1 /*
2  * Copyright (c) 2020 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "star-platinum.h"
18 
19 #include <err.h>
20 #include <signal.h>
21 #include <stdarg.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <unistd.h>
25 
26 #include <X11/XKBlib.h>
27 #include <X11/Xutil.h>
28 
29 #ifndef __OpenBSD__
30 # define pledge(a, b) 0
31 #endif
32 
33 extern FILE *yyin;
34 char *fname;
35 
36 extern int yylineno;
37 int yyparse(void);
38 
39 struct group *config;
40 int goterror = 0;
41 
42 Display *d;
43 
44 int ignored_modifiers[] = {
45 	0,			/* no modifiers */
46 	LockMask,		/* caps lock */
47 	Mod2Mask,		/* num lock */
48 	Mod3Mask,		/* scroll lock */
49 	Mod5Mask,		/* ? */
50 };
51 
52 #define IGNORE_MODIFIERS (LockMask | Mod2Mask | Mod3Mask | Mod5Mask)
53 
54 __attribute__((__format__ (__printf__, 1, 2)))
55 void
56 yyerror(const char *fmt, ...)
57 {
58 	va_list ap;
59 	size_t l;
60 
61 	va_start(ap, fmt);
62 
63 	goterror = 1;
64 	fprintf(stderr, "%s:%d ", fname, yylineno);
65 	vfprintf(stderr, fmt, ap);
66 
67 	l = strlen(fmt);
68 	if (l > 0 && fmt[l-1] != '\n')
69 		fprintf(stderr, "\n");
70 
71 	va_end(ap);
72 }
73 
74 char *
75 find_config()
76 {
77 	char *home, *xdg, *t;
78 	int free_xdg = 0;
79 
80 	home = getenv("HOME");
81 	xdg = getenv("XDG_CONFIG_HOME");
82 
83 	if (home == NULL && xdg == NULL)
84 		return NULL;
85 
86 	/* file in home directory >>>>>> XDG shit */
87 	if (home != NULL) {
88 		if (asprintf(&t, "%s/.star-platinum.conf", home) == -1)
89 			return NULL;
90 		if (access(t, R_OK) == 0)
91 			return t;
92 
93 		free(t);
94 		/* continue to search */
95 	}
96 
97 	/* sanitize XDG_CONFIG_HOME */
98 	if (xdg == NULL) {
99 		free_xdg = 1;
100 		if (asprintf(&xdg, "%s/.config", home) == -1)
101 			return NULL;
102 	}
103 
104 	if (asprintf(&t, "%s/star-platinum.conf", xdg) == -1)
105 		goto err;
106 
107 	if (access(t, R_OK) == 0)
108 		return t;
109 	free(t);
110 
111 err:
112 	if (free_xdg)
113 		free(xdg);
114 
115 	return NULL;
116 }
117 
118 int
119 main(int argc, char **argv)
120 {
121 	int status = 0, dump_config = 0, conftest = 0, ch;
122 	struct group *g;
123 	struct rule *r;
124 	XEvent e;
125 	Window root;
126 
127 	signal(SIGCHLD, SIG_IGN); /* don't allow zombies */
128 
129 	fname = NULL;
130 	while ((ch = getopt(argc, argv, "c:dn")) != -1) {
131 		switch (ch) {
132 		case 'c':
133 			free(fname);
134 			if ((fname = strdup(optarg)) == NULL)
135 				err(1, "strdup");
136 			break;
137 
138 		case 'd':
139 			dump_config = 1;
140 			break;
141 
142 		case 'n':
143 			conftest = 1;
144 			break;
145 
146 		default:
147 			fprintf(stderr, "USAGE: %s [-dn] [-c conf]\n", *argv);
148 			return 1;
149 		}
150 	}
151 
152 	if (fname == NULL) {
153 		if ((fname = find_config()) == NULL)
154 			errx(1, "can't find a configuration file");
155 	}
156 
157 	if ((yyin = fopen(fname, "r")) == NULL)
158 		err(1, "cannot open %s", fname);
159 	yyparse();
160 	fclose(yyin);
161 
162 	free(fname);
163 	fname = NULL;
164 
165 	if (goterror)
166 		return 1;
167 
168 	if (dump_config)
169 		printgroup(config);
170 
171 	if (conftest) {
172 		recfree_group(config);
173 		return 0;
174 	}
175 
176 	if ((d = XOpenDisplay(NULL)) == NULL) {
177 		recfree_group(config);
178 		return 1;
179 	}
180 
181 	XSetErrorHandler(&error_handler);
182 
183 	root = DefaultRootWindow(d);
184 
185 	/* grab all the keys */
186 	for (g = config; g != NULL; g = g->next)
187 		for (r = g->rules; r != NULL; r = r->next)
188 			grabkey(r->key);
189 
190 	XSelectInput(d, root, KeyPressMask);
191 	XFlush(d);
192 
193 	pledge("stdio proc exec", NULL);
194 
195 	while (1) {
196 		XNextEvent(d, &e);
197 		switch (e.type) {
198 		case KeyRelease:
199 		case KeyPress:
200 			process_event(config, (XKeyEvent*)&e);
201 			break;
202 
203 		default:
204 			printf("Unknown event %d\n", e.type);
205 			break;
206 		}
207 	}
208 
209 	XCloseDisplay(d);
210 	recfree_group(config);
211 	return status;
212 }
213 
214 
215 /* xlib */
216 
217 int
218 error_handler(Display *d, XErrorEvent *e)
219 {
220 	fprintf(stderr, "Xlib error %d\n", e->type);
221 	return 1;
222 }
223 
224 /* TODO: it should grab ALL POSSIBLE COMBINATIONS of `ignored_modifiers`! */
225 void
226 grabkey(struct key k)
227 {
228 	static size_t len = sizeof(ignored_modifiers)/sizeof(int);
229 	size_t i;
230 	Window root;
231 
232 	root = DefaultRootWindow(d);
233 
234 	/* printf("Grabbing "); printkey(k); printf("\n"); */
235 	for (i = 0; i < len; ++i) {
236 		XGrabKey(d, XKeysymToKeycode(d, k.key),
237 		    k.modifier | ignored_modifiers[i],
238 		    root, False, GrabModeAsync, GrabModeAsync);
239 	}
240 }
241 
242 KeySym
243 keycode_to_keysym(unsigned int kc)
244 {
245 	/* group 0 (?). shift level is 0 because we don't want it*/
246 	return XkbKeycodeToKeysym(d, kc, 0, 0);
247 }
248 
249 Window
250 focused_window()
251 {
252 	Window w;
253 	int revert_to;
254 
255 	/* one can use (at least) three way to obtain the current
256 	 * focused window using xlib:
257 	 *
258 	 * - XQueryTree : you traverse tre tree until you find the
259 	 *     window
260 	 *
261 	 * - looking at _NET_ACTIVE_WINDOW in the root window, but
262 	 *    depedns on the window manager to set it
263 	 *
264 	 * - using XGetInputFocus
265 	 *
266 	 * I don't know the pro/cons of these, but XGetInputFocus
267 	 * seems the easiest.
268 	 */
269 	XGetInputFocus(d, &w, &revert_to);
270 	return w;
271 }
272 
273 void
274 send_fake(Window w, struct key k, XKeyEvent *original)
275 {
276 	XKeyEvent e;
277 
278 	/*
279 	 * this needs to be hijacked. original->window is the root
280 	 * window (since we grabbed the key there) and we want to
281 	 * deliver the key to another window.
282 	 */
283 	e.window = w;
284 
285 	/* this is the fake key */
286 	e.keycode = XKeysymToKeycode(d, k.key);
287 	e.state = k.modifier;
288 
289 	/* the rest is just copying fields from the original event */
290 	e.type = original->type;
291 	e.display = original->display;
292 	e.root = original->root;
293 	e.subwindow = original->subwindow;
294 	e.time = original->time;
295 	e.same_screen = original->same_screen;
296 	e.x = original->x;
297 	e.y = original->y;
298 	e.x_root = original->x_root;
299 	e.y_root = original->y_root;
300 
301 	XSendEvent(d, w, True, KeyPressMask, (XEvent*)&e);
302 	XFlush(d);
303 }
304 
305 int
306 window_match_class(Window w, const char *class)
307 {
308 	XClassHint ch;
309 	int matched;
310 
311 	if (!XGetClassHint(d, w, &ch)) {
312 		fprintf(stderr, "XGetClassHint failed\n");
313 		return 0;
314 	}
315 
316 	matched = !strcmp(ch.res_class, class);
317 
318 	XFree(ch.res_name);
319 	XFree(ch.res_class);
320 
321 	return matched;
322 }
323 
324 
325 /* action */
326 
327 void
328 do_action(struct action a, Window focused, XKeyEvent *original)
329 {
330 	switch (a.type) {
331 	case AFAKE:
332 		send_fake(focused, a.send_key, original);
333 		break;
334 
335 	case ASPECIAL:
336 		switch (a.special) {
337 		case ATOGGLE:
338 		case AACTIVATE:
339 		case ADEACTIVATE:
340 			printf("TODO\n");
341 			break;
342 
343 		case AIGNORE:
344 			break;
345 
346 		default:
347 			/* unreachable */
348 			abort();
349 		}
350 		break;
351 
352 	case AEXEC: {
353 		pid_t p;
354 		const char *sh;
355 
356 		switch (p = fork()) {
357 		case -1:
358 			err(1, "fork");
359 
360 		case 0:
361 			if ((sh = getenv("SHELL")) == NULL)
362 				sh = "/bin/sh";
363 			printf("before exec'ing %s -c '%s'\n", sh, a.str);
364 			execlp(sh, sh, "-c", a.str, NULL);
365 			err(1, "execlp");
366 		}
367 
368 		break;
369 	}
370 
371 	default:
372 		/* unreachable */
373 		abort();
374 	}
375 }
376 
377 void
378 free_action(struct action a)
379 {
380 	if (a.type == AEXEC)
381 		free(a.str);
382 }
383 
384 
385 /* match */
386 
387 struct match *
388 new_match(int prop, char *s)
389 {
390 	struct match *m;
391 
392 	if ((m = calloc(1, sizeof(*m))) == NULL)
393 		err(1, "calloc");
394 	m->prop = prop;
395 	m->str = s;
396 	return m;
397 }
398 
399 void
400 recfree_match(struct match *m)
401 {
402 	struct match *mt;
403 
404 	if (m == NULL)
405 		return;
406 
407 	mt = m->next;
408 	free(m->str);
409 	free(m);
410 	recfree_match(mt);
411 }
412 
413 int
414 match_window(struct match *m, Window w)
415 {
416 	switch (m->prop) {
417 	case MANY:
418 		return 1;
419 
420 	case MCLASS:
421 		return window_match_class(w, m->str);
422 		break;
423 
424 	default:
425 		/* unreachable */
426 		abort();
427 	}
428 }
429 
430 
431 /* rule */
432 
433 struct rule *
434 new_rule(struct key k, struct action a)
435 {
436 	struct rule *r;
437 
438 	if ((r = calloc(1, sizeof(*r))) == NULL)
439 		err(1, "calloc");
440 	memcpy(&r->key, &k, sizeof(k));
441 	memcpy(&r->action, &a, sizeof(a));
442 	return r;
443 }
444 
445 void
446 recfree_rule(struct rule *r)
447 {
448 	struct rule *rt;
449 
450 	if (r == NULL)
451 		return;
452 
453 	rt = r->next;
454 	free(r);
455 	recfree_rule(rt);
456 }
457 
458 int
459 rule_matched(struct rule *r, struct key k)
460 {
461 	unsigned int m;
462 
463 	m = k.modifier;
464 	m &= ~IGNORE_MODIFIERS; /* clear ignored modifiers */
465 
466 	return r->key.modifier == m
467 		&& r->key.key == k.key;
468 }
469 
470 
471 /* group */
472 
473 struct group *
474 new_group(struct match *matches, struct rule *rules)
475 {
476 	struct group *g;
477 
478 	if ((g = calloc(1, sizeof(*g))) == NULL)
479 		err(1, "calloc");
480 	g->matches = matches;
481 	g->rules = rules;
482 	return g;
483 }
484 
485 void
486 recfree_group(struct group *g)
487 {
488 	struct group *gt;
489 
490 	if (g == NULL)
491 		return;
492 
493 	gt = g->next;
494 	recfree_match(g->matches);
495 	recfree_rule(g->rules);
496 	free(g);
497 	recfree_group(gt);
498 }
499 
500 void
501 process_event(struct group *g, XKeyEvent *e)
502 {
503 	Window focused;
504 	struct rule *r;
505 	struct key pressed = {
506 		.modifier = e->state,
507 		.key = keycode_to_keysym(e->keycode),
508 	};
509 
510 	focused = focused_window();
511 
512 	for (; g != NULL; g = g->next) {
513 		if (!group_match(g, focused))
514 			continue;
515 
516 		for (r = g->rules; r != NULL; r = r->next) {
517 			if (rule_matched(r, pressed)) {
518 				do_action(r->action, focused, e);
519 				return;
520 			}
521 		}
522 	}
523 
524 	send_fake(focused, pressed, e);
525 }
526 
527 int
528 group_match(struct group *g, Window w)
529 {
530 	struct match *m;
531 
532 	for (m = g->matches; m != NULL; m = m->next)
533 		if (match_window(m, w))
534 			return 1;
535 	return 0;
536 }
537 
538 
539 /* debug/dump stuff */
540 
541 void
542 printkey(struct key k)
543 {
544 	if (k.modifier & ControlMask)
545 		printf("C-");
546 	if (k.modifier & ShiftMask)
547 		printf("S-");
548 	if (k.modifier & Mod1Mask)
549 		printf("M-");
550 	if (k.modifier & Mod4Mask)
551 		printf("s-");
552 
553 	printf("%s", XKeysymToString(k.key));
554 }
555 
556 void
557 printaction(struct action a)
558 {
559 	switch (a.type) {
560 	case ASPECIAL:
561 		switch (a.special) {
562 		case ATOGGLE: printf("toggle"); break;
563 		case AACTIVATE: printf("activate"); break;
564 		case ADEACTIVATE: printf("deactivate"); break;
565 		case AIGNORE: printf("ignore"); break;
566 		default: abort(); /* unreachable */
567 		}
568 		break;
569 
570 	case AFAKE:
571 		printf("send key ");
572 		printkey(a.send_key);
573 		break;
574 
575 	case AEXEC:
576 		printf("exec %s", a.str);
577 		break;
578 
579 	default:
580 		/* unreachable */
581 		abort();
582 	}
583 }
584 
585 void
586 printmatch(struct match *m)
587 {
588 	if (m == NULL) {
589 		printf("(null)");
590 		return;
591 	}
592 	printf("match ");
593 	switch (m->prop) {
594 	case MANY:
595 		printf("all");
596 		break;
597 	case MCLASS:
598 		printf("class %s", m->str);
599 		break;
600 	default:
601 		/* unreachable */
602 		abort();
603 	}
604 
605 	if (m->next == NULL)
606 		printf("\n");
607 	else {
608 		printf(" ; ");
609 		printmatch(m->next);
610 	}
611 }
612 
613 void
614 printrule(struct rule *r)
615 {
616 	if (r == NULL) {
617 		printf("(null)");
618 		return;
619 	}
620 	printf("on ");
621 	printkey(r->key);
622 	printf(" do ");
623 	printaction(r->action);
624 	printf("\n");
625 
626 	if (r->next != NULL)
627 		printrule(r->next);
628 }
629 
630 void
631 printgroup(struct group *g)
632 {
633 	if (g == NULL) {
634 		printf("(null)");
635 		return;
636 	}
637 	printmatch(g->matches);
638 	printf("\n");
639 	printrule(g->rules);
640 	printf("\n\n");
641 
642 	if (g->next != NULL)
643 		printgroup(g->next);
644 }