Handle zygote death

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "loader/src/external/parallel-hashmap"]
 	path = loader/src/external/parallel-hashmap
 	url = https://github.com/greg7mdp/parallel-hashmap
+[submodule "zygiskd/src/external/binder_rs"]
+	path = zygiskd/src/external/binder_rs
+	url = https://github.com/Kernel-SU/binder_rs

README.md

@@ -2,12 +2,12 @@
 
 Zygisk loader for KernelSU, allowing Zygisk modules to run without Magisk environment.
 
-Warning: The current version of Zygisksu is UNSTABLE. You may suffer boot loop or even data loss so use with caution.
+Also works as standalone loader for Magisk on purpose of getting rid of LD_PRELOAD. (Coming soon)
 
 ## Requirements
 
 + Minimal KernelSU version: 10575
-+ Minimal ksud version: 10200
++ Minimal ksud version: 10616
 + Full SELinux patch support (If non-gki kernel)
 
 ## Compatibility
@@ -22,11 +22,5 @@ Should work with everything except those rely on Magisk internal behaviors.
 - [x] [Daemon] Linker namespace
 - [x] [Daemon] Separate zygiskd process
 - [x] [Daemon] Handle 64 bit only devices
-- [ ] [Daemon] Handle zygote death
-
-## Running on Magisk
-
-It is possible to run Zygisksu on Magisk with a few steps:
-
-1. `mkdir /data/adb/ksu`
-2. `ln -s /data/adb/modules /data/adb/ksu/`
+- [x] [Daemon] Handle zygote death
+- [ ] [ Misc ] Support Magisk out of box

module/src/customize.sh

@@ -1,6 +1,8 @@
 # shellcheck disable=SC2034
 SKIPUNZIP=1
 
+DEBUG=@DEBUG@
+
 if [ $BOOTMODE ] && [ "$KSU" == "true" ]; then
   ui_print "- Installing from KernelSU app"
 else
@@ -14,8 +16,8 @@ VERSION=$(grep_prop version "${TMPDIR}/module.prop")
 ui_print "- Installing Zygisksu $VERSION"
 
 # check KernelSU
-ui_print "- KernelSU version: $KSU_VER ($KSU_VER_CODE)"
-if [ "$KSU_VER_CODE" -lt 10200 ]; then
+ui_print "- KernelSU version: $KSU_KERNEL_VER_CODE (kernel) + $KSU_VER_CODE (ksud)"
+if [ "$KSU_KERNEL_VER_CODE" -lt 10575 ]; then
   ui_print "*********************************************************"
   ui_print "! KernelSU version is too old!"
   ui_print "! Please update KernelSU to latest version"
@@ -25,7 +27,7 @@ fi
 # check android
 if [ "$API" -lt 29 ]; then
   ui_print "! Unsupported sdk: $API"
-  abort "! Minimal supported sdk is 29 (Android 10.0)"
+  abort "! Minimal supported sdk is 29 (Android 10)"
 else
   ui_print "- Device sdk: $API"
 fi
@@ -51,7 +53,7 @@ extract "$ZIPFILE" 'verify.sh'     "$TMPDIR/.vunzip"
 extract "$ZIPFILE" 'sepolicy.rule' "$TMPDIR"
 
 ui_print "- Checking SELinux patches"
-if ! /data/adb/ksud sepolicy check "$TMPDIR/sepolicy.rule"; then
+if ! check_sepolicy "$TMPDIR/sepolicy.rule"; then
   ui_print "*********************************************************"
   ui_print "! Unable to apply SELinux patches!"
   ui_print "! Your kernel may not support SELinux patch fully"
@@ -110,17 +112,19 @@ else
   fi
 fi
 
-ui_print "- Hex patching"
-SOCKET_PATCH=$(tr -dc 'a-f0-9' </dev/urandom | head -c 18)
-if [ "$HAS32BIT" = true ]; then
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/bin/zygiskd32"
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib/libinjector.so"
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib/libzygiskloader.so"
-fi
-if [ "$HAS64BIT" = true ]; then
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/bin/zygiskd64"
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib64/libinjector.so"
-  sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib64/libzygiskloader.so"
+if [ $DEBUG = false ]; then
+  ui_print "- Hex patching"
+  SOCKET_PATCH=$(tr -dc 'a-f0-9' </dev/urandom | head -c 18)
+  if [ "$HAS32BIT" = true ]; then
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/bin/zygiskd32"
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib/libinjector.so"
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib/libzygiskloader.so"
+  fi
+  if [ "$HAS64BIT" = true ]; then
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/bin/zygiskd64"
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib64/libinjector.so"
+    sed -i "s/socket_placeholder/$SOCKET_PATCH/g" "$MODPATH/system/lib64/libzygiskloader.so"
+  fi
 fi
 
 ui_print "- Setting permissions"

zygiskd/Cargo.toml

@@ -10,6 +10,7 @@ android_logger = "0.12.0"
 anyhow = { version = "1.0.68", features = ["backtrace"] }
 clap = { version = "4.1.4", features = ["derive"] }
 const_format = "0.2.5"
+lazy_static = "1.4.0"
 log = "0.4.17"
 memfd = "0.6.2"
 nix = "0.26.2"
@@ -17,6 +18,8 @@ num_enum = "0.5.9"
 passfd = "0.1.5"
 rand = "0.8.5"
 
+binder = { path = "src/external/binder_rs/binder" }
+
 [profile.release]
 strip = true
 opt-level = "z"

zygiskd/build.gradle.kts

@@ -20,6 +20,7 @@ cargo {
     val isDebug = gradle.startParameter.taskNames.any { it.toLowerCase().contains("debug") }
     profile = if (isDebug) "debug" else "release"
     exec = { spec, _ ->
+        spec.environment("ANDROID_NDK_HOME", android.ndkDirectory.path)
         spec.environment("VERSION_CODE", verCode)
         spec.environment("VERSION_NAME", verName)
     }

zygiskd/src/constants.rs

@@ -23,6 +23,8 @@ macro_rules! lp_select {
 }
 
 pub const PROP_NATIVE_BRIDGE: &str = "ro.dalvik.vm.native.bridge";
+pub const PROP_SVC_ZYGOTE: &str = "init.svc.zygote";
+pub const ZYGISK_LOADER: &str = "libzygiskloader.so";
 
 pub const SOCKET_PLACEHOLDER: &str = "socket_placeholder";
 

zygiskd/src/utils.rs

@@ -1,4 +1,3 @@
-use crate::constants;
 use anyhow::Result;
 use nix::unistd::gettid;
 use std::{fs, io::{Read, Write}, os::unix::net::UnixStream, process::Command};
@@ -27,10 +26,10 @@ pub fn get_native_bridge() -> String {
     std::env::var("NATIVE_BRIDGE").unwrap_or_default()
 }
 
-pub fn restore_native_bridge() -> Result<()> {
+pub fn set_property(name: &str, value: &str) -> Result<()> {
     Command::new("resetprop")
-        .arg(constants::PROP_NATIVE_BRIDGE)
-        .arg(get_native_bridge())
+        .arg(name)
+        .arg(value)
         .spawn()?.wait()?;
     Ok(())
 }

zygiskd/src/watchdog.rs

@@ -1,12 +1,13 @@
 use crate::{constants, utils};
 use anyhow::{bail, Result};
-use nix::unistd::{getgid, getuid};
+use nix::unistd::{getgid, getuid, Pid};
 use std::process::{Child, Command};
 use std::sync::mpsc;
 use std::{fs, thread};
 use std::os::unix::net::UnixListener;
-use std::path::Path;
 use std::time::Duration;
+use binder::IBinder;
+use nix::sys::signal::{kill, Signal};
 
 static mut LOCK: Option<UnixListener> = None;
 
@@ -49,36 +50,56 @@ fn ensure_single_instance() -> Result<()> {
 }
 
 fn spawn_daemon() -> Result<()> {
-    let daemon32 = Command::new(constants::PATH_ZYGISKD32).arg("daemon").spawn();
-    let daemon64 = Command::new(constants::PATH_ZYGISKD64).arg("daemon").spawn();
-    let (sender, receiver) = mpsc::channel();
-    let mut waiting = vec![];
-    let mut spawn = |mut daemon: Child, socket: &'static str| {
-        waiting.push(socket);
-        let sender = sender.clone();
-        thread::spawn(move || {
-            let result = daemon.wait().unwrap();
-            log::error!("Daemon process {} died: {}", daemon.id(), result);
-            drop(daemon);
-            sender.send(()).unwrap();
-        });
-    };
-    if let Ok(it) = daemon32 { spawn(it, "/dev/socket/zygote_secondary") }
-    if let Ok(it) = daemon64 { spawn(it, "/dev/socket/zygote") }
-
-    waiting.into_iter().for_each(|socket| wait_zygote(socket));
-    log::info!("Zygote ready, restore native bridge");
-    utils::restore_native_bridge()?;
-
-    let _ = receiver.recv();
-    bail!("Daemon process died");
-}
-
-fn wait_zygote(socket: &str) -> () {
-    let path = Path::new(socket);
+    let mut lives = 5;
     loop {
-        if path.exists() { return; }
-        log::debug!("{socket} not exists, wait for 1s...");
-        thread::sleep(Duration::from_secs(1));
+        let daemon32 = Command::new(constants::PATH_ZYGISKD32).arg("daemon").spawn();
+        let daemon64 = Command::new(constants::PATH_ZYGISKD64).arg("daemon").spawn();
+        let mut child_ids = vec![];
+        let (sender, receiver) = mpsc::channel();
+        let mut spawn = |mut daemon: Child| {
+            child_ids.push(daemon.id());
+            let sender = sender.clone();
+            thread::spawn(move || {
+                let result = daemon.wait().unwrap();
+                log::error!("Daemon process {} died: {}", daemon.id(), result);
+                drop(daemon);
+                let _ = sender.send(());
+            });
+        };
+        if let Ok(it) = daemon32 { spawn(it) }
+        if let Ok(it) = daemon64 { spawn(it) }
+
+        let mut binder = loop {
+            if receiver.try_recv().is_ok() {
+                bail!("Daemon died before system server ready");
+            }
+            match binder::get_service("activity") {
+                Some(binder) => break binder,
+                None => {
+                    log::trace!("System server not ready, wait for 1s...");
+                    thread::sleep(Duration::from_secs(1));
+                }
+            };
+        };
+        log::info!("System server ready, restore native bridge");
+        utils::set_property(constants::PROP_NATIVE_BRIDGE, &utils::get_native_bridge())?;
+
+        loop {
+            if receiver.try_recv().is_ok() || binder.ping_binder().is_err() { break; }
+            thread::sleep(Duration::from_secs(1))
+        }
+        for child in child_ids {
+            let _ = kill(Pid::from_raw(child as i32), Signal::SIGKILL);
+        }
+
+        lives -= 1;
+        if lives == 0 {
+            bail!("Too many crashes, abort");
+        }
+
+        log::error!("Restarting zygote...");
+        utils::set_property(constants::PROP_NATIVE_BRIDGE, constants::ZYGISK_LOADER)?;
+        utils::set_property(constants::PROP_SVC_ZYGOTE, "restart")?;
+        thread::sleep(Duration::from_secs(2));
     }
 }