slock.c

   1 /* © 2006-2007 Anselm R. Garbe <garbeam at gmail dot com>
   2  * See LICENSE file for license details. */
   3 #define _XOPEN_SOURCE 500
   4 #if HAVE_SHADOW_H
   5 #include <shadow.h>
   6 #endif
   7
   8 #include <ctype.h>
   9 #include <pwd.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14 #include <sys/types.h>
  15 #include <X11/keysym.h>
  16 #include <X11/Xlib.h>
  17 #include <X11/Xutil.h>
  18
  19 const char *
  20 get_password() { /* only run as root */
  21         const char *rval;
  22         struct passwd *pw;
  23
  24         if(geteuid() != 0) {
  25                 fputs("slock: cannot retrieve password entry (make sure to suid slock)\n", stderr);
  26                 exit(EXIT_FAILURE);
  27         }
  28         pw = getpwuid(getuid());
  29         endpwent();
  30         rval =  pw->pw_passwd;
  31
  32 #if HAVE_SHADOW_H
  33         {
  34                 struct spwd *sp;
  35                 sp = getspnam(getenv("USER"));
  36                 endspent();
  37                 rval = sp->sp_pwdp;
  38         }
  39 #endif
  40         /* drop privileges */
  41         if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) {
  42                 fputs("slock: cannot drop privileges\n",stdout);
  43                 exit(EXIT_FAILURE);
  44         }
  45         return rval;
  46 }
  47
  48 int
  49 main(int argc, char **argv) {
  50         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
  51         char buf[32], passwd[256];
  52         int num, screen;
  53         const char *pws;
  54         unsigned int len;
  55         Bool running = True;
  56         Cursor invisible;
  57         Display *dpy;
  58         KeySym ksym;
  59         Pixmap pmap;
  60         Window root, w;
  61         XColor black, dummy;
  62         XEvent ev;
  63         XSetWindowAttributes wa;
  64
  65         if((argc > 1) && !strncmp(argv[1], "-v", 3)) {
  66                 fputs("slock-"VERSION", © 2006-2007 Anselm R. Garbe\n", stdout);
  67                 exit(EXIT_SUCCESS);
  68         }
  69         pws = get_password();
  70         if(!(dpy = XOpenDisplay(0))) {
  71                 fputs("slock: cannot open display\n", stderr);
  72                 exit(EXIT_FAILURE);
  73         }
  74         screen = DefaultScreen(dpy);
  75         root = RootWindow(dpy, screen);
  76
  77         /* init */
  78         wa.override_redirect = 1;
  79         wa.background_pixel = BlackPixel(dpy, screen);
  80         w = XCreateWindow(dpy, root, 0, 0, DisplayWidth(dpy, screen), DisplayHeight(dpy, screen),
  81                         0, DefaultDepth(dpy, screen), CopyFromParent,
  82                         DefaultVisual(dpy, screen), CWOverrideRedirect | CWBackPixel, &wa);
  83         XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);
  84         pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
  85         invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
  86         XDefineCursor(dpy, w, invisible);
  87         XMapRaised(dpy, w);
  88         for(len = 1000; len; len--) {
  89                 if(XGrabPointer(dpy, root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
  90                         GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
  91                         break;
  92                 usleep(1000);
  93         }
  94         if((running = running && (len > 0))) {
  95                 for(len = 1000; len; len--) {
  96                         if(XGrabKeyboard(dpy, root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
  97                                 == GrabSuccess)
  98                                 break;
  99                         usleep(1000);
 100                 }
 101                 running = (len > 0);
 102         }
 103         len = 0;
 104         XSync(dpy, False);
 105
 106         /* main event loop */
 107         while(running && !XNextEvent(dpy, &ev))
 108                 if(ev.type == KeyPress) {
 109                         buf[0] = 0;
 110                         num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
 111                         if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
 112                                         || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
 113                                         || IsPrivateKeypadKey(ksym))
 114                                 continue;
 115                         switch(ksym) {
 116                         case XK_Return:
 117                                 passwd[len] = 0;
 118                                 if((running = strcmp(crypt(passwd, pws), pws)) != 0)
 119                                         XBell(dpy, 100);
 120                                 len = 0;
 121                                 break;
 122                         case XK_Escape:
 123                                 len = 0;
 124                                 break;
 125                         case XK_BackSpace:
 126                                 if(len)
 127                                         --len;
 128                                 break;
 129                         default:
 130                                 if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {
 131                                         memcpy(passwd + len, buf, num);
 132                                         len += num;
 133                                 }
 134                                 break;
 135                         }
 136                 }
 137         XUngrabPointer(dpy, CurrentTime);
 138         XFreePixmap(dpy, pmap);
 139         XDestroyWindow(dpy, w);
 140         XCloseDisplay(dpy);
 141         return 0;
 142 }