2019-05-27 09:29:43 +02:00
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#include <sys/sysmacros.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <linux/input.h>
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#include <fcntl.h>
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2019-07-02 07:58:19 +02:00
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#include <vector>
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2019-05-27 09:29:43 +02:00
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2020-03-09 09:50:30 +01:00
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#include <utils.hpp>
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2019-05-27 09:29:43 +02:00
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2020-03-09 09:50:30 +01:00
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#include "init.hpp"
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2019-05-27 09:29:43 +02:00
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using namespace std;
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2020-10-27 04:46:15 +01:00
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template<typename Func>
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2020-10-28 12:17:34 +01:00
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static void parse_cmdline(const Func &fn) {
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2019-05-27 09:29:43 +02:00
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char cmdline[4096];
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2020-05-04 07:49:54 +02:00
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int fd = xopen("/proc/cmdline", O_RDONLY | O_CLOEXEC);
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2019-05-27 09:29:43 +02:00
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cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
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close(fd);
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char *tok, *eql, *tmp, *saveptr;
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saveptr = cmdline;
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while ((tok = strtok_r(nullptr, " \n", &saveptr)) != nullptr) {
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eql = strchr(tok, '=');
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if (eql) {
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*eql = '\0';
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if (eql[1] == '"') {
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tmp = strchr(saveptr, '"');
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if (tmp != nullptr) {
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*tmp = '\0';
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saveptr[-1] = ' ';
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saveptr = tmp + 1;
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eql++;
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}
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}
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fn(tok, eql + 1);
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} else {
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fn(tok, "");
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}
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}
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}
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#define test_bit(bit, array) (array[bit / 8] & (1 << (bit % 8)))
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static bool check_key_combo() {
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uint8_t bitmask[(KEY_MAX + 1) / 8];
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vector<int> events;
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constexpr const char *name = "/event";
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for (int minor = 64; minor < 96; ++minor) {
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2020-05-19 13:53:16 +02:00
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if (xmknod(name, S_IFCHR | 0444, makedev(13, minor)))
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2019-05-27 09:29:43 +02:00
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continue;
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int fd = open(name, O_RDONLY | O_CLOEXEC);
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unlink(name);
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if (fd < 0)
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continue;
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memset(bitmask, 0, sizeof(bitmask));
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ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(bitmask)), bitmask);
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if (test_bit(KEY_VOLUMEUP, bitmask))
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events.push_back(fd);
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2020-05-19 13:53:16 +02:00
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else
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close(fd);
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2019-05-27 09:29:43 +02:00
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}
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if (events.empty())
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return false;
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2020-05-19 13:53:16 +02:00
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run_finally fin([&]{ std::for_each(events.begin(), events.end(), close); });
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2019-05-27 09:29:43 +02:00
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2020-05-19 13:53:16 +02:00
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// Return true if volume up key is held for more than 3 seconds
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2019-05-27 09:29:43 +02:00
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int count = 0;
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for (int i = 0; i < 500; ++i) {
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for (const int &fd : events) {
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memset(bitmask, 0, sizeof(bitmask));
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ioctl(fd, EVIOCGKEY(sizeof(bitmask)), bitmask);
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if (test_bit(KEY_VOLUMEUP, bitmask)) {
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count++;
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break;
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}
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}
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if (count >= 300) {
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LOGD("KEY_VOLUMEUP detected: disable system-as-root\n");
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return true;
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}
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// Check every 10ms
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usleep(10000);
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}
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return false;
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}
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2020-06-01 13:15:37 +02:00
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static FILE *kmsg;
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static char kmsg_buf[4096];
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static int vprintk(const char *fmt, va_list ap) {
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vsnprintf(kmsg_buf + 12, sizeof(kmsg_buf) - 12, fmt, ap);
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return fprintf(kmsg, "%s", kmsg_buf);
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}
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void setup_klog() {
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// Shut down first 3 fds
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int fd;
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if (access("/dev/null", W_OK) == 0) {
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fd = xopen("/dev/null", O_RDWR | O_CLOEXEC);
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} else {
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mknod("/null", S_IFCHR | 0666, makedev(1, 3));
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fd = xopen("/null", O_RDWR | O_CLOEXEC);
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unlink("/null");
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}
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xdup3(fd, STDIN_FILENO, O_CLOEXEC);
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xdup3(fd, STDOUT_FILENO, O_CLOEXEC);
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xdup3(fd, STDERR_FILENO, O_CLOEXEC);
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if (fd > STDERR_FILENO)
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close(fd);
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if (access("/dev/kmsg", W_OK) == 0) {
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fd = xopen("/dev/kmsg", O_WRONLY | O_CLOEXEC);
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} else {
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mknod("/kmsg", S_IFCHR | 0666, makedev(1, 11));
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fd = xopen("/kmsg", O_WRONLY | O_CLOEXEC);
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unlink("/kmsg");
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}
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kmsg = fdopen(fd, "w");
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setbuf(kmsg, nullptr);
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log_cb.d = log_cb.i = log_cb.w = log_cb.e = vprintk;
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log_cb.ex = nop_ex;
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strcpy(kmsg_buf, "magiskinit: ");
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2019-05-27 09:29:43 +02:00
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2020-04-22 05:04:29 +02:00
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// Disable kmsg rate limiting
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2020-05-04 08:07:40 +02:00
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if (FILE *rate = fopen("/proc/sys/kernel/printk_devkmsg", "w")) {
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2020-04-22 05:04:29 +02:00
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fprintf(rate, "on\n");
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fclose(rate);
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}
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2020-06-01 13:15:37 +02:00
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}
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2020-12-09 13:22:17 +01:00
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#define read_dt(name, key) \
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sprintf(file_name, "%s/" name, cmd->dt_dir); \
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if (access(file_name, R_OK) == 0){ \
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string data = full_read(file_name); \
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if (!data.empty()) { \
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data.pop_back(); \
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strcpy(cmd->key, data.data()); \
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} \
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}
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2020-06-01 13:15:37 +02:00
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void load_kernel_info(cmdline *cmd) {
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// Get kernel data using procfs and sysfs
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xmkdir("/proc", 0755);
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xmount("proc", "/proc", "proc", 0, nullptr);
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xmkdir("/sys", 0755);
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xmount("sysfs", "/sys", "sysfs", 0, nullptr);
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// Log to kernel
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setup_klog();
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2020-04-22 05:04:29 +02:00
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2020-10-28 12:17:34 +01:00
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parse_cmdline([=](string_view key, const char *value) -> void {
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2019-05-27 09:29:43 +02:00
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if (key == "androidboot.slot_suffix") {
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2019-06-16 07:25:09 +02:00
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strcpy(cmd->slot, value);
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2019-05-27 09:29:43 +02:00
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} else if (key == "androidboot.slot") {
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2019-06-16 07:25:09 +02:00
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cmd->slot[0] = '_';
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strcpy(cmd->slot + 1, value);
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2019-05-27 09:29:43 +02:00
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} else if (key == "skip_initramfs") {
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2019-12-06 18:02:34 +01:00
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cmd->skip_initramfs = true;
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Logical Resizable Android Partitions support
The way how logical partition, or "Logical Resizable Android Partitions"
as they say in AOSP source code, is setup makes it impossible to early
mount the partitions from the shared super partition with just
a few lines of code; in fact, AOSP has a whole "fs_mgr" folder which
consist of multiple complex libraries, with 15K lines of code just
to deal with the device mapper shenanigans.
In order to keep the already overly complicated MagiskInit more
managable, I chose NOT to go the route of including fs_mgr directly
into MagiskInit. Luckily, starting from Android Q, Google decided to
split init startup into 3 stages, with the first stage doing _only_
early mount. This is great news, because we can simply let the stock
init do its own thing for us, and we intercept the bootup sequence.
So the workflow can be visualized roughly below:
Magisk First Stage --> First Stage Mount --> Magisk Second Stage --+
(MagiskInit) (Original Init) (MagiskInit) +
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...Rest of the boot... <-- Second Stage <-- Selinux Setup <--+
(__________________ Original Init ____________________)
The catch here is that after doing all the first stage mounting, /init
will pivot /system as root directory (/), leaving us impossible to
regain control after we hand it over. So the solution here is to patch
fstab in /first_stage_ramdisk on-the-fly to redirect /system to
/system_root, making the original init do all the hard work for
us and mount required early mount partitions, but skips the step of
switching root directory. It will also conveniently hand over execution
back to MagiskInit, which we will reuse the routine for patching
root directory in normal system-as-root situations.
2019-06-29 09:47:29 +02:00
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} else if (key == "androidboot.force_normal_boot") {
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cmd->force_normal_boot = value[0] == '1';
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2020-12-30 12:56:40 +01:00
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} else if (key == "rootwait") {
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cmd->rootwait = true;
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2019-05-27 09:29:43 +02:00
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} else if (key == "androidboot.android_dt_dir") {
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2019-06-16 07:25:09 +02:00
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strcpy(cmd->dt_dir, value);
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2019-05-27 09:29:43 +02:00
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} else if (key == "androidboot.hardware") {
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2020-05-04 07:49:54 +02:00
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strcpy(cmd->hardware, value);
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} else if (key == "androidboot.hardware.platform") {
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strcpy(cmd->hardware_plat, value);
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2020-10-08 12:04:12 +02:00
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} else if (key == "androidboot.fstab_suffix") {
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strcpy(cmd->fstab_suffix, value);
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2019-05-27 09:29:43 +02:00
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}
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});
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2020-12-09 13:22:17 +01:00
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LOGD("Kernel cmdline info:\n");
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2020-10-28 12:17:34 +01:00
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LOGD("skip_initramfs=[%d]\n", cmd->skip_initramfs);
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LOGD("force_normal_boot=[%d]\n", cmd->force_normal_boot);
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2020-12-30 12:56:40 +01:00
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LOGD("rootwait=[%d]\n", cmd->rootwait);
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2020-10-28 12:17:34 +01:00
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LOGD("slot=[%s]\n", cmd->slot);
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LOGD("dt_dir=[%s]\n", cmd->dt_dir);
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LOGD("fstab_suffix=[%s]\n", cmd->fstab_suffix);
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LOGD("hardware=[%s]\n", cmd->hardware);
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LOGD("hardware.platform=[%s]\n", cmd->hardware_plat);
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2020-05-04 08:07:40 +02:00
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parse_prop_file("/.backup/.magisk", [=](auto key, auto value) -> bool {
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if (key == "RECOVERYMODE" && value == "true") {
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LOGD("Running in recovery mode, waiting for key...\n");
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cmd->skip_initramfs = !check_key_combo();
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return false;
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}
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2019-05-27 09:29:43 +02:00
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return true;
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});
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2019-06-16 07:25:09 +02:00
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if (cmd->dt_dir[0] == '\0')
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strcpy(cmd->dt_dir, DEFAULT_DT_DIR);
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2020-12-09 13:22:17 +01:00
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char file_name[128];
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read_dt("fstab_suffix", fstab_suffix)
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read_dt("hardware", hardware)
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read_dt("hardware.platform", hardware_plat)
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LOGD("Device tree info:\n");
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LOGD("dt_dir=[%s]\n", cmd->dt_dir);
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LOGD("fstab_suffix=[%s]\n", cmd->fstab_suffix);
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LOGD("hardware=[%s]\n", cmd->hardware);
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LOGD("hardware.platform=[%s]\n", cmd->hardware_plat);
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2019-05-27 09:29:43 +02:00
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}
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2020-09-03 06:20:00 +02:00
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bool check_two_stage() {
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if (access("/apex", F_OK) == 0)
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return true;
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2020-09-04 15:06:03 +02:00
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if (access("/system/bin/init", F_OK) == 0)
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return true;
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// If we still have no indication, parse the original init and see what's up
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auto init = raw_data::mmap_ro("/.backup/init");
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2020-09-04 15:21:25 +02:00
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return init.contains("selinux_setup");
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2020-09-03 06:20:00 +02:00
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}
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