(node_entry *root) {
char buf1[4096];
char buf2[4096];
LOGI("* Loading modules\n");
bool has_modules = false;
for (const auto &m : module_list) {
auto module = m.data();
char *b1 = buf1 + sprintf(buf1, MODULEROOT "/%s/", module);
// Read props
strcpy(b1, "system.prop");
if (access(buf1, F_OK) == 0) {
LOGI("%s: loading [system.prop]\n", module);
load_prop_file(buf1, false);
}
// Copy sepolicy rules
strcpy(b1, "sepolicy.rule");
char *b2 = buf2 + sprintf(buf2, "%s/" MIRRDIR "/persist", MAGISKTMP.data());
if (access(buf2, F_OK) == 0 && access(buf1, F_OK) == 0) {
b2 += sprintf(b2, "/magisk/%s", module);
xmkdirs(buf2, 0755);
strcpy(b2, "/sepolicy.rule");
cp_afc(buf1, buf2);
}
// Check whether skip mounting
strcpy(b1, "skip_mount");
if (access(buf1, F_OK) == 0)
continue;
// Double check whether the system folder exists
strcpy(b1, "system");
if (access(buf1, F_OK) != 0)
continue;
// Construct structure
has_modules = true;
LOGI("%s: constructing magic mount structure\n", module);
// If /system/vendor exists in module, create a link outside
strcpy(b1, "system/vendor");
if (node_entry::vendor_root && access(buf1, F_OK) == 0) {
sprintf(buf2, MODULEROOT "/%s/vendor", module);
unlink(buf2);
xsymlink("./system/vendor", buf2);
}
// If /system/product exists in module, create a link outside
strcpy(b1, "system/product");
if (node_entry::product_root && access(buf1, F_OK) == 0) {
sprintf(buf2, MODULEROOT "/%s/product", module);
unlink(buf2);
xsymlink("./system/product", buf2);
}
root->create_module_tree(module);
}
return has_modules;
}
static bool check_data() { static bool check_data() {
bool mnt = false; bool mnt = false;
bool data = false; bool data = false;
@ -682,45 +297,11 @@ void post_fs_data(int client) {
LOGI("* Running post-fs-data.d scripts\n"); LOGI("* Running post-fs-data.d scripts\n");
exec_common_script("post-fs-data"); exec_common_script("post-fs-data");
prepare_modules();
// Core only mode // Core only mode
if (access(DISABLEFILE, F_OK) == 0) if (access(DISABLEFILE, F_OK) == 0)
core_only(); core_only();
collect_modules(); handle_modules();
// Execute module scripts
LOGI("* Running module post-fs-data scripts\n");
exec_module_script("post-fs-data", module_list);
// Recollect modules
module_list.clear();
collect_modules();
node_entry::vendor_root = access("/vendor", F_OK) == 0;
node_entry::product_root = access("/product", F_OK) == 0;
// Create the system root entry
auto sys_root = new node_entry("system");
if (load_modules(sys_root)) {
// Pull out special nodes if exist
node_entry *special;
if (node_entry::vendor_root && (special = sys_root->extract("vendor"))) {
special->magic_mount();
delete special;
}
if (node_entry::product_root && (special = sys_root->extract("product"))) {
special->magic_mount();
delete special;
}
sys_root->magic_mount();
}
// Cleanup memory
delete sys_root;
core_only(); core_only();
} }

619
native/jni/core/module.cpp Normal file
View File

@ -0,0 +1,619 @@
#include <sys/mount.h>
#include <map>
#include <utility>
#include <utils.hpp>
#include <magisk.hpp>
#include <selinux.hpp>
#include <daemon.hpp>
#include <resetprop.hpp>
#include <flags.h>
using namespace std;
#define SKIP_DOTS {\
if (entry->d_name == "."sv || entry->d_name == ".."sv) \
continue;\
}
#ifdef MAGISK_DEBUG
#define VLOGI(tag, from, to) LOGI("%-8s: %s <- %s\n", tag, to, from)
#else
#define VLOGI(tag, from, to) LOGI("%-8s: %s\n", tag, to)
#endif
#define TYPE_INTER (1 << 0) /* intermediate node */
#define TYPE_MIRROR (1 << 1) /* mount from mirror */
#define TYPE_SKEL (1 << 2) /* replace with tmpfs */
#define TYPE_MODULE (1 << 3) /* mount from module */
#define TYPE_ROOT (1 << 4) /* partition root */
#define TYPE_DIR (TYPE_INTER|TYPE_MIRROR|TYPE_SKEL|TYPE_ROOT)
vector<string> module_list;
class node_entry;
class dir_node;
class inter_node;
class mirror_node;
class skel_node;
class module_node;
class root_node;
static void merge_node(node_entry *a, node_entry *b);
template<class T> 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)
VLOGI("bind_mnt", from, to);
return ret;
}
template<class T> uint8_t type_id() { return 0; }
template<> uint8_t type_id<dir_node>() { return TYPE_DIR; }
template<> uint8_t type_id<inter_node>() { return TYPE_INTER; }
template<> uint8_t type_id<mirror_node>() { return TYPE_MIRROR; }
template<> uint8_t type_id<skel_node>() { return TYPE_SKEL; }
template<> uint8_t type_id<module_node>() { return TYPE_MODULE; }
template<> uint8_t type_id<root_node>() { return TYPE_ROOT; }
class node_entry {
public:
virtual ~node_entry() = default;
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; }
dir_node *parent() { return _parent; }
virtual void mount() = 0;
static string module_mnt;
static string mirror_dir;
protected:
template<class T>
node_entry(const char *name, uint8_t file_type, T*)
: _name(name), _file_type(file_type), node_type(type_id<T>()) {}
template<class T>
node_entry(T*) : node_type(type_id<T>()) {}
// Paths
const string &node_path();
string mirror_path() { return mirror_dir + node_path(); }
void create_and_mount(const string &src);
/* Use top bit of _file_type for node exist status */
bool exist() { return static_cast<bool>(_file_type & (1 << 7)); }
void set_exist() { _file_type |= (1 << 7); }
uint8_t file_type() { return static_cast<uint8_t>(_file_type & ~(1 << 7)); }
private:
friend void merge_node(node_entry *a, node_entry *b);
friend class dir_node;
bool need_clone();
// 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 merge_node(node_entry *a, node_entry *b);
typedef map<string_view, node_entry *> map_type;
typedef map_type::iterator map_iter;
~dir_node() override;
// 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<class T>
T *child(string_view name) { return iter_to_node<T>(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) {
return node
? iter_to_node(insert(children.find(node->_name), node->node_type,
[=](auto _) { return node; })) != nullptr
: false;
}
// Return inserted node or null if rejected
template<class T, class ...Args>
T *emplace(string_view name, Args &...args) {
return iter_to_node<T>(insert(children.find(name), type_id<T>(),
[&](auto _) { return new T(std::forward<Args>(args)...); }));
}
// Return inserted node, existing node with same rank, or null
template<class T, class ...Args>
T *emplace_or_get(string_view name, Args &...args) {
return iter_to_node<T>(insert(children.find(name), type_id<T>(),
[&](auto _) { return new T(std::forward<Args>(args)...); }, true));
}
// Return upgraded node or null if rejected
template<class T, class ...Args>
T *upgrade(string_view name, Args &...args) {
return iter_to_node<T>(upgrade<T>(children.find(name), args...));
}
protected:
template<class T>
dir_node(const char *name, uint8_t file_type, T *self) : node_entry(name, file_type, self) {
if constexpr (std::is_same_v<T, root_node>)
_root = self;
}
template<class T>
dir_node(node_entry *node, T *self) : node_entry(self) {
merge_node(this, node);
if constexpr (std::is_same_v<T, root_node>)
_root = self;
}
template<class T>
dir_node(const char *name, T *self) : dir_node(name, DT_DIR, self) {}
private:
// Root node lookup cache
root_node *_root;
// dir nodes host children
map_type children;
template<class T = node_entry>
T *iter_to_node(const map_iter &it) {
return reinterpret_cast<T*>(it == children.end() ? nullptr : it->second);
}
/* fn signature: (node_ent *&) -> node_ent *
* fn gets reference to the existing node, may be null.
* If fn consumes input, need to set reference to null.
* Returns new node or null to reject the insertion. */
template<typename Func>
map_iter insert(map_iter it, uint8_t type, Func fn, bool allow_same = false);
template<class To, class From = node_entry, class ...Args>
map_iter upgrade(map_iter it, Args &...args) {
return insert(it, type_id<To>(), [&](node_entry *&ex) -> node_entry * {
if (!ex)
return nullptr;
if constexpr (!std::is_same_v<From, node_entry>) {
// Type check if specific type is selected
if (!isa<From>(ex))
return nullptr;
}
auto node = new To(reinterpret_cast<From *>(ex), std::forward<Args>(args)...);
ex = nullptr;
return node;
});
}
};
class root_node : public dir_node {
public:
root_node(const char *name) : dir_node(name, this), prefix("") {}
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;
};
void node_entry::create_and_mount(const string &src) {
const string &dest = node_path();
if (is_lnk()) {
VLOGI("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());
}
}
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(this, node);
}
module_node(inter_node *node) : module_node(node, node->module) {}
void mount() override {
string src = module_mnt + module + parent()->root()->prefix + node_path();
if (exist())
clone_attr(mirror_path().data(), src.data());
if (isa<skel_node>(parent()))
create_and_mount(src);
else if (is_dir() || is_reg())
bind_mount(src.data(), node_path().data());
}
private:
const char *module;
};
class mirror_node : public dir_node {
public:
mirror_node(dirent *entry) : dir_node(entry->d_name, entry->d_type, this) {}
void mount() override {
create_and_mount(mirror_path());
dir_node::mount();
}
};
class skel_node : public dir_node {
public:
skel_node(node_entry *node) : dir_node(node, this) {}
void mount() override {
string src = mirror_path();
const string &dest = node_path();
file_attr a;
getattr(src.data(), &a);
xmount("tmpfs", dest.data(), "tmpfs", 0, nullptr);
VLOGI("mnt_tmp", "tmpfs", dest.data());
setattr(dest.data(), &a);
dir_node::mount();
}
};
// Poor man's dynamic cast without RTTI
template<class T>
static bool isa(node_entry *node) {
return node && (node->type() & type_id<T>());
}
template<class T>
static T *dyn_cast(node_entry *node) {
return isa<T>(node) ? reinterpret_cast<T*>(node) : nullptr;
}
// Merge b -> a, b will be deleted
static void merge_node(node_entry *a, node_entry *b) {
a->_name.swap(b->_name);
a->_file_type = b->_file_type;
a->_parent = b->_parent;
// Merge children if both is dir
if (auto aa = dyn_cast<dir_node>(a); aa) {
if (auto bb = dyn_cast<dir_node>(b); bb) {
aa->children.merge(bb->children);
for (auto &pair : aa->children)
pair.second->_parent = aa;
}
}
delete b;
}
string node_entry::module_mnt;
string node_entry::mirror_dir;
const string &node_entry::node_path() {
if (_parent && _node_path.empty())
_node_path = _parent->node_path() + '/' + _name;
return _node_path;
}
dir_node::~dir_node() {
for (auto &it : children)
delete it.second;
children.clear();
}
template<typename Func>
dir_node::map_iter dir_node::insert(dir_node::map_iter it, uint8_t type, Func fn, bool allow_same) {
node_entry *node = nullptr;
if (it != children.end()) {
if (it->second->node_type < type) {
// Upgrade existing node only if higher precedence
node = fn(it->second);
if (!node)
return children.end();
if (it->second)
merge_node(node, 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 (allow_same && it->second->node_type == type)
return it;
return children.end();
}
} else {
node = fn(node);
if (!node)
return it;
node->_parent = this;
it = children.emplace(node->_name, node).first;
}
return it;
}
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;
}
bool node_entry::need_clone() {
/* We need to upgrade parent to skeleton if:
* - Target does not exist
* - Source or target is a symlink */
bool clone = false;
struct stat st;
if (lstat(node_path().data(), &st) != 0) {
clone = true;
} else {
set_exist(); // cache exist result
if (is_lnk() || S_ISLNK(st.st_mode))
clone = true;
}
return clone;
}
bool dir_node::prepare() {
bool upgrade_skel = false;
for (auto it = children.begin(); it != children.end();) {
auto child = it->second;
if (child->need_clone()) {
if (node_type > type_id<skel_node>()) {
// Upgrade will fail, remove unsupported child node
delete child;
it = children.erase(it);
continue;
}
// Tell parent to upgrade self to skel
upgrade_skel = true;
// If child is inter_node, upgrade to module
if (auto nit = upgrade<module_node, inter_node>(it); nit != children.end()) {
it = nit;
goto increment;
}
}
if (auto dn = dyn_cast<dir_node>(child); dn && dn->is_dir() && !dn->prepare()) {
// Upgrade child to skeleton (shall always success)
it = upgrade<skel_node>(it);
auto skel = iter_to_node<skel_node>(it);
string mirror = skel->mirror_path();
auto dir = xopen_dir(mirror.data());
for (dirent *entry; (entry = xreaddir(dir.get()));) {
SKIP_DOTS
// Insert mirror nodes
skel->emplace<mirror_node>(entry->d_name, entry);
}
}
increment:
++it;
}
return !upgrade_skel;
}
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()));) {
SKIP_DOTS
if (entry->d_name == ".replace"sv) {
// Stop traversing and tell parent to upgrade self to module
return false;
}
if (entry->d_type == DT_DIR) {
// Need check cause emplace could fail due to previous module dir replace
if (auto dn = emplace_or_get<inter_node>(entry->d_name, entry->d_name, module); dn &&
!dn->collect_files(module, dirfd(dir.get()))) {
// Upgrade node to module due to '.replace'
upgrade<module_node>(dn->name(), module);
}
} else {
emplace<module_node>(entry->d_name, module, entry);
}
}
return true;
}
static void mount_modules() {
node_entry::mirror_dir = MAGISKTMP + "/" MIRRDIR;
node_entry::module_mnt = MAGISKTMP + "/" MODULEMNT "/";
auto root = make_unique<root_node>("");
auto system = new root_node("system");
root->insert(system);
char buf1[4096];
char buf2[4096];
LOGI("* Loading modules\n");
for (const auto &m : module_list) {
auto module = m.data();
char *b1 = buf1 + sprintf(buf1, MODULEROOT "/%s/", module);
// Read props
strcpy(b1, "system.prop");
if (access(buf1, F_OK) == 0) {
LOGI("%s: loading [system.prop]\n", module);
load_prop_file(buf1, false);
}
// Copy sepolicy rules
strcpy(b1, "sepolicy.rule");
char *b2 = buf2 + sprintf(buf2, "%s/" MIRRDIR "/persist", MAGISKTMP.data());
if (access(buf1, F_OK) == 0 && access(buf2, F_OK) == 0) {
b2 += sprintf(b2, "/magisk/%s", module);
xmkdirs(buf2, 0755);
strcpy(b2, "/sepolicy.rule");
cp_afc(buf1, buf2);
}
// Check whether skip mounting
strcpy(b1, "skip_mount");
if (access(buf1, F_OK) == 0)
continue;
// Double check whether the system folder exists
strcpy(b1, "system");
if (access(buf1, F_OK) != 0)
continue;
LOGI("%s: loading mount files\n", module);
b1[-1] = '\0';
int fd = xopen(buf1, O_RDONLY | O_CLOEXEC);
system->collect_files(module, fd);
close(fd);
}
if (system->is_empty())
return;
// 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); old) {
auto new_node = new root_node(old);
root->insert(new_node);
}
}
}
root->prepare();
root->mount();
}
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) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
// Cleanup old module if exists
if (faccessat(mfd, entry->d_name, F_OK, 0) == 0) {
frm_rf(xopenat(mfd, entry->d_name, O_RDONLY | O_CLOEXEC));
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;
bind_mount(src.data(), dest.data());
restorecon();
chmod(SECURE_DIR, 0700);
}
static void collect_modules() {
auto dir = xopen_dir(MODULEROOT);
int dfd = dirfd(dir.get());
for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (entry->d_type == DT_DIR) {
if (entry->d_name == "."sv || entry->d_name == ".."sv || entry->d_name == ".core"sv)
continue;
int modfd = xopenat(dfd, entry->d_name, O_RDONLY);
run_finally f([=]{ close(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);
continue;
}
unlinkat(modfd, "update", 0);
if (faccessat(modfd, "disable", F_OK, 0) != 0)
module_list.emplace_back(entry->d_name);
}
}
}
void handle_modules() {
prepare_modules();
collect_modules();
// Execute module scripts
LOGI("* Running module post-fs-data scripts\n");
exec_module_script("post-fs-data", module_list);
// Recollect modules (module scripts could remove itself)
module_list.clear();
collect_modules();
mount_modules();
}

1
native/jni/include/daemon.hpp
View File

@ -41,6 +41,7 @@ void unlock_blocks();
void post_fs_data(int client); void post_fs_data(int client);
void late_start(int client); void late_start(int client);
void boot_complete(int client); void boot_complete(int client);
void handle_modules();
void remove_modules(); void remove_modules();
/************* /*************