mirror of
https://github.com/topjohnwu/Magisk.git
synced 2024-12-11 02:34:31 +00:00
412 lines
11 KiB
C++
412 lines
11 KiB
C++
#include <sys/mount.h>
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#include <sys/sysmacros.h>
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#include <libgen.h>
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#include <utils.hpp>
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#include <selinux.hpp>
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#include <magisk.hpp>
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#include "init.hpp"
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using namespace std;
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static string rtrim(string &&str) {
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// Trim space, newline, and null byte from end of string
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while (memchr(" \n\r", str[str.length() - 1], 4))
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str.pop_back();
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return std::move(str);
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}
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struct devinfo {
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int major;
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int minor;
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char devname[32];
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char partname[32];
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char dmname[32];
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};
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static vector<devinfo> dev_list;
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static void parse_device(devinfo *dev, const char *uevent) {
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dev->partname[0] = '\0';
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parse_prop_file(uevent, [=](string_view key, string_view value) -> bool {
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if (key == "MAJOR")
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dev->major = parse_int(value.data());
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else if (key == "MINOR")
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dev->minor = parse_int(value.data());
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else if (key == "DEVNAME")
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strcpy(dev->devname, value.data());
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else if (key == "PARTNAME")
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strcpy(dev->partname, value.data());
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return true;
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});
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}
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static void collect_devices() {
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char path[128];
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devinfo dev{};
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if (auto dir = xopen_dir("/sys/dev/block"); dir) {
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for (dirent *entry; (entry = readdir(dir.get()));) {
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if (entry->d_name == "."sv || entry->d_name == ".."sv)
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continue;
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sprintf(path, "/sys/dev/block/%s/uevent", entry->d_name);
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parse_device(&dev, path);
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sprintf(path, "/sys/dev/block/%s/dm/name", entry->d_name);
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if (access(path, F_OK) == 0) {
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auto name = rtrim(full_read(path));
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strcpy(dev.dmname, name.data());
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}
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dev_list.push_back(dev);
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}
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}
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}
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static struct {
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char partname[32];
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char block_dev[64];
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} blk_info;
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static int64_t setup_block(bool write_block) {
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if (dev_list.empty())
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collect_devices();
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xmkdir("/dev", 0755);
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xmkdir("/dev/block", 0755);
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for (int tries = 0; tries < 3; ++tries) {
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for (auto &dev : dev_list) {
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if (strcasecmp(dev.partname, blk_info.partname) == 0)
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LOGD("Setup %s: [%s] (%d, %d)\n", dev.partname, dev.devname, dev.major, dev.minor);
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else if (strcasecmp(dev.dmname, blk_info.partname) == 0)
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LOGD("Setup %s: [%s] (%d, %d)\n", dev.dmname, dev.devname, dev.major, dev.minor);
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else
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continue;
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if (write_block) {
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sprintf(blk_info.block_dev, "/dev/block/%s", dev.devname);
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}
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dev_t rdev = makedev(dev.major, dev.minor);
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xmknod(blk_info.block_dev, S_IFBLK | 0600, rdev);
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return rdev;
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}
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// Wait 10ms and try again
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usleep(10000);
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dev_list.clear();
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collect_devices();
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}
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// The requested partname does not exist
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return -1;
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}
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static bool is_lnk(const char *name) {
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struct stat st;
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if (lstat(name, &st))
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return false;
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return S_ISLNK(st.st_mode);
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}
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#define read_info(val) \
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if (access(#val, F_OK) == 0) {\
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entry.val = rtrim(full_read(#val)); \
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}
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void BaseInit::read_dt_fstab(vector<fstab_entry> &fstab) {
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if (access(cmd->dt_dir, F_OK) != 0)
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return;
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char cwd[128];
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getcwd(cwd, sizeof(cwd));
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chdir(cmd->dt_dir);
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run_finally cd([&]{ chdir(cwd); });
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if (access("fstab", F_OK) != 0)
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return;
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chdir("fstab");
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// Make sure dt fstab is enabled
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if (access("status", F_OK) == 0) {
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auto status = rtrim(full_read("status"));
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if (status != "okay" && status != "ok")
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return;
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}
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auto dir = xopen_dir(".");
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for (dirent *dp; (dp = xreaddir(dir.get()));) {
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if (dp->d_type != DT_DIR)
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continue;
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chdir(dp->d_name);
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run_finally f([]{ chdir(".."); });
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if (access("status", F_OK) == 0) {
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auto status = rtrim(full_read("status"));
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if (status != "okay" && status != "ok")
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continue;
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}
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fstab_entry entry;
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read_info(dev);
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read_info(mnt_point) else {
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entry.mnt_point = "/";
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entry.mnt_point += dp->d_name;
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}
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read_info(type);
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read_info(mnt_flags);
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read_info(fsmgr_flags);
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fstab.emplace_back(std::move(entry));
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}
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}
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void MagiskInit::mount_with_dt() {
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vector<fstab_entry> fstab;
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read_dt_fstab(fstab);
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for (const auto &entry : fstab) {
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if (is_lnk(entry.mnt_point.data()))
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continue;
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// Derive partname from dev
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sprintf(blk_info.partname, "%s%s", basename(entry.dev.data()), cmd->slot);
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setup_block(true);
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xmkdir(entry.mnt_point.data(), 0755);
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xmount(blk_info.block_dev, entry.mnt_point.data(), entry.type.data(), MS_RDONLY, nullptr);
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mount_list.push_back(entry.mnt_point);
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}
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}
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static void switch_root(const string &path) {
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LOGD("Switch root to %s\n", path.data());
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int root = xopen("/", O_RDONLY);
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vector<string> mounts;
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parse_mnt("/proc/mounts", [&](mntent *me) {
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// Skip root and self
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if (me->mnt_dir == "/"sv || me->mnt_dir == path)
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return true;
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// Do not include subtrees
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for (const auto &m : mounts) {
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if (strncmp(me->mnt_dir, m.data(), m.length()) == 0 && me->mnt_dir[m.length()] == '/')
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return true;
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}
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mounts.emplace_back(me->mnt_dir);
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return true;
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});
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for (auto &dir : mounts) {
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auto new_path = path + dir;
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mkdir(new_path.data(), 0755);
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xmount(dir.data(), new_path.data(), nullptr, MS_MOVE, nullptr);
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}
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chdir(path.data());
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xmount(path.data(), "/", nullptr, MS_MOVE, nullptr);
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chroot(".");
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LOGD("Cleaning rootfs\n");
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frm_rf(root);
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}
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void MagiskInit::mount_rules_dir(const char *dev_base, const char *mnt_base) {
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char path[128];
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xrealpath(dev_base, blk_info.block_dev);
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xrealpath(mnt_base, path);
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char *b = blk_info.block_dev + strlen(blk_info.block_dev);
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char *p = path + strlen(path);
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auto do_mount = [&](const char *type) -> bool {
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xmkdir(path, 0755);
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bool success = xmount(blk_info.block_dev, path, type, 0, nullptr) == 0;
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if (success)
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mount_list.emplace_back(path);
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return success;
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};
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// First try userdata
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strcpy(blk_info.partname, "userdata");
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strcpy(b, "/data");
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strcpy(p, "/data");
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if (setup_block(false) < 0) {
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// Try NVIDIA naming scheme
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strcpy(blk_info.partname, "UDA");
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if (setup_block(false) < 0)
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goto cache;
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}
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// WARNING: DO NOT ATTEMPT TO MOUNT F2FS AS IT MAY CRASH THE KERNEL
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// Failure means either f2fs, FDE, or metadata encryption
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if (!do_mount("ext4"))
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goto cache;
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strcpy(p, "/data/unencrypted");
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if (xaccess(path, F_OK) == 0) {
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// FBE, need to use an unencrypted path
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custom_rules_dir = path + "/magisk"s;
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} else {
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// Skip if /data/adb does not exist
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strcpy(p, SECURE_DIR);
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if (xaccess(path, F_OK) != 0)
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return;
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strcpy(p, MODULEROOT);
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if (xaccess(path, F_OK) != 0) {
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goto cache;
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}
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// Unencrypted, directly use module paths
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custom_rules_dir = string(path);
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}
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goto success;
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cache:
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// Fallback to cache
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strcpy(blk_info.partname, "cache");
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strcpy(b, "/cache");
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strcpy(p, "/cache");
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if (setup_block(false) < 0) {
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// Try NVIDIA naming scheme
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strcpy(blk_info.partname, "CAC");
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if (setup_block(false) < 0)
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goto metadata;
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}
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if (!do_mount("ext4"))
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goto metadata;
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custom_rules_dir = path + "/magisk"s;
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goto success;
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metadata:
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// Fallback to metadata
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strcpy(blk_info.partname, "metadata");
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strcpy(b, "/metadata");
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strcpy(p, "/metadata");
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if (setup_block(false) < 0 || !do_mount("ext4"))
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goto persist;
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custom_rules_dir = path + "/magisk"s;
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goto success;
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persist:
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// Fallback to persist
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strcpy(blk_info.partname, "persist");
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strcpy(b, "/persist");
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strcpy(p, "/persist");
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if (setup_block(false) < 0 || !do_mount("ext4"))
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return;
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custom_rules_dir = path + "/magisk"s;
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success:
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// Create symlinks so we don't need to go through this logic again
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strcpy(p, "/sepolicy.rules");
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xsymlink(custom_rules_dir.data(), path);
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}
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void RootFSInit::early_mount() {
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self = mmap_data::ro("/init");
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LOGD("Restoring /init\n");
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rename("/.backup/init", "/init");
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mount_with_dt();
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}
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void SARBase::backup_files() {
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if (access("/overlay.d", F_OK) == 0)
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backup_folder("/overlay.d", overlays);
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self = mmap_data::ro("/proc/self/exe");
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if (access("/.backup/.magisk", R_OK) == 0)
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config = mmap_data::ro("/.backup/.magisk");
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}
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void SARBase::mount_system_root() {
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LOGD("Early mount system_root\n");
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strcpy(blk_info.block_dev, "/dev/root");
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do {
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// Try legacy SAR dm-verity
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strcpy(blk_info.partname, "vroot");
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auto dev = setup_block(false);
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if (dev >= 0)
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goto mount_root;
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// Try NVIDIA naming scheme
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strcpy(blk_info.partname, "APP");
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dev = setup_block(false);
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if (dev >= 0)
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goto mount_root;
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sprintf(blk_info.partname, "system%s", cmd->slot);
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dev = setup_block(false);
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if (dev >= 0)
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goto mount_root;
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// Poll forever if rootwait was given in cmdline
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} while (cmd->rootwait);
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// We don't really know what to do at this point...
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LOGE("Cannot find root partition, abort\n");
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exit(1);
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mount_root:
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xmkdir("/system_root", 0755);
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if (xmount("/dev/root", "/system_root", "ext4", MS_RDONLY, nullptr))
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xmount("/dev/root", "/system_root", "erofs", MS_RDONLY, nullptr);
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}
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void SARInit::early_mount() {
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backup_files();
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mount_system_root();
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switch_root("/system_root");
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// Use the apex folder to determine whether 2SI (Android 10+)
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is_two_stage = access("/apex", F_OK) == 0;
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LOGD("is_two_stage: [%d]\n", is_two_stage);
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if (!is_two_stage) {
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// Make dev writable
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xmkdir("/dev", 0755);
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xmount("tmpfs", "/dev", "tmpfs", 0, "mode=755");
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mount_list.emplace_back("/dev");
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mount_with_dt();
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}
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}
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void SecondStageInit::prepare() {
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backup_files();
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umount2("/init", MNT_DETACH);
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umount2("/proc/self/exe", MNT_DETACH);
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if (access("/system_root", F_OK) == 0)
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switch_root("/system_root");
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}
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void BaseInit::exec_init() {
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// Unmount in reverse order
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for (auto &p : reversed(mount_list)) {
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if (xumount(p.data()) == 0)
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LOGD("Unmount [%s]\n", p.data());
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}
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execv("/init", argv);
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exit(1);
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}
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void MagiskInit::setup_tmp(const char *path) {
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LOGD("Setup Magisk tmp at %s\n", path);
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xmount("tmpfs", path, "tmpfs", 0, "mode=755");
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chdir(path);
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xmkdir(INTLROOT, 0755);
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xmkdir(MIRRDIR, 0);
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xmkdir(BLOCKDIR, 0);
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int fd = xopen(INTLROOT "/config", O_WRONLY | O_CREAT, 0);
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xwrite(fd, config.buf, config.sz);
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close(fd);
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fd = xopen("magiskinit", O_WRONLY | O_CREAT, 0755);
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xwrite(fd, self.buf, self.sz);
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close(fd);
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// The magisk binary will be handled later
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// Create applet symlinks
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for (int i = 0; applet_names[i]; ++i)
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xsymlink("./magisk", applet_names[i]);
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xsymlink("./magiskinit", "magiskpolicy");
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xsymlink("./magiskinit", "supolicy");
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chdir("/");
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}
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