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 } Lock;
  30
  31 static Lock **locks;
  32 static int nscreens;
  33 static Bool running = True;
  34
  35 static void
  36 die(const char *errstr, ...) {
  37         va_list ap;
  38
  39         va_start(ap, errstr);
  40         vfprintf(stderr, errstr, ap);
  41         va_end(ap);
  42         exit(EXIT_FAILURE);
  43 }
  44
  45 #ifndef HAVE_BSD_AUTH
  46 static const char *
  47 getpw(void) { /* only run as root */
  48         const char *rval;
  49         struct passwd *pw;
  50
  51         pw = getpwuid(getuid());
  52         if(!pw)
  53                 die("slock: cannot retrieve password entry (make sure to suid or sgid slock)");
  54         endpwent();
  55         rval =  pw->pw_passwd;
  56
  57 #if HAVE_SHADOW_H
  58         {
  59                 struct spwd *sp;
  60                 sp = getspnam(getenv("USER"));
  61                 if(!sp)
  62                         die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
  63                 endspent();
  64                 rval = sp->sp_pwdp;
  65         }
  66 #endif
  67
  68         /* drop privileges */
  69         if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
  70                 die("slock: cannot drop privileges");
  71         return rval;
  72 }
  73 #endif
  74
  75 static void
  76 #ifdef HAVE_BSD_AUTH
  77 readpw(Display *dpy)
  78 #else
  79 readpw(Display *dpy, const char *pws)
  80 #endif
  81 {
  82         char buf[32], passwd[256];
  83         int num, screen;
  84         unsigned int len;
  85         KeySym ksym;
  86         XEvent ev;
  87
  88         len = 0;
  89         running = True;
  90
  91         /* As "slock" stands for "Simple X display locker", the DPMS settings
  92          * had been removed and you can set it with "xset" or some other
  93          * utility. This way the user can easily set a customized DPMS
  94          * timeout. */
  95         while(running && !XNextEvent(dpy, &ev)) {
  96                 if(ev.type == KeyPress) {
  97                         buf[0] = 0;
  98                         num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
  99                         if(IsKeypadKey(ksym)) {
 100                                 if(ksym == XK_KP_Enter)
 101                                         ksym = XK_Return;
 102                                 else if(ksym >= XK_KP_0 && ksym <= XK_KP_9)
 103                                         ksym = (ksym - XK_KP_0) + XK_0;
 104                         }
 105                         if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
 106                                         || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
 107                                         || IsPrivateKeypadKey(ksym))
 108                                 continue;
 109                         switch(ksym) {
 110                         case XK_Return:
 111                                 passwd[len] = 0;
 112 #ifdef HAVE_BSD_AUTH
 113                                 running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 114 #else
 115                                 running = strcmp(crypt(passwd, pws), pws);
 116 #endif
 117                                 if(running != False)
 118                                         XBell(dpy, 100);
 119                                 len = 0;
 120                                 break;
 121                         case XK_Escape:
 122                                 len = 0;
 123                                 break;
 124                         case XK_BackSpace:
 125                                 if(len)
 126                                         --len;
 127                                 break;
 128                         default:
 129                                 if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {
 130                                         memcpy(passwd + len, buf, num);
 131                                         len += num;
 132                                 }
 133                                 break;
 134                         }
 135                 }
 136                 else for(screen = 0; screen < nscreens; screen++)
 137                         XMapRaised(dpy, locks[screen]->win);
 138         }
 139 }
 140
 141 static void
 142 unlockscreen(Display *dpy, Lock *lock) {
 143         if(dpy == NULL || lock == NULL)
 144                 return;
 145
 146         XUngrabPointer(dpy, CurrentTime);
 147         XFreePixmap(dpy, lock->pmap);
 148         XDestroyWindow(dpy, lock->win);
 149
 150         free(lock);
 151 }
 152
 153 static Lock *
 154 lockscreen(Display *dpy, int screen) {
 155         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 156         unsigned int len;
 157         Lock *lock;
 158         XColor black, dummy;
 159         XSetWindowAttributes wa;
 160         Cursor invisible;
 161
 162         if(dpy == NULL || screen < 0)
 163                 return NULL;
 164
 165         lock = malloc(sizeof(Lock));
 166         if(lock == NULL)
 167                 return NULL;
 168
 169         lock->screen = screen;
 170
 171         lock->root = RootWindow(dpy, lock->screen);
 172
 173         /* init */
 174         wa.override_redirect = 1;
 175         wa.background_pixel = BlackPixel(dpy, lock->screen);
 176         lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
 177                         0, DefaultDepth(dpy, lock->screen), CopyFromParent,
 178                         DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
 179         XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), "black", &black, &dummy);
 180         lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
 181         invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &black, &black, 0, 0);
 182         XDefineCursor(dpy, lock->win, invisible);
 183         XMapRaised(dpy, lock->win);
 184         for(len = 1000; len; len--) {
 185                 if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 186                         GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
 187                         break;
 188                 usleep(1000);
 189         }
 190         if(running && (len > 0)) {
 191                 for(len = 1000; len; len--) {
 192                         if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
 193                                 == GrabSuccess)
 194                                 break;
 195                         usleep(1000);
 196                 }
 197                 running = (len > 0);
 198         }
 199
 200         if(!running) {
 201                 unlockscreen(dpy, lock);
 202                 lock = NULL;
 203         }
 204
 205         return lock;
 206 }
 207
 208 static void
 209 usage(void) {
 210         fprintf(stderr, "usage: slock [-v]");
 211         exit(EXIT_FAILURE);
 212 }
 213
 214 int
 215 main(int argc, char **argv) {
 216 #ifndef HAVE_BSD_AUTH
 217         const char *pws;
 218 #endif
 219         Display *dpy;
 220         int screen;
 221
 222         if((argc == 2) && !strcmp("-v", argv[1]))
 223                 die("slock-%s, © 2006-2012 Anselm R Garbe", VERSION);
 224         else if(argc != 1)
 225                 usage();
 226
 227         if(!getpwuid(getuid()))
 228                 die("slock: no passwd entry for you");
 229
 230 #ifndef HAVE_BSD_AUTH
 231         pws = getpw();
 232 #endif
 233
 234         if(!(dpy = XOpenDisplay(0)))
 235                 die("slock: cannot open display");
 236         /* Get the number of screens in display "dpy" and blank them all. */
 237         nscreens = ScreenCount(dpy);
 238         locks = malloc(sizeof(Lock *) * nscreens);
 239         if(locks == NULL)
 240                 die("slock: malloc: %s", strerror(errno));
 241         for(screen = 0; screen < nscreens; screen++)
 242                 locks[screen] = lockscreen(dpy, screen);
 243         XSync(dpy, False);
 244
 245         /* Everything is now blank. Now wait for the correct password. */
 246 #ifdef HAVE_BSD_AUTH
 247         readpw(dpy);
 248 #else
 249         readpw(dpy, pws);
 250 #endif
 251
 252         /* Password ok, unlock everything and quit. */
 253         for(screen = 0; screen < nscreens; screen++)
 254                 unlockscreen(dpy, locks[screen]);
 255
 256         free(locks);
 257         XCloseDisplay(dpy);
 258
 259         return 0;
 260 }