main.c File Reference

#include <X11/X.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/cursorfont.h>
#include <X11/keysym.h>
#include <fcntl.h>
#include <locale.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "auth_child.h"
#include "env_settings.h"
#include "logging.h"
#include "mlock_page.h"
#include "saver_child.h"
#include "unmap_all.h"
#include "util.h"
#include "version.h"
#include "wait_pgrp.h"
#include "wm_properties.h"
#include "env_helpstr.inc"

Data Structures
struct	AcquireGrabsState

Macros
#define	WATCH_CHILDREN_HZ   10
	XSecureLock. More...
#define	ALL_POINTER_EVENTS
	Try to reinstate grabs in regular intervals. More...

Enumerations
enum	WatchChildrenState { WATCH_CHILDREN_NORMAL, WATCH_CHILDREN_SAVER_DISABLED, WATCH_CHILDREN_FORCE_AUTH }

Functions
void	ResetBlankScreenTimer (void)
void	InitBlankScreen (void)
void	MaybeBlankScreen (Display *display)
void	ScreenNoLongerBlanked (Display *display)
void	UnblankScreen (Display *display)
static void	HandleSIGTERM (int signo)
int	WatchChildren (Display *dpy, Window auth_win, Window saver_win, enum WatchChildrenState state, const char *stdinbuf)
	Watch the child processes, and bring them into the desired state. More...
int	WakeUp (Display *dpy, Window auth_win, Window saver_win, const char *stdinbuf)
	Wake up the screen saver in response to a keyboard or mouse event. More...
int	JustLogErrorsHandler (Display *display, XErrorEvent *error)
	An X11 error handler that merely logs errors to stderr. More...
int	SilentlyIgnoreErrorsHandler (Display *display, XErrorEvent *error)
	An X11 error handler that does nothing at all. More...
void	Version (void)
	Print a version message. More...
void	Usage (const char *me)
	Print an usage message. More...
void	LoadDefaults ()
	Load default settings from environment variables. More...
void	ParseArgumentsOrExit (int argc, char **argv)
	Parse the command line arguments, or exit in case of failure. More...
int	CheckSettings ()
	Check the settings. More...
void	DebugDumpWindowInfo (Window w)
	Print some debug info about a window. More...
void	MaybeRaiseWindow (Display *display, Window w, int silent, int force)
	Raise a window if necessary. More...
int	TryAcquireGrabs (Window w, void *state_voidp)
int	AcquireGrabs (Display *display, Window root_window, Window *ignored_windows, unsigned int n_ignored_windows, Cursor cursor, int silent, int force)
	Acquire all necessary grabs to lock the screen. More...
void	NotifyOfLock (int xss_sleep_lock_fd)
	Tell xss-lock or others that we're done locking. More...
int	CheckLockingEffectiveness ()
int	main (int argc, char **argv)
	The main program. More...

Variables
struct {
XEvent   ev
char   buf [16]
KeySym   keysym
int   len
}	priv
	Private (possibly containing information about the user's password) data. More...
const char *	auth_executable
	The name of the auth child to execute, relative to HELPER_PATH. More...
const char *	saver_executable
	The name of the saver child to execute, relative to HELPER_PATH. More...
char *const *	notify_command = NULL
	The command to run once screen locking is complete. More...
int	have_switch_user_command = 0
	If set, we can start a new login session. More...
int	force_grab = 0
	If set, we try to force grabbing by "evil" means. More...
int	debug_window_info = 0
	If set, print window info about any "conflicting" windows to stderr. More...
int	blank_timeout = -1
	If nonnegative, the time in seconds till we blank the screen explicitly. More...
const char *	blank_dpms_state = "off"
	The DPMS state to switch the screen to when blanking. More...
int	saver_reset_on_auth_close = 0
	Whether to reset the saver module when auth closes. More...
pid_t	notify_command_pid = 0
	The PID of a currently running notify command, or 0 if none is running. More...
struct timeval	time_to_blank
	The time when we will blank the screen. More...
int	blanked = 0
	Whether the screen is currently blanked by us. More...

Macro Definition Documentation

ALL_POINTER_EVENTS

#define ALL_POINTER_EVENTS

Value:

(ButtonPressMask | ButtonReleaseMask | EnterWindowMask | LeaveWindowMask | \
   PointerMotionMask | Button1MotionMask | Button2MotionMask |               \
   Button3MotionMask | Button4MotionMask | Button5MotionMask |               \
   ButtonMotionMask)

Try to reinstate grabs in regular intervals.

This will reinstate the grabs WATCH_CHILDREN_HZ times per second. This appears to be required with some XScreenSaver hacks that cause XSecureLock to lose MotionNotify events, but nothing else.

Try to bring the grab window to foreground in regular intervals.

Some desktop environments have transparent OverrideRedirect notifications. These do not send a VisibilityNotify to this window, as some part still shines through. As a workaround, this enables raising the grab window periodically.

Show cursor during auth.

If enabled, a mouse cursor is shown whenever the auth_window is mapped.

Note that proper use of this also would require a way to forward click events to the auth helper, which doesn't exist yet.

Exhaustive list of all mouse related X11 events.

These will be selected for grab. It is important that this contains all pointer event types, to not let any through to other applications.

WATCH_CHILDREN_HZ

#define WATCH_CHILDREN_HZ   10

XSecureLock.

XSecureLock is an X11 screen lock utility designed with the primary goal of security.

How often (in times per second) to watch child processes.

This defines the minimum frequency to call WatchChildren().

Enumeration Type Documentation

WatchChildrenState

enum WatchChildrenState

Enumerator
WATCH_CHILDREN_NORMAL	Request saver child.
WATCH_CHILDREN_SAVER_DISABLED	Request no saver to run (DPMS!).
WATCH_CHILDREN_FORCE_AUTH	Request auth child.

Function Documentation

AcquireGrabs()

int AcquireGrabs	(	Display *	display,
		Window	root_window,
		Window *	ignored_windows,
		unsigned int	n_ignored_windows,
		Cursor	cursor,
		int	silent,
		int	force
	)

Acquire all necessary grabs to lock the screen.

Parameters

display	The X11 display.
root_window	The root window.
silent	Do not log errors.
force	Try extra hard (1), or even harder (2). The latter mode will very likely interfere strongly with window managers.

Returns

true if grabbing succeeded, false otherwise.

CheckLockingEffectiveness()

int CheckLockingEffectiveness

(

)

CheckSettings()

int CheckSettings

(

)

Check the settings.

This tests whether the selected auth and saver executables are valid and actually executable. Failure of this could lead to an un-unlockable screen, and we sure don't want that.

Possible errors will be printed on stderr.

Returns

true if everything is OK, false otherwise.

DebugDumpWindowInfo()

void DebugDumpWindowInfo

(

Window

w

)

Print some debug info about a window.

Only enabled if debug_window_info is set.

Spammy.

HandleSIGTERM()

static void HandleSIGTERM ( int  signo )

static

InitBlankScreen()

void InitBlankScreen

(

void

)

JustLogErrorsHandler()

int JustLogErrorsHandler	(	Display *	display,
		XErrorEvent *	error
	)

An X11 error handler that merely logs errors to stderr.

This is used to prevent X11 errors from terminating XSecureLock.

LoadDefaults()

void LoadDefaults

(

)

Load default settings from environment variables.

These settings override what was figured out at ./configure time.

main()

int main	(	int	argc,
		char **	argv
	)

The main program.

Usage: see Usage().

MaybeBlankScreen()

void MaybeBlankScreen

(

Display *

display

)

MaybeRaiseWindow()

void MaybeRaiseWindow	(	Display *	display,
		Window	w,
		int	silent,
		int	force
	)

Raise a window if necessary.

Does not cause any events if the window is already on the top.

Parameters

display	The X11 display.
w	The window to raise.
silent	Whether to output something if we can't detect what is wrong.
force	Whether to always raise our window, even if we can't find what covers us. Set this only if confident that there is something overlapping us, like in response to a negative VisibilityNotify.

NotifyOfLock()

void NotifyOfLock

(

int

xss_sleep_lock_fd

)

Tell xss-lock or others that we're done locking.

This enables xss-lock to delay going to sleep until the screen is actually locked - useful to prevent information leaks after wakeup.

Parameters

fd	The file descriptor of the X11 connection that we shouldn't close.

ParseArgumentsOrExit()

void ParseArgumentsOrExit	(	int	argc,
		char **	argv
	)

Parse the command line arguments, or exit in case of failure.

This accepts saver_* or auth_* arguments, and puts them in their respective global variable.

This is DEPRECATED - use the XSECURELOCK_SAVER and XSECURELOCK_AUTH environment variables instead!

Possible errors will be printed on stderr.

ResetBlankScreenTimer()

void ResetBlankScreenTimer

(

void

)

ScreenNoLongerBlanked()

void ScreenNoLongerBlanked

(

Display *

display

)

SilentlyIgnoreErrorsHandler()

int SilentlyIgnoreErrorsHandler	(	Display *	display,
		XErrorEvent *	error
	)

An X11 error handler that does nothing at all.

This is used for calls where we expect errors to happen.

TryAcquireGrabs()

int TryAcquireGrabs	(	Window	w,
		void *	state_voidp
	)

UnblankScreen()

void UnblankScreen

(

Display *

display

)

Usage()

void Usage

(

const char *

me

)

Print an usage message.

A message is shown explaining how to use XSecureLock.

Parameters

me	The name this executable was invoked as.

Version()

void Version

(

void

)

Print a version message.

WakeUp()

int WakeUp	(	Display *	dpy,
		Window	auth_win,
		Window	saver_win,
		const char *	stdinbuf
	)

Wake up the screen saver in response to a keyboard or mouse event.

Returns

If true, authentication was successful, and the program should exit.

WatchChildren()

int WatchChildren	(	Display *	dpy,
		Window	auth_win,
		Window	saver_win,
		enum WatchChildrenState	state,
		const char *	stdinbuf
	)

Watch the child processes, and bring them into the desired state.

If the requested state is WATCH_CHILDREN_NORMAL and neither auth nor saver child are running, the saver child will be spawned.

If the requested state is WATCH_CHILDREN_SAVER_DISABLED, a possibly running saver child will be killed.

If the requested state is WATCH_CHILDREN_FORCE_AUTH, a possibly running saver child will be killed, and an auth child will be spawned.

If the auth child was already running, the stdinbuf is sent to the auth child on standard input.

Parameters

state	The request to perform.
stdinbuf	Key presses to send to the auth child, if set.

Returns

If true, authentication was successful and the program should exit.

Variable Documentation

auth_executable

const char* auth_executable

The name of the auth child to execute, relative to HELPER_PATH.

blank_dpms_state

const char* blank_dpms_state = "off"

The DPMS state to switch the screen to when blanking.

blank_timeout

int blank_timeout = -1

If nonnegative, the time in seconds till we blank the screen explicitly.

blanked

int blanked = 0

Whether the screen is currently blanked by us.

buf

char buf[16]

debug_window_info

int debug_window_info = 0

If set, print window info about any "conflicting" windows to stderr.

ev

XEvent ev

force_grab

int force_grab = 0

If set, we try to force grabbing by "evil" means.

have_switch_user_command

int have_switch_user_command = 0

If set, we can start a new login session.

keysym

KeySym keysym

len

int len

notify_command

char* const* notify_command = NULL

The command to run once screen locking is complete.

notify_command_pid

pid_t notify_command_pid = 0

The PID of a currently running notify command, or 0 if none is running.

priv

struct { ... } priv

Private (possibly containing information about the user's password) data.

saver_executable

const char* saver_executable

The name of the saver child to execute, relative to HELPER_PATH.

saver_reset_on_auth_close

int saver_reset_on_auth_close = 0

Whether to reset the saver module when auth closes.

time_to_blank

struct timeval time_to_blank

The time when we will blank the screen.