/* 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 <spawn.h>
#include <sys/types.h>
#include <time.h>
#include <poll.h>
#include <X11/extensions/Xrandr.h>
#include <X11/keysym.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xft/Xft.h>
#include <Imlib2.h>
#include "../accent.h"

#include "arg.h"
#include "util.h"

char *argv0;

enum {
	INIT,
	INPUT,
	FAILED,
	NUMCOLS
};

struct lock {
        int screen;
        Window root, win;
        Pixmap pmap;
        Pixmap bgmap;
        unsigned long colors[NUMCOLS];
        XftDraw *draw;
};

struct xrandr {
        int active;
        int evbase;
        int errbase;
};

#include "config.h"

static ColorShm *accentshm;
static char accentcol[8] = "#005577";
static XftFont *font;

static const char *icon[] = {
"                   ██████████████                                   ██████████████                   ",
"                   ██████████████                                   █████████████                   ",
"                   ██████▓▓▓█████                                   █████▓▓▓██████                   ",
"                   █████▓▓▓▓█████                                   █████▓▓▓▓█████                   ",
"                   █████▓▓▓▓█████                                   █████▓▓▓▓█████                   ",
"                   █████▓▓▓▓▓████                                   ████▓▓▓▓▓█████                   ",
"                   █████▓▓▓▓▓████████   █████████████████████   ████████▓▓▓▓▓█████                   ",
"                   ██████▓▓▓▓▓▓▓█████   █████████████████████   █████▓▓▓▓▓▓▓██████                   ",
"▓▓▓▓▓▓▓▓           ██████▓▓▓▓▓▓▓█████   █████████████████████   █████▓▓▓▓▓▓▓██████           ▓▓▓▓▓▓▓▓",
"▓▓▓▓▓▓▓▓▓              █████▓▓▓▓▓████   ████▓▒▒▒▒▓▓▓▒▒▒▒▓████   ████▓▓▓▓▓█████              ▓▓▓▓▓▓▓▓▓",
"▓▓▓▓▓▓▓▓▓              █████▓▓▓▓▓████   ████▓▒▒▒▒▓▓▓▒▒▒▒▓████   ████▓▓▓▓▓█████              ▓▓▓▓▓▓▓▓▓",
"▓▓▓▓▒░░░▒▓▓▓▓          █████▓▓▓▓▓▓▓▓█████▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▒▓▓▓█████▓▓▓▓▓▓▓▓█████          ▓▓▓▓▒░░░▒▓▓▓▓",
"▓▓▓▓▒░░░▒▓▓▓▓          █████▓▓▓▓▓▓▓▓█████▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▒▓▓▓█████▓▓▓▓▓▓▓▓█████          ▓▓▓▓▒░░░░▓▓▓▓",
"▓▓▓▓▒▒▒▒░░░░▒▓▓▓▓  █████████▓▓▓▓▓▒▒▒▓███▓▓▓▓▓▓▓▓█████▓▓▓▓▓▓▓▓███▓▒▒▒▒▓▓▓▓█████████  ▓▓▓▓▒░░░░▒▒▒▒▓▓▓▓",
"   ▒▒▒▒▒░░░░▒▓▓▓▓  ██████████▓▓▓▒▒▒▒▓███▓▓▓▓▓███████████▓▓▓▓▓███▓▒▒▒▒▓▓▓▓█████████  ▓▓▓▓▒░░░░▒▒▒▒▒   ",
"   ▓▓▓▓▓░░░░▒▒▒▒▓▓▓▓████████████▓▒▒▒▓███████▓▓▓▓█████▓▓▓▓███████▓▒▒▒▒▓████████████▓▓▓▒▒▒▒░░░░▒▓▓▓▓   ",
"   ████▓▒░░░░░░▒▒▓▓▓████████████▓▒▒▒▓████████▓▓▓▓▓▓▓▓▓▓▓████████▓▒▒▒▓████████████▓▓▓▓▒░░░░░░░▓████   ",
"   ████▓▒▒▒▒░░░░▒▓▓▓▓███████████▓▒▒▒▓▓▓▓████▓▒▒▒▒▒▒▒▒▒▒▒▓████▓▓▓▓▒▒▒▓████████████▓▓▓▒▒░░░▒▒▒▒▓████   ",
"       ▓▓▓▓▓▒░░░▒▒▒▒▓▓▓▓▓███████▓▒▒▒▒▒▒▒▓███▒░░░░░░░░░░░▒▓██▓▒▒▒▒▒▒▒▒▓██████▓▓▓▓▓▒▒▒▒░░░▒▓▓▓▓▓       ",
"       ▓▓▓▓▓▒░░░▒▒▒▒▒▓▓▓▓███████▓▒▒▒▒▒▒▒▓███▒░░░░░░░░░░▒▓██▓▒▒▒▒▒▒▒▓▓██████▓▓▓▓▓▒▒▒▒░░░▒▓▓▓▓▓       ",
"       ▓▓▓▓▓▒░░░▒▒▒▒▒▒▒▒▓▓▓▓████▓▓▓▒▒░░░▒███▒░░░░░░░░░░░▒▓██▓░░░▒▒▓▓▓████▓▓▓▓▒▒▒▒▒▒▒▒░░░▒▓▓▓▓▓       ",
"       ▓▓▓▓▓▒░░░▒▒▒▒▒▒▒▒▓▓▓▓████▓▓▓▒▒░░░▒███▒░░░░░░░░░░░▒▓██▓░░░▒▒▓▓▓████▓▓▓▓▒▒▒▒▒▒▒▒░░░▒▓▓▓▓▓       ",
"           ▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▓██████▓▒░░░░░░░▒▒▒▒▒▒▒▒▒▒▒▒▒▒░░░░░░▒▓██████▓▒▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓           ",
"           ▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▓██████▓▒░░░░░░░▒▒▒▒▒▒▒▒▒▒▒▒▒░░░░░░░▒▓██████▓▒▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓           ",
"           ████▓▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▓▓████           ",
"           ████▓▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓███▓▓▓▓▓▓▓▓▓▓▓▓▓███▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▓▓████           ",
"           █████▓▓▓▓▓███▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓███▓▓▓▓█████           ",
"           █████████████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓█████████████           ",
"           █████▓▓▓▓████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓████▓▓▓▓█████           ",
"           ████▓▓▒▒▒▓███████████▓▓▓▓▓▓▓▓▒░░░░░░░░░░░░░░░░░░░▒▒▓▓▓▓▓▓▓███████████▓▒▒▒▒▓████           ",
"        ████▓▓▓▓▒▒▒▒▓▓▓▓████████▓▓▓▓▓▓▓▓▒▒▒▒▒░░░░░░░░░░░░▒▒▒▒▓▓▓▓▓▓▓▓█████████▓▓▓▒▒▒▒▓▓▓▓████        ",
"       █████▓▒▒▒▒▒▒▒▒▓▓▓▓▓▓▓████████████▓▓▓▓▒░░░░░░░░░░░▒▓▓▓▓████████████▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓█████       ",
"       █████▓▒▒▒▒▒▒▒▒▓▓▓▓▓▓▓████████████▓▓▓▓▒░░░░░░░░░░░▒▓▓▓▓████████████▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓█████       ",
"       █████▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓███████████████████████████████████████████▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▓█████       ",
"       █████▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓██████████████████████████████████████████▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒▓█████       ",
"       █████▓▓▓▓▓▓▓▓▓▓▓▓█████████████████████▓▓▓██████▓▓█████████████████████▓▓▓▓▓▓▓▓▓▓▓▓█████       ",
"       ██████▓▓▓▓▓▓▓▓████████▓▓▓█████████████▓▓▓█████▓▓▓█████████████▓▓▓████████▓▓▓▓▓▓▓▓▓█████       ",
"       █████████▓▓▓▓▓████████▓▓▓▓████████████▓▓▓█████▓▓▓▓████████████▓▓▓████████▓▓▓▓▓█████████       ",
"           █████▓▓▓▓▓████████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓█████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓████████▓▓▓▓▓█████           ",
"           ██████▓▓▓▓▓▓▓████████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓█████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓████████▓▓▓▓▓▓▓▓█████           ",
"           ██████▓▓▓▓▓▓▓▓████████▓▓▓█████████▓▓▓▓▓▓▓▓▓▓▓█████████▓▓▓████████▓▓▓▓▓▓▓▓██████           ",
"           ██████▓▓▓▓▓▓▓▓████████████████████▓▓▓▓▓▓▓▓▓▓▓████████████████████▓▓▓▓▓▓▓▓██████           ",
"           ██████████████████████████████████▓▓▓▓▓▓▓▓▓▓▓██████████████████████████████████           ",
"           ██████████████████████████████████▓▓▓▓▓▓▓▓▓▓▓██████████████████████████████████           ",
"                       ██████▓▓▓▓▓▓██████▓▓▓████▓▓▓▓▓████▓▓▓██████▓▓▓▓▓▓▓█████                       ",
"                       ██████▓▓▓▓▓▓▓█████▓▓▓████▓▓▓▓▓████▓▓▓██████▓▓▓▓▓▓▓█████                       ",
"                       █████▓▓▓▓▓▓▓▓█████████████████████████████▓▓▓▓▓▓▓▓█████                       ",
"                       █████▓▓▓▓▓▓▓▓█████████▓▓▓█████▓▓▓█████████▓▓▓▓▓▓▓▓█████                       ",
"                       ██████▓▓▓▓▓▓▓█████████▓▓▓▓███▓▓▓▓██████████▓▓▓▓▓▓██████                       ",
"                       ██████████████████▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓██████████████████                       ",
"                       █████████████████████▓▓▓▓▓▓▓▓▓▓▓▓▓█████████████████████                       ",
"                            ████████████████▓▓▓▓▓▓▓▓▓▓▓██████████████████                           ",
"                            ██████████████████████████████████████████████                           ",
"                                            █████████████                                            ",
"                                            █████████████                                            ",
NULL};

static void
updateaccent(void)
{
        if (!readaccent(&accentshm, accentcol))
                memcpy(accentcol, "#005577", 8);
}

static void
drawlogo(Display *dpy, struct lock *lock, const char *col)
{
        XftColor xftc;
        XGlyphInfo ext;
        int i, x, y, w, h, lines = 0, maxw = 0, lineh;
        size_t len;

        w = DisplayWidth(dpy, lock->screen);
        h = DisplayHeight(dpy, lock->screen);
        lineh = font->ascent + font->descent;

        for (i = 0; icon[i]; i++) {
                len = strlen(icon[i]);
                while (len && icon[i][len - 1] == ' ')
                        len--;
                XftTextExtentsUtf8(dpy, font, (FcChar8 *)icon[i], len, &ext);
                if (ext.xOff > maxw)
                        maxw = ext.xOff;
                lines++;
        }
        x = (w - maxw) / 2;
        y = (h - lines * lineh) / 2 + font->ascent;

        if (!XftColorAllocName(dpy, DefaultVisual(dpy, lock->screen),
                               DefaultColormap(dpy, lock->screen), col, &xftc))
                return;

        XClearWindow(dpy, lock->win);
        for (i = 0; icon[i]; i++) {
                len = strlen(icon[i]);
                while (len && icon[i][len - 1] == ' ')
                        len--;
                XftDrawStringUtf8(lock->draw, &xftc, font, x, y,
                                  (FcChar8 *)icon[i], len);
                y += lineh;
        }

        XftColorFree(dpy, DefaultVisual(dpy, lock->screen),
                     DefaultColormap(dpy, lock->screen), &xftc);
}

static void
blurbackground(Display *dpy, struct lock *lock)
{
        int w = DisplayWidth(dpy, lock->screen);
        int h = DisplayHeight(dpy, lock->screen);

        imlib_context_set_display(dpy);
        imlib_context_set_visual(DefaultVisual(dpy, lock->screen));
        imlib_context_set_colormap(DefaultColormap(dpy, lock->screen));
        imlib_context_set_drawable(lock->root);

        Imlib_Image img = imlib_create_image_from_drawable(0, 0, 0, w, h, 1);
        if (!img)
                return;
        imlib_context_set_image(img);
        imlib_image_blur(75);

        lock->bgmap = XCreatePixmap(dpy, lock->root, w, h,
                                    DefaultDepth(dpy, lock->screen));
        imlib_context_set_drawable(lock->bgmap);
        imlib_render_image_on_drawable(0, 0);
        imlib_free_image();

        XSetWindowBackgroundPixmap(dpy, lock->win, lock->bgmap);
}

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 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 num, screen, running, failure;
        unsigned int len;
        KeySym ksym;
        XEvent ev;
        struct pollfd pfd;
        time_t last;
        const char *col, *oldcol = NULL;
        char lastaccent[8];

        len = 0;
        running = 1;
        failure = 0;

        updateaccent();
        memcpy(lastaccent, accentcol, 8);
        col = accentcol;
        last = time(NULL);
        for (screen = 0; screen < nscreens; screen++)
                drawlogo(dpy, locks[screen], col);

        pfd.fd = ConnectionNumber(dpy);
        pfd.events = POLLIN;

        while (running) {
               /* poll at ~60Hz so accent gradients appear smooth */
               if (poll(&pfd, 1, 5) > 0) {
                        while (XPending(dpy)) {
                                XNextEvent(dpy, &ev);
                                if (ev.type == KeyPress) {
                                        last = time(NULL);
                                        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 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;
                                        default:
                                                if (num && !iscntrl((int)buf[0]) &&
                                                    (len + num < sizeof(passwd))) {
                                                        memcpy(passwd + len, buf, num);
                                                        len += num;
                                                } else if (buf[0] == '\025') { /* ctrl-u clears input */
                                                        explicit_bzero(&passwd, sizeof(passwd));
                                                        len = 0;
                                                }
                                                break;
                                        }
                                } 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);
                                                        drawlogo(dpy, locks[screen], col);
                                                        break;
                                                }
                                        }
                                } else {
                                        for (screen = 0; screen < nscreens; screen++)
                                                XRaiseWindow(dpy, locks[screen]->win);
                                }
                        }
                }

                updateaccent();
                int idle = time(NULL) - last >= 3;

                if (!idle && len)
                        col = colorname[INPUT];
                else if (!idle && (failure || failonclear))
                        col = colorname[FAILED];
                else
                        col = accentcol;

                if ((col == accentcol && memcmp(accentcol, lastaccent, 8) != 0) || col != oldcol) {
                        memcpy(lastaccent, accentcol, 8);
                        for (screen = 0; screen < nscreens; screen++)
                                drawlogo(dpy, locks[screen], col);
                        oldcol = col;
                }
        }
}

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);

        blurbackground(dpy, lock);

        if (!font)
                font = XftFontOpenName(dpy, lock->screen, "monospace:size=10");
        lock->draw = XftDrawCreate(dpy, lock->win,
                                   DefaultVisual(dpy, lock->screen),
                                   DefaultColormap(dpy, lock->screen));

	/* 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);
			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] [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 s, nlocks, nscreens;

	ARGBEGIN {
	case 'v':
		puts("slock-"VERSION);
		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)
			nlocks++;
		else
			break;
	}
	XSync(dpy, 0);

	/* did we manage to lock everything? */
	if (nlocks != nscreens)
		return 1;

	/* run post-lock command */
	if (argc > 0) {
		pid_t pid;
		extern char **environ;
		int err = posix_spawnp(&pid, argv[0], NULL, NULL, argv, environ);
		if (err) {
			die("slock: failed to execute post-lock command: %s: %s\n",
			    argv[0], strerror(err));
		}
	}

	/* everything is now blank. Wait for the correct password */
	readpw(dpy, &rr, locks, nscreens, hash);

	return 0;
}