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 struct st_lock {
  26         int screen;
  27         Window root, w;
  28         Pixmap pmap;
  29 };
  30
  31 extern const char *__progname;
  32
  33 static void
  34 die(const char *errstr, ...) {
  35         va_list ap;
  36
  37         fprintf(stderr, "%s: ", __progname);
  38         va_start(ap, errstr);
  39         vfprintf(stderr, errstr, ap);
  40         va_end(ap);
  41         fprintf(stderr, "\n");
  42         fflush(stderr);
  43
  44         exit(EXIT_FAILURE);
  45 }
  46
  47 #ifndef HAVE_BSD_AUTH
  48 static const char *
  49 get_password(void) { /* only run as root */
  50         const char *rval;
  51         struct passwd *pw;
  52
  53         if(geteuid() != 0)
  54                 die("cannot retrieve password entry (make sure to suid slock)");
  55         pw = getpwuid(getuid());
  56         endpwent();
  57         rval =  pw->pw_passwd;
  58
  59 #if HAVE_SHADOW_H
  60         {
  61                 struct spwd *sp;
  62                 sp = getspnam(getenv("USER"));
  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("cannot drop privileges");
  71         return rval;
  72 }
  73 #endif
  74
  75 static void
  76 #ifdef HAVE_BSD_AUTH
  77 read_password(Display *dpy)
  78 #else
  79 read_password(Display *dpy, const char *pws)
  80 #endif
  81 {
  82         char buf[32], passwd[256];
  83         int num;
  84
  85         unsigned int len;
  86         Bool running = True;
  87         KeySym ksym;
  88         XEvent ev;
  89
  90         len = 0;
  91         running = True;
  92
  93         /* As "slock" stands for "Simple X display locker", the DPMS settings
  94          * had been removed and you can set it with "xset" or some other
  95          * utility. This way the user can easily set a customized DPMS
  96          * timeout. */
  97
  98         while(running && !XNextEvent(dpy, &ev)) {
  99                 if(ev.type == KeyPress) {
 100                         buf[0] = 0;
 101                         num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
 102                         if(IsKeypadKey(ksym)) {
 103                                 if(ksym == XK_KP_Enter)
 104                                         ksym = XK_Return;
 105                                 else if(ksym >= XK_KP_0 && ksym <= XK_KP_9)
 106                                         ksym = (ksym - XK_KP_0) + XK_0;
 107                         }
 108                         if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
 109                                         || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
 110                                         || IsPrivateKeypadKey(ksym))
 111                                 continue;
 112                         switch(ksym) {
 113                         case XK_Return:
 114                                 passwd[len] = 0;
 115 #ifdef HAVE_BSD_AUTH
 116                                 running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 117 #else
 118                                 running = strcmp(crypt(passwd, pws), pws);
 119 #endif
 120                                 if (running != 0)
 121                                         XBell(dpy, 100);
 122                                 len = 0;
 123                                 break;
 124                         case XK_Escape:
 125                                 len = 0;
 126                                 break;
 127                         case XK_BackSpace:
 128                                 if(len)
 129                                         --len;
 130                                 break;
 131                         default:
 132                                 if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {
 133                                         memcpy(passwd + len, buf, num);
 134                                         len += num;
 135                                 }
 136                                 break;
 137                         }
 138                 }
 139         }
 140 }
 141
 142 static void
 143 unlockscreen(Display *dpy, struct st_lock *lock) {
 144         if (dpy == NULL || lock == NULL)
 145                 return;
 146
 147         XUngrabPointer(dpy, CurrentTime);
 148         XFreePixmap(dpy, lock->pmap);
 149         XDestroyWindow(dpy, lock->w);
 150
 151         free(lock);
 152 }
 153
 154 static struct st_lock *
 155 lockscreen(Display *dpy, int screen) {
 156         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 157         unsigned int len;
 158         struct st_lock *lock;
 159         Bool running = True;
 160         XColor black, dummy;
 161         XSetWindowAttributes wa;
 162         Cursor invisible;
 163
 164         if (dpy == NULL || screen < 0)
 165                 return NULL;
 166
 167         lock = malloc(sizeof(struct st_lock));
 168         if (lock == NULL)
 169                 return NULL;
 170
 171         lock->screen = screen;
 172
 173         lock->root = RootWindow(dpy, lock->screen);
 174
 175         /* init */
 176         wa.override_redirect = 1;
 177         wa.background_pixel = BlackPixel(dpy, lock->screen);
 178         lock->w = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
 179                         0, DefaultDepth(dpy, lock->screen), CopyFromParent,
 180                         DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
 181         XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), "black", &black, &dummy);
 182         lock->pmap = XCreateBitmapFromData(dpy, lock->w, curs, 8, 8);
 183         invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &black, &black, 0, 0);
 184         XDefineCursor(dpy, lock->w, invisible);
 185         XMapRaised(dpy, lock->w);
 186         for(len = 1000; len; len--) {
 187                 if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 188                         GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
 189                         break;
 190                 usleep(1000);
 191         }
 192         if((running = running && (len > 0))) {
 193                 for(len = 1000; len; len--) {
 194                         if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
 195                                 == GrabSuccess)
 196                                 break;
 197                         usleep(1000);
 198                 }
 199                 running = (len > 0);
 200         }
 201
 202         if (!running) {
 203                 unlockscreen(dpy, lock);
 204                 lock = NULL;
 205         }
 206
 207         return lock;
 208 }
 209
 210 static void
 211 usage(void) {
 212         fprintf(stderr, "usage: %s -v", __progname);
 213         exit(EXIT_FAILURE);
 214 }
 215
 216 int
 217 main(int argc, char **argv) {
 218 #ifndef HAVE_BSD_AUTH
 219         const char *pws;
 220 #endif
 221         Display *dpy;
 222         int nscreens, screen;
 223
 224         struct st_lock **locks;
 225
 226         if((argc == 2) && !strcmp("-v", argv[1]))
 227                 die("slock-%s, © 2006-2008 Anselm R Garbe", VERSION);
 228         else if(argc != 1)
 229                 usage();
 230
 231         if(!getpwuid(getuid()))
 232                 die("no passwd entry for you");
 233
 234 #ifndef HAVE_BSD_AUTH
 235         pws = get_password();
 236 #endif
 237
 238         if(!(dpy = XOpenDisplay(0)))
 239                 die("cannot open display");
 240
 241         /* Get the number of screens in display "dpy" and blank them all. */
 242         nscreens = ScreenCount(dpy);
 243         locks = malloc(sizeof(struct st_lock *) * nscreens);
 244         if (locks == NULL)
 245                 die("malloc: %s", strerror(errno));
 246
 247         for (screen = 0; screen < nscreens; screen++)
 248                 locks[screen] = lockscreen(dpy, screen);
 249
 250         XSync(dpy, False);
 251
 252         /* Everything is now blank. Now wait for the correct password. */
 253 #ifdef HAVE_BSD_AUTH
 254         read_password(dpy);
 255 #else
 256         read_password(dpy, pws);
 257 #endif
 258
 259         /* Password ok, unlock everything and quit. */
 260         for (screen = 0; screen < nscreens; screen++)
 261                 unlockscreen(dpy, locks[screen]);
 262
 263         free(locks);
 264
 265         XCloseDisplay(dpy);
 266
 267         return 0;
 268 }