Clean rootfs in switch_root

native/jni/core/bootstages.cpp

@@ -478,7 +478,7 @@ static void collect_modules() {
 				fd_pathat(modfd, "uninstall.sh", buf, sizeof(buf));
 				if (access(buf, F_OK) == 0)
 					exec_script(buf);
-				frm_rf(modfd);
+				frm_rf(xdup(modfd));
 				unlinkat(dfd, entry->d_name, AT_REMOVEDIR);
 				continue;
 			}

native/jni/init/mount.cpp

@@ -121,6 +121,7 @@ if (!is_lnk("/" #name) && read_dt_fstab(cmd, #name)) { \
 
 static void switch_root(const string &path) {
 	LOGD("Switch root to %s\n", path.data());
+	int root = xopen("/", O_RDONLY);
 	vector<string> mounts;
 	parse_mnt("/proc/mounts", [&](mntent *me) {
 		// Skip root and self
@@ -142,6 +143,9 @@ static void switch_root(const string &path) {
 	chdir(path.data());
 	xmount(path.data(), "/", nullptr, MS_MOVE, nullptr);
 	chroot(".");
+
+	LOGD("Cleaning rootfs\n");
+	frm_rf(root);
 }
 
 static void mount_persist(const char *dev_base, const char *mnt_base) {
@@ -219,11 +223,6 @@ void SARInit::early_mount() {
 
 	backup_files();
 
-	LOGD("Cleaning rootfs\n");
-	int root = xopen("/", O_RDONLY | O_CLOEXEC);
-	frm_rf(root, { "proc", "sys", "dev" });
-	close(root);
-
 	mount_system_root();
 	switch_root("/system_root");
 

native/jni/utils/file.cpp

@@ -47,27 +47,15 @@ int mkdirs(const char *pathname, mode_t mode) {
 	return 0;
 }
 
-static bool is_excl(initializer_list<const char *> excl, const char *name) {
+static void post_order_walk(int dirfd, function<int(int, dirent *)> &&fn) {
-	for (auto item : excl)
-		if (strcmp(item, name) == 0)
-			return true;
-	return false;
-}
-
-static void post_order_walk(int dirfd, initializer_list<const char *> excl,
-		function<int(int, dirent *)> &&fn) {
 	auto dir = xopen_dir(dirfd);
 	if (!dir) return;
 
 	for (dirent *entry; (entry = xreaddir(dir.get()));) {
-		if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+		if (entry->d_name == "."sv || entry->d_name == ".."sv)
 			continue;
-		if (is_excl(excl, entry->d_name))
+		if (entry->d_type == DT_DIR)
-			continue;
+			post_order_walk(xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC), std::move(fn));
-		if (entry->d_type == DT_DIR) {
-			int newfd = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC);
-			post_order_walk(newfd, excl, std::move(fn));
-		}
 		fn(dirfd, entry);
 	}
 }
@@ -80,15 +68,13 @@ void rm_rf(const char *path) {
 	struct stat st;
 	if (lstat(path, &st) < 0)
 		return;
-	if (S_ISDIR(st.st_mode)) {
+	if (S_ISDIR(st.st_mode))
-		int fd = xopen(path, O_RDONLY | O_CLOEXEC);
+		frm_rf(xopen(path, O_RDONLY | O_CLOEXEC));
-		frm_rf(fd);
-	}
 	remove(path);
 }
 
-void frm_rf(int dirfd, initializer_list<const char *> excl) {
+void frm_rf(int dirfd) {
-	post_order_walk(dup(dirfd), excl, remove_at);
+	post_order_walk(dirfd, remove_at);
 }
 
 /* This will only on the same file system */
@@ -389,7 +375,7 @@ void parse_prop_file(const char *file, const function<bool (string_view, string_
 }
 
 void parse_mnt(const char *file, const function<bool (mntent*)> &fn) {
-	unique_ptr<FILE, decltype(&endmntent)> fp(setmntent(file, "re"), &endmntent);
+	auto fp = sFILE(setmntent(file, "re"), endmntent);
 	if (fp) {
 		mntent mentry{};
 		char buf[4096];
@@ -404,11 +390,11 @@ void backup_folder(const char *dir, vector<raw_file> &files) {
 	char path[4096];
 	realpath(dir, path);
 	int len = strlen(path);
-	int dirfd = xopen(dir, O_RDONLY);
+	post_order_walk(xopen(dir, O_RDONLY), [&](int dfd, dirent *entry) -> int {
-	post_order_walk(dirfd, {}, [&](int dfd, dirent *entry) -> int {
 		int fd = xopenat(dfd, entry->d_name, O_RDONLY);
 		if (fd < 0)
 			return -1;
+		run_finally f([&]{ close(fd); });
 		if (fd_path(fd, path, sizeof(path)) < 0)
 			return -1;
 		raw_file file;
@@ -423,11 +409,9 @@ void backup_folder(const char *dir, vector<raw_file> &files) {
 			file.buf = (uint8_t *) xmalloc(file.sz);
 			memcpy(file.buf, path, file.sz);
 		}
-		close(fd);
 		files.emplace_back(std::move(file));
 		return 0;
 	});
-	close(dirfd);
 }
 
 void restore_folder(const char *dir, vector<raw_file> &files) {
@@ -438,7 +422,7 @@ void restore_folder(const char *dir, vector<raw_file> &files) {
 		if (S_ISDIR(file.attr.st.st_mode)) {
 			mkdirs(path.data(), 0);
 		} else if (S_ISREG(file.attr.st.st_mode)) {
-			auto fp = xopen_file(path.data(), "w");
+			auto fp = xopen_file(path.data(), "we");
 			fwrite(file.buf, 1, file.sz, fp.get());
 		} else if (S_ISLNK(file.attr.st.st_mode)) {
 			symlink((char *)file.buf, path.data());

native/jni/utils/files.hpp

@@ -66,7 +66,7 @@ static inline void file_readline(const char *file,
 void parse_prop_file(const char *file,
 		const std::function<bool(std::string_view, std::string_view)> &fn);
 void *__mmap(const char *filename, size_t *size, bool rw);
-void frm_rf(int dirfd, std::initializer_list<const char *> excl = {});
+void frm_rf(int dirfd);
 void clone_dir(int src, int dest, bool overwrite = true);
 void parse_mnt(const char *file, const std::function<bool(mntent*)> &fn);
 void backup_folder(const char *dir, std::vector<raw_file> &files);

native/jni/utils/xwrap.cpp

@@ -258,6 +258,14 @@ int xfstat(int fd, struct stat *buf) {
 	return ret;
 }
 
+int xdup(int fd) {
+	int ret = dup(fd);
+	if (ret == -1) {
+		PLOGE("dup");
+	}
+	return ret;
+}
+
 int xdup2(int oldfd, int newfd) {
 	int ret = dup2(oldfd, newfd);
 	if (ret == -1) {

native/jni/utils/xwrap.hpp

@@ -35,6 +35,7 @@ int xpthread_create(pthread_t *thread, const pthread_attr_t *attr,
 int xstat(const char *pathname, struct stat *buf);
 int xlstat(const char *pathname, struct stat *buf);
 int xfstat(int fd, struct stat *buf);
+int xdup(int fd);
 int xdup2(int oldfd, int newfd);
 int xdup3(int oldfd, int newfd, int flags);
 ssize_t xreadlink(const char *pathname, char *buf, size_t bufsiz);