The current system-as-root magiskinit implementation (converting root directory in system partition to legacy rootfs setup) is now considered as backwards compatible only. The new implementation that is hide and Android Q friendly is coming soon.
163 lines
3.9 KiB
C++
163 lines
3.9 KiB
C++
#include <sys/mount.h>
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#include <sys/sysmacros.h>
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#include <string.h>
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#include <stdio.h>
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#include <utils.h>
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#include <logging.h>
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#include <selinux.h>
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#include "init.h"
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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 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 = atoi(value.data());
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else if (key == "MINOR")
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dev->minor = atoi(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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struct dirent *entry;
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devinfo dev;
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DIR *dir = xopendir("/sys/dev/block");
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if (dir == nullptr)
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return;
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while ((entry = readdir(dir))) {
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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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closedir(dir);
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}
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static void setup_block(const char *partname, char *block_dev) {
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if (dev_list.empty())
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collect_devices();
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for (;;) {
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for (auto &dev : dev_list) {
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if (strcasecmp(dev.partname, partname) == 0) {
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sprintf(block_dev, "/dev/block/%s", dev.devname);
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LOGD("Found %s: [%s] (%d, %d)\n", dev.partname, dev.devname, dev.major, dev.minor);
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xmkdir("/dev", 0755);
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xmkdir("/dev/block", 0755);
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mknod(block_dev, S_IFBLK | 0600, makedev(dev.major, dev.minor));
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return;
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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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}
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bool MagiskInit::read_dt_fstab(const char *name, char *partname, char *fstype) {
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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 = xopen(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 link_root(name) \
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if (is_lnk("/system_root" name)) \
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cp_afc("/system_root" name, name)
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#define mount_root(name) \
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if (!is_lnk("/" #name) && read_dt_fstab(#name, partname, fstype)) { \
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LOGD("Early mount " #name "\n"); \
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setup_block(partname, block_dev); \
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xmkdir("/" #name, 0755); \
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xmount(block_dev, "/" #name, fstype, MS_RDONLY, nullptr); \
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mnt_##name = true; \
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}
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void LegacyInit::early_mount() {
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char partname[32];
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char fstype[32];
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char block_dev[64];
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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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}
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void SARCompatInit::early_mount() {
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char partname[32];
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char fstype[32];
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char block_dev[64];
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LOGD("Early mount system_root\n");
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sprintf(partname, "system%s", cmd->slot);
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setup_block(partname, block_dev);
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xmkdir("/system_root", 0755);
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if (xmount(block_dev, "/system_root", "ext4", MS_RDONLY, nullptr))
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xmount(block_dev, "/system_root", "erofs", MS_RDONLY, nullptr);
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xmkdir("/system", 0755);
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xmount("/system_root/system", "/system", nullptr, MS_BIND, nullptr);
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// Android Q
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if (is_lnk("/system_root/init"))
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load_sepol = true;
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// System-as-root with monolithic sepolicy
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if (access("/system_root/sepolicy", F_OK) == 0)
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cp_afc("/system_root/sepolicy", "/sepolicy");
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link_root("/vendor");
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link_root("/product");
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link_root("/odm");
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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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#define umount_root(name) \
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if (mnt_##name) \
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umount("/" #name);
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void MagiskInit::cleanup() {
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BaseInit::cleanup();
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umount(SELINUX_MNT);
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umount_root(system);
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umount_root(vendor);
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umount_root(product);
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umount_root(odm);
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}
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