Magisk/native/jni/init/getinfo.cpp
2020-10-08 03:04:12 -07:00

193 lines
5.0 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;
static void parse_cmdline(const std::function<void (std::string_view, const char *)> &fn) {
char cmdline[4096];
int fd = xopen("/proc/cmdline", O_RDONLY | O_CLOEXEC);
cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
close(fd);
char *tok, *eql, *tmp, *saveptr;
saveptr = cmdline;
while ((tok = strtok_r(nullptr, " \n", &saveptr)) != nullptr) {
eql = strchr(tok, '=');
if (eql) {
*eql = '\0';
if (eql[1] == '"') {
tmp = strchr(saveptr, '"');
if (tmp != nullptr) {
*tmp = '\0';
saveptr[-1] = ' ';
saveptr = tmp + 1;
eql++;
}
}
fn(tok, eql + 1);
} else {
fn(tok, "");
}
}
}
#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([&]{ std::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 load_kernel_info(cmdline *cmd) {
// 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);
// Log to kernel
setup_klog();
parse_cmdline([&](auto key, auto value) -> void {
if (key == "androidboot.slot_suffix") {
strcpy(cmd->slot, value);
} else if (key == "androidboot.slot") {
cmd->slot[0] = '_';
strcpy(cmd->slot + 1, value);
} else if (key == "skip_initramfs") {
cmd->skip_initramfs = true;
} else if (key == "androidboot.force_normal_boot") {
cmd->force_normal_boot = value[0] == '1';
} else if (key == "androidboot.android_dt_dir") {
strcpy(cmd->dt_dir, value);
} else if (key == "androidboot.hardware") {
strcpy(cmd->hardware, value);
} else if (key == "androidboot.hardware.platform") {
strcpy(cmd->hardware_plat, value);
} else if (key == "androidboot.fstab_suffix") {
strcpy(cmd->fstab_suffix, value);
}
});
parse_prop_file("/.backup/.magisk", [=](auto key, auto value) -> bool {
if (key == "RECOVERYMODE" && value == "true") {
LOGD("Running in recovery mode, waiting for key...\n");
cmd->skip_initramfs = !check_key_combo();
return false;
}
return true;
});
if (cmd->dt_dir[0] == '\0')
strcpy(cmd->dt_dir, DEFAULT_DT_DIR);
LOGD("Device info:\n");
LOGD("skip_initramfs=[%d]\n", cmd->skip_initramfs);
LOGD("force_normal_boot=[%d]\n", cmd->force_normal_boot);
LOGD("slot=[%s]\n", cmd->slot);
LOGD("dt_dir=[%s]\n", cmd->dt_dir);
LOGD("hardware=[%s]\n", cmd->hardware);
LOGD("hardware.platform=[%s]\n", cmd->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 = raw_data::mmap_ro("/.backup/init");
return init.contains("selinux_setup");
}