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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ | |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2011 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <errno.h> | |
23 | #include <fcntl.h> | |
24 | #include <string.h> | |
25 | #include <unistd.h> | |
26 | ||
27 | #include "sd-messages.h" | |
28 | ||
29 | #include "alloc-util.h" | |
30 | #include "fd-util.h" | |
31 | #include "fileio.h" | |
32 | #include "formats-util.h" | |
33 | #include "logind-acl.h" | |
34 | #include "logind-seat.h" | |
35 | #include "mkdir.h" | |
36 | #include "parse-util.h" | |
37 | #include "string-util.h" | |
38 | #include "terminal-util.h" | |
39 | #include "util.h" | |
40 | ||
41 | Seat *seat_new(Manager *m, const char *id) { | |
42 | Seat *s; | |
43 | ||
44 | assert(m); | |
45 | assert(id); | |
46 | ||
47 | s = new0(Seat, 1); | |
48 | if (!s) | |
49 | return NULL; | |
50 | ||
51 | s->state_file = strappend("/run/systemd/seats/", id); | |
52 | if (!s->state_file) { | |
53 | free(s); | |
54 | return NULL; | |
55 | } | |
56 | ||
57 | s->id = basename(s->state_file); | |
58 | s->manager = m; | |
59 | ||
60 | if (hashmap_put(m->seats, s->id, s) < 0) { | |
61 | free(s->state_file); | |
62 | free(s); | |
63 | return NULL; | |
64 | } | |
65 | ||
66 | return s; | |
67 | } | |
68 | ||
69 | void seat_free(Seat *s) { | |
70 | assert(s); | |
71 | ||
72 | if (s->in_gc_queue) | |
73 | LIST_REMOVE(gc_queue, s->manager->seat_gc_queue, s); | |
74 | ||
75 | while (s->sessions) | |
76 | session_free(s->sessions); | |
77 | ||
78 | assert(!s->active); | |
79 | ||
80 | while (s->devices) | |
81 | device_free(s->devices); | |
82 | ||
83 | hashmap_remove(s->manager->seats, s->id); | |
84 | ||
85 | free(s->positions); | |
86 | free(s->state_file); | |
87 | free(s); | |
88 | } | |
89 | ||
90 | int seat_save(Seat *s) { | |
91 | _cleanup_free_ char *temp_path = NULL; | |
92 | _cleanup_fclose_ FILE *f = NULL; | |
93 | int r; | |
94 | ||
95 | assert(s); | |
96 | ||
97 | if (!s->started) | |
98 | return 0; | |
99 | ||
100 | r = mkdir_safe_label("/run/systemd/seats", 0755, 0, 0); | |
101 | if (r < 0) | |
102 | goto fail; | |
103 | ||
104 | r = fopen_temporary(s->state_file, &f, &temp_path); | |
105 | if (r < 0) | |
106 | goto fail; | |
107 | ||
108 | fchmod(fileno(f), 0644); | |
109 | ||
110 | fprintf(f, | |
111 | "# This is private data. Do not parse.\n" | |
112 | "IS_SEAT0=%i\n" | |
113 | "CAN_MULTI_SESSION=%i\n" | |
114 | "CAN_TTY=%i\n" | |
115 | "CAN_GRAPHICAL=%i\n", | |
116 | seat_is_seat0(s), | |
117 | seat_can_multi_session(s), | |
118 | seat_can_tty(s), | |
119 | seat_can_graphical(s)); | |
120 | ||
121 | if (s->active) { | |
122 | assert(s->active->user); | |
123 | ||
124 | fprintf(f, | |
125 | "ACTIVE=%s\n" | |
126 | "ACTIVE_UID="UID_FMT"\n", | |
127 | s->active->id, | |
128 | s->active->user->uid); | |
129 | } | |
130 | ||
131 | if (s->sessions) { | |
132 | Session *i; | |
133 | ||
134 | fputs("SESSIONS=", f); | |
135 | LIST_FOREACH(sessions_by_seat, i, s->sessions) { | |
136 | fprintf(f, | |
137 | "%s%c", | |
138 | i->id, | |
139 | i->sessions_by_seat_next ? ' ' : '\n'); | |
140 | } | |
141 | ||
142 | fputs("UIDS=", f); | |
143 | LIST_FOREACH(sessions_by_seat, i, s->sessions) | |
144 | fprintf(f, | |
145 | UID_FMT"%c", | |
146 | i->user->uid, | |
147 | i->sessions_by_seat_next ? ' ' : '\n'); | |
148 | } | |
149 | ||
150 | r = fflush_and_check(f); | |
151 | if (r < 0) | |
152 | goto fail; | |
153 | ||
154 | if (rename(temp_path, s->state_file) < 0) { | |
155 | r = -errno; | |
156 | goto fail; | |
157 | } | |
158 | ||
159 | return 0; | |
160 | ||
161 | fail: | |
162 | (void) unlink(s->state_file); | |
163 | ||
164 | if (temp_path) | |
165 | (void) unlink(temp_path); | |
166 | ||
167 | return log_error_errno(r, "Failed to save seat data %s: %m", s->state_file); | |
168 | } | |
169 | ||
170 | int seat_load(Seat *s) { | |
171 | assert(s); | |
172 | ||
173 | /* There isn't actually anything to read here ... */ | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | static int vt_allocate(unsigned int vtnr) { | |
179 | char p[sizeof("/dev/tty") + DECIMAL_STR_MAX(unsigned int)]; | |
180 | _cleanup_close_ int fd = -1; | |
181 | ||
182 | assert(vtnr >= 1); | |
183 | ||
184 | snprintf(p, sizeof(p), "/dev/tty%u", vtnr); | |
185 | fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC); | |
186 | if (fd < 0) | |
187 | return -errno; | |
188 | ||
189 | return 0; | |
190 | } | |
191 | ||
192 | int seat_preallocate_vts(Seat *s) { | |
193 | int r = 0; | |
194 | unsigned i; | |
195 | ||
196 | assert(s); | |
197 | assert(s->manager); | |
198 | ||
199 | log_debug("Preallocating VTs..."); | |
200 | ||
201 | if (s->manager->n_autovts <= 0) | |
202 | return 0; | |
203 | ||
204 | if (!seat_has_vts(s)) | |
205 | return 0; | |
206 | ||
207 | for (i = 1; i <= s->manager->n_autovts; i++) { | |
208 | int q; | |
209 | ||
210 | q = vt_allocate(i); | |
211 | if (q < 0) { | |
212 | log_error_errno(q, "Failed to preallocate VT %u: %m", i); | |
213 | r = q; | |
214 | } | |
215 | } | |
216 | ||
217 | return r; | |
218 | } | |
219 | ||
220 | int seat_apply_acls(Seat *s, Session *old_active) { | |
221 | int r; | |
222 | ||
223 | assert(s); | |
224 | ||
225 | r = devnode_acl_all(s->manager->udev, | |
226 | s->id, | |
227 | false, | |
228 | !!old_active, old_active ? old_active->user->uid : 0, | |
229 | !!s->active, s->active ? s->active->user->uid : 0); | |
230 | ||
231 | if (r < 0) | |
232 | log_error_errno(r, "Failed to apply ACLs: %m"); | |
233 | ||
234 | return r; | |
235 | } | |
236 | ||
237 | int seat_set_active(Seat *s, Session *session) { | |
238 | Session *old_active; | |
239 | ||
240 | assert(s); | |
241 | assert(!session || session->seat == s); | |
242 | ||
243 | if (session == s->active) | |
244 | return 0; | |
245 | ||
246 | old_active = s->active; | |
247 | s->active = session; | |
248 | ||
249 | if (old_active) { | |
250 | session_device_pause_all(old_active); | |
251 | session_send_changed(old_active, "Active", NULL); | |
252 | } | |
253 | ||
254 | seat_apply_acls(s, old_active); | |
255 | ||
256 | if (session && session->started) { | |
257 | session_send_changed(session, "Active", NULL); | |
258 | session_device_resume_all(session); | |
259 | } | |
260 | ||
261 | if (!session || session->started) | |
262 | seat_send_changed(s, "ActiveSession", NULL); | |
263 | ||
264 | seat_save(s); | |
265 | ||
266 | if (session) { | |
267 | session_save(session); | |
268 | user_save(session->user); | |
269 | } | |
270 | ||
271 | if (old_active) { | |
272 | session_save(old_active); | |
273 | if (!session || session->user != old_active->user) | |
274 | user_save(old_active->user); | |
275 | } | |
276 | ||
277 | return 0; | |
278 | } | |
279 | ||
280 | int seat_switch_to(Seat *s, unsigned int num) { | |
281 | /* Public session positions skip 0 (there is only F1-F12). Maybe it | |
282 | * will get reassigned in the future, so return error for now. */ | |
283 | if (num == 0) | |
284 | return -EINVAL; | |
285 | ||
286 | if (num >= s->position_count || !s->positions[num]) { | |
287 | /* allow switching to unused VTs to trigger auto-activate */ | |
288 | if (seat_has_vts(s) && num < 64) | |
289 | return chvt(num); | |
290 | ||
291 | return -EINVAL; | |
292 | } | |
293 | ||
294 | return session_activate(s->positions[num]); | |
295 | } | |
296 | ||
297 | int seat_switch_to_next(Seat *s) { | |
298 | unsigned int start, i; | |
299 | ||
300 | if (s->position_count == 0) | |
301 | return -EINVAL; | |
302 | ||
303 | start = 1; | |
304 | if (s->active && s->active->position > 0) | |
305 | start = s->active->position; | |
306 | ||
307 | for (i = start + 1; i < s->position_count; ++i) | |
308 | if (s->positions[i]) | |
309 | return session_activate(s->positions[i]); | |
310 | ||
311 | for (i = 1; i < start; ++i) | |
312 | if (s->positions[i]) | |
313 | return session_activate(s->positions[i]); | |
314 | ||
315 | return -EINVAL; | |
316 | } | |
317 | ||
318 | int seat_switch_to_previous(Seat *s) { | |
319 | unsigned int start, i; | |
320 | ||
321 | if (s->position_count == 0) | |
322 | return -EINVAL; | |
323 | ||
324 | start = 1; | |
325 | if (s->active && s->active->position > 0) | |
326 | start = s->active->position; | |
327 | ||
328 | for (i = start - 1; i > 0; --i) | |
329 | if (s->positions[i]) | |
330 | return session_activate(s->positions[i]); | |
331 | ||
332 | for (i = s->position_count - 1; i > start; --i) | |
333 | if (s->positions[i]) | |
334 | return session_activate(s->positions[i]); | |
335 | ||
336 | return -EINVAL; | |
337 | } | |
338 | ||
339 | int seat_active_vt_changed(Seat *s, unsigned int vtnr) { | |
340 | Session *i, *new_active = NULL; | |
341 | int r; | |
342 | ||
343 | assert(s); | |
344 | assert(vtnr >= 1); | |
345 | ||
346 | if (!seat_has_vts(s)) | |
347 | return -EINVAL; | |
348 | ||
349 | log_debug("VT changed to %u", vtnr); | |
350 | ||
351 | /* we might have earlier closing sessions on the same VT, so try to | |
352 | * find a running one first */ | |
353 | LIST_FOREACH(sessions_by_seat, i, s->sessions) | |
354 | if (i->vtnr == vtnr && !i->stopping) { | |
355 | new_active = i; | |
356 | break; | |
357 | } | |
358 | ||
359 | if (!new_active) { | |
360 | /* no running one? then we can't decide which one is the | |
361 | * active one, let the first one win */ | |
362 | LIST_FOREACH(sessions_by_seat, i, s->sessions) | |
363 | if (i->vtnr == vtnr) { | |
364 | new_active = i; | |
365 | break; | |
366 | } | |
367 | } | |
368 | ||
369 | r = seat_set_active(s, new_active); | |
370 | manager_spawn_autovt(s->manager, vtnr); | |
371 | ||
372 | return r; | |
373 | } | |
374 | ||
375 | int seat_read_active_vt(Seat *s) { | |
376 | char t[64]; | |
377 | ssize_t k; | |
378 | unsigned int vtnr; | |
379 | int r; | |
380 | ||
381 | assert(s); | |
382 | ||
383 | if (!seat_has_vts(s)) | |
384 | return 0; | |
385 | ||
386 | lseek(s->manager->console_active_fd, SEEK_SET, 0); | |
387 | ||
388 | k = read(s->manager->console_active_fd, t, sizeof(t)-1); | |
389 | if (k <= 0) { | |
390 | log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF"); | |
391 | return k < 0 ? -errno : -EIO; | |
392 | } | |
393 | ||
394 | t[k] = 0; | |
395 | truncate_nl(t); | |
396 | ||
397 | if (!startswith(t, "tty")) { | |
398 | log_error("Hm, /sys/class/tty/tty0/active is badly formatted."); | |
399 | return -EIO; | |
400 | } | |
401 | ||
402 | r = safe_atou(t+3, &vtnr); | |
403 | if (r < 0) { | |
404 | log_error("Failed to parse VT number %s", t+3); | |
405 | return r; | |
406 | } | |
407 | ||
408 | if (!vtnr) { | |
409 | log_error("VT number invalid: %s", t+3); | |
410 | return -EIO; | |
411 | } | |
412 | ||
413 | return seat_active_vt_changed(s, vtnr); | |
414 | } | |
415 | ||
416 | int seat_start(Seat *s) { | |
417 | assert(s); | |
418 | ||
419 | if (s->started) | |
420 | return 0; | |
421 | ||
422 | log_struct(LOG_INFO, | |
423 | LOG_MESSAGE_ID(SD_MESSAGE_SEAT_START), | |
424 | "SEAT_ID=%s", s->id, | |
425 | LOG_MESSAGE("New seat %s.", s->id), | |
426 | NULL); | |
427 | ||
428 | /* Initialize VT magic stuff */ | |
429 | seat_preallocate_vts(s); | |
430 | ||
431 | /* Read current VT */ | |
432 | seat_read_active_vt(s); | |
433 | ||
434 | s->started = true; | |
435 | ||
436 | /* Save seat data */ | |
437 | seat_save(s); | |
438 | ||
439 | seat_send_signal(s, true); | |
440 | ||
441 | return 0; | |
442 | } | |
443 | ||
444 | int seat_stop(Seat *s, bool force) { | |
445 | int r = 0; | |
446 | ||
447 | assert(s); | |
448 | ||
449 | if (s->started) | |
450 | log_struct(LOG_INFO, | |
451 | LOG_MESSAGE_ID(SD_MESSAGE_SEAT_STOP), | |
452 | "SEAT_ID=%s", s->id, | |
453 | LOG_MESSAGE("Removed seat %s.", s->id), | |
454 | NULL); | |
455 | ||
456 | seat_stop_sessions(s, force); | |
457 | ||
458 | unlink(s->state_file); | |
459 | seat_add_to_gc_queue(s); | |
460 | ||
461 | if (s->started) | |
462 | seat_send_signal(s, false); | |
463 | ||
464 | s->started = false; | |
465 | ||
466 | return r; | |
467 | } | |
468 | ||
469 | int seat_stop_sessions(Seat *s, bool force) { | |
470 | Session *session; | |
471 | int r = 0, k; | |
472 | ||
473 | assert(s); | |
474 | ||
475 | LIST_FOREACH(sessions_by_seat, session, s->sessions) { | |
476 | k = session_stop(session, force); | |
477 | if (k < 0) | |
478 | r = k; | |
479 | } | |
480 | ||
481 | return r; | |
482 | } | |
483 | ||
484 | void seat_evict_position(Seat *s, Session *session) { | |
485 | Session *iter; | |
486 | unsigned int pos = session->position; | |
487 | ||
488 | session->position = 0; | |
489 | ||
490 | if (pos == 0) | |
491 | return; | |
492 | ||
493 | if (pos < s->position_count && s->positions[pos] == session) { | |
494 | s->positions[pos] = NULL; | |
495 | ||
496 | /* There might be another session claiming the same | |
497 | * position (eg., during gdm->session transition), so let's look | |
498 | * for it and set it on the free slot. */ | |
499 | LIST_FOREACH(sessions_by_seat, iter, s->sessions) { | |
500 | if (iter->position == pos && session_get_state(iter) != SESSION_CLOSING) { | |
501 | s->positions[pos] = iter; | |
502 | break; | |
503 | } | |
504 | } | |
505 | } | |
506 | } | |
507 | ||
508 | void seat_claim_position(Seat *s, Session *session, unsigned int pos) { | |
509 | /* with VTs, the position is always the same as the VTnr */ | |
510 | if (seat_has_vts(s)) | |
511 | pos = session->vtnr; | |
512 | ||
513 | if (!GREEDY_REALLOC0(s->positions, s->position_count, pos + 1)) | |
514 | return; | |
515 | ||
516 | seat_evict_position(s, session); | |
517 | ||
518 | session->position = pos; | |
519 | if (pos > 0) | |
520 | s->positions[pos] = session; | |
521 | } | |
522 | ||
523 | static void seat_assign_position(Seat *s, Session *session) { | |
524 | unsigned int pos; | |
525 | ||
526 | if (session->position > 0) | |
527 | return; | |
528 | ||
529 | for (pos = 1; pos < s->position_count; ++pos) | |
530 | if (!s->positions[pos]) | |
531 | break; | |
532 | ||
533 | seat_claim_position(s, session, pos); | |
534 | } | |
535 | ||
536 | int seat_attach_session(Seat *s, Session *session) { | |
537 | assert(s); | |
538 | assert(session); | |
539 | assert(!session->seat); | |
540 | ||
541 | if (!seat_has_vts(s) != !session->vtnr) | |
542 | return -EINVAL; | |
543 | ||
544 | session->seat = s; | |
545 | LIST_PREPEND(sessions_by_seat, s->sessions, session); | |
546 | seat_assign_position(s, session); | |
547 | ||
548 | seat_send_changed(s, "Sessions", NULL); | |
549 | ||
550 | /* On seats with VTs, the VT logic defines which session is active. On | |
551 | * seats without VTs, we automatically activate new sessions. */ | |
552 | if (!seat_has_vts(s)) | |
553 | seat_set_active(s, session); | |
554 | ||
555 | return 0; | |
556 | } | |
557 | ||
558 | void seat_complete_switch(Seat *s) { | |
559 | Session *session; | |
560 | ||
561 | assert(s); | |
562 | ||
563 | /* if no session-switch is pending or if it got canceled, do nothing */ | |
564 | if (!s->pending_switch) | |
565 | return; | |
566 | ||
567 | session = s->pending_switch; | |
568 | s->pending_switch = NULL; | |
569 | ||
570 | seat_set_active(s, session); | |
571 | } | |
572 | ||
573 | bool seat_has_vts(Seat *s) { | |
574 | assert(s); | |
575 | ||
576 | return seat_is_seat0(s) && s->manager->console_active_fd >= 0; | |
577 | } | |
578 | ||
579 | bool seat_is_seat0(Seat *s) { | |
580 | assert(s); | |
581 | ||
582 | return s->manager->seat0 == s; | |
583 | } | |
584 | ||
585 | bool seat_can_multi_session(Seat *s) { | |
586 | assert(s); | |
587 | ||
588 | return seat_has_vts(s); | |
589 | } | |
590 | ||
591 | bool seat_can_tty(Seat *s) { | |
592 | assert(s); | |
593 | ||
594 | return seat_has_vts(s); | |
595 | } | |
596 | ||
597 | bool seat_has_master_device(Seat *s) { | |
598 | assert(s); | |
599 | ||
600 | /* device list is ordered by "master" flag */ | |
601 | return !!s->devices && s->devices->master; | |
602 | } | |
603 | ||
604 | bool seat_can_graphical(Seat *s) { | |
605 | assert(s); | |
606 | ||
607 | return seat_has_master_device(s); | |
608 | } | |
609 | ||
610 | int seat_get_idle_hint(Seat *s, dual_timestamp *t) { | |
611 | Session *session; | |
612 | bool idle_hint = true; | |
613 | dual_timestamp ts = DUAL_TIMESTAMP_NULL; | |
614 | ||
615 | assert(s); | |
616 | ||
617 | LIST_FOREACH(sessions_by_seat, session, s->sessions) { | |
618 | dual_timestamp k; | |
619 | int ih; | |
620 | ||
621 | ih = session_get_idle_hint(session, &k); | |
622 | if (ih < 0) | |
623 | return ih; | |
624 | ||
625 | if (!ih) { | |
626 | if (!idle_hint) { | |
627 | if (k.monotonic > ts.monotonic) | |
628 | ts = k; | |
629 | } else { | |
630 | idle_hint = false; | |
631 | ts = k; | |
632 | } | |
633 | } else if (idle_hint) { | |
634 | ||
635 | if (k.monotonic > ts.monotonic) | |
636 | ts = k; | |
637 | } | |
638 | } | |
639 | ||
640 | if (t) | |
641 | *t = ts; | |
642 | ||
643 | return idle_hint; | |
644 | } | |
645 | ||
646 | bool seat_check_gc(Seat *s, bool drop_not_started) { | |
647 | assert(s); | |
648 | ||
649 | if (drop_not_started && !s->started) | |
650 | return false; | |
651 | ||
652 | if (seat_is_seat0(s)) | |
653 | return true; | |
654 | ||
655 | return seat_has_master_device(s); | |
656 | } | |
657 | ||
658 | void seat_add_to_gc_queue(Seat *s) { | |
659 | assert(s); | |
660 | ||
661 | if (s->in_gc_queue) | |
662 | return; | |
663 | ||
664 | LIST_PREPEND(gc_queue, s->manager->seat_gc_queue, s); | |
665 | s->in_gc_queue = true; | |
666 | } | |
667 | ||
668 | static bool seat_name_valid_char(char c) { | |
669 | return | |
670 | (c >= 'a' && c <= 'z') || | |
671 | (c >= 'A' && c <= 'Z') || | |
672 | (c >= '0' && c <= '9') || | |
673 | c == '-' || | |
674 | c == '_'; | |
675 | } | |
676 | ||
677 | bool seat_name_is_valid(const char *name) { | |
678 | const char *p; | |
679 | ||
680 | assert(name); | |
681 | ||
682 | if (!startswith(name, "seat")) | |
683 | return false; | |
684 | ||
685 | if (!name[4]) | |
686 | return false; | |
687 | ||
688 | for (p = name; *p; p++) | |
689 | if (!seat_name_valid_char(*p)) | |
690 | return false; | |
691 | ||
692 | if (strlen(name) > 255) | |
693 | return false; | |
694 | ||
695 | return true; | |
696 | } |