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.
368 lines
8.6 KiB
C++
368 lines
8.6 KiB
C++
#include <sys/mount.h>
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#include <sys/wait.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <dirent.h>
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#include <libgen.h>
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#include <vector>
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#include <string>
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#include <magisk.hpp>
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#include <db.hpp>
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#include <utils.hpp>
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#include <daemon.hpp>
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#include <resetprop.hpp>
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#include <selinux.hpp>
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using namespace std;
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extern vector<string> module_list;
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static bool no_secure_dir = false;
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static bool pfs_done = false;
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extern void auto_start_magiskhide();
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/*********
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* Setup *
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*********/
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#define DIR_IS(part) (me->mnt_dir == "/" #part ""sv)
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#define SETMIR(b, part) sprintf(b, "%s/" MIRRDIR "/" #part, MAGISKTMP.data())
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#define SETBLK(b, part) sprintf(b, "%s/" BLOCKDIR "/" #part, MAGISKTMP.data())
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#define mount_mirror(part, flag) { \
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xstat(me->mnt_fsname, &st); \
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SETMIR(buf1, part); \
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SETBLK(buf2, part); \
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mknod(buf2, (st.st_mode & S_IFMT) | 0600, st.st_rdev); \
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xmkdir(buf1, 0755); \
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xmount(buf2, buf1, me->mnt_type, flag, nullptr); \
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LOGI("mount: %s\n", buf1); \
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}
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static bool magisk_env() {
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LOGI("* Initializing Magisk environment\n");
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string pkg;
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check_manager(&pkg);
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char buf1[4096];
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char buf2[4096];
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sprintf(buf1, "%s/0/%s/install", APP_DATA_DIR, pkg.data());
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// Alternative binaries paths
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const char *alt_bin[] = { "/cache/data_adb/magisk", "/data/magisk", buf1 };
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for (auto alt : alt_bin) {
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struct stat st;
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if (lstat(alt, &st) != -1) {
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if (S_ISLNK(st.st_mode)) {
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unlink(alt);
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continue;
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}
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rm_rf(DATABIN);;
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cp_afc(alt, DATABIN);
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rm_rf(alt);
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break;
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}
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}
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// Remove stuffs
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rm_rf("/cache/data_adb");
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rm_rf("/data/adb/modules/.core");
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unlink("/data/adb/magisk.img");
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unlink("/data/adb/magisk_merge.img");
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unlink("/data/magisk.img");
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unlink("/data/magisk_merge.img");
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unlink("/data/magisk_debug.log");
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sprintf(buf1, "%s/" MODULEMNT, MAGISKTMP.data());
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xmkdir(buf1, 0755);
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// TODO: Remove. Backwards compatibility for old manager
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sprintf(buf1, "%s/" INTLROOT "/img", MAGISKTMP.data());
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xsymlink("./modules", buf1);
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// Directories in /data/adb
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xmkdir(DATABIN, 0755);
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xmkdir(MODULEROOT, 0755);
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xmkdir(SECURE_DIR "/post-fs-data.d", 0755);
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xmkdir(SECURE_DIR "/service.d", 0755);
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LOGI("* Mounting mirrors");
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bool system_as_root = false;
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struct stat st;
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parse_mnt("/proc/mounts", [&](mntent *me) {
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if (DIR_IS(system_root)) {
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mount_mirror(system_root, MS_RDONLY);
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SETMIR(buf1, system);
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xsymlink("./system_root/system", buf1);
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LOGI("link: %s\n", buf1);
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system_as_root = true;
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} else if (!system_as_root && DIR_IS(system)) {
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mount_mirror(system, MS_RDONLY);
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} else if (DIR_IS(vendor)) {
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mount_mirror(vendor, MS_RDONLY);
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} else if (DIR_IS(product)) {
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mount_mirror(product, MS_RDONLY);
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} else if (DIR_IS(data) && me->mnt_type != "tmpfs"sv) {
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mount_mirror(data, 0);
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} else if (SDK_INT >= 24 && DIR_IS(proc) && !strstr(me->mnt_opts, "hidepid=2")) {
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xmount(nullptr, "/proc", nullptr, MS_REMOUNT, "hidepid=2,gid=3009");
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}
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return true;
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});
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SETMIR(buf1, system);
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SETMIR(buf2, system_root);
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if (access(buf1, F_OK) != 0 && access(buf2, F_OK) == 0) {
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// Pre-init mirrors
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xsymlink("./system_root/system", buf1);
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LOGI("link: %s\n", buf1);
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}
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SETMIR(buf1, vendor);
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if (access(buf1, F_OK) != 0) {
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xsymlink("./system/vendor", buf1);
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LOGI("link: %s\n", buf1);
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}
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SETMIR(buf1, product);
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if (access("/system/product", F_OK) == 0 && access(buf1, F_OK) != 0) {
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xsymlink("./system/product", buf1);
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LOGI("link: %s\n", buf1);
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}
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// Disable/remove magiskhide, resetprop
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if (SDK_INT < 19) {
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unlink("/sbin/resetprop");
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unlink("/sbin/magiskhide");
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}
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if (access(DATABIN "/busybox", X_OK) == -1)
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return false;
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// TODO: Remove. Backwards compatibility for old manager
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LOGI("* Setting up internal busybox\n");
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sprintf(buf1, "%s/" BBPATH "/busybox", MAGISKTMP.data());
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mkdir(dirname(buf1), 0755);
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cp_afc(DATABIN "/busybox", buf1);
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exec_command_sync(buf1, "--install", "-s", dirname(buf1));
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return true;
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}
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static void reboot() {
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if (RECOVERY_MODE)
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exec_command_sync("/system/bin/reboot", "recovery");
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else
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exec_command_sync("/system/bin/reboot");
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}
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void remove_modules() {
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LOGI("* Remove all modules and reboot");
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auto dir = xopen_dir(MODULEROOT);
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int dfd = dirfd(dir.get());
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for (dirent *entry; (entry = xreaddir(dir.get()));) {
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if (entry->d_type == DT_DIR) {
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if (entry->d_name == "."sv || entry->d_name == ".."sv || entry->d_name == ".core"sv)
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continue;
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int modfd = xopenat(dfd, entry->d_name, O_RDONLY | O_CLOEXEC);
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close(xopenat(modfd, "remove", O_RDONLY | O_CREAT | O_CLOEXEC));
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close(modfd);
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}
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}
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reboot();
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}
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static bool check_data() {
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bool mnt = false;
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bool data = false;
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file_readline("/proc/mounts", [&](string_view s) -> bool {
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if (str_contains(s, " /data ") && !str_contains(s, "tmpfs"))
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mnt = true;
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return true;
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});
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if (mnt) {
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auto crypto = getprop("ro.crypto.state");
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if (!crypto.empty()) {
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if (crypto == "unencrypted") {
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// Unencrypted, we can directly access data
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data = true;
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} else {
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// Encrypted, check whether vold is started
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data = !getprop("init.svc.vold").empty();
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}
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} else {
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// ro.crypto.state is not set, assume it's unencrypted
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data = true;
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}
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}
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return data;
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}
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void unlock_blocks() {
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int fd, dev, OFF = 0;
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auto dir = xopen_dir("/dev/block");
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if (!dir)
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return;
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dev = dirfd(dir.get());
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for (dirent *entry; (entry = readdir(dir.get()));) {
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if (entry->d_type == DT_BLK) {
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if ((fd = openat(dev, entry->d_name, O_RDONLY | O_CLOEXEC)) < 0)
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continue;
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if (ioctl(fd, BLKROSET, &OFF) < 0)
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PLOGE("unlock %s", entry->d_name);
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close(fd);
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}
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}
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}
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static bool log_dump = false;
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static void dump_logs() {
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if (log_dump)
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return;
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int test = exec_command_sync("/system/bin/logcat", "-d", "-f", "/dev/null");
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chmod("/dev/null", 0666);
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if (test != 0)
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return;
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rename(LOGFILE, LOGFILE ".bak");
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log_dump = true;
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// Start a daemon thread and wait indefinitely
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new_daemon_thread([]() -> void {
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int fd = xopen(LOGFILE, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644);
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exec_t exec {
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.fd = fd,
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.fork = fork_no_zombie
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};
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int pid = exec_command(exec, "/system/bin/logcat", "-s", "Magisk");
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close(fd);
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if (pid < 0) {
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log_dump = false;
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} else {
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waitpid(pid, nullptr, 0);
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}
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});
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}
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/****************
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* Entry points *
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****************/
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[[noreturn]] static void unblock_boot_process() {
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close(xopen(UNBLOCKFILE, O_RDONLY | O_CREAT, 0));
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pthread_exit(nullptr);
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}
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[[noreturn]] static void core_only() {
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pfs_done = true;
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auto_start_magiskhide();
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unblock_boot_process();
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}
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void post_fs_data(int client) {
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// ack
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write_int(client, 0);
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close(client);
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if (getenv("REMOUNT_ROOT"))
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xmount(nullptr, "/", nullptr, MS_REMOUNT | MS_RDONLY, nullptr);
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if (!check_data())
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unblock_boot_process();
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dump_logs();
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LOGI("** post-fs-data mode running\n");
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// Unlock all blocks for rw
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unlock_blocks();
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if (access(SECURE_DIR, F_OK) != 0) {
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/* If the folder is not automatically created by the system,
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* do NOT proceed further. Manual creation of the folder
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* will cause bootloops on FBE devices. */
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LOGE(SECURE_DIR " is not present, abort...");
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no_secure_dir = true;
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unblock_boot_process();
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}
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if (!magisk_env()) {
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LOGE("* Magisk environment setup incomplete, abort\n");
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unblock_boot_process();
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}
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LOGI("* Running post-fs-data.d scripts\n");
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exec_common_script("post-fs-data");
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// Core only mode
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if (access(DISABLEFILE, F_OK) == 0)
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core_only();
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handle_modules();
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core_only();
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}
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void late_start(int client) {
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LOGI("** late_start service mode running\n");
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// ack
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write_int(client, 0);
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close(client);
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dump_logs();
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if (no_secure_dir) {
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// It's safe to create the folder at this point if the system didn't create it
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if (access(SECURE_DIR, F_OK) != 0)
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xmkdir(SECURE_DIR, 0700);
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// And reboot to make proper setup possible
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reboot();
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}
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if (!pfs_done)
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return;
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auto_start_magiskhide();
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LOGI("* Running service.d scripts\n");
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exec_common_script("service");
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// Core only mode
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if (access(DISABLEFILE, F_OK) != 0) {
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LOGI("* Running module service scripts\n");
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exec_module_script("service", module_list);
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}
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// All boot stage done, cleanup
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module_list.clear();
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module_list.shrink_to_fit();
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}
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void boot_complete(int client) {
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LOGI("** boot_complete triggered\n");
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// ack
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write_int(client, 0);
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close(client);
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if (!pfs_done)
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return;
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auto_start_magiskhide();
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if (access(MANAGERAPK, F_OK) == 0) {
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// Install Magisk Manager if exists
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rename(MANAGERAPK, "/data/magisk.apk");
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install_apk("/data/magisk.apk");
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} else {
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// Check whether we have manager installed
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if (!check_manager()) {
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// Install stub
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exec_command_sync("/sbin/magiskinit", "-x", "manager", "/data/magisk.apk");
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install_apk("/data/magisk.apk");
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}
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}
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}
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