Use a better function to read through files

native/jni/core/bootstages.cpp

@@ -378,35 +378,35 @@ static bool magisk_env() {
 	xmkdir(SECURE_DIR "/service.d", 0755);
 
 	LOGI("* Mounting mirrors");
-	auto mounts = file_to_vector("/proc/mounts");
 	bool system_as_root = false;
-	for (auto &line : mounts) {
+	file_readline("/proc/mounts", [&](string_view &line) -> bool {
 		if (str_contains(line, " /system_root ")) {
 			bind_mount("/system_root/system", MIRRDIR "/system");
-			sscanf(line.c_str(), "%s", buf);
+			sscanf(line.data(), "%s", buf);
 			system_block = strdup(buf);
 			system_as_root = true;
 		} else if (!system_as_root && str_contains(line, " /system ")) {
-			sscanf(line.c_str(), "%s %*s %s", buf, buf2);
+			sscanf(line.data(), "%s %*s %s", buf, buf2);
 			system_block = strdup(buf);
 			xmount(system_block, MIRRDIR "/system", buf2, MS_RDONLY, nullptr);
 			VLOGI("mount", system_block, MIRRDIR "/system");
 		} else if (str_contains(line, " /vendor ")) {
 			seperate_vendor = true;
-			sscanf(line.c_str(), "%s %*s %s", buf, buf2);
+			sscanf(line.data(), "%s %*s %s", buf, buf2);
 			vendor_block = strdup(buf);
 			xmkdir(MIRRDIR "/vendor", 0755);
 			xmount(vendor_block, MIRRDIR "/vendor", buf2, MS_RDONLY, nullptr);
 			VLOGI("mount", vendor_block, MIRRDIR "/vendor");
 		} else if (str_contains(line, " /data ")) {
-			sscanf(line.c_str(), "%s", buf);
+			sscanf(line.data(), "%s", buf);
 			data_block = strdup(buf);
 		} else if (SDK_INT >= 24 &&
 		str_contains(line, " /proc ") && !str_contains(line, "hidepid=2")) {
 			// Enforce hidepid
 			xmount(nullptr, "/proc", nullptr, MS_REMOUNT, "hidepid=2,gid=3009");
 		}
-	}
+		return true;
+	});
 	if (!seperate_vendor) {
 		xsymlink(MIRRDIR "/system/vendor", MIRRDIR "/vendor");
 		VLOGI("link", MIRRDIR "/system/vendor", MIRRDIR "/vendor");
@@ -492,12 +492,11 @@ static void collect_modules() {
 static bool check_data() {
 	bool mnt = false;
 	bool data = false;
-	auto mounts = file_to_vector("/proc/mounts");
-	for (auto &line : mounts) {
-		if (line.find(" /data ") != string::npos &&
-			line.find("tmpfs") == string::npos)
+	file_readline("/proc/mounts", [&](string_view &s) -> bool {
+		if (str_contains(s, " /data ") && !str_contains(s, "tmpfs"))
 			mnt = true;
-	}
+		return true;
+	});
 	if (mnt) {
 		auto crypto = getprop("ro.crypto.state");
 		if (!crypto.empty()) {

native/jni/magiskhide/hide_utils.cpp

@@ -263,9 +263,10 @@ bool init_list() {
 
 	// Migrate old hide list into database
 	if (access(LEGACY_LIST, R_OK) == 0) {
-		auto tmp = file_to_vector(LEGACY_LIST);
-		for (auto &s : tmp)
-			add_list(s.c_str());
+		file_readline(LEGACY_LIST, [](string_view &s) -> bool {
+			add_list(s.data());
+			return true;
+		});
 		unlink(LEGACY_LIST);
 	}
 

native/jni/magiskhide/proc_monitor.cpp

@@ -97,41 +97,36 @@ static bool is_pid_safetynet_process(const int pid) {
 }
 
 static void hide_daemon(int pid) {
-	LOGD("hide_daemon: handling PID=[%d]\n", pid);
-
 	char buffer[4096];
-	vector<string> mounts;
-
-	manage_selinux();
-	clean_magisk_props();
-
 	if (switch_mnt_ns(pid))
 		goto exit;
 
+	LOGD("hide_daemon: handling PID=[%d]\n", pid);
+	manage_selinux();
+	clean_magisk_props();
 	snprintf(buffer, sizeof(buffer), "/proc/%d", pid);
 	chdir(buffer);
 
-	mounts = file_to_vector("mounts");
 	// Unmount dummy skeletons and /sbin links
-	for (auto &s : mounts) {
+	file_readline("mounts", [&](string_view &s) -> bool {
 		if (str_contains(s, "tmpfs /system/") || str_contains(s, "tmpfs /vendor/") ||
 			str_contains(s, "tmpfs /sbin")) {
-			sscanf(s.c_str(), "%*s %4096s", buffer);
+			sscanf(s.data(), "%*s %4096s", buffer);
 			lazy_unmount(buffer);
 		}
-	}
-
-	// Re-read mount infos
-	mounts = file_to_vector("mounts");
+		return true;
+	});
 
 	// Unmount everything under /system, /vendor, and data mounts
-	for (auto &s : mounts) {
+	file_readline("mounts", [&](string_view &s) -> bool {
 		if ((str_contains(s, " /system/") || str_contains(s, " /vendor/")) &&
-			(str_contains(s, system_block) || str_contains(s, vendor_block) || str_contains(s, data_block))) {
-			sscanf(s.c_str(), "%*s %4096s", buffer);
+			(str_contains(s, system_block) || str_contains(s, vendor_block) ||
+			 str_contains(s, data_block))) {
+			sscanf(s.data(), "%*s %4096s", buffer);
 			lazy_unmount(buffer);
 		}
-	}
+		return true;
+	});
 
 exit:
 	// Send resume signal

native/jni/utils/file.cpp

@@ -384,25 +384,26 @@ void write_zero(int fd, size_t size) {
 	lseek(fd, pos + size, SEEK_SET);
 }
 
-vector<string> file_to_vector(const char *filename) {
-	vector<string> arr;
-	if (access(filename, R_OK) != 0)
-		return arr;
-	char *line = nullptr;
-	size_t len = 0;
-	ssize_t read;
-
+void file_readline(const char *filename, const function<bool (string_view&)> &fn, bool trim) {
 	FILE *fp = xfopen(filename, "re");
 	if (fp == nullptr)
-		return arr;
-
-	while ((read = getline(&line, &len, fp)) != -1) {
-		// Remove end newline
-		if (line[read - 1] == '\n')
-			line[read - 1] = '\0';
-		arr.emplace_back(line);
+		return;
+	size_t len = 1024;
+	char *buf = (char *) malloc(len);
+	char *start;
+	ssize_t read;
+	while ((read = getline(&buf, &len, fp)) >= 0) {
+		start = buf;
+		if (trim) {
+			while (buf[read - 1] == '\n' || buf[read - 1] == ' ')
+				buf[read-- - 1] = '\0';
+			while (*start == ' ')
+				++start;
+		}
+		string_view s(start);
+		if (!fn(s))
+			break;
 	}
 	fclose(fp);
-	free(line);
-	return arr;
+	free(buf);
 }

native/jni/utils/include/utils.h

@@ -140,13 +140,15 @@ void write_zero(int fd, size_t size);
 
 #include <string>
 #include <vector>
+#include <functional>
+#include <string_view>
 
 #define str_contains(s, ss) ((ss) != nullptr && (s).find(ss) != std::string::npos)
 #define str_starts(s, ss) ((ss) != nullptr && (s).compare(0, strlen(ss), ss) == 0)
 
 // file.cpp
 
-std::vector<std::string> file_to_vector(const char *filename);
+void file_readline(const char *filename, const std::function<bool (std::string_view&)> &fn, bool trim = false);
 
 // misc.cpp