jcs.org
slock with DPMS and other tweaks
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/dpms.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
26char *argv0;
27
28enum {
29 INIT,
30 INPUT,
31 FAILED,
32 NUMCOLS
33};
34
35struct lock {
36 int screen;
37 Window root, win;
38 Pixmap pmap;
39 unsigned long colors[NUMCOLS];
40};
41
42struct xrandr {
43 int active;
44 int evbase;
45 int errbase;
46};
47
48#include "config.h"
49
50static void
51die(const char *errstr, ...)
52{
53 va_list ap;
54
55 va_start(ap, errstr);
56 vfprintf(stderr, errstr, ap);
57 va_end(ap);
58 exit(1);
59}
60
61#ifdef __linux__
62#include <fcntl.h>
63#include <linux/oom.h>
64
65static void
66dontkillme(void)
67{
68 FILE *f;
69 const char oomfile[] = "/proc/self/oom_score_adj";
70
71 if (!(f = fopen(oomfile, "w"))) {
72 if (errno == ENOENT)
73 return;
74 die("slock: fopen %s: %s\n", oomfile, strerror(errno));
75 }
76 fprintf(f, "%d", OOM_SCORE_ADJ_MIN);
77 if (fclose(f)) {
78 if (errno == EACCES)
79 die("slock: unable to disable OOM killer. "
80 "Make sure to suid or sgid slock.\n");
81 else
82 die("slock: fclose %s: %s\n", oomfile, strerror(errno));
83 }
84}
85#endif
86
87static const char *
88gethash(void)
89{
90 const char *hash;
91 struct passwd *pw;
92
93 /* Check if the current user has a password entry */
94 errno = 0;
95 if (!(pw = getpwuid(getuid()))) {
96 if (errno)
97 die("slock: getpwuid: %s\n", strerror(errno));
98 else
99 die("slock: cannot retrieve password entry\n");
100 }
101 hash = pw->pw_passwd;
102
103#if HAVE_SHADOW_H
104 if (!strcmp(hash, "x")) {
105 struct spwd *sp;
106 if (!(sp = getspnam(pw->pw_name)))
107 die("slock: getspnam: cannot retrieve shadow entry. "
108 "Make sure to suid or sgid slock.\n");
109 hash = sp->sp_pwdp;
110 }
111#else
112 if (!strcmp(hash, "*")) {
113#ifdef __OpenBSD__
114 if (!(pw = getpwuid_shadow(getuid())))
115 die("slock: getpwnam_shadow: cannot retrieve shadow entry. "
116 "Make sure to suid or sgid slock.\n");
117 hash = pw->pw_passwd;
118#else
119 die("slock: getpwuid: cannot retrieve shadow entry. "
120 "Make sure to suid or sgid slock.\n");
121#endif /* __OpenBSD__ */
122 }
123#endif /* HAVE_SHADOW_H */
124
125 return hash;
126}
127
128static void
129readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
130 const char *hash)
131{
132 XRRScreenChangeNotifyEvent *rre;
133 char buf[32], passwd[256], *inputhash;
134 int num, screen, running, failure, oldc;
135 unsigned int len, color;
136 KeySym ksym;
137 XEvent ev;
138 CARD16 dstandby, dsuspend, doff;
139
140 len = 0;
141 running = 1;
142 failure = 0;
143 oldc = INIT;
144
145 /*
146 * if dpms is available, store the current values, set a low timeout,
147 * and then force the screen off. when the user starts typing, dpms
148 * will force the screen on and then after a few seconds of no typing,
149 * the low timeout will force the screen off again. we'll restore the
150 * user's previous timeouts at the end of the loop.
151 */
152
153 if (DPMSCapable(dpy) && DPMSEnable(dpy)) {
154 /* allow the initial window paint to actually happen */
155 usleep(100000);
156
157 DPMSGetTimeouts(dpy, &dstandby, &dsuspend, &doff);
158 DPMSSetTimeouts(dpy, 0, 0, dpmstimeout);
159 DPMSForceLevel(dpy, DPMSModeOff);
160 }
161
162 while (running && !XNextEvent(dpy, &ev)) {
163 if (ev.type == KeyPress) {
164 explicit_bzero(&buf, sizeof(buf));
165 num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
166 if (IsKeypadKey(ksym)) {
167 if (ksym == XK_KP_Enter)
168 ksym = XK_Return;
169 else if (ksym >= XK_KP_0 && ksym <= XK_KP_9)
170 ksym = (ksym - XK_KP_0) + XK_0;
171 }
172 if (IsFunctionKey(ksym) ||
173 IsKeypadKey(ksym) ||
174 IsMiscFunctionKey(ksym) ||
175 IsPFKey(ksym) ||
176 IsPrivateKeypadKey(ksym))
177 continue;
178 switch (ksym) {
179 case XK_Return:
180 passwd[len] = '\0';
181 errno = 0;
182 if (!(inputhash = crypt(passwd, hash)))
183 fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
184 else
185 running = !!strcmp(inputhash, hash);
186 if (running) {
187 XBell(dpy, 100);
188 failure = 1;
189 }
190 explicit_bzero(&passwd, sizeof(passwd));
191 len = 0;
192 break;
193 case XK_Escape:
194 explicit_bzero(&passwd, sizeof(passwd));
195 len = 0;
196 break;
197 case XK_BackSpace:
198 if (len)
199 passwd[--len] = '\0';
200 break;
201 default:
202 if (num && !iscntrl((int)buf[0]) &&
203 (len + num < sizeof(passwd))) {
204 memcpy(passwd + len, buf, num);
205 len += num;
206 }
207 break;
208 }
209 color = len ? INPUT : ((failure || failonclear) ? FAILED : INIT);
210 if (running && oldc != color) {
211 for (screen = 0; screen < nscreens; screen++) {
212 XSetWindowBackground(dpy,
213 locks[screen]->win,
214 locks[screen]->colors[color]);
215 XClearWindow(dpy, locks[screen]->win);
216 }
217 oldc = color;
218 }
219 } else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
220 rre = (XRRScreenChangeNotifyEvent*)&ev;
221 for (screen = 0; screen < nscreens; screen++) {
222 if (locks[screen]->win == rre->window) {
223 if (rre->rotation == RR_Rotate_90 ||
224 rre->rotation == RR_Rotate_270)
225 XResizeWindow(dpy, locks[screen]->win,
226 rre->height, rre->width);
227 else
228 XResizeWindow(dpy, locks[screen]->win,
229 rre->width, rre->height);
230 XClearWindow(dpy, locks[screen]->win);
231 break;
232 }
233 }
234 } else {
235 for (screen = 0; screen < nscreens; screen++)
236 XRaiseWindow(dpy, locks[screen]->win);
237 }
238 }
239
240 if (DPMSCapable(dpy) && DPMSEnable(dpy)) {
241 DPMSSetTimeouts(dpy, dstandby, dsuspend, doff);
242 XFlush(dpy);
243 }
244}
245
246static struct lock *
247lockscreen(Display *dpy, struct xrandr *rr, int screen)
248{
249 char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
250 int i, ptgrab, kbgrab;
251 struct lock *lock;
252 XColor color, dummy;
253 XSetWindowAttributes wa;
254 Cursor invisible;
255
256 if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(struct lock))))
257 return NULL;
258
259 lock->screen = screen;
260 lock->root = RootWindow(dpy, lock->screen);
261
262 for (i = 0; i < NUMCOLS; i++) {
263 XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen),
264 colorname[i], &color, &dummy);
265 lock->colors[i] = color.pixel;
266 }
267
268 /* init */
269 wa.override_redirect = 1;
270 wa.background_pixel = lock->colors[INIT];
271 lock->win = XCreateWindow(dpy, lock->root, 0, 0,
272 DisplayWidth(dpy, lock->screen),
273 DisplayHeight(dpy, lock->screen),
274 0, DefaultDepth(dpy, lock->screen),
275 CopyFromParent,
276 DefaultVisual(dpy, lock->screen),
277 CWOverrideRedirect | CWBackPixel, &wa);
278 lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
279 invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
280 &color, &color, 0, 0);
281 XDefineCursor(dpy, lock->win, invisible);
282
283 /* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
284 for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
285 if (ptgrab != GrabSuccess) {
286 ptgrab = XGrabPointer(dpy, lock->root, False,
287 ButtonPressMask | ButtonReleaseMask |
288 PointerMotionMask, GrabModeAsync,
289 GrabModeAsync, None, invisible, CurrentTime);
290 }
291 if (kbgrab != GrabSuccess) {
292 kbgrab = XGrabKeyboard(dpy, lock->root, True,
293 GrabModeAsync, GrabModeAsync, CurrentTime);
294 }
295
296 /* input is grabbed: we can lock the screen */
297 if (ptgrab == GrabSuccess && kbgrab == GrabSuccess) {
298 XMapRaised(dpy, lock->win);
299 if (rr->active)
300 XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
301
302 XSelectInput(dpy, lock->root, SubstructureNotifyMask);
303 return lock;
304 }
305
306 /* retry on AlreadyGrabbed but fail on other errors */
307 if ((ptgrab != AlreadyGrabbed && ptgrab != GrabSuccess) ||
308 (kbgrab != AlreadyGrabbed && kbgrab != GrabSuccess))
309 break;
310
311 usleep(100000);
312 }
313
314 /* we couldn't grab all input: fail out */
315 if (ptgrab != GrabSuccess)
316 fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n",
317 screen);
318 if (kbgrab != GrabSuccess)
319 fprintf(stderr, "slock: unable to grab keyboard for screen %d\n",
320 screen);
321 return NULL;
322}
323
324static void
325usage(void)
326{
327 die("usage: slock [-v] [cmd [arg ...]]\n");
328}
329
330int
331main(int argc, char **argv) {
332 struct xrandr rr;
333 struct lock **locks;
334 struct passwd *pwd;
335 struct group *grp;
336 uid_t duid;
337 gid_t dgid;
338 const char *hash;
339 Display *dpy;
340 int s, nlocks, nscreens;
341
342 ARGBEGIN {
343 case 'v':
344 fprintf(stderr, "slock-"VERSION"\n");
345 return 0;
346 default:
347 usage();
348 } ARGEND
349
350 /* validate drop-user and -group */
351 errno = 0;
352 if (!(pwd = getpwnam(user)))
353 die("slock: getpwnam %s: %s\n", user,
354 errno ? strerror(errno) : "user entry not found");
355 duid = pwd->pw_uid;
356 errno = 0;
357 if (!(grp = getgrnam(group)))
358 die("slock: getgrnam %s: %s\n", group,
359 errno ? strerror(errno) : "group entry not found");
360 dgid = grp->gr_gid;
361
362#ifdef __linux__
363 dontkillme();
364#endif
365
366 hash = gethash();
367 errno = 0;
368 if (!crypt("", hash))
369 die("slock: crypt: %s\n", strerror(errno));
370
371 if (!(dpy = XOpenDisplay(NULL)))
372 die("slock: cannot open display\n");
373
374 /* drop privileges */
375 if (setgroups(0, NULL) < 0)
376 die("slock: setgroups: %s\n", strerror(errno));
377 if (setgid(dgid) < 0)
378 die("slock: setgid: %s\n", strerror(errno));
379 if (setuid(duid) < 0)
380 die("slock: setuid: %s\n", strerror(errno));
381
382 /* check for Xrandr support */
383 rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
384
385 /* get number of screens in display "dpy" and blank them */
386 nscreens = ScreenCount(dpy);
387 if (!(locks = calloc(nscreens, sizeof(struct lock *))))
388 die("slock: out of memory\n");
389 for (nlocks = 0, s = 0; s < nscreens; s++) {
390 if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL)
391 nlocks++;
392 else
393 break;
394 }
395 XSync(dpy, 0);
396
397 /* did we manage to lock everything? */
398 if (nlocks != nscreens)
399 return 1;
400
401 /* run post-lock command */
402 if (argc > 0) {
403 switch (fork()) {
404 case -1:
405 die("slock: fork failed: %s\n", strerror(errno));
406 case 0:
407 if (close(ConnectionNumber(dpy)) < 0)
408 die("slock: close: %s\n", strerror(errno));
409 execvp(argv[0], argv);
410 fprintf(stderr, "slock: execvp %s: %s\n", argv[0], strerror(errno));
411 _exit(1);
412 }
413 }
414
415 /* everything is now blank. Wait for the correct password */
416 readpw(dpy, &rr, locks, nscreens, hash);
417
418 return 0;
419}