Magisk/native/jni/init/getinfo.cpp
2021-10-26 00:35:55 -07:00

258 lines
8.5 KiB
C++

#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/input.h>
#include <fcntl.h>
#include <vector>
#include <utils.hpp>
#include "init.hpp"
using namespace std;
vector<string> mount_list;
template<char... cs> using chars = integer_sequence<char, cs...>;
// If quoted, parsing ends when we find char in [breaks]
// If not quoted, parsing ends when we find char in [breaks] + [escapes]
template<char... escapes, char... breaks>
static string extract_quoted_str_until(chars<escapes...>, chars<breaks...>,
string_view str, size_t &pos, bool &quoted) {
string result;
char match_array[] = {escapes..., breaks..., '"'};
string_view match(match_array, std::size(match_array));
for (size_t cur = pos;; ++cur) {
cur = str.find_first_of(match, cur);
if (cur == string_view::npos ||
((str[cur] == breaks) || ...) ||
(!quoted && ((str[cur] == escapes) || ...))) {
result.append(str.substr(pos, cur - pos));
pos = cur;
return result;
}
if (str[cur] == '"') {
quoted = !quoted;
result.append(str.substr(pos, cur - pos));
pos = cur + 1;
}
}
}
// Parse string into key value pairs.
// The string format: [delim][key][padding]=[padding][value][delim]
template<char delim, char... padding>
static kv_pairs parse_impl(chars<padding...>, string_view str) {
kv_pairs kv;
char skip_array[] = {'=', padding...};
string_view skip(skip_array, std::size(skip_array));
bool quoted = false;
for (size_t pos = 0u; pos < str.size(); pos = str.find_first_not_of(delim, pos)) {
auto key = extract_quoted_str_until(
chars<padding..., delim>{}, chars<'='>{}, str, pos, quoted);
pos = str.find_first_not_of(skip, pos);
if (pos == string_view::npos || str[pos] == delim) {
kv.emplace_back(key, "");
continue;
}
auto value = extract_quoted_str_until(chars<delim>{}, chars<>{}, str, pos, quoted);
kv.emplace_back(key, value);
}
return kv;
}
static kv_pairs parse_cmdline(string_view str) {
return parse_impl<' '>(chars<>{}, str);
}
static kv_pairs parse_bootconfig(string_view str) {
return parse_impl<'\n'>(chars<' '>{}, str);
}
#define test_bit(bit, array) (array[bit / 8] & (1 << (bit % 8)))
static bool check_key_combo() {
uint8_t bitmask[(KEY_MAX + 1) / 8];
vector<int> events;
constexpr const char *name = "/event";
for (int minor = 64; minor < 96; ++minor) {
if (xmknod(name, S_IFCHR | 0444, makedev(13, minor)))
continue;
int fd = open(name, O_RDONLY | O_CLOEXEC);
unlink(name);
if (fd < 0)
continue;
memset(bitmask, 0, sizeof(bitmask));
ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(bitmask)), bitmask);
if (test_bit(KEY_VOLUMEUP, bitmask))
events.push_back(fd);
else
close(fd);
}
if (events.empty())
return false;
run_finally fin([&] { for_each(events.begin(), events.end(), close); });
// Return true if volume up key is held for more than 3 seconds
int count = 0;
for (int i = 0; i < 500; ++i) {
for (const int &fd : events) {
memset(bitmask, 0, sizeof(bitmask));
ioctl(fd, EVIOCGKEY(sizeof(bitmask)), bitmask);
if (test_bit(KEY_VOLUMEUP, bitmask)) {
count++;
break;
}
}
if (count >= 300) {
LOGD("KEY_VOLUMEUP detected: disable system-as-root\n");
return true;
}
// Check every 10ms
usleep(10000);
}
return false;
}
static FILE *kmsg;
static char kmsg_buf[4096];
static int vprintk(const char *fmt, va_list ap) {
vsnprintf(kmsg_buf + 12, sizeof(kmsg_buf) - 12, fmt, ap);
return fprintf(kmsg, "%s", kmsg_buf);
}
void setup_klog() {
// Shut down first 3 fds
int fd;
if (access("/dev/null", W_OK) == 0) {
fd = xopen("/dev/null", O_RDWR | O_CLOEXEC);
} else {
mknod("/null", S_IFCHR | 0666, makedev(1, 3));
fd = xopen("/null", O_RDWR | O_CLOEXEC);
unlink("/null");
}
xdup3(fd, STDIN_FILENO, O_CLOEXEC);
xdup3(fd, STDOUT_FILENO, O_CLOEXEC);
xdup3(fd, STDERR_FILENO, O_CLOEXEC);
if (fd > STDERR_FILENO)
close(fd);
if (access("/dev/kmsg", W_OK) == 0) {
fd = xopen("/dev/kmsg", O_WRONLY | O_CLOEXEC);
} else {
mknod("/kmsg", S_IFCHR | 0666, makedev(1, 11));
fd = xopen("/kmsg", O_WRONLY | O_CLOEXEC);
unlink("/kmsg");
}
kmsg = fdopen(fd, "w");
setbuf(kmsg, nullptr);
log_cb.d = log_cb.i = log_cb.w = log_cb.e = vprintk;
log_cb.ex = nop_ex;
strcpy(kmsg_buf, "magiskinit: ");
// Disable kmsg rate limiting
if (FILE *rate = fopen("/proc/sys/kernel/printk_devkmsg", "w")) {
fprintf(rate, "on\n");
fclose(rate);
}
}
void BootConfig::set(const kv_pairs &kv) {
for (const auto &[key, value] : kv) {
if (key == "androidboot.slot_suffix") {
strlcpy(slot, value.data(), sizeof(slot));
} else if (key == "androidboot.slot") {
slot[0] = '_';
strlcpy(slot + 1, value.data(), sizeof(slot) - 1);
} else if (key == "skip_initramfs") {
skip_initramfs = true;
} else if (key == "androidboot.force_normal_boot") {
force_normal_boot = !value.empty() && value[0] == '1';
} else if (key == "rootwait") {
rootwait = true;
} else if (key == "androidboot.android_dt_dir") {
strlcpy(dt_dir, value.data(), sizeof(dt_dir));
} else if (key == "androidboot.hardware") {
strlcpy(hardware, value.data(), sizeof(hardware));
} else if (key == "androidboot.hardware.platform") {
strlcpy(hardware_plat, value.data(), sizeof(hardware_plat));
} else if (key == "androidboot.fstab_suffix") {
strlcpy(fstab_suffix, value.data(), sizeof(fstab_suffix));
}
}
}
void BootConfig::print() {
LOGD("skip_initramfs=[%d]\n", skip_initramfs);
LOGD("force_normal_boot=[%d]\n", force_normal_boot);
LOGD("rootwait=[%d]\n", rootwait);
LOGD("slot=[%s]\n", slot);
LOGD("dt_dir=[%s]\n", dt_dir);
LOGD("fstab_suffix=[%s]\n", fstab_suffix);
LOGD("hardware=[%s]\n", hardware);
LOGD("hardware.platform=[%s]\n", hardware_plat);
}
#define read_dt(name, key) \
snprintf(file_name, sizeof(file_name), "%s/" name, config->key); \
if (access(file_name, R_OK) == 0) { \
string data = full_read(file_name); \
if (!data.empty()) { \
data.pop_back(); \
LOGD(name "=[%s]\n", data.data()); \
strlcpy(config->key, data.data(), sizeof(config->key)); \
} \
}
void load_kernel_info(BootConfig *config) {
// Get kernel data using procfs and sysfs
xmkdir("/proc", 0755);
xmount("proc", "/proc", "proc", 0, nullptr);
xmkdir("/sys", 0755);
xmount("sysfs", "/sys", "sysfs", 0, nullptr);
mount_list.emplace_back("/proc");
mount_list.emplace_back("/sys");
// Log to kernel
setup_klog();
config->set(parse_cmdline(full_read("/proc/cmdline")));
LOGD("Kernel cmdline info:\n");
config->print();
config->set(parse_bootconfig(full_read("/proc/bootconfig")));
LOGD("Boot config info:\n");
config->print();
parse_prop_file("/.backup/.magisk", [=](auto key, auto value) -> bool {
if (key == "RECOVERYMODE" && value == "true") {
LOGD("Running in recovery mode, waiting for key...\n");
config->skip_initramfs = !check_key_combo();
return false;
}
return true;
});
if (config->dt_dir[0] == '\0')
strlcpy(config->dt_dir, DEFAULT_DT_DIR, sizeof(config->dt_dir));
LOGD("Device tree:\n");
char file_name[128];
read_dt("fstab_suffix", fstab_suffix)
read_dt("hardware", hardware)
read_dt("hardware.platform", hardware_plat)
}
bool check_two_stage() {
if (access("/apex", F_OK) == 0)
return true;
if (access("/system/bin/init", F_OK) == 0)
return true;
// If we still have no indication, parse the original init and see what's up
auto init = mmap_data::ro("/.backup/init");
return init.contains("selinux_setup");
}