forked from MarcoBuster/Magisk
274 lines
6.7 KiB
C++
274 lines
6.7 KiB
C++
#include <sys/sysmacros.h>
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#include <string.h>
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#include <stdio.h>
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#include <vector>
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#include <utils.hpp>
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#include <logging.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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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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};
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static vector<devinfo> dev_list;
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static char partname[32];
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static char fstype[32];
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static char block_dev[64];
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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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dev_list.push_back(dev);
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}
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}
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}
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static int64_t setup_block(bool write_block = true) {
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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, partname) == 0) {
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if (write_block) {
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sprintf(block_dev, "/dev/block/%s", dev.devname);
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}
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LOGD("Found %s: [%s] (%d, %d)\n", dev.partname, dev.devname, dev.major, dev.minor);
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dev_t rdev = makedev(dev.major, dev.minor);
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mknod(block_dev, S_IFBLK | 0600, rdev);
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return rdev;
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}
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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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static bool read_dt_fstab(cmdline *cmd, const char *name) {
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char path[128];
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int fd;
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sprintf(path, "%s/fstab/%s/dev", cmd->dt_dir, name);
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if ((fd = open(path, O_RDONLY | O_CLOEXEC)) >= 0) {
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read(fd, path, sizeof(path));
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close(fd);
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// Some custom treble use different names, so use what we read
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char *part = rtrim(strrchr(path, '/') + 1);
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sprintf(partname, "%s%s", part, strend(part, cmd->slot) ? cmd->slot : "");
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sprintf(path, "%s/fstab/%s/type", cmd->dt_dir, name);
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if ((fd = xopen(path, O_RDONLY | O_CLOEXEC)) >= 0) {
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read(fd, fstype, 32);
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close(fd);
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return true;
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}
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}
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return false;
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}
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#define mount_root(name) \
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if (!is_lnk("/" #name) && read_dt_fstab(cmd, #name)) { \
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LOGD("Early mount " #name "\n"); \
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setup_block(); \
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xmkdir("/" #name, 0755); \
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xmount(block_dev, "/" #name, fstype, MS_RDONLY, nullptr); \
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mount_list.emplace_back("/" #name); \
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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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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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}
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static void mount_persist(const char *dev_base, const char *mnt_base) {
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string mnt_point = mnt_base + "/persist"s;
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strcpy(partname, "persist");
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sprintf(block_dev, "%s/persist", dev_base);
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if (setup_block(false) < 0) {
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// Fallback to cache
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strcpy(partname, "cache");
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sprintf(block_dev, "%s/cache", dev_base);
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if (setup_block(false) < 0) {
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// Try NVIDIA's BS
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strcpy(partname, "CAC");
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if (setup_block(false) < 0)
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return;
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}
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xsymlink("./cache", mnt_point.data());
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mnt_point = mnt_base + "/cache"s;
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}
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xmkdir(mnt_point.data(), 0755);
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xmount(block_dev, mnt_point.data(), "ext4", 0, nullptr);
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}
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void RootFSInit::early_mount() {
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full_read("/init", self.buf, self.sz);
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LOGD("Reverting /init\n");
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root = xopen("/", O_RDONLY | O_CLOEXEC);
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rename("/.backup/init", "/init");
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mount_root(system);
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mount_root(vendor);
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mount_root(product);
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mount_root(odm);
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xmkdir("/dev/mnt", 0755);
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mount_persist("/dev/block", "/dev/mnt");
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mount_list.emplace_back("/dev/mnt/persist");
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mount_list.emplace_back("/dev/mnt/cache");
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}
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void SARBase::backup_files(const char *self_path) {
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if (access("/overlay.d", F_OK) == 0)
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cp_afc("/overlay.d", "/dev/overlay.d");
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full_read(self_path, self.buf, self.sz);
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full_read("/.backup/.magisk", config.buf, config.sz);
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}
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void SARInit::early_mount() {
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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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backup_files("/init");
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LOGD("Cleaning rootfs\n");
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int root = xopen("/", O_RDONLY | O_CLOEXEC);
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frm_rf(root, { "proc", "sys", "dev" });
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close(root);
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LOGD("Early mount system_root\n");
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sprintf(partname, "system%s", cmd->slot);
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strcpy(block_dev, "/dev/root");
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auto dev = setup_block(false);
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if (dev < 0) {
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// Try NVIDIA naming scheme
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strcpy(partname, "APP");
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dev = setup_block(false);
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if (dev < 0) {
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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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}
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}
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system_dev = dev;
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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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switch_root("/system_root");
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mount_root(vendor);
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mount_root(product);
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mount_root(odm);
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}
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void SecondStageInit::early_mount() {
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// Early mounts should already be done by first stage init
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backup_files("/system/bin/init");
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rm_rf("/system");
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rm_rf("/.backup");
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rm_rf("/overlay.d");
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// Find system_dev
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parse_mnt("/proc/mounts", [&](mntent *me) -> bool {
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if (me->mnt_dir == "/system_root"sv) {
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struct stat st;
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stat(me->mnt_fsname, &st);
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system_dev = st.st_rdev;
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return false;
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}
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return true;
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});
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switch_root("/system_root");
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}
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void BaseInit::cleanup() {
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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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mount_list.clear();
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mount_list.shrink_to_fit();
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}
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void mount_sbin() {
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LOGD("Mount /sbin tmpfs overlay\n");
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xmount("tmpfs", "/sbin", "tmpfs", 0, "mode=755");
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xmkdir(MAGISKTMP, 0755);
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xmkdir(MIRRDIR, 0);
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xmkdir(BLOCKDIR, 0);
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mount_persist(BLOCKDIR, MIRRDIR);
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}
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