chiark / gitweb /
logind: trivial simplification
[elogind.git] / src / login / logind-seat.c
1 /***
2   This file is part of systemd.
3
4   Copyright 2011 Lennart Poettering
5
6   systemd is free software; you can redistribute it and/or modify it
7   under the terms of the GNU Lesser General Public License as published by
8   the Free Software Foundation; either version 2.1 of the License, or
9   (at your option) any later version.
10
11   systemd is distributed in the hope that it will be useful, but
12   WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
18 ***/
19
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include "sd-messages.h"
26
27 #include "alloc-util.h"
28 #include "fd-util.h"
29 #include "fileio.h"
30 #include "format-util.h"
31 #include "logind-acl.h"
32 #include "logind-seat.h"
33 #include "mkdir.h"
34 #include "parse-util.h"
35 #include "stdio-util.h"
36 #include "string-util.h"
37 #include "terminal-util.h"
38 #include "util.h"
39
40 Seat *seat_new(Manager *m, const char *id) {
41         Seat *s;
42
43         assert(m);
44         assert(id);
45
46         s = new0(Seat, 1);
47         if (!s)
48                 return NULL;
49
50         s->state_file = strappend("/run/systemd/seats/", id);
51         if (!s->state_file)
52                 return mfree(s);
53
54         s->id = basename(s->state_file);
55         s->manager = m;
56
57         if (hashmap_put(m->seats, s->id, s) < 0) {
58                 free(s->state_file);
59                 return mfree(s);
60         }
61
62         return s;
63 }
64
65 void seat_free(Seat *s) {
66         assert(s);
67
68         if (s->in_gc_queue)
69                 LIST_REMOVE(gc_queue, s->manager->seat_gc_queue, s);
70
71         while (s->sessions)
72                 session_free(s->sessions);
73
74         assert(!s->active);
75
76         while (s->devices)
77                 device_free(s->devices);
78
79         hashmap_remove(s->manager->seats, s->id);
80
81         free(s->positions);
82         free(s->state_file);
83         free(s);
84 }
85
86 int seat_save(Seat *s) {
87         _cleanup_free_ char *temp_path = NULL;
88         _cleanup_fclose_ FILE *f = NULL;
89         int r;
90
91         assert(s);
92
93         if (!s->started)
94                 return 0;
95
96         r = mkdir_safe_label("/run/systemd/seats", 0755, 0, 0);
97         if (r < 0)
98                 goto fail;
99
100         r = fopen_temporary(s->state_file, &f, &temp_path);
101         if (r < 0)
102                 goto fail;
103
104         fchmod(fileno(f), 0644);
105
106         fprintf(f,
107                 "# This is private data. Do not parse.\n"
108                 "IS_SEAT0=%i\n"
109                 "CAN_MULTI_SESSION=%i\n"
110                 "CAN_TTY=%i\n"
111                 "CAN_GRAPHICAL=%i\n",
112                 seat_is_seat0(s),
113                 seat_can_multi_session(s),
114                 seat_can_tty(s),
115                 seat_can_graphical(s));
116
117         if (s->active) {
118                 assert(s->active->user);
119
120                 fprintf(f,
121                         "ACTIVE=%s\n"
122                         "ACTIVE_UID="UID_FMT"\n",
123                         s->active->id,
124                         s->active->user->uid);
125         }
126
127         if (s->sessions) {
128                 Session *i;
129
130                 fputs("SESSIONS=", f);
131                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
132                         fprintf(f,
133                                 "%s%c",
134                                 i->id,
135                                 i->sessions_by_seat_next ? ' ' : '\n');
136                 }
137
138                 fputs("UIDS=", f);
139                 LIST_FOREACH(sessions_by_seat, i, s->sessions)
140                         fprintf(f,
141                                 UID_FMT"%c",
142                                 i->user->uid,
143                                 i->sessions_by_seat_next ? ' ' : '\n');
144         }
145
146         r = fflush_and_check(f);
147         if (r < 0)
148                 goto fail;
149
150         if (rename(temp_path, s->state_file) < 0) {
151                 r = -errno;
152                 goto fail;
153         }
154
155         return 0;
156
157 fail:
158         (void) unlink(s->state_file);
159
160         if (temp_path)
161                 (void) unlink(temp_path);
162
163         return log_error_errno(r, "Failed to save seat data %s: %m", s->state_file);
164 }
165
166 int seat_load(Seat *s) {
167         assert(s);
168
169         /* There isn't actually anything to read here ... */
170
171         return 0;
172 }
173
174 #if 0 /// UNNEEDED by elogind
175 static int vt_allocate(unsigned int vtnr) {
176         char p[sizeof("/dev/tty") + DECIMAL_STR_MAX(unsigned int)];
177         _cleanup_close_ int fd = -1;
178
179         assert(vtnr >= 1);
180
181         xsprintf(p, "/dev/tty%u", vtnr);
182         fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
183         if (fd < 0)
184                 return -errno;
185
186         return 0;
187 }
188
189 int seat_preallocate_vts(Seat *s) {
190         int r = 0;
191         unsigned i;
192
193         assert(s);
194         assert(s->manager);
195
196         log_debug("Preallocating VTs...");
197
198         if (s->manager->n_autovts <= 0)
199                 return 0;
200
201         if (!seat_has_vts(s))
202                 return 0;
203
204         for (i = 1; i <= s->manager->n_autovts; i++) {
205                 int q;
206
207                 q = vt_allocate(i);
208                 if (q < 0) {
209                         log_error_errno(q, "Failed to preallocate VT %u: %m", i);
210                         r = q;
211                 }
212         }
213
214         return r;
215 }
216 #endif // 0
217
218 int seat_apply_acls(Seat *s, Session *old_active) {
219         int r;
220
221         assert(s);
222
223         r = devnode_acl_all(s->manager->udev,
224                             s->id,
225                             false,
226                             !!old_active, old_active ? old_active->user->uid : 0,
227                             !!s->active, s->active ? s->active->user->uid : 0);
228
229         if (r < 0)
230                 log_error_errno(r, "Failed to apply ACLs: %m");
231
232         return r;
233 }
234
235 int seat_set_active(Seat *s, Session *session) {
236         Session *old_active;
237
238         assert(s);
239         assert(!session || session->seat == s);
240
241         if (session == s->active)
242                 return 0;
243
244         old_active = s->active;
245         s->active = session;
246
247         if (old_active) {
248                 session_device_pause_all(old_active);
249                 session_send_changed(old_active, "Active", NULL);
250         }
251
252         seat_apply_acls(s, old_active);
253
254         if (session && session->started) {
255                 session_send_changed(session, "Active", NULL);
256                 session_device_resume_all(session);
257         }
258
259         if (!session || session->started)
260                 seat_send_changed(s, "ActiveSession", NULL);
261
262         seat_save(s);
263
264         if (session) {
265                 session_save(session);
266                 user_save(session->user);
267         }
268
269         if (old_active) {
270                 session_save(old_active);
271                 if (!session || session->user != old_active->user)
272                         user_save(old_active->user);
273         }
274
275         return 0;
276 }
277
278 int seat_switch_to(Seat *s, unsigned int num) {
279         /* Public session positions skip 0 (there is only F1-F12). Maybe it
280          * will get reassigned in the future, so return error for now. */
281         if (num == 0)
282                 return -EINVAL;
283
284         if (num >= s->position_count || !s->positions[num]) {
285                 /* allow switching to unused VTs to trigger auto-activate */
286                 if (seat_has_vts(s) && num < 64)
287                         return chvt(num);
288
289                 return -EINVAL;
290         }
291
292         return session_activate(s->positions[num]);
293 }
294
295 int seat_switch_to_next(Seat *s) {
296         unsigned int start, i;
297
298         if (s->position_count == 0)
299                 return -EINVAL;
300
301         start = 1;
302         if (s->active && s->active->position > 0)
303                 start = s->active->position;
304
305         for (i = start + 1; i < s->position_count; ++i)
306                 if (s->positions[i])
307                         return session_activate(s->positions[i]);
308
309         for (i = 1; i < start; ++i)
310                 if (s->positions[i])
311                         return session_activate(s->positions[i]);
312
313         return -EINVAL;
314 }
315
316 int seat_switch_to_previous(Seat *s) {
317         unsigned int start, i;
318
319         if (s->position_count == 0)
320                 return -EINVAL;
321
322         start = 1;
323         if (s->active && s->active->position > 0)
324                 start = s->active->position;
325
326         for (i = start - 1; i > 0; --i)
327                 if (s->positions[i])
328                         return session_activate(s->positions[i]);
329
330         for (i = s->position_count - 1; i > start; --i)
331                 if (s->positions[i])
332                         return session_activate(s->positions[i]);
333
334         return -EINVAL;
335 }
336
337 int seat_active_vt_changed(Seat *s, unsigned int vtnr) {
338         Session *i, *new_active = NULL;
339         int r;
340
341         assert(s);
342         assert(vtnr >= 1);
343
344         if (!seat_has_vts(s))
345                 return -EINVAL;
346
347         log_debug("VT changed to %u", vtnr);
348
349         /* we might have earlier closing sessions on the same VT, so try to
350          * find a running one first */
351         LIST_FOREACH(sessions_by_seat, i, s->sessions)
352                 if (i->vtnr == vtnr && !i->stopping) {
353                         new_active = i;
354                         break;
355                 }
356
357         if (!new_active) {
358                 /* no running one? then we can't decide which one is the
359                  * active one, let the first one win */
360                 LIST_FOREACH(sessions_by_seat, i, s->sessions)
361                         if (i->vtnr == vtnr) {
362                                 new_active = i;
363                                 break;
364                         }
365         }
366
367         r = seat_set_active(s, new_active);
368 #if 0 /// elogind does not spawn autovt
369         manager_spawn_autovt(s->manager, vtnr);
370 #endif // 0
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 #if 0 /// elogind does not support autospawning vts
430         seat_preallocate_vts(s);
431 #endif // 0
432
433         /* Read current VT */
434         seat_read_active_vt(s);
435
436         s->started = true;
437
438         /* Save seat data */
439         seat_save(s);
440
441         seat_send_signal(s, true);
442
443         return 0;
444 }
445
446 int seat_stop(Seat *s, bool force) {
447         int r = 0;
448
449         assert(s);
450
451         if (s->started)
452                 log_struct(LOG_INFO,
453                            LOG_MESSAGE_ID(SD_MESSAGE_SEAT_STOP),
454                            "SEAT_ID=%s", s->id,
455                            LOG_MESSAGE("Removed seat %s.", s->id),
456                            NULL);
457
458         seat_stop_sessions(s, force);
459
460         unlink(s->state_file);
461         seat_add_to_gc_queue(s);
462
463         if (s->started)
464                 seat_send_signal(s, false);
465
466         s->started = false;
467
468         return r;
469 }
470
471 int seat_stop_sessions(Seat *s, bool force) {
472         Session *session;
473         int r = 0, k;
474
475         assert(s);
476
477         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
478                 k = session_stop(session, force);
479                 if (k < 0)
480                         r = k;
481         }
482
483         return r;
484 }
485
486 void seat_evict_position(Seat *s, Session *session) {
487         Session *iter;
488         unsigned int pos = session->position;
489
490         session->position = 0;
491
492         if (pos == 0)
493                 return;
494
495         if (pos < s->position_count && s->positions[pos] == session) {
496                 s->positions[pos] = NULL;
497
498                 /* There might be another session claiming the same
499                  * position (eg., during gdm->session transition), so let's look
500                  * for it and set it on the free slot. */
501                 LIST_FOREACH(sessions_by_seat, iter, s->sessions) {
502                         if (iter->position == pos && session_get_state(iter) != SESSION_CLOSING) {
503                                 s->positions[pos] = iter;
504                                 break;
505                         }
506                 }
507         }
508 }
509
510 void seat_claim_position(Seat *s, Session *session, unsigned int pos) {
511         /* with VTs, the position is always the same as the VTnr */
512         if (seat_has_vts(s))
513                 pos = session->vtnr;
514
515         if (!GREEDY_REALLOC0(s->positions, s->position_count, pos + 1))
516                 return;
517
518         seat_evict_position(s, session);
519
520         session->position = pos;
521         if (pos > 0)
522                 s->positions[pos] = session;
523 }
524
525 static void seat_assign_position(Seat *s, Session *session) {
526         unsigned int pos;
527
528         if (session->position > 0)
529                 return;
530
531         for (pos = 1; pos < s->position_count; ++pos)
532                 if (!s->positions[pos])
533                         break;
534
535         seat_claim_position(s, session, pos);
536 }
537
538 int seat_attach_session(Seat *s, Session *session) {
539         assert(s);
540         assert(session);
541         assert(!session->seat);
542
543         if (!seat_has_vts(s) != !session->vtnr)
544                 return -EINVAL;
545
546         session->seat = s;
547         LIST_PREPEND(sessions_by_seat, s->sessions, session);
548         seat_assign_position(s, session);
549
550         seat_send_changed(s, "Sessions", NULL);
551
552         /* On seats with VTs, the VT logic defines which session is active. On
553          * seats without VTs, we automatically activate new sessions. */
554         if (!seat_has_vts(s))
555                 seat_set_active(s, session);
556
557         return 0;
558 }
559
560 void seat_complete_switch(Seat *s) {
561         Session *session;
562
563         assert(s);
564
565         /* if no session-switch is pending or if it got canceled, do nothing */
566         if (!s->pending_switch)
567                 return;
568
569         session = s->pending_switch;
570         s->pending_switch = NULL;
571
572         seat_set_active(s, session);
573 }
574
575 bool seat_has_vts(Seat *s) {
576         assert(s);
577
578         return seat_is_seat0(s) && s->manager->console_active_fd >= 0;
579 }
580
581 bool seat_is_seat0(Seat *s) {
582         assert(s);
583
584         return s->manager->seat0 == s;
585 }
586
587 bool seat_can_multi_session(Seat *s) {
588         assert(s);
589
590         return seat_has_vts(s);
591 }
592
593 bool seat_can_tty(Seat *s) {
594         assert(s);
595
596         return seat_has_vts(s);
597 }
598
599 bool seat_has_master_device(Seat *s) {
600         assert(s);
601
602         /* device list is ordered by "master" flag */
603         return !!s->devices && s->devices->master;
604 }
605
606 bool seat_can_graphical(Seat *s) {
607         assert(s);
608
609         return seat_has_master_device(s);
610 }
611
612 int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
613         Session *session;
614         bool idle_hint = true;
615         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
616
617         assert(s);
618
619         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
620                 dual_timestamp k;
621                 int ih;
622
623                 ih = session_get_idle_hint(session, &k);
624                 if (ih < 0)
625                         return ih;
626
627                 if (!ih) {
628                         if (!idle_hint) {
629                                 if (k.monotonic > ts.monotonic)
630                                         ts = k;
631                         } else {
632                                 idle_hint = false;
633                                 ts = k;
634                         }
635                 } else if (idle_hint) {
636
637                         if (k.monotonic > ts.monotonic)
638                                 ts = k;
639                 }
640         }
641
642         if (t)
643                 *t = ts;
644
645         return idle_hint;
646 }
647
648 bool seat_check_gc(Seat *s, bool drop_not_started) {
649         assert(s);
650
651         if (drop_not_started && !s->started)
652                 return false;
653
654         if (seat_is_seat0(s))
655                 return true;
656
657         return seat_has_master_device(s);
658 }
659
660 void seat_add_to_gc_queue(Seat *s) {
661         assert(s);
662
663         if (s->in_gc_queue)
664                 return;
665
666         LIST_PREPEND(gc_queue, s->manager->seat_gc_queue, s);
667         s->in_gc_queue = true;
668 }
669
670 static bool seat_name_valid_char(char c) {
671         return
672                 (c >= 'a' && c <= 'z') ||
673                 (c >= 'A' && c <= 'Z') ||
674                 (c >= '0' && c <= '9') ||
675                 c == '-' ||
676                 c == '_';
677 }
678
679 bool seat_name_is_valid(const char *name) {
680         const char *p;
681
682         assert(name);
683
684         if (!startswith(name, "seat"))
685                 return false;
686
687         if (!name[4])
688                 return false;
689
690         for (p = name; *p; p++)
691                 if (!seat_name_valid_char(*p))
692                         return false;
693
694         if (strlen(name) > 255)
695                 return false;
696
697         return true;
698 }