Magisk/native/jni/init/init.cpp
2020-09-02 21:20:15 -07:00

255 lines
5.5 KiB
C++

#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <fcntl.h>
#include <libgen.h>
#include <vector>
#include <xz.h>
#include <magisk.hpp>
#include <cpio.hpp>
#include <utils.hpp>
#include "binaries.h"
#ifdef USE_64BIT
#include "binaries_arch64.h"
#else
#include "binaries_arch.h"
#endif
#include "init.hpp"
using namespace std;
constexpr int (*init_applet_main[])(int, char *[]) =
{ magiskpolicy_main, magiskpolicy_main, nullptr };
int data_holder::patch(str_pairs list) {
int count = 0;
for (uint8_t *p = buf, *eof = buf + sz; p < eof; ++p) {
for (auto [from, to] : list) {
if (memcmp(p, from.data(), from.length() + 1) == 0) {
LOGD("Replace [%s] -> [%s]\n", from.data(), to.data());
memset(p, 0, from.length());
memcpy(p, to.data(), to.length());
++count;
p += from.length();
}
}
}
return count;
}
bool data_holder::find(string_view pattern) {
for (uint8_t *p = buf, *eof = buf + sz; p < eof; ++p) {
if (memcmp(p, pattern.data(), pattern.length() + 1) == 0)
return true;
}
return false;
}
void data_holder::consume(data_holder &other) {
buf = other.buf;
sz = other.sz;
other.buf = nullptr;
other.sz = 0;
}
auto_data<HEAP> raw_data::read(int fd) {
auto_data<HEAP> data;
fd_full_read(fd, data.buf, data.sz);
return data;
}
auto_data<HEAP> raw_data::read(const char *name) {
auto_data<HEAP> data;
full_read(name, data.buf, data.sz);
return data;
}
auto_data<MMAP> raw_data::mmap_rw(const char *name) {
auto_data<MMAP> data;
::mmap_rw(name, data.buf, data.sz);
return data;
}
auto_data<MMAP> raw_data::mmap_ro(const char *name) {
auto_data<MMAP> data;
::mmap_ro(name, data.buf, data.sz);
return data;
}
static bool unxz(int fd, const uint8_t *buf, size_t size) {
uint8_t out[8192];
xz_crc32_init();
struct xz_dec *dec = xz_dec_init(XZ_DYNALLOC, 1 << 26);
struct xz_buf b = {
.in = buf,
.in_pos = 0,
.in_size = size,
.out = out,
.out_pos = 0,
.out_size = sizeof(out)
};
enum xz_ret ret;
do {
ret = xz_dec_run(dec, &b);
if (ret != XZ_OK && ret != XZ_STREAM_END)
return false;
write(fd, out, b.out_pos);
b.out_pos = 0;
} while (b.in_pos != size);
return true;
}
static void decompress_ramdisk() {
constexpr char tmp[] = "tmp.cpio";
constexpr char ramdisk_xz[] = "ramdisk.cpio.xz";
if (access(ramdisk_xz, F_OK))
return;
LOGD("Decompressing ramdisk from %s\n", ramdisk_xz);
uint8_t *buf;
size_t sz;
mmap_ro(ramdisk_xz, buf, sz);
int fd = xopen(tmp, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
unxz(fd, buf, sz);
munmap(buf, sz);
close(fd);
cpio_mmap cpio(tmp);
cpio.extract();
unlink(tmp);
unlink(ramdisk_xz);
}
int dump_magisk(const char *path, mode_t mode) {
int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, mode);
if (fd < 0)
return 1;
if (!unxz(fd, magisk_xz, sizeof(magisk_xz)))
return 1;
close(fd);
return 0;
}
static int dump_manager(const char *path, mode_t mode) {
int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, mode);
if (fd < 0)
return 1;
if (!unxz(fd, manager_xz, sizeof(manager_xz)))
return 1;
close(fd);
return 0;
}
class RecoveryInit : public BaseInit {
public:
RecoveryInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
void start() override {
LOGD("Ramdisk is recovery, abort\n");
rename("/.backup/init", "/init");
rm_rf("/.backup");
exec_init();
}
};
class TestInit : public BaseInit {
public:
TestInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
void start() override {
// Place init tests here
}
};
[[maybe_unused]] static int test_main(int argc, char *argv[]) {
// Log to console
cmdline_logging();
log_cb.ex = nop_ex;
// Switch to isolate namespace
xunshare(CLONE_NEWNS);
xmount(nullptr, "/", nullptr, MS_PRIVATE | MS_REC, nullptr);
// Unmount everything in reverse
vector<string> mounts;
parse_mnt("/proc/mounts", [&](mntent *me) {
if (me->mnt_dir != "/"sv)
mounts.emplace_back(me->mnt_dir);
return true;
});
for (auto &m : reversed(mounts))
xumount(m.data());
// chroot jail
chdir(dirname(argv[0]));
chroot(".");
chdir("/");
cmdline cmd{};
load_kernel_info(&cmd);
auto init = make_unique<TestInit>(argv, &cmd);
init->start();
return 1;
}
int main(int argc, char *argv[]) {
umask(0);
auto name = basename(argv[0]);
if (name == "magisk"sv)
return magisk_proxy_main(argc, argv);
for (int i = 0; init_applet[i]; ++i) {
if (strcmp(name, init_applet[i]) == 0)
return (*init_applet_main[i])(argc, argv);
}
#if 0
if (getenv("INIT_TEST") != nullptr)
return test_main(argc, argv);
#endif
if (argc > 1 && argv[1] == "-x"sv) {
if (argv[2] == "magisk"sv)
return dump_magisk(argv[3], 0755);
else if (argv[2] == "manager"sv)
return dump_manager(argv[3], 0644);
}
if (getpid() != 1)
return 1;
BaseInit *init;
cmdline cmd{};
if (argc > 1 && argv[1] == "selinux_setup"sv) {
setup_klog();
init = new SecondStageInit(argv);
} else {
// This will also mount /sys and /proc
load_kernel_info(&cmd);
bool two_stage = check_two_stage();
if (cmd.skip_initramfs) {
if (two_stage)
init = new SARFirstStageInit(argv, &cmd);
else
init = new SARInit(argv, &cmd);
} else {
decompress_ramdisk();
if (cmd.force_normal_boot)
init = new FirstStageInit(argv, &cmd);
else if (access("/sbin/recovery", F_OK) == 0 || access("/system/bin/recovery", F_OK) == 0)
init = new RecoveryInit(argv, &cmd);
else if (two_stage)
init = new FirstStageInit(argv, &cmd);
else
init = new RootFSInit(argv, &cmd);
}
}
// Run the main routine
init->start();
exit(1);
}