From 614c552e5553888e51b59c0bb4663c18125c10a6 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Sat, 21 Apr 2018 20:16:59 +0800
Subject: [PATCH] Improve daemon startup

---
 native/jni/core/daemon.c     | 28 +++++++++++++++-------------
 native/jni/core/magiskinit.c | 34 ++++++++++++++++++----------------
 2 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/native/jni/core/daemon.c b/native/jni/core/daemon.c
index af3438c93..86cda78ba 100644
--- a/native/jni/core/daemon.c
+++ b/native/jni/core/daemon.c
@@ -137,29 +137,33 @@ void daemon_init() {
 	DIR *dir;
 	struct dirent *entry;
 	int root, sbin, fd;
-	char buf[PATH_MAX], buf2[PATH_MAX];
-	void *data;
-	size_t size;
+	char buf[PATH_MAX];
+	void *magisk, *init;
+	size_t magisk_size, init_size;
 
 	// Create hardlink mirror of /sbin to /root
 	xmount(NULL, "/", NULL, MS_REMOUNT, NULL);
-	full_read("/sbin/magisk", &data, &size);
+	mkdir("/root", 0750);
+	full_read("/sbin/magisk", &magisk, &magisk_size);
+	full_read("/sbin/magiskinit", &init, &init_size);
 	root = xopen("/root", O_RDONLY | O_CLOEXEC);
 	sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
+//	unlink("/sbin/magisk");
+	unlink("/sbin/magiskinit");
 	link_dir(sbin, root);
-	unlink("/sbin/magisk");
 	close(sbin);
 
 	// Mount the /sbin tmpfs overlay
 	xmount("tmpfs", "/sbin", "tmpfs", 0, NULL);
 	chmod("/sbin", 0755);
 	setfilecon("/sbin", "u:object_r:rootfs:s0");
+	sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
 
 	// Setup magisk
 	fd = creat("/sbin/magisk", 0755);
-	xwrite(fd, data, size);
+	xwrite(fd, magisk, magisk_size);
 	close(fd);
-	free(data);
+	free(magisk);
 	setfilecon("/sbin/magisk", "u:object_r:"SEPOL_FILE_DOMAIN":s0");
 	for (int i = 0; applet[i]; ++i) {
 		snprintf(buf, PATH_MAX, "/sbin/%s", applet[i]);
@@ -167,12 +171,10 @@ void daemon_init() {
 	}
 
 	// Setup magiskinit
-	full_read("/root/magiskinit", &data, &size);
-	unlink("/root/magiskinit");
 	fd = creat("/sbin/magiskinit", 0755);
-	xwrite(fd, data, size);
+	xwrite(fd, init, init_size);
 	close(fd);
-	free(data);
+	free(init);
 	setfilecon("/sbin/magiskinit", "u:object_r:"SEPOL_FILE_DOMAIN":s0");
 	for (int i = 0; init_applet[i]; ++i) {
 		snprintf(buf, PATH_MAX, "/sbin/%s", init_applet[i]);
@@ -184,10 +186,10 @@ void daemon_init() {
 	while((entry = xreaddir(dir))) {
 		if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0) continue;
 		snprintf(buf, PATH_MAX, "/root/%s", entry->d_name);
-		snprintf(buf2, PATH_MAX, "/sbin/%s", entry->d_name);
-		xsymlink(buf, buf2);
+		symlinkat(buf, sbin, entry->d_name);
 	}
 
+	close(sbin);
 	close(root);
 	xmount(NULL, "/", NULL, MS_REMOUNT | MS_RDONLY, NULL);
 
diff --git a/native/jni/core/magiskinit.c b/native/jni/core/magiskinit.c
index c24e80e02..f36e4147e 100644
--- a/native/jni/core/magiskinit.c
+++ b/native/jni/core/magiskinit.c
@@ -375,14 +375,8 @@ int main(int argc, char *argv[]) {
 	if (null > STDERR_FILENO)
 		close(null);
 
-	// Extract and link files
-	mkdir("/overlay", 0000);
-	dump_magiskrc("/overlay/init.magisk.rc", 0750);
-	mkdir("/overlay/sbin", 0755);
-	dump_magisk("/overlay/sbin/magisk", 0755);
-	patch_socket_name("/overlay/sbin/magisk");
-	mkdir("/overlay/root", 0750);
-	link("/init", "/overlay/root/magiskinit");
+	// Backup self
+	link("/init", "/init.bak");
 
 	struct cmdline cmd;
 	parse_cmdline(&cmd);
@@ -395,7 +389,7 @@ int main(int argc, char *argv[]) {
 
 	if (cmd.skip_initramfs) {
 		// Clear rootfs
-		excl_list = (char *[]) { "overlay", ".backup", NULL };
+		excl_list = (char *[]) { "overlay", ".backup", "init.bak", NULL };
 		frm_rf(root);
 	} else if (access("/ramdisk.cpio.xz", R_OK) == 0) {
 		// High compression mode
@@ -464,20 +458,28 @@ int main(int argc, char *argv[]) {
 
 	// Only patch rootfs if not intended to run in recovery
 	if (access("/etc/recovery.fstab", F_OK) != 0) {
-		int overlay = open("/overlay", O_RDONLY | O_CLOEXEC);
-		mv_dir(overlay, root);
-		close(overlay);
-		rmdir("/overlay");
+		int fd;
+
+		// Handle ramdisk overlays
+		fd = open("/overlay", O_RDONLY | O_CLOEXEC);
+		if (fd >= 0) {
+			mv_dir(fd, root);
+			close(fd);
+			rmdir("/overlay");
+		}
 
 		patch_ramdisk();
 		patch_sepolicy();
+
+		// Dump binaries
+		dump_magiskrc("/init.magisk.rc", 0750);
+		dump_magisk("/sbin/magisk", 0755);
+		patch_socket_name("/sbin/magisk");
+		rename("/init.bak", "/sbin/magiskinit");
 	}
 
 	// Clean up
 	close(root);
-	close(STDIN_FILENO);
-	close(STDOUT_FILENO);
-	close(STDERR_FILENO);
 	if (!cmd.skip_initramfs)
 		umount("/system");
 	umount("/vendor");