~ob/slock

ref: 3092d3b3146720b2279df202382864454c12cc98 slock/slock.c -rw-r--r-- 6.7 KiB
3092d3b3 — anselm@garbe.us prepared 1.1 8 years ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
/* See LICENSE file for license details. */
#define _XOPEN_SOURCE 500
#if HAVE_SHADOW_H
#include <shadow.h>
#endif

#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <X11/keysym.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

#if HAVE_BSD_AUTH
#include <login_cap.h>
#include <bsd_auth.h>
#endif

typedef struct {
	int screen;
	Window root, win;
	Pixmap pmap;
	unsigned long colors[2];
} Lock;

static Lock **locks;
static int nscreens;
static Bool running = True;

static void
die(const char *errstr, ...) {
	va_list ap;

	va_start(ap, errstr);
	vfprintf(stderr, errstr, ap);
	va_end(ap);
	exit(EXIT_FAILURE);
}

#ifndef HAVE_BSD_AUTH
static const char *
getpw(void) { /* only run as root */
	const char *rval;
	struct passwd *pw;

	pw = getpwuid(getuid());
	if(!pw)
		die("slock: cannot retrieve password entry (make sure to suid or sgid slock)");
	endpwent();
	rval =  pw->pw_passwd;

#if HAVE_SHADOW_H
	if (strlen(rval) >= 1) { /* kludge, assumes pw placeholder entry has len >= 1 */
		struct spwd *sp;
		sp = getspnam(getenv("USER"));
		if(!sp)
			die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
		endspent();
		rval = sp->sp_pwdp;
	}
#endif

	/* drop privileges */
	if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
		die("slock: cannot drop privileges");
	return rval;
}
#endif

static void
#ifdef HAVE_BSD_AUTH
readpw(Display *dpy)
#else
readpw(Display *dpy, const char *pws)
#endif
{
	char buf[32], passwd[256];
	int num, screen;
	unsigned int len, llen;
	KeySym ksym;
	XEvent ev;

	len = llen = 0;
	running = True;

	/* As "slock" stands for "Simple X display locker", the DPMS settings
	 * had been removed and you can set it with "xset" or some other
	 * utility. This way the user can easily set a customized DPMS
	 * timeout. */
	while(running && !XNextEvent(dpy, &ev)) {
		if(ev.type == KeyPress) {
			buf[0] = 0;
			num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
			if(IsKeypadKey(ksym)) {
				if(ksym == XK_KP_Enter)
					ksym = XK_Return;
				else if(ksym >= XK_KP_0 && ksym <= XK_KP_9)
					ksym = (ksym - XK_KP_0) + XK_0;
			}
			if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
					|| IsMiscFunctionKey(ksym) || IsPFKey(ksym)
					|| IsPrivateKeypadKey(ksym))
				continue;
			switch(ksym) {
			case XK_Return:
				passwd[len] = 0;
#ifdef HAVE_BSD_AUTH
				running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
#else
				running = strcmp(crypt(passwd, pws), pws);
#endif
				if(running != False)
					XBell(dpy, 100);
				len = 0;
				break;
			case XK_Escape:
				len = 0;
				break;
			case XK_BackSpace:
				if(len)
					--len;
				break;
			default:
				if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) { 
					memcpy(passwd + len, buf, num);
					len += num;
				}
				break;
			}
			if(llen == 0 && len != 0) {
				for(screen = 0; screen < nscreens; screen++) {
					XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[1]);
					XClearWindow(dpy, locks[screen]->win);
				}
			} else if(llen != 0 && len == 0) {
				for(screen = 0; screen < nscreens; screen++) {
					XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[0]);
					XClearWindow(dpy, locks[screen]->win);
				}
			}
			llen = len;
		}
		else for(screen = 0; screen < nscreens; screen++)
			XRaiseWindow(dpy, locks[screen]->win);
	}
}

static void
unlockscreen(Display *dpy, Lock *lock) {
	if(dpy == NULL || lock == NULL)
		return;

	XUngrabPointer(dpy, CurrentTime);
	XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, 2, 0);
	XFreePixmap(dpy, lock->pmap);
	XDestroyWindow(dpy, lock->win);

	free(lock);
}

static Lock *
lockscreen(Display *dpy, int screen) {
	char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
	unsigned int len;
	Lock *lock;
	XColor color, dummy;
	XSetWindowAttributes wa;
	Cursor invisible;

	if(dpy == NULL || screen < 0)
		return NULL;

	lock = malloc(sizeof(Lock));
	if(lock == NULL)
		return NULL;

	lock->screen = screen;

	lock->root = RootWindow(dpy, lock->screen);

	/* init */
	wa.override_redirect = 1;
	wa.background_pixel = BlackPixel(dpy, lock->screen);
	lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
			0, DefaultDepth(dpy, lock->screen), CopyFromParent,
			DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
	XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR2, &color, &dummy);
	lock->colors[1] = color.pixel;
	XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR1, &color, &dummy);
	lock->colors[0] = color.pixel;
	lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
	invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
	XDefineCursor(dpy, lock->win, invisible);
	XMapRaised(dpy, lock->win);
	for(len = 1000; len; len--) {
		if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
			GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
			break;
		usleep(1000);
	}
	if(running && (len > 0)) {
		for(len = 1000; len; len--) {
			if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
				== GrabSuccess)
				break;
			usleep(1000);
		}
	}

	running &= (len > 0);
	if(!running) {
		unlockscreen(dpy, lock);
		lock = NULL;
	}
	else 
		XSelectInput(dpy, lock->root, SubstructureNotifyMask);

	return lock;
}

static void
usage(void) {
	fprintf(stderr, "usage: slock [-v]\n");
	exit(EXIT_FAILURE);
}

int
main(int argc, char **argv) {
#ifndef HAVE_BSD_AUTH
	const char *pws;
#endif
	Display *dpy;
	int screen;

	if((argc == 2) && !strcmp("-v", argv[1]))
		die("slock-%s, © 2006-2012 Anselm R Garbe\n", VERSION);
	else if(argc != 1)
		usage();

	if(!getpwuid(getuid()))
		die("slock: no passwd entry for you");

#ifndef HAVE_BSD_AUTH
	pws = getpw();
#endif

	if(!(dpy = XOpenDisplay(0)))
		die("slock: cannot open display");
	/* Get the number of screens in display "dpy" and blank them all. */
	nscreens = ScreenCount(dpy);
	locks = malloc(sizeof(Lock *) * nscreens);
	if(locks == NULL)
		die("slock: malloc: %s", strerror(errno));
	int nlocks = 0;
	for(screen = 0; screen < nscreens; screen++) {
		if ( (locks[screen] = lockscreen(dpy, screen)) != NULL)
			nlocks++;
	}
	XSync(dpy, False);

	/* Did we actually manage to lock something? */
	if (nlocks == 0) { // nothing to protect
		free(locks);
		XCloseDisplay(dpy);
		return 1;
	}

	/* Everything is now blank. Now wait for the correct password. */
#ifdef HAVE_BSD_AUTH
	readpw(dpy);
#else
	readpw(dpy, pws);
#endif

	/* Password ok, unlock everything and quit. */
	for(screen = 0; screen < nscreens; screen++)
		unlockscreen(dpy, locks[screen]);

	free(locks);
	XCloseDisplay(dpy);

	return 0;
}