slock.c

   1 /* See LICENSE file for license details. */
   2 #define _XOPEN_SOURCE 500
   3 #if HAVE_SHADOW_H
   4 #include <shadow.h>
   5 #endif
   6
   7 #include <ctype.h>
   8 #include <errno.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
  20 #if HAVE_BSD_AUTH
  21 #include <login_cap.h>
  22 #include <bsd_auth.h>
  23 #endif
  24
  25 typedef struct {
  26         int screen;
  27         Window root, win;
  28         Pixmap pmap;
  29         unsigned long colors[2];
  30 } Lock;
  31
  32 static Lock **locks;
  33 static int nscreens;
  34 static Bool running = True;
  35
  36 static void
  37 die(const char *errstr, ...) {
  38         va_list ap;
  39
  40         va_start(ap, errstr);
  41         vfprintf(stderr, errstr, ap);
  42         va_end(ap);
  43         exit(EXIT_FAILURE);
  44 }
  45
  46 #ifndef HAVE_BSD_AUTH
  47 static const char *
  48 getpw(void) { /* only run as root */
  49         const char *rval;
  50         struct passwd *pw;
  51
  52         pw = getpwuid(getuid());
  53         if(!pw)
  54                 die("slock: cannot retrieve password entry (make sure to suid or sgid slock)");
  55         endpwent();
  56         rval =  pw->pw_passwd;
  57
  58 #if HAVE_SHADOW_H
  59         if (strlen(rval) >= 1) { /* kludge, assumes pw placeholder entry has len >= 1 */
  60                 struct spwd *sp;
  61                 sp = getspnam(getenv("USER"));
  62                 if(!sp)
  63                         die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
  64                 endspent();
  65                 rval = sp->sp_pwdp;
  66         }
  67 #endif
  68
  69         /* drop privileges */
  70         if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
  71                 die("slock: cannot drop privileges");
  72         return rval;
  73 }
  74 #endif
  75
  76 static void
  77 #ifdef HAVE_BSD_AUTH
  78 readpw(Display *dpy)
  79 #else
  80 readpw(Display *dpy, const char *pws)
  81 #endif
  82 {
  83         char buf[32], passwd[256];
  84         int num, screen;
  85         unsigned int len, llen;
  86         KeySym ksym;
  87         XEvent ev;
  88
  89         len = llen = 0;
  90         running = True;
  91
  92         /* As "slock" stands for "Simple X display locker", the DPMS settings
  93          * had been removed and you can set it with "xset" or some other
  94          * utility. This way the user can easily set a customized DPMS
  95          * timeout. */
  96         while(running && !XNextEvent(dpy, &ev)) {
  97                 if(ev.type == KeyPress) {
  98                         buf[0] = 0;
  99                         num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
 100                         if(IsKeypadKey(ksym)) {
 101                                 if(ksym == XK_KP_Enter)
 102                                         ksym = XK_Return;
 103                                 else if(ksym >= XK_KP_0 && ksym <= XK_KP_9)
 104                                         ksym = (ksym - XK_KP_0) + XK_0;
 105                         }
 106                         if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
 107                                         || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
 108                                         || IsPrivateKeypadKey(ksym))
 109                                 continue;
 110                         switch(ksym) {
 111                         case XK_Return:
 112                                 passwd[len] = 0;
 113 #ifdef HAVE_BSD_AUTH
 114                                 running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 115 #else
 116                                 running = strcmp(crypt(passwd, pws), pws);
 117 #endif
 118                                 if(running != False)
 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                         if(llen == 0 && len != 0) {
 137                                 for(screen = 0; screen < nscreens; screen++) {
 138                                         XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[1]);
 139                                         XClearWindow(dpy, locks[screen]->win);
 140                                 }
 141                         } else if(llen != 0 && len == 0) {
 142                                 for(screen = 0; screen < nscreens; screen++) {
 143                                         XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[0]);
 144                                         XClearWindow(dpy, locks[screen]->win);
 145                                 }
 146                         }
 147                         llen = len;
 148                 }
 149                 else for(screen = 0; screen < nscreens; screen++)
 150                         XRaiseWindow(dpy, locks[screen]->win);
 151         }
 152 }
 153
 154 static void
 155 unlockscreen(Display *dpy, Lock *lock) {
 156         if(dpy == NULL || lock == NULL)
 157                 return;
 158
 159         XUngrabPointer(dpy, CurrentTime);
 160         XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, 2, 0);
 161         XFreePixmap(dpy, lock->pmap);
 162         XDestroyWindow(dpy, lock->win);
 163
 164         free(lock);
 165 }
 166
 167 static Lock *
 168 lockscreen(Display *dpy, int screen) {
 169         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 170         unsigned int len;
 171         Lock *lock;
 172         XColor color, dummy;
 173         XSetWindowAttributes wa;
 174         Cursor invisible;
 175
 176         if(dpy == NULL || screen < 0)
 177                 return NULL;
 178
 179         lock = malloc(sizeof(Lock));
 180         if(lock == NULL)
 181                 return NULL;
 182
 183         lock->screen = screen;
 184
 185         lock->root = RootWindow(dpy, lock->screen);
 186
 187         /* init */
 188         wa.override_redirect = 1;
 189         wa.background_pixel = BlackPixel(dpy, lock->screen);
 190         lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
 191                         0, DefaultDepth(dpy, lock->screen), CopyFromParent,
 192                         DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
 193         XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR2, &color, &dummy);
 194         lock->colors[1] = color.pixel;
 195         XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR1, &color, &dummy);
 196         lock->colors[0] = color.pixel;
 197         lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
 198         invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
 199         XDefineCursor(dpy, lock->win, invisible);
 200         XMapRaised(dpy, lock->win);
 201         for(len = 1000; len; len--) {
 202                 if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 203                         GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
 204                         break;
 205                 usleep(1000);
 206         }
 207         if(running && (len > 0)) {
 208                 for(len = 1000; len; len--) {
 209                         if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
 210                                 == GrabSuccess)
 211                                 break;
 212                         usleep(1000);
 213                 }
 214                 running = (len > 0);
 215         }
 216
 217         if(!running) {
 218                 unlockscreen(dpy, lock);
 219                 lock = NULL;
 220         }
 221         else
 222                 XSelectInput(dpy, lock->root, SubstructureNotifyMask);
 223
 224         return lock;
 225 }
 226
 227 static void
 228 usage(void) {
 229         fprintf(stderr, "usage: slock [-v]\n");
 230         exit(EXIT_FAILURE);
 231 }
 232
 233 int
 234 main(int argc, char **argv) {
 235 #ifndef HAVE_BSD_AUTH
 236         const char *pws;
 237 #endif
 238         Display *dpy;
 239         int screen;
 240
 241         if((argc == 2) && !strcmp("-v", argv[1]))
 242                 die("slock-%s, © 2006-2012 Anselm R Garbe\n", VERSION);
 243         else if(argc != 1)
 244                 usage();
 245
 246         if(!getpwuid(getuid()))
 247                 die("slock: no passwd entry for you");
 248
 249 #ifndef HAVE_BSD_AUTH
 250         pws = getpw();
 251 #endif
 252
 253         if(!(dpy = XOpenDisplay(0)))
 254                 die("slock: cannot open display");
 255         /* Get the number of screens in display "dpy" and blank them all. */
 256         nscreens = ScreenCount(dpy);
 257         locks = malloc(sizeof(Lock *) * nscreens);
 258         if(locks == NULL)
 259                 die("slock: malloc: %s", strerror(errno));
 260         for(screen = 0; screen < nscreens; screen++)
 261                 locks[screen] = lockscreen(dpy, screen);
 262         XSync(dpy, False);
 263
 264         /* Everything is now blank. Now wait for the correct password. */
 265 #ifdef HAVE_BSD_AUTH
 266         readpw(dpy);
 267 #else
 268         readpw(dpy, pws);
 269 #endif
 270
 271         /* Password ok, unlock everything and quit. */
 272         for(screen = 0; screen < nscreens; screen++)
 273                 unlockscreen(dpy, locks[screen]);
 274
 275         free(locks);
 276         XCloseDisplay(dpy);
 277
 278         return 0;
 279 }