text: /* See LICENSE file for license details. */
  #define _XOPEN_SOURCE 500
  #if HAVE_SHADOW_H
  #include <shadow.h>
  #endif
  
  #include <ctype.h>
  #include <errno.h>
  #include <grp.h>
  #include <pwd.h>
  #include <stdarg.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include <unistd.h>
  #include <time.h>
  #include <sys/types.h>
  #include <X11/extensions/Xrandr.h>
  #include <X11/extensions/Xinerama.h>
  #include <X11/keysym.h>
  #include <X11/Xlib.h>
  #include <X11/Xutil.h>
  #include <X11/XKBlib.h>
  #include <X11/XF86keysym.h>
  
  #include "arg.h"
  #include "util.h"
  
  char *argv0;
  
  /* global count to prevent repeated error messages */
  int count_error = 0;
  
  static time_t locktime;
  
  enum {
  	INIT,
  	INPUT,
  	FAILED,
  	CAPS,
  	NUMCOLS
  };
  
  struct lock {
  	int screen;
  	Window root, win;
  	Pixmap pmap;
  	unsigned long colors[NUMCOLS];
  };
  
  struct xrandr {
  	int active;
  	int evbase;
  	int errbase;
  };
  
  #include "config.h"
  
  static void
  die(const char *errstr, ...)
  {
  	va_list ap;
  
  	va_start(ap, errstr);
  	vfprintf(stderr, errstr, ap);
  	va_end(ap);
  	exit(1);
  }
  
  #ifdef __linux__
  #include <fcntl.h>
  #include <linux/oom.h>
  
  static void
  dontkillme(void)
  {
  	FILE *f;
  	const char oomfile[] = "/proc/self/oom_score_adj";
  
  	if (!(f = fopen(oomfile, "w"))) {
  		if (errno == ENOENT)
  			return;
  		die("slock: fopen %s: %s\n", oomfile, strerror(errno));
  	}
  	fprintf(f, "%d", OOM_SCORE_ADJ_MIN);
  	if (fclose(f)) {
  		if (errno == EACCES)
  			die("slock: unable to disable OOM killer. "
  			    "Make sure to suid or sgid slock.\n");
  		else
  			die("slock: fclose %s: %s\n", oomfile, strerror(errno));
  	}
  }
  #endif
  
  static void
  writemessage(Display *dpy, Window win, int screen)
  {
  	int len, line_len, width, height, s_width, s_height, i, j, k, tab_replace, tab_size;
  	XGCValues gr_values;
  	XFontStruct *fontinfo;
  	XColor color, dummy;
  	XineramaScreenInfo *xsi;
  	GC gc;
  	fontinfo = XLoadQueryFont(dpy, font_name);
  
  	if (fontinfo == NULL) {
  		if (count_error == 0) {
  			fprintf(stderr, "slock: Unable to load font \"%s\"\n", font_name);
  			fprintf(stderr, "slock: Try listing fonts with 'slock -f'\n");
  			count_error++;
  		}
  		return;
  	}
  
  	tab_size = 8 * XTextWidth(fontinfo, " ", 1);
  
  	XAllocNamedColor(dpy, DefaultColormap(dpy, screen),
  		 text_color, &color, &dummy);
  
  	gr_values.font = fontinfo->fid;
  	gr_values.foreground = color.pixel;
  	gc=XCreateGC(dpy,win,GCFont+GCForeground, &gr_values);
  
  	/*  To prevent "Uninitialized" warnings. */
  	xsi = NULL;
  
  	/*
  	 * Start formatting and drawing text
  	 */
  
  	len = strlen(message);
  
  	/* Max max line length (cut at '\n') */
  	line_len = 0;
  	k = 0;
  	for (i = j = 0; i < len; i++) {
  		if (message[i] == '\n') {
  			if (i - j > line_len)
  				line_len = i - j;
  			k++;
  			i++;
  			j = i;
  		}
  	}
  	/* If there is only one line */
  	if (line_len == 0)
  		line_len = len;
  
  	if (XineramaIsActive(dpy)) {
  		xsi = XineramaQueryScreens(dpy, &i);
  		s_width = xsi[0].width;
  		s_height = xsi[0].height;
  	} else {
  		s_width = DisplayWidth(dpy, screen);
  		s_height = DisplayHeight(dpy, screen);
  	}
  
  	height = s_height*3/7 - (k*20)/3;
  	width  = (s_width - XTextWidth(fontinfo, message, line_len))/2;
  
  	/* Look for '\n' and print the text between them. */
  	for (i = j = k = 0; i <= len; i++) {
  		/* i == len is the special case for the last line */
  		if (i == len || message[i] == '\n') {
  			tab_replace = 0;
  			while (message[j] == '\t' && j < i) {
  				tab_replace++;
  				j++;
  			}
  
  			XDrawString(dpy, win, gc, width + tab_size*tab_replace, height + 20*k, message + j, i - j);
  			while (i < len && message[i] == '\n') {
  				i++;
  				j = i;
  				k++;
  			}
  		}
  	}
  
  	/* xsi should not be NULL anyway if Xinerama is active, but to be safe */
  	if (XineramaIsActive(dpy) && xsi != NULL)
  			XFree(xsi);
  }
  
  
  
  static const char *
  gethash(void)
  {
  	const char *hash;
  	struct passwd *pw;
  
  	/* Check if the current user has a password entry */
  	errno = 0;
  	if (!(pw = getpwuid(getuid()))) {
  		if (errno)
  			die("slock: getpwuid: %s\n", strerror(errno));
  		else
  			die("slock: cannot retrieve password entry\n");
  	}
  	hash = pw->pw_passwd;
  
  #if HAVE_SHADOW_H
  	if (!strcmp(hash, "x")) {
  		struct spwd *sp;
  		if (!(sp = getspnam(pw->pw_name)))
  			die("slock: getspnam: cannot retrieve shadow entry. "
  			    "Make sure to suid or sgid slock.\n");
  		hash = sp->sp_pwdp;
  	}
  #else
  	if (!strcmp(hash, "*")) {
  #ifdef __OpenBSD__
  		if (!(pw = getpwuid_shadow(getuid())))
  			die("slock: getpwnam_shadow: cannot retrieve shadow entry. "
  			    "Make sure to suid or sgid slock.\n");
  		hash = pw->pw_passwd;
  #else
  		die("slock: getpwuid: cannot retrieve shadow entry. "
  		    "Make sure to suid or sgid slock.\n");
  #endif /* __OpenBSD__ */
  	}
  #endif /* HAVE_SHADOW_H */
  
  	return hash;
  }
  
  static void
  readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
         const char *hash)
  {
  	XRRScreenChangeNotifyEvent *rre;
  	char buf[32], passwd[256], *inputhash;
  	int caps, num, screen, running, failure, oldc;
  	unsigned int len, color, indicators;
  	KeySym ksym;
  	XEvent ev;
  
  	len = 0;
  	caps = 0;
  	running = 1;
  	failure = 0;
  	oldc = INIT;
  
  	if (!XkbGetIndicatorState(dpy, XkbUseCoreKbd, &indicators))
  		caps = indicators & 1;
  
  	while (running && !XNextEvent(dpy, &ev)) {
  		running = !((time(NULL) - locktime < timetocancel) && (ev.type == MotionNotify));
  		if (ev.type == KeyPress) {
  			explicit_bzero(&buf, sizeof(buf));
  			num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
  			if (IsKeypadKey(ksym)) {
  				if (ksym == XK_KP_Enter)
  					ksym = XK_Return;
  				else if (ksym >= XK_KP_0 && ksym <= XK_KP_9)
  					ksym = (ksym - XK_KP_0) + XK_0;
  			}
  			if (IsFunctionKey(ksym) ||
  			    IsKeypadKey(ksym) ||
  			    IsMiscFunctionKey(ksym) ||
  			    IsPFKey(ksym) ||
  			    IsPrivateKeypadKey(ksym))
  				continue;
  			switch (ksym) {
        case XF86XK_AudioPlay:
        case XF86XK_AudioStop:
        case XF86XK_AudioPrev:
        case XF86XK_AudioNext:
        case XF86XK_AudioRaiseVolume:
        case XF86XK_AudioLowerVolume:
        case XF86XK_AudioMute:
        case XF86XK_AudioMicMute:
        case XF86XK_MonBrightnessDown:
        case XF86XK_MonBrightnessUp:
          XSendEvent(dpy, DefaultRootWindow(dpy), True, KeyPressMask, &ev);
          break;
  			case XK_Return:
  				passwd[len] = '\0';
  				errno = 0;
  				if (!(inputhash = crypt(passwd, hash)))
  					fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
  				else
  					running = !!strcmp(inputhash, hash);
  				if (running) {
  					XBell(dpy, 100);
  					failure = 1;
  				}
  				explicit_bzero(&passwd, sizeof(passwd));
  				len = 0;
  				break;
  			case XK_Escape:
  				explicit_bzero(&passwd, sizeof(passwd));
  				len = 0;
  				break;
  			case XK_BackSpace:
  				if (len)
  					passwd[--len] = '\0';
  				break;
  			case XK_Caps_Lock:
  				caps = !caps;
  				break;
  			default:
  				if (num && !iscntrl((int)buf[0]) &&
  				    (len + num < sizeof(passwd))) {
  					memcpy(passwd + len, buf, num);
  					len += num;
  				}
  				break;
  			}
  			color = len ? (caps ? CAPS : INPUT) : (failure || failonclear ? FAILED : INIT);
  			if (running && oldc != color) {
  				for (screen = 0; screen < nscreens; screen++) {
  					XSetWindowBackground(dpy,
  					                     locks[screen]->win,
  					                     locks[screen]->colors[color]);
  					XClearWindow(dpy, locks[screen]->win);
  					writemessage(dpy, locks[screen]->win, screen);
  				}
  				oldc = color;
  			}
  		} else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
  			rre = (XRRScreenChangeNotifyEvent*)&ev;
  			for (screen = 0; screen < nscreens; screen++) {
  				if (locks[screen]->win == rre->window) {
  					if (rre->rotation == RR_Rotate_90 ||
  					    rre->rotation == RR_Rotate_270)
  						XResizeWindow(dpy, locks[screen]->win,
  						              rre->height, rre->width);
  					else
  						XResizeWindow(dpy, locks[screen]->win,
  						              rre->width, rre->height);
  					XClearWindow(dpy, locks[screen]->win);
  					break;
  				}
  			}
  		} else {
  			for (screen = 0; screen < nscreens; screen++)
  				XRaiseWindow(dpy, locks[screen]->win);
  		}
  	}
  }
  
  static struct lock *
  lockscreen(Display *dpy, struct xrandr *rr, int screen)
  {
  	char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
  	int i, ptgrab, kbgrab;
  	struct lock *lock;
  	XColor color, dummy;
  	XSetWindowAttributes wa;
  	Cursor invisible;
  
  	if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(struct lock))))
  		return NULL;
  
  	lock->screen = screen;
  	lock->root = RootWindow(dpy, lock->screen);
  
  	for (i = 0; i < NUMCOLS; i++) {
  		XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen),
  		                 colorname[i], &color, &dummy);
  		lock->colors[i] = color.pixel;
  	}
  
  	/* init */
  	wa.override_redirect = 1;
  	wa.background_pixel = lock->colors[INIT];
  	lock->win = XCreateWindow(dpy, lock->root, 0, 0,
  	                          DisplayWidth(dpy, lock->screen),
  	                          DisplayHeight(dpy, lock->screen),
  	                          0, DefaultDepth(dpy, lock->screen),
  	                          CopyFromParent,
  	                          DefaultVisual(dpy, lock->screen),
  	                          CWOverrideRedirect | CWBackPixel, &wa);
  	lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
  	invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
  	                                &color, &color, 0, 0);
  	XDefineCursor(dpy, lock->win, invisible);
  
  	/* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
  	for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
  		if (ptgrab != GrabSuccess) {
  			ptgrab = XGrabPointer(dpy, lock->root, False,
  			                      ButtonPressMask | ButtonReleaseMask |
  			                      PointerMotionMask, GrabModeAsync,
  			                      GrabModeAsync, None, invisible, CurrentTime);
  		}
  		if (kbgrab != GrabSuccess) {
  			kbgrab = XGrabKeyboard(dpy, lock->root, True,
  			                       GrabModeAsync, GrabModeAsync, CurrentTime);
  		}
  
  		/* input is grabbed: we can lock the screen */
  		if (ptgrab == GrabSuccess && kbgrab == GrabSuccess) {
  			XMapRaised(dpy, lock->win);
  			if (rr->active)
  				XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
  
  			XSelectInput(dpy, lock->root, SubstructureNotifyMask);
  			locktime = time(NULL);
  			return lock;
  		}
  
  		/* retry on AlreadyGrabbed but fail on other errors */
  		if ((ptgrab != AlreadyGrabbed && ptgrab != GrabSuccess) ||
  		    (kbgrab != AlreadyGrabbed && kbgrab != GrabSuccess))
  			break;
  
  		usleep(100000);
  	}
  
  	/* we couldn't grab all input: fail out */
  	if (ptgrab != GrabSuccess)
  		fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n",
  		        screen);
  	if (kbgrab != GrabSuccess)
  		fprintf(stderr, "slock: unable to grab keyboard for screen %d\n",
  		        screen);
  	return NULL;
  }
  
  static void
  usage(void)
  {
  	die("usage: slock [-v] [-f] [-m message] [cmd [arg ...]]\n");
  }
  
  int
  main(int argc, char **argv) {
  	struct xrandr rr;
  	struct lock **locks;
  	struct passwd *pwd;
  	struct group *grp;
  	uid_t duid;
  	gid_t dgid;
  	const char *hash;
  	Display *dpy;
  	int i, s, nlocks, nscreens;
  	int count_fonts;
  	char **font_names;
  
  	ARGBEGIN {
  	case 'v':
  		fprintf(stderr, "slock-"VERSION"\n");
  		return 0;
  	case 'm':
  		message = EARGF(usage());
  		break;
  	case 'f':
  		if (!(dpy = XOpenDisplay(NULL)))
  			die("slock: cannot open display\n");
  		font_names = XListFonts(dpy, "*", 10000 /* list 10000 fonts*/, &count_fonts);
  		for (i=0; i<count_fonts; i++) {
  			fprintf(stderr, "%s\n", *(font_names+i));
  		}
  		return 0;
  	default:
  		usage();
  	} ARGEND
  
  	/* validate drop-user and -group */
  	errno = 0;
  	if (!(pwd = getpwnam(user)))
  		die("slock: getpwnam %s: %s\n", user,
  		    errno ? strerror(errno) : "user entry not found");
  	duid = pwd->pw_uid;
  	errno = 0;
  	if (!(grp = getgrnam(group)))
  		die("slock: getgrnam %s: %s\n", group,
  		    errno ? strerror(errno) : "group entry not found");
  	dgid = grp->gr_gid;
  
  #ifdef __linux__
  	dontkillme();
  #endif
  
  	hash = gethash();
  	errno = 0;
  	if (!crypt("", hash))
  		die("slock: crypt: %s\n", strerror(errno));
  
  	if (!(dpy = XOpenDisplay(NULL)))
  		die("slock: cannot open display\n");
  
  	/* drop privileges */
  	if (setgroups(0, NULL) < 0)
  		die("slock: setgroups: %s\n", strerror(errno));
  	if (setgid(dgid) < 0)
  		die("slock: setgid: %s\n", strerror(errno));
  	if (setuid(duid) < 0)
  		die("slock: setuid: %s\n", strerror(errno));
  
  	/* check for Xrandr support */
  	rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
  
  	/* get number of screens in display "dpy" and blank them */
  	nscreens = ScreenCount(dpy);
  	if (!(locks = calloc(nscreens, sizeof(struct lock *))))
  		die("slock: out of memory\n");
  	for (nlocks = 0, s = 0; s < nscreens; s++) {
  		if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL) {
  			writemessage(dpy, locks[s]->win, s);
  			nlocks++;
  		} else {
  			break;
  		}
  	}
  	XSync(dpy, 0);
  
  	/* did we manage to lock everything? */
  	if (nlocks != nscreens)
  		return 1;
  
  	/* run post-lock command */
  	if (argc > 0) {
  		switch (fork()) {
  		case -1:
  			die("slock: fork failed: %s\n", strerror(errno));
  		case 0:
  			if (close(ConnectionNumber(dpy)) < 0)
  				die("slock: close: %s\n", strerror(errno));
  			execvp(argv[0], argv);
  			fprintf(stderr, "slock: execvp %s: %s\n", argv[0], strerror(errno));
  			_exit(1);
  		}
  	}
  
  	/* everything is now blank. Wait for the correct password */
  	readpw(dpy, &rr, locks, nscreens, hash);
  
  	return 0;
  }
  