From e7155837d79177c1ac77288924073b78b9c7b16a Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Thu, 31 Oct 2019 01:57:47 -0400
Subject: [PATCH] Make sure magisk daemon won't get killed by init

According to this comment in #1880:
https://github.com/topjohnwu/Magisk/issues/1880#issuecomment-546657588

If Linux recycled our PPID, and coincidentally the process that reused
the PPID is root, AND init wants to kill the whole process group,
magiskd will get killed as a result.

There is no real way to block a SIGKILL signal, so we simply make sure
our daemon PID is the process group leader by renaming the directory.

Close #1880
---
 native/jni/core/daemon.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/native/jni/core/daemon.cpp b/native/jni/core/daemon.cpp
index f13f05d3e..0964b23d6 100644
--- a/native/jni/core/daemon.cpp
+++ b/native/jni/core/daemon.cpp
@@ -210,9 +210,17 @@ int connect_daemon(bool create) {
 			exit(1);
 		}
 
+		int ppid = getpid();
 		LOGD("client: launching new main daemon process\n");
 		if (fork_dont_care() == 0) {
 			close(fd);
+
+			// Make sure ppid is not in acct
+			char src[64], dest[64];
+			sprintf(src, "/acct/uid_0/pid_%d", ppid);
+			sprintf(dest, "/acct/uid_0/pid_%d", getpid());
+			rename(src, dest);
+
 			main_daemon();
 		}