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 <grp.h>
  10 #include <pwd.h>
  11 #include <stdarg.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <sys/types.h>
  17 #include <X11/extensions/Xrandr.h>
  18 #include <X11/extensions/Xinerama.h>
  19 #include <X11/keysym.h>
  20 #include <X11/Xlib.h>
  21 #include <X11/Xutil.h>
  22
  23 #include "arg.h"
  24 #include "util.h"
  25
  26 char *argv0;
  27
  28 /* global count to prevent repeated error messages */
  29 int count_error = 0;
  30
  31 enum {
  32         INIT,
  33         INPUT,
  34         FAILED,
  35         NUMCOLS
  36 };
  37
  38 struct lock {
  39         int screen;
  40         Window root, win;
  41         Pixmap pmap;
  42         unsigned long colors[NUMCOLS];
  43 };
  44
  45 struct xrandr {
  46         int active;
  47         int evbase;
  48         int errbase;
  49 };
  50
  51 #include "config.h"
  52
  53 static void
  54 die(const char *errstr, ...)
  55 {
  56         va_list ap;
  57
  58         va_start(ap, errstr);
  59         vfprintf(stderr, errstr, ap);
  60         va_end(ap);
  61         exit(1);
  62 }
  63
  64 #ifdef __linux__
  65 #include <fcntl.h>
  66 #include <linux/oom.h>
  67
  68 static void
  69 dontkillme(void)
  70 {
  71         FILE *f;
  72         const char oomfile[] = "/proc/self/oom_score_adj";
  73
  74         if (!(f = fopen(oomfile, "w"))) {
  75                 if (errno == ENOENT)
  76                         return;
  77                 die("slock: fopen %s: %s\n", oomfile, strerror(errno));
  78         }
  79         fprintf(f, "%d", OOM_SCORE_ADJ_MIN);
  80         if (fclose(f)) {
  81                 if (errno == EACCES)
  82                         die("slock: unable to disable OOM killer. "
  83                             "Make sure to suid or sgid slock.\n");
  84                 else
  85                         die("slock: fclose %s: %s\n", oomfile, strerror(errno));
  86         }
  87 }
  88 #endif
  89
  90 static void
  91 writemessage(Display *dpy, Window win, int screen)
  92 {
  93         int len, line_len, width, height, s_width, s_height, i, j, k, tab_replace, tab_size;
  94         XGCValues gr_values;
  95         XFontStruct *fontinfo;
  96         XColor color, dummy;
  97         XineramaScreenInfo *xsi;
  98         GC gc;
  99         fontinfo = XLoadQueryFont(dpy, font_name);
 100
 101         if (fontinfo == NULL) {
 102                 if (count_error == 0) {
 103                         fprintf(stderr, "slock: Unable to load font \"%s\"\n", font_name);
 104                         fprintf(stderr, "slock: Try listing fonts with 'slock -f'\n");
 105                         count_error++;
 106                 }
 107                 return;
 108         }
 109
 110         tab_size = 8 * XTextWidth(fontinfo, " ", 1);
 111
 112         XAllocNamedColor(dpy, DefaultColormap(dpy, screen),
 113                  text_color, &color, &dummy);
 114
 115         gr_values.font = fontinfo->fid;
 116         gr_values.foreground = color.pixel;
 117         gc=XCreateGC(dpy,win,GCFont+GCForeground, &gr_values);
 118
 119         /*  To prevent "Uninitialized" warnings. */
 120         xsi = NULL;
 121
 122         /*
 123          * Start formatting and drawing text
 124          */
 125
 126         len = strlen(message);
 127
 128         /* Max max line length (cut at '\n') */
 129         line_len = 0;
 130         k = 0;
 131         for (i = j = 0; i < len; i++) {
 132                 if (message[i] == '\n') {
 133                         if (i - j > line_len)
 134                                 line_len = i - j;
 135                         k++;
 136                         i++;
 137                         j = i;
 138                 }
 139         }
 140         /* If there is only one line */
 141         if (line_len == 0)
 142                 line_len = len;
 143
 144         if (XineramaIsActive(dpy)) {
 145                 xsi = XineramaQueryScreens(dpy, &i);
 146                 s_width = xsi[0].width;
 147                 s_height = xsi[0].height;
 148         } else {
 149                 s_width = DisplayWidth(dpy, screen);
 150                 s_height = DisplayHeight(dpy, screen);
 151         }
 152
 153         height = s_height*3/7 - (k*20)/3;
 154         width  = (s_width - XTextWidth(fontinfo, message, line_len))/2;
 155
 156         /* Look for '\n' and print the text between them. */
 157         for (i = j = k = 0; i <= len; i++) {
 158                 /* i == len is the special case for the last line */
 159                 if (i == len || message[i] == '\n') {
 160                         tab_replace = 0;
 161                         while (message[j] == '\t' && j < i) {
 162                                 tab_replace++;
 163                                 j++;
 164                         }
 165
 166                         XDrawString(dpy, win, gc, width + tab_size*tab_replace, height + 20*k, message + j, i - j);
 167                         while (i < len && message[i] == '\n') {
 168                                 i++;
 169                                 j = i;
 170                                 k++;
 171                         }
 172                 }
 173         }
 174
 175         /* xsi should not be NULL anyway if Xinerama is active, but to be safe */
 176         if (XineramaIsActive(dpy) && xsi != NULL)
 177                         XFree(xsi);
 178 }
 179
 180
 181
 182 static const char *
 183 gethash(void)
 184 {
 185         const char *hash;
 186         struct passwd *pw;
 187
 188         /* Check if the current user has a password entry */
 189         errno = 0;
 190         if (!(pw = getpwuid(getuid()))) {
 191                 if (errno)
 192                         die("slock: getpwuid: %s\n", strerror(errno));
 193                 else
 194                         die("slock: cannot retrieve password entry\n");
 195         }
 196         hash = pw->pw_passwd;
 197
 198 #if HAVE_SHADOW_H
 199         if (!strcmp(hash, "x")) {
 200                 struct spwd *sp;
 201                 if (!(sp = getspnam(pw->pw_name)))
 202                         die("slock: getspnam: cannot retrieve shadow entry. "
 203                             "Make sure to suid or sgid slock.\n");
 204                 hash = sp->sp_pwdp;
 205         }
 206 #else
 207         if (!strcmp(hash, "*")) {
 208 #ifdef __OpenBSD__
 209                 if (!(pw = getpwuid_shadow(getuid())))
 210                         die("slock: getpwnam_shadow: cannot retrieve shadow entry. "
 211                             "Make sure to suid or sgid slock.\n");
 212                 hash = pw->pw_passwd;
 213 #else
 214                 die("slock: getpwuid: cannot retrieve shadow entry. "
 215                     "Make sure to suid or sgid slock.\n");
 216 #endif /* __OpenBSD__ */
 217         }
 218 #endif /* HAVE_SHADOW_H */
 219
 220         return hash;
 221 }
 222
 223 static void
 224 readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
 225        const char *hash)
 226 {
 227         XRRScreenChangeNotifyEvent *rre;
 228         char buf[32], passwd[256], *inputhash;
 229         int num, screen, running, failure, oldc;
 230         unsigned int len, color;
 231         KeySym ksym;
 232         XEvent ev;
 233
 234         len = 0;
 235         running = 1;
 236         failure = 0;
 237         oldc = INIT;
 238
 239         while (running && !XNextEvent(dpy, &ev)) {
 240                 if (ev.type == KeyPress) {
 241                         explicit_bzero(&buf, sizeof(buf));
 242                         num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
 243                         if (IsKeypadKey(ksym)) {
 244                                 if (ksym == XK_KP_Enter)
 245                                         ksym = XK_Return;
 246                                 else if (ksym >= XK_KP_0 && ksym <= XK_KP_9)
 247                                         ksym = (ksym - XK_KP_0) + XK_0;
 248                         }
 249                         if (IsFunctionKey(ksym) ||
 250                             IsKeypadKey(ksym) ||
 251                             IsMiscFunctionKey(ksym) ||
 252                             IsPFKey(ksym) ||
 253                             IsPrivateKeypadKey(ksym))
 254                                 continue;
 255                         switch (ksym) {
 256                         case XK_Return:
 257                                 passwd[len] = '\0';
 258                                 errno = 0;
 259                                 if (!(inputhash = crypt(passwd, hash)))
 260                                         fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
 261                                 else
 262                                         running = !!strcmp(inputhash, hash);
 263                                 if (running) {
 264                                         XBell(dpy, 100);
 265                                         failure = 1;
 266                                 }
 267                                 explicit_bzero(&passwd, sizeof(passwd));
 268                                 len = 0;
 269                                 break;
 270                         case XK_Escape:
 271                                 explicit_bzero(&passwd, sizeof(passwd));
 272                                 len = 0;
 273                                 break;
 274                         case XK_BackSpace:
 275                                 if (len)
 276                                         passwd[--len] = '\0';
 277                                 break;
 278                         default:
 279                                 if (num && !iscntrl((int)buf[0]) &&
 280                                     (len + num < sizeof(passwd))) {
 281                                         memcpy(passwd + len, buf, num);
 282                                         len += num;
 283                                 }
 284                                 break;
 285                         }
 286                         color = len ? INPUT : ((failure || failonclear) ? FAILED : INIT);
 287                         if (running && oldc != color) {
 288                                 for (screen = 0; screen < nscreens; screen++) {
 289                                         XSetWindowBackground(dpy,
 290                                                              locks[screen]->win,
 291                                                              locks[screen]->colors[color]);
 292                                         XClearWindow(dpy, locks[screen]->win);
 293                                         writemessage(dpy, locks[screen]->win, screen);
 294                                 }
 295                                 oldc = color;
 296                         }
 297                 } else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
 298                         rre = (XRRScreenChangeNotifyEvent*)&ev;
 299                         for (screen = 0; screen < nscreens; screen++) {
 300                                 if (locks[screen]->win == rre->window) {
 301                                         if (rre->rotation == RR_Rotate_90 ||
 302                                             rre->rotation == RR_Rotate_270)
 303                                                 XResizeWindow(dpy, locks[screen]->win,
 304                                                               rre->height, rre->width);
 305                                         else
 306                                                 XResizeWindow(dpy, locks[screen]->win,
 307                                                               rre->width, rre->height);
 308                                         XClearWindow(dpy, locks[screen]->win);
 309                                         break;
 310                                 }
 311                         }
 312                 } else {
 313                         for (screen = 0; screen < nscreens; screen++)
 314                                 XRaiseWindow(dpy, locks[screen]->win);
 315                 }
 316         }
 317 }
 318
 319 static struct lock *
 320 lockscreen(Display *dpy, struct xrandr *rr, int screen)
 321 {
 322         char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 323         int i, ptgrab, kbgrab;
 324         struct lock *lock;
 325         XColor color, dummy;
 326         XSetWindowAttributes wa;
 327         Cursor invisible;
 328
 329         if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(struct lock))))
 330                 return NULL;
 331
 332         lock->screen = screen;
 333         lock->root = RootWindow(dpy, lock->screen);
 334
 335         for (i = 0; i < NUMCOLS; i++) {
 336                 XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen),
 337                                  colorname[i], &color, &dummy);
 338                 lock->colors[i] = color.pixel;
 339         }
 340
 341         /* init */
 342         wa.override_redirect = 1;
 343         wa.background_pixel = lock->colors[INIT];
 344         lock->win = XCreateWindow(dpy, lock->root, 0, 0,
 345                                   DisplayWidth(dpy, lock->screen),
 346                                   DisplayHeight(dpy, lock->screen),
 347                                   0, DefaultDepth(dpy, lock->screen),
 348                                   CopyFromParent,
 349                                   DefaultVisual(dpy, lock->screen),
 350                                   CWOverrideRedirect | CWBackPixel, &wa);
 351         lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
 352         invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
 353                                         &color, &color, 0, 0);
 354         XDefineCursor(dpy, lock->win, invisible);
 355
 356         /* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
 357         for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
 358                 if (ptgrab != GrabSuccess) {
 359                         ptgrab = XGrabPointer(dpy, lock->root, False,
 360                                               ButtonPressMask | ButtonReleaseMask |
 361                                               PointerMotionMask, GrabModeAsync,
 362                                               GrabModeAsync, None, invisible, CurrentTime);
 363                 }
 364                 if (kbgrab != GrabSuccess) {
 365                         kbgrab = XGrabKeyboard(dpy, lock->root, True,
 366                                                GrabModeAsync, GrabModeAsync, CurrentTime);
 367                 }
 368
 369                 /* input is grabbed: we can lock the screen */
 370                 if (ptgrab == GrabSuccess && kbgrab == GrabSuccess) {
 371                         XMapRaised(dpy, lock->win);
 372                         if (rr->active)
 373                                 XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
 374
 375                         XSelectInput(dpy, lock->root, SubstructureNotifyMask);
 376                         return lock;
 377                 }
 378
 379                 /* retry on AlreadyGrabbed but fail on other errors */
 380                 if ((ptgrab != AlreadyGrabbed && ptgrab != GrabSuccess) ||
 381                     (kbgrab != AlreadyGrabbed && kbgrab != GrabSuccess))
 382                         break;
 383
 384                 usleep(100000);
 385         }
 386
 387         /* we couldn't grab all input: fail out */
 388         if (ptgrab != GrabSuccess)
 389                 fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n",
 390                         screen);
 391         if (kbgrab != GrabSuccess)
 392                 fprintf(stderr, "slock: unable to grab keyboard for screen %d\n",
 393                         screen);
 394         return NULL;
 395 }
 396
 397 static void
 398 usage(void)
 399 {
 400         die("usage: slock [-v] [-f] [-m message] [cmd [arg ...]]\n");
 401 }
 402
 403 int
 404 main(int argc, char **argv) {
 405         struct xrandr rr;
 406         struct lock **locks;
 407         struct passwd *pwd;
 408         struct group *grp;
 409         uid_t duid;
 410         gid_t dgid;
 411         const char *hash;
 412         Display *dpy;
 413         int i, s, nlocks, nscreens;
 414         int count_fonts;
 415         char **font_names;
 416
 417         ARGBEGIN {
 418         case 'v':
 419                 fprintf(stderr, "slock-"VERSION"\n");
 420                 return 0;
 421         case 'm':
 422                 message = EARGF(usage());
 423                 break;
 424         case 'f':
 425                 if (!(dpy = XOpenDisplay(NULL)))
 426                         die("slock: cannot open display\n");
 427                 font_names = XListFonts(dpy, "*", 10000 /* list 10000 fonts*/, &count_fonts);
 428                 for (i=0; i<count_fonts; i++) {
 429                         fprintf(stderr, "%s\n", *(font_names+i));
 430                 }
 431                 return 0;
 432         default:
 433                 usage();
 434         } ARGEND
 435
 436         /* validate drop-user and -group */
 437         errno = 0;
 438         if (!(pwd = getpwnam(user)))
 439                 die("slock: getpwnam %s: %s\n", user,
 440                     errno ? strerror(errno) : "user entry not found");
 441         duid = pwd->pw_uid;
 442         errno = 0;
 443         if (!(grp = getgrnam(group)))
 444                 die("slock: getgrnam %s: %s\n", group,
 445                     errno ? strerror(errno) : "group entry not found");
 446         dgid = grp->gr_gid;
 447
 448 #ifdef __linux__
 449         dontkillme();
 450 #endif
 451
 452         hash = gethash();
 453         errno = 0;
 454         if (!crypt("", hash))
 455                 die("slock: crypt: %s\n", strerror(errno));
 456
 457         if (!(dpy = XOpenDisplay(NULL)))
 458                 die("slock: cannot open display\n");
 459
 460         /* drop privileges */
 461         if (setgroups(0, NULL) < 0)
 462                 die("slock: setgroups: %s\n", strerror(errno));
 463         if (setgid(dgid) < 0)
 464                 die("slock: setgid: %s\n", strerror(errno));
 465         if (setuid(duid) < 0)
 466                 die("slock: setuid: %s\n", strerror(errno));
 467
 468         /* check for Xrandr support */
 469         rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
 470
 471         /* get number of screens in display "dpy" and blank them */
 472         nscreens = ScreenCount(dpy);
 473         if (!(locks = calloc(nscreens, sizeof(struct lock *))))
 474                 die("slock: out of memory\n");
 475         for (nlocks = 0, s = 0; s < nscreens; s++) {
 476                 if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL) {
 477                         writemessage(dpy, locks[s]->win, s);
 478                         nlocks++;
 479                 } else {
 480                         break;
 481                 }
 482         }
 483         XSync(dpy, 0);
 484
 485         /* did we manage to lock everything? */
 486         if (nlocks != nscreens)
 487                 return 1;
 488
 489         /* run post-lock command */
 490         if (argc > 0) {
 491                 switch (fork()) {
 492                 case -1:
 493                         die("slock: fork failed: %s\n", strerror(errno));
 494                 case 0:
 495                         if (close(ConnectionNumber(dpy)) < 0)
 496                                 die("slock: close: %s\n", strerror(errno));
 497                         execvp(argv[0], argv);
 498                         fprintf(stderr, "slock: execvp %s: %s\n", argv[0], strerror(errno));
 499                         _exit(1);
 500                 }
 501         }
 502
 503         /* everything is now blank. Wait for the correct password */
 504         readpw(dpy, &rr, locks, nscreens, hash);
 505
 506         return 0;
 507 }