Init code rearrangement

native/jni/init/early_mount.cpp

@@ -1,4 +1,3 @@
-#include <sys/mount.h>
 #include <sys/sysmacros.h>
 #include <string.h>
 #include <stdio.h>
@@ -77,6 +76,13 @@ static dev_t setup_block(const char *partname, char *block_dev = nullptr) {
 	}
 }
 
+static bool is_lnk(const char *name) {
+	struct stat st;
+	if (lstat(name, &st))
+		return false;
+	return S_ISLNK(st.st_mode);
+}
+
 bool MagiskInit::read_dt_fstab(const char *name, char *partname, char *fstype) {
 	char path[128];
 	int fd;

native/jni/init/init.cpp

@@ -1,10 +1,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <sys/mount.h>
 #include <sys/sysmacros.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
 #include <string.h>
 #include <fcntl.h>
 #include <libgen.h>
@@ -48,7 +45,7 @@ static void setup_klog() {
 
 	// Prevent file descriptor confusion
 	mknod("/null", S_IFCHR | 0666, makedev(1, 3));
-	int null = open("/null", O_RDWR | O_CLOEXEC);
+	int null = xopen("/null", O_RDWR | O_CLOEXEC);
 	unlink("/null");
 	xdup3(null, STDIN_FILENO, O_CLOEXEC);
 	xdup3(null, STDOUT_FILENO, O_CLOEXEC);
@@ -122,38 +119,6 @@ static int dump_manager(const char *path, mode_t mode) {
 	return 0;
 }
 
-void BaseInit::cleanup() {
-	umount("/sys");
-	umount("/proc");
-	umount("/dev");
-}
-
-void BaseInit::re_exec_init() {
-	LOGD("Re-exec /init\n");
-	cleanup();
-	execv("/init", argv);
-	exit(1);
-}
-
-void RootFSInit::start() {
-	early_mount();
-	setup_rootfs();
-	re_exec_init();
-}
-
-void SARCommon::start() {
-	early_mount();
-	patch_rootdir();
-	re_exec_init();
-}
-
-void FirstStageInit::start() {
-	patch_fstab();
-	cleanup();
-	execv("/system/bin/init", argv);
-	exit(1);
-}
-
 class RecoveryInit : public BaseInit {
 public:
 	RecoveryInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
@@ -161,7 +126,7 @@ public:
 		LOGD("Ramdisk is recovery, abort\n");
 		rename("/.backup/init", "/init");
 		rm_rf("/.backup");
-		re_exec_init();
+		exec_init();
 	}
 };
 

native/jni/init/init.h

@@ -1,3 +1,5 @@
+#include <sys/mount.h>
+#include <unistd.h>
 #include <stdlib.h>
 
 struct cmdline {
@@ -21,8 +23,16 @@ protected:
 	cmdline *cmd;
 	char **argv;
 
-	void re_exec_init();
-	virtual void cleanup();
+	void exec_init(const char *init = "/init") {
+		cleanup();
+		execv(init, argv);
+		exit(1);
+	}
+	virtual void cleanup() {
+		umount("/sys");
+		umount("/proc");
+		umount("/dev");
+	}
 public:
 	BaseInit(char *argv[], cmdline *cmd) : cmd(cmd), argv(argv) {}
 	virtual ~BaseInit() = default;
@@ -52,7 +62,11 @@ protected:
 	virtual void setup_rootfs();
 public:
 	RootFSInit(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {};
-	void start() override;
+	void start() override {
+		early_mount();
+		setup_rootfs();
+		exec_init();
+	}
 };
 
 class SARCommon : public MagiskInit {
@@ -63,7 +77,11 @@ protected:
 	void patch_rootdir();
 public:
 	SARCommon(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {};
-	void start() override;
+	void start() override {
+		early_mount();
+		patch_rootdir();
+		exec_init();
+	}
 };
 
 /* *******************
@@ -75,7 +93,10 @@ protected:
 	void patch_fstab();
 public:
 	FirstStageInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
-	void start() override;
+	void start() override {
+		patch_fstab();
+		exec_init("/system/bin/init");
+	}
 };
 
 class SecondStageInit : public SARCommon {
@@ -120,13 +141,6 @@ public:
 	SARCompatInit(char *argv[], cmdline *cmd) : RootFSInit(argv, cmd) {};
 };
 
-static inline bool is_lnk(const char *name) {
-	struct stat st;
-	if (lstat(name, &st))
-		return false;
-	return S_ISLNK(st.st_mode);
-}
-
 void load_kernel_info(cmdline *cmd);
 int dump_magisk(const char *path, mode_t mode);
 int magisk_proxy_main(int argc, char *argv[]);

native/jni/init/rootdir.cpp

@@ -1,6 +1,5 @@
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/mount.h>
 #include <fcntl.h>
 
 #include <magisk.h>
@@ -396,19 +395,18 @@ int magisk_proxy_main(int argc, char *argv[]) {
 	sbin_overlay(self, config);
 
 	// Create symlinks pointing back to /root
-	{
-		char path[256];
-		int sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
-		unique_ptr<DIR, decltype(&closedir)> dir(xopendir("/root"), &closedir);
-		struct dirent *entry;
-		while((entry = xreaddir(dir.get()))) {
-			if (entry->d_name == "."sv || entry->d_name == ".."sv)
-				continue;
-			sprintf(path, "/root/%s", entry->d_name);
-			xsymlinkat(path, sbin, entry->d_name);
-		}
-		close(sbin);
+	char path[256];
+	int sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
+	DIR *dir = xopendir("/root");
+	struct dirent *entry;
+	while((entry = xreaddir(dir))) {
+		if (entry->d_name == "."sv || entry->d_name == ".."sv)
+			continue;
+		sprintf(path, "/root/%s", entry->d_name);
+		xsymlinkat(path, sbin, entry->d_name);
 	}
+	close(sbin);
+	closedir(dir);
 
 	setenv("REMOUNT_ROOT", "1", 1);
 	execv("/sbin/magisk", argv);