summaryrefslogtreecommitdiffstats
path: root/src/tty-ask-password-agent/tty-ask-password-agent.c
blob: fc165ffc01ca686062ebc6ff581908bbd2cb87ff (plain)
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
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  Copyright © 2015 Werner Fink
***/

#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <poll.h>
#include <signal.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include <sys/inotify.h>
#include <sys/prctl.h>
#include <sys/signalfd.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <unistd.h>

#include "alloc-util.h"
#include "ask-password-api.h"
#include "conf-parser.h"
#include "def.h"
#include "dirent-util.h"
#include "exit-status.h"
#include "fd-util.h"
#include "fileio.h"
#include "hashmap.h"
#include "io-util.h"
#include "macro.h"
#include "main-func.h"
#include "mkdir.h"
#include "path-util.h"
#include "pretty-print.h"
#include "process-util.h"
#include "signal-util.h"
#include "socket-util.h"
#include "string-util.h"
#include "strv.h"
#include "terminal-util.h"
#include "util.h"
#include "utmp-wtmp.h"

static enum {
        ACTION_LIST,
        ACTION_QUERY,
        ACTION_WATCH,
        ACTION_WALL
} arg_action = ACTION_QUERY;

static bool arg_plymouth = false;
static bool arg_console = false;
static const char *arg_device = NULL;

static int ask_password_plymouth(
                const char *message,
                usec_t until,
                AskPasswordFlags flags,
                const char *flag_file,
                char ***ret) {

        static const union sockaddr_union sa = PLYMOUTH_SOCKET;
        _cleanup_close_ int fd = -1, notify = -1;
        _cleanup_free_ char *packet = NULL;
        ssize_t k;
        int r, n;
        struct pollfd pollfd[2] = {};
        char buffer[LINE_MAX];
        size_t p = 0;
        enum {
                POLL_SOCKET,
                POLL_INOTIFY
        };

        assert(ret);

        if (flag_file) {
                notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
                if (notify < 0)
                        return -errno;

                r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
                if (r < 0)
                        return -errno;
        }

        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (fd < 0)
                return -errno;

        r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
        if (r < 0)
                return -errno;

        if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
                packet = strdup("c");
                n = 1;
        } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
                packet = NULL;
        if (!packet)
                return -ENOMEM;

        r = loop_write(fd, packet, n + 1, true);
        if (r < 0)
                return r;

        pollfd[POLL_SOCKET].fd = fd;
        pollfd[POLL_SOCKET].events = POLLIN;
        pollfd[POLL_INOTIFY].fd = notify;
        pollfd[POLL_INOTIFY].events = POLLIN;

        for (;;) {
                int sleep_for = -1, j;

                if (until > 0) {
                        usec_t y;

                        y = now(CLOCK_MONOTONIC);

                        if (y > until) {
                                r = -ETIME;
                                goto finish;
                        }

                        sleep_for = (int) ((until - y) / USEC_PER_MSEC);
                }

                if (flag_file && access(flag_file, F_OK) < 0) {
                        r = -errno;
                        goto finish;
                }

                j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
                if (j < 0) {
                        if (errno == EINTR)
                                continue;

                        r = -errno;
                        goto finish;
                } else if (j == 0) {
                        r = -ETIME;
                        goto finish;
                }

                if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
                        (void) flush_fd(notify);

                if (pollfd[POLL_SOCKET].revents == 0)
                        continue;

                k = read(fd, buffer + p, sizeof(buffer) - p);
                if (k < 0) {
                        if (IN_SET(errno, EINTR, EAGAIN))
                                continue;

                        r = -errno;
                        goto finish;
                } else if (k == 0) {
                        r = -EIO;
                        goto finish;
                }

                p += k;

                if (p < 1)
                        continue;

                if (buffer[0] == 5) {

                        if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
                                /* Hmm, first try with cached
                                 * passwords failed, so let's retry
                                 * with a normal password request */
                                packet = mfree(packet);

                                if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
                                        r = -ENOMEM;
                                        goto finish;
                                }

                                r = loop_write(fd, packet, n+1, true);
                                if (r < 0)
                                        goto finish;

                                flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
                                p = 0;
                                continue;
                        }

                        /* No password, because UI not shown */
                        r = -ENOENT;
                        goto finish;

                } else if (IN_SET(buffer[0], 2, 9)) {
                        uint32_t size;
                        char **l;

                        /* One or more answers */
                        if (p < 5)
                                continue;

                        memcpy(&size, buffer+1, sizeof(size));
                        size = le32toh(size);
                        if (size + 5 > sizeof(buffer)) {
                                r = -EIO;
                                goto finish;
                        }

                        if (p-5 < size)
                                continue;

                        l = strv_parse_nulstr(buffer + 5, size);
                        if (!l) {
                                r = -ENOMEM;
                                goto finish;
                        }

                        *ret = l;
                        break;

                } else {
                        /* Unknown packet */
                        r = -EIO;
                        goto finish;
                }
        }

        r = 0;

finish:
        explicit_bzero_safe(buffer, sizeof(buffer));
        return r;
}

static int send_passwords(const char *socket_name, char **passwords) {
        _cleanup_free_ char *packet = NULL;
        _cleanup_close_ int socket_fd = -1;
        union sockaddr_union sa = {};
        size_t packet_length = 1;
        char **p, *d;
        ssize_t n;
        int r, salen;

        assert(socket_name);

        salen = sockaddr_un_set_path(&sa.un, socket_name);
        if (salen < 0)
                return salen;

        STRV_FOREACH(p, passwords)
                packet_length += strlen(*p) + 1;

        packet = new(char, packet_length);
        if (!packet)
                return -ENOMEM;

        packet[0] = '+';

        d = packet + 1;
        STRV_FOREACH(p, passwords)
                d = stpcpy(d, *p) + 1;

        socket_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
        if (socket_fd < 0) {
                r = log_debug_errno(errno, "socket(): %m");
                goto finish;
        }

        n = sendto(socket_fd, packet, packet_length, MSG_NOSIGNAL, &sa.sa, salen);
        if (n < 0) {
                r = log_debug_errno(errno, "sendto(): %m");
                goto finish;
        }

        r = (int) n;

finish:
        explicit_bzero_safe(packet, packet_length);
        return r;
}

static int parse_password(const char *filename, char **wall) {
        _cleanup_free_ char *socket_name = NULL, *message = NULL;
        bool accept_cached = false, echo = false;
        uint64_t not_after = 0;
        unsigned pid = 0;

        const ConfigTableItem items[] = {
                { "Ask", "Socket",       config_parse_string,   0, &socket_name   },
                { "Ask", "NotAfter",     config_parse_uint64,   0, &not_after     },
                { "Ask", "Message",      config_parse_string,   0, &message       },
                { "Ask", "PID",          config_parse_unsigned, 0, &pid           },
                { "Ask", "AcceptCached", config_parse_bool,     0, &accept_cached },
                { "Ask", "Echo",         config_parse_bool,     0, &echo          },
                {}
        };

        int r;

        assert(filename);

        r = config_parse(NULL, filename, NULL,
                         NULL,
                         config_item_table_lookup, items,
                         CONFIG_PARSE_RELAXED|CONFIG_PARSE_WARN, NULL);
        if (r < 0)
                return r;

        if (!socket_name)
                return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
                                       "Invalid password file %s", filename);

        if (not_after > 0 && now(CLOCK_MONOTONIC) > not_after)
                return 0;

        if (pid > 0 && !pid_is_alive(pid))
                return 0;

        if (arg_action == ACTION_LIST)
                printf("'%s' (PID %u)\n", message, pid);

        else if (arg_action == ACTION_WALL) {
                char *_wall;

                if (asprintf(&_wall,
                             "%s%sPassword entry required for \'%s\' (PID %u).\r\n"
                             "Please enter password with the systemd-tty-ask-password-agent tool:",
                             strempty(*wall),
                             *wall ? "\r\n\r\n" : "",
                             message,
                             pid) < 0)
                        return log_oom();

                free(*wall);
                *wall = _wall;

        } else {
                _cleanup_strv_free_erase_ char **passwords = NULL;

                assert(IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH));

                if (access(socket_name, W_OK) < 0) {
                        if (arg_action == ACTION_QUERY)
                                log_info("Not querying '%s' (PID %u), lacking privileges.", message, pid);

                        return 0;
                }

                if (arg_plymouth)
                        r = ask_password_plymouth(message, not_after, accept_cached ? ASK_PASSWORD_ACCEPT_CACHED : 0, filename, &passwords);
                else {
                        int tty_fd = -1;

                        if (arg_console) {
                                const char *con = arg_device ?: "/dev/console";

                                tty_fd = acquire_terminal(con, ACQUIRE_TERMINAL_WAIT, USEC_INFINITY);
                                if (tty_fd < 0)
                                        return log_error_errno(tty_fd, "Failed to acquire %s: %m", con);

                                r = reset_terminal_fd(tty_fd, true);
                                if (r < 0)
                                        log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
                        }

                        r = ask_password_tty(tty_fd, message, NULL, not_after,
                                             (echo ? ASK_PASSWORD_ECHO : 0) |
                                             (arg_console ? ASK_PASSWORD_CONSOLE_COLOR : 0),
                                             filename, &passwords);

                        if (arg_console) {
                                tty_fd = safe_close(tty_fd);
                                release_terminal();
                        }
                }

                /* If the query went away, that's OK */
                if (IN_SET(r, -ETIME, -ENOENT))
                        return 0;

                if (r < 0)
                        return log_error_errno(r, "Failed to query password: %m");

                r = send_passwords(socket_name, passwords);
                if (r < 0)
                        return log_error_errno(r, "Failed to send: %m");
        }

        return 0;
}

static int wall_tty_block(void) {
        _cleanup_free_ char *p = NULL;
        dev_t devnr;
        int fd, r;

        r = get_ctty_devnr(0, &devnr);
        if (r == -ENXIO) /* We have no controlling tty */
                return -ENOTTY;
        if (r < 0)
                return log_error_errno(r, "Failed to get controlling TTY: %m");

        if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(devnr), minor(devnr)) < 0)
                return log_oom();

        (void) mkdir_parents_label(p, 0700);
        (void) mkfifo(p, 0600);

        fd = open(p, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
        if (fd < 0)
                return log_debug_errno(errno, "Failed to open %s: %m", p);

        return fd;
}

static bool wall_tty_match(const char *path, void *userdata) {
        _cleanup_free_ char *p = NULL;
        _cleanup_close_ int fd = -1;
        struct stat st;

        if (!path_is_absolute(path))
                path = strjoina("/dev/", path);

        if (lstat(path, &st) < 0) {
                log_debug_errno(errno, "Failed to stat %s: %m", path);
                return true;
        }

        if (!S_ISCHR(st.st_mode)) {
                log_debug("%s is not a character device.", path);
                return true;
        }

        /* We use named pipes to ensure that wall messages suggesting
         * password entry are not printed over password prompts
         * already shown. We use the fact here that opening a pipe in
         * non-blocking mode for write-only will succeed only if
         * there's some writer behind it. Using pipes has the
         * advantage that the block will automatically go away if the
         * process dies. */

        if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(st.st_rdev), minor(st.st_rdev)) < 0) {
                log_oom();
                return true;
        }

        fd = open(p, O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
        if (fd < 0) {
                log_debug_errno(errno, "Failed to open the wall pipe: %m");
                return 1;
        }

        /* What, we managed to open the pipe? Then this tty is filtered. */
        return 0;
}

static int show_passwords(void) {
        _cleanup_closedir_ DIR *d;
        struct dirent *de;
        int r = 0;

        d = opendir("/run/systemd/ask-password");
        if (!d) {
                if (errno == ENOENT)
                        return 0;

                return log_error_errno(errno, "Failed to open /run/systemd/ask-password: %m");
        }

        FOREACH_DIRENT_ALL(de, d, return log_error_errno(errno, "Failed to read directory: %m")) {
                _cleanup_free_ char *p = NULL, *wall = NULL;
                int q;

                /* We only support /dev on tmpfs, hence we can rely on
                 * d_type to be reliable */

                if (de->d_type != DT_REG)
                        continue;

                if (hidden_or_backup_file(de->d_name))
                        continue;

                if (!startswith(de->d_name, "ask."))
                        continue;

                p = strappend("/run/systemd/ask-password/", de->d_name);
                if (!p)
                        return log_oom();

                q = parse_password(p, &wall);
                if (q < 0 && r == 0)
                        r = q;

                if (wall)
                        (void) utmp_wall(wall, NULL, NULL, wall_tty_match, NULL);
        }

        return r;
}

static int watch_passwords(void) {
        enum {
                FD_INOTIFY,
                FD_SIGNAL,
                _FD_MAX
        };

        _cleanup_close_ int notify = -1, signal_fd = -1, tty_block_fd = -1;
        struct pollfd pollfd[_FD_MAX] = {};
        sigset_t mask;
        int r;

        tty_block_fd = wall_tty_block();

        (void) mkdir_p_label("/run/systemd/ask-password", 0755);

        notify = inotify_init1(IN_CLOEXEC);
        if (notify < 0)
                return log_error_errno(errno, "Failed to allocate directory watch: %m");

        if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_CLOSE_WRITE|IN_MOVED_TO) < 0) {
                if (errno == ENOSPC)
                        return log_error_errno(errno, "Failed to add /run/systemd/ask-password to directory watch: inotify watch limit reached");
                else
                        return log_error_errno(errno, "Failed to add /run/systemd/ask-password to directory watch: %m");
        }

        assert_se(sigemptyset(&mask) >= 0);
        assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
        assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) >= 0);

        signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
        if (signal_fd < 0)
                return log_error_errno(errno, "Failed to allocate signal file descriptor: %m");

        pollfd[FD_INOTIFY].fd = notify;
        pollfd[FD_INOTIFY].events = POLLIN;
        pollfd[FD_SIGNAL].fd = signal_fd;
        pollfd[FD_SIGNAL].events = POLLIN;

        for (;;) {
                r = show_passwords();
                if (r < 0)
                        log_error_errno(r, "Failed to show password: %m");

                if (poll(pollfd, _FD_MAX, -1) < 0) {
                        if (errno == EINTR)
                                continue;

                        return -errno;
                }

                if (pollfd[FD_INOTIFY].revents != 0)
                        (void) flush_fd(notify);

                if (pollfd[FD_SIGNAL].revents != 0)
                        break;
        }

        return 0;
}

static int help(void) {
        _cleanup_free_ char *link = NULL;
        int r;

        r = terminal_urlify_man("systemd-tty-ask-password-agent", "1", &link);
        if (r < 0)
                return log_oom();

        printf("%s [OPTIONS...]\n\n"
               "Process system password requests.\n\n"
               "  -h --help     Show this help\n"
               "     --version  Show package version\n"
               "     --list     Show pending password requests\n"
               "     --query    Process pending password requests\n"
               "     --watch    Continuously process password requests\n"
               "     --wall     Continuously forward password requests to wall\n"
               "     --plymouth Ask question with Plymouth instead of on TTY\n"
               "     --console  Ask question on /dev/console instead of current TTY\n"
               "\nSee the %s for details.\n"
               , program_invocation_short_name
               , link
        );

        return 0;
}

static int parse_argv(int argc, char *argv[]) {

        enum {
                ARG_LIST = 0x100,
                ARG_QUERY,
                ARG_WATCH,
                ARG_WALL,
                ARG_PLYMOUTH,
                ARG_CONSOLE,
                ARG_VERSION
        };

        static const struct option options[] = {
                { "help",     no_argument,       NULL, 'h'          },
                { "version",  no_argument,       NULL, ARG_VERSION  },
                { "list",     no_argument,       NULL, ARG_LIST     },
                { "query",    no_argument,       NULL, ARG_QUERY    },
                { "watch",    no_argument,       NULL, ARG_WATCH    },
                { "wall",     no_argument,       NULL, ARG_WALL     },
                { "plymouth", no_argument,       NULL, ARG_PLYMOUTH },
                { "console",  optional_argument, NULL, ARG_CONSOLE  },
                {}
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)

                switch (c) {

                case 'h':
                        return help();

                case ARG_VERSION:
                        return version();

                case ARG_LIST:
                        arg_action = ACTION_LIST;
                        break;

                case ARG_QUERY:
                        arg_action = ACTION_QUERY;
                        break;

                case ARG_WATCH:
                        arg_action = ACTION_WATCH;
                        break;

                case ARG_WALL:
                        arg_action = ACTION_WALL;
                        break;

                case ARG_PLYMOUTH:
                        arg_plymouth = true;
                        break;

                case ARG_CONSOLE:
                        arg_console = true;
                        if (optarg) {

                                if (isempty(optarg))
                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                                               "Empty console device path is not allowed.");

                                arg_device = optarg;
                        }
                        break;

                case '?':
                        return -EINVAL;

                default:
                        assert_not_reached("Unhandled option");
                }

        if (optind != argc)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "%s takes no arguments.", program_invocation_short_name);

        if (arg_plymouth || arg_console) {

                if (!IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH))
                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                               "Options --query and --watch conflict.");

                if (arg_plymouth && arg_console)
                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                               "Options --plymouth and --console conflict.");
        }

        return 1;
}

/*
 * To be able to ask on all terminal devices of /dev/console
 * the devices are collected. If more than one device is found,
 * then on each of the terminals a inquiring task is forked.
 * Every task has its own session and its own controlling terminal.
 * If one of the tasks does handle a password, the remaining tasks
 * will be terminated.
 */
static int ask_on_this_console(const char *tty, pid_t *ret_pid, int argc, char *argv[]) {
        struct sigaction sig = {
                .sa_handler = nop_signal_handler,
                .sa_flags = SA_NOCLDSTOP | SA_RESTART,
        };
        pid_t pid;
        int r;

        assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD, -1) >= 0);

        assert_se(sigemptyset(&sig.sa_mask) >= 0);
        assert_se(sigaction(SIGCHLD, &sig, NULL) >= 0);

        sig.sa_handler = SIG_DFL;
        assert_se(sigaction(SIGHUP, &sig, NULL) >= 0);

        r = safe_fork("(sd-passwd)", FORK_RESET_SIGNALS|FORK_LOG, &pid);
        if (r < 0)
                return r;
        if (r == 0) {
                int ac;

                assert_se(prctl(PR_SET_PDEATHSIG, SIGHUP) >= 0);

                for (ac = 0; ac < argc; ac++) {
                        if (streq(argv[ac], "--console")) {
                                argv[ac] = strjoina("--console=", tty);
                                break;
                        }
                }

                assert(ac < argc);

                execv(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, argv);
                _exit(EXIT_FAILURE);
        }

        *ret_pid = pid;
        return 0;
}

static void terminate_agents(Set *pids) {
        struct timespec ts;
        siginfo_t status = {};
        sigset_t set;
        Iterator i;
        void *p;
        int r, signum;

        /*
         * Request termination of the remaining processes as those
         * are not required anymore.
         */
        SET_FOREACH(p, pids, i)
                (void) kill(PTR_TO_PID(p), SIGTERM);

        /*
         * Collect the processes which have go away.
         */
        assert_se(sigemptyset(&set) >= 0);
        assert_se(sigaddset(&set, SIGCHLD) >= 0);
        timespec_store(&ts, 50 * USEC_PER_MSEC);

        while (!set_isempty(pids)) {

                zero(status);
                r = waitid(P_ALL, 0, &status, WEXITED|WNOHANG);
                if (r < 0 && errno == EINTR)
                        continue;

                if (r == 0 && status.si_pid > 0) {
                        set_remove(pids, PID_TO_PTR(status.si_pid));
                        continue;
                }

                signum = sigtimedwait(&set, NULL, &ts);
                if (signum < 0) {
                        if (errno != EAGAIN)
                                log_error_errno(errno, "sigtimedwait() failed: %m");
                        break;
                }
                assert(signum == SIGCHLD);
        }

        /*
         * Kill hanging processes.
         */
        SET_FOREACH(p, pids, i) {
                log_warning("Failed to terminate child %d, killing it", PTR_TO_PID(p));
                (void) kill(PTR_TO_PID(p), SIGKILL);
        }
}

static int ask_on_consoles(int argc, char *argv[]) {
        _cleanup_set_free_ Set *pids = NULL;
        _cleanup_strv_free_ char **consoles = NULL;
        siginfo_t status = {};
        char **tty;
        pid_t pid;
        int r;

        r = get_kernel_consoles(&consoles);
        if (r < 0)
                return log_error_errno(r, "Failed to determine devices of /dev/console: %m");

        pids = set_new(NULL);
        if (!pids)
                return log_oom();

        /* Start an agent on each console. */
        STRV_FOREACH(tty, consoles) {
                r = ask_on_this_console(*tty, &pid, argc, argv);
                if (r < 0)
                        return r;

                if (set_put(pids, PID_TO_PTR(pid)) < 0)
                        return log_oom();
        }

        /* Wait for an agent to exit. */
        for (;;) {
                zero(status);

                if (waitid(P_ALL, 0, &status, WEXITED) < 0) {
                        if (errno == EINTR)
                                continue;

                        return log_error_errno(errno, "waitid() failed: %m");
                }

                set_remove(pids, PID_TO_PTR(status.si_pid));
                break;
        }

        if (!is_clean_exit(status.si_code, status.si_status, EXIT_CLEAN_DAEMON, NULL))
                log_error("Password agent failed with: %d", status.si_status);

        terminate_agents(pids);
        return 0;
}

static int run(int argc, char *argv[]) {
        int r;

        log_setup_service();

        umask(0022);

        r = parse_argv(argc, argv);
        if (r <= 0)
                return r;

        if (arg_console && !arg_device)
                /*
                 * Spawn a separate process for each console device.
                 */
                return ask_on_consoles(argc, argv);

        if (arg_device) {
                /*
                 * Later on, a controlling terminal will be acquired,
                 * therefore the current process has to become a session
                 * leader and should not have a controlling terminal already.
                 */
                (void) setsid();
                (void) release_terminal();
        }

        if (IN_SET(arg_action, ACTION_WATCH, ACTION_WALL))
                return watch_passwords();
        else
                return show_passwords();
}

DEFINE_MAIN_FUNCTION(run);