improve retrieving of session related environment variables

src/AppConsole.vala

@@ -75,6 +75,8 @@ public class AppConsole : GLib.Object {
 			return 0;
 		}
 
+		Main.copy_env();
+
 		LOG_ENABLE = false;
 		init_tmp();
 		LOG_ENABLE = true;

src/AppGtk.vala

@@ -66,6 +66,8 @@ public class AppGtk : GLib.Object {
 			}
 		}
 
+		Main.copy_env();
+
 		Gtk.init(ref args);
 
 		GTK_INITIALIZED = true;

src/Core/Main.vala

@@ -376,6 +376,24 @@ public class Main : GLib.Object{
 		}
 	}
 
+	// copy env from the spawning parent to this
+	public static void copy_env() {
+		Pid user_pid = TeeJee.ProcessHelper.get_user_process();
+		string[]? user_env = TeeJee.ProcessHelper.get_process_env(user_pid);
+		if(user_env == null) {
+			return;
+		}
+
+		// copy all required enviroment vars from the user to this process
+		string[] targets = {"DISPLAY", "XAUTHORITY", "DBUS_SESSION_BUS_ADDRESS"};
+		foreach (string target in targets) {
+			string user_var = TeeJee.ProcessHelper.get_env(user_env, target);
+			if(user_var != null) {
+				GLib.Environment.set_variable(target, user_var, true);
+			}
+		}
+	}
+
     private int[]? get_btrfs_version_array () {
         string stdout;
         string stderr;

src/Utility/TeeJee.FileSystem.vala

@@ -67,8 +67,8 @@
 
 	public bool file_exists (string file_path){
 		/* Check if file exists */
 		return (FileUtils.test(file_path, GLib.FileTest.EXISTS)
 			&& !FileUtils.test(file_path, GLib.FileTest.IS_DIR));
 	}
 
 	public bool file_delete(string file_path){
@@ -131,6 +131,37 @@
 	    return null;
 	}
 
+	// read a file with a delimiter into an array
+	// this function is not very optimized so avoid using it for large files
+	public string[]? file_read_array(string file_path, char delimiter = '\n'){
+		try{
+			uint8[] content;
+			GLib.FileUtils.get_data(file_path, out content);
+
+			// count elements
+			string[] parsed = {""};
+			int element = 0;
+			foreach (uint8 byte in content) {
+				// create a new element
+				if(byte == delimiter) {
+					element ++;
+					parsed += "";
+					continue;
+				}
+
+				parsed[element] += ((char) byte).to_string();
+			}
+
+			return parsed;
+		}
+		catch (Error e){
+			log_error (e.message);
+			log_error(_("Failed to read file") + ": %s".printf(file_path));
+		}
+
+		return null;
+	}
+
 	public bool file_write (string file_path, string contents){
 
 		/* Write text to file */
@@ -265,7 +296,7 @@
 
 	public bool dir_exists (string dir_path){
 		/* Check if directory exists */
 		return ( FileUtils.test(dir_path, GLib.FileTest.EXISTS) && FileUtils.test(dir_path, GLib.FileTest.IS_DIR));
 	}
 
 	public bool dir_create (string dir_path, bool show_message = false){

src/Utility/TeeJee.Process.vala

@@ -302,6 +302,71 @@
         return GLib.Path.get_basename(link);
 	}
 
+	// get the parent pid of process or self
+	public Pid get_process_parent(Pid process = -1) {
+		string pidStr = (process <= 0 ? "self" : process.to_string());
+		string path = "/proc/%s/stat".printf(pidStr);
+		string stats = file_read(path);
+		string details = stats.split(")", 2)[1];
+		string[] splitted = details.split(" ", 3);
+		if(splitted.length == 3) {
+			return int.parse(splitted[2]);
+		}
+
+		log_debug("can not parse process stat %s".printf(stats));
+		return -1;
+	}
+
+	// get the effective user pid of an process
+	// returns -1 on error
+	public int get_euid_of_process(Pid process) {
+		GLib.File file = GLib.File.new_for_path("/proc/%d".printf(process));
+		try {
+			GLib.FileInfo info = file.query_info(FileAttribute.UNIX_UID, GLib.FileQueryInfoFlags.NONE);
+			return (int) info.get_attribute_uint32(FileAttribute.UNIX_UID);
+		} catch(GLib.Error e) {
+			log_debug("failed to fetch user of process %i %s".printf(process, e.message));
+		}
+		return -1;
+	}
+
+	// find the first parent process, that is owned by the user and not root
+	public Pid get_user_process() {
+		Pid ppid = -1;
+		int targetUser = TeeJee.System.get_user_id();
+		int user = 0;
+
+		do {
+			ppid = get_process_parent(ppid);
+			user = get_euid_of_process (ppid);
+		} while(user != targetUser && ppid > 1);
+		if(user == targetUser) {
+			return ppid;
+		}
+		return -1;
+	}
+
+	// get the env of an process
+	public string[]? get_process_env(Pid pid) {
+		if(pid < 1) {
+			return null;
+		}
+		return file_read_array("/proc/%i/environ".printf(pid), '\0');
+	}
+
+	// get the value of name in env if it exists or return default_value
+	public string? get_env(string[] env, string name, string? default_value = null) {
+		foreach(string env_var in env) {
+			string[] splitted = env_var.split("=", 2);
+			if(splitted[0] == name) {
+				if (splitted.length == 2) {
+					return splitted[1];
+				}
+			}
+		}
+		return default_value;
+	}
+
 	public Pid[] get_process_children (Pid parent_pid){
 
 		/* Returns the list of child processes owned by a given process */

src/timeshift-launcher

@@ -9,16 +9,16 @@ else
 	# user is not admin
 	if echo $- | grep "i" >/dev/null 2>&1; then
 		# script is running in interactive mode
-		su - -c "pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY ${app_command}"
+		su - -c "${app_command}"
 	else
 		# script is running in non-interactive mode
 		if [ "$XDG_SESSION_TYPE" = "wayland" ] ; then
 			xhost +SI:localuser:root
-			pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY ${app_command}
+			pkexec "${app_command}"
 			xhost -SI:localuser:root
 			xhost
 		elif command -v pkexec >/dev/null 2>&1; then
-			pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY ${app_command}
+			pkexec "${app_command}"
 		elif command -v sudo >/dev/null 2>&1; then
 			x-terminal-emulator -e "sudo ${app_command}"
 		elif command -v su >/dev/null 2>&1; then