slock.c

   1 /* © 2006-2008 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 <stdarg.h>
  11 #include <stdlib.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <sys/types.h>
  16 #include <X11/keysym.h>
  17 #include <X11/Xlib.h>
  18 #include <X11/Xutil.h>
  19 #include <X11/extensions/dpms.h>
  20
  21 #if HAVE_BSD_AUTH
  22 #include <login_cap.h>
  23 #include <bsd_auth.h>
  24 #endif
  25
  26 void
  27 eprint(const char *errstr, ...) {
  28         va_list ap;
  29
  30         va_start(ap, errstr);
  31         vfprintf(stderr, errstr, ap);
  32         va_end(ap);
  33         exit(EXIT_FAILURE);
  34 }
  35
  36 #ifndef HAVE_BSD_AUTH
  37 const char *
  38 get_password() { /* only run as root */
  39         const char *rval;
  40         struct passwd *pw;
  41
  42         if(geteuid() != 0)
  43                 eprint("slock: cannot retrieve password entry (make sure to suid slock)\n");
  44         pw = getpwuid(getuid());
  45         endpwent();
  46         rval =  pw->pw_passwd;
  47
  48 #if HAVE_SHADOW_H
  49         {
  50                 struct spwd *sp;
  51                 sp = getspnam(getenv("USER"));
  52                 endspent();
  53                 rval = sp->sp_pwdp;
  54         }
  55 #endif
  56
  57         /* drop privileges */
  58         if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
  59                 eprint("slock: cannot drop privileges\n");
  60         return rval;
  61 }
  62 #endif
  63
  64 int
  65 main(int argc, char **argv) {
  66         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
  67         char buf[32], passwd[256];
  68         int num, screen;
  69
  70 #ifndef HAVE_BSD_AUTH
  71         const char *pws;
  72 #endif
  73         unsigned int len;
  74         Bool running = True;
  75         Cursor invisible;
  76         Display *dpy;
  77         KeySym ksym;
  78         Pixmap pmap;
  79         Window root, w;
  80         XColor black, dummy;
  81         XEvent ev;
  82         XSetWindowAttributes wa;
  83
  84         if((argc == 2) && !strcmp("-v", argv[1]))
  85                 eprint("slock-"VERSION", © 2006-2008 Anselm R Garbe\n");
  86         else if(argc != 1)
  87                 eprint("usage: slock [-v]\n");
  88
  89 #ifndef HAVE_BSD_AUTH
  90         pws = get_password();
  91 #endif
  92
  93         if(!(dpy = XOpenDisplay(0)))
  94                 eprint("slock: cannot open display\n");
  95         screen = DefaultScreen(dpy);
  96         root = RootWindow(dpy, screen);
  97
  98         /* init */
  99         wa.override_redirect = 1;
 100         wa.background_pixel = BlackPixel(dpy, screen);
 101         w = XCreateWindow(dpy, root, 0, 0, DisplayWidth(dpy, screen), DisplayHeight(dpy, screen),
 102                         0, DefaultDepth(dpy, screen), CopyFromParent,
 103                         DefaultVisual(dpy, screen), CWOverrideRedirect | CWBackPixel, &wa);
 104         XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);
 105         pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
 106         invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
 107         XDefineCursor(dpy, w, invisible);
 108         XMapRaised(dpy, w);
 109         for(len = 1000; len; len--) {
 110                 if(XGrabPointer(dpy, root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 111                         GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
 112                         break;
 113                 usleep(1000);
 114         }
 115         if((running = running && (len > 0))) {
 116                 for(len = 1000; len; len--) {
 117                         if(XGrabKeyboard(dpy, root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
 118                                 == GrabSuccess)
 119                                 break;
 120                         usleep(1000);
 121                 }
 122                 running = (len > 0);
 123         }
 124         len = 0;
 125         XSync(dpy, False);
 126
 127         /* main event loop */
 128         while(running && !XNextEvent(dpy, &ev)) {
 129                 if(len == 0)
 130                         DPMSForceLevel(dpy, DPMSModeOff);
 131                 if(ev.type == KeyPress) {
 132                         buf[0] = 0;
 133                         num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
 134                         if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
 135                                         || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
 136                                         || IsPrivateKeypadKey(ksym))
 137                                 continue;
 138                         switch(ksym) {
 139                         case XK_Return:
 140                                 passwd[len] = 0;
 141
 142 #ifdef HAVE_BSD_AUTH
 143                                 running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 144 #else
 145                                 running = strcmp(crypt(passwd, pws), pws);
 146 #endif
 147
 148                                 if (running != 0)
 149                                         XBell(dpy, 100);
 150                                 len = 0;
 151                                 break;
 152                         case XK_Escape:
 153                                 len = 0;
 154                                 break;
 155                         case XK_BackSpace:
 156                                 if(len)
 157                                         --len;
 158                                 break;
 159                         default:
 160                                 if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {
 161                                         memcpy(passwd + len, buf, num);
 162                                         len += num;
 163                                 }
 164                                 break;
 165                         }
 166                 }
 167         }
 168         XUngrabPointer(dpy, CurrentTime);
 169         XFreePixmap(dpy, pmap);
 170         XDestroyWindow(dpy, w);
 171         XCloseDisplay(dpy);
 172         return 0;
 173 }