src/login/logind-utmp.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright © 2015 Daniel Mack
   4 ***/
   5
   6 #include <errno.h>
   7 #include <pwd.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10
  11 #include "sd-messages.h"
  12
  13 #include "alloc-util.h"
  14 #include "audit-util.h"
  15 #include "bus-common-errors.h"
  16 #include "bus-error.h"
  17 #include "bus-util.h"
  18 #include "format-util.h"
  19 #include "logind.h"
  20 #include "path-util.h"
  21 #include "special.h"
  22 #include "strv.h"
  23 #include "unit-name.h"
  24 #include "user-util.h"
  25 #include "utmp-wtmp.h"
  26
  27 _const_ static usec_t when_wall(usec_t n, usec_t elapse) {
  28
  29         usec_t left;
  30         unsigned int i;
  31         static const int wall_timers[] = {
  32                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
  33                 25, 40, 55, 70, 100, 130, 150, 180,
  34         };
  35
  36         /* If the time is already passed, then don't announce */
  37         if (n >= elapse)
  38                 return 0;
  39
  40         left = elapse - n;
  41
  42         for (i = 1; i < ELEMENTSOF(wall_timers); i++)
  43                 if (wall_timers[i] * USEC_PER_MINUTE >= left)
  44                         return left - wall_timers[i-1] * USEC_PER_MINUTE;
  45
  46         return left % USEC_PER_HOUR;
  47 }
  48
  49 bool logind_wall_tty_filter(const char *tty, void *userdata) {
  50         Manager *m = userdata;
  51         const char *p;
  52
  53         assert(m);
  54
  55         if (!m->scheduled_shutdown_tty)
  56                 return true;
  57
  58         p = path_startswith(tty, "/dev/");
  59         if (!p)
  60                 return true;
  61
  62         return !streq(p, m->scheduled_shutdown_tty);
  63 }
  64
  65 static int warn_wall(Manager *m, usec_t n) {
  66         char date[FORMAT_TIMESTAMP_MAX] = {};
  67         _cleanup_free_ char *l = NULL;
  68         usec_t left;
  69         int r;
  70
  71         assert(m);
  72
  73         if (!m->enable_wall_messages)
  74                 return 0;
  75
  76         left = m->scheduled_shutdown_timeout > n;
  77
  78         r = asprintf(&l, "%s%sThe system is going down for %s %s%s!",
  79                      strempty(m->wall_message),
  80                      isempty(m->wall_message) ? "" : "\n",
  81                      m->scheduled_shutdown_type,
  82                      left ? "at " : "NOW",
  83                      left ? format_timestamp(date, sizeof(date), m->scheduled_shutdown_timeout) : "");
  84         if (r < 0) {
  85                 log_oom();
  86                 return 0;
  87         }
  88
  89         utmp_wall(l, uid_to_name(m->scheduled_shutdown_uid),
  90                   m->scheduled_shutdown_tty, logind_wall_tty_filter, m);
  91
  92         return 1;
  93 }
  94
  95 static int wall_message_timeout_handler(
  96                         sd_event_source *s,
  97                         uint64_t usec,
  98                         void *userdata) {
  99
 100         Manager *m = userdata;
 101         usec_t n, next;
 102         int r;
 103
 104         assert(m);
 105         assert(s == m->wall_message_timeout_source);
 106
 107         n = now(CLOCK_REALTIME);
 108
 109         r = warn_wall(m, n);
 110         if (r == 0)
 111                 return 0;
 112
 113         next = when_wall(n, m->scheduled_shutdown_timeout);
 114         if (next > 0) {
 115                 r = sd_event_source_set_time(s, n + next);
 116                 if (r < 0)
 117                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 118
 119                 r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
 120                 if (r < 0)
 121                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 122         }
 123
 124         return 0;
 125 }
 126
 127 int manager_setup_wall_message_timer(Manager *m) {
 128
 129         usec_t n, elapse;
 130         int r;
 131
 132         assert(m);
 133
 134         n = now(CLOCK_REALTIME);
 135         elapse = m->scheduled_shutdown_timeout;
 136
 137         /* wall message handling */
 138
 139         if (isempty(m->scheduled_shutdown_type)) {
 140                 warn_wall(m, n);
 141                 return 0;
 142         }
 143
 144         if (elapse < n)
 145                 return 0;
 146
 147         /* Warn immediately if less than 15 minutes are left */
 148         if (elapse - n < 15 * USEC_PER_MINUTE) {
 149                 r = warn_wall(m, n);
 150                 if (r == 0)
 151                         return 0;
 152         }
 153
 154         elapse = when_wall(n, elapse);
 155         if (elapse == 0)
 156                 return 0;
 157
 158         if (m->wall_message_timeout_source) {
 159                 r = sd_event_source_set_time(m->wall_message_timeout_source, n + elapse);
 160                 if (r < 0)
 161                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 162
 163                 r = sd_event_source_set_enabled(m->wall_message_timeout_source, SD_EVENT_ONESHOT);
 164                 if (r < 0)
 165                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 166         } else {
 167                 r = sd_event_add_time(m->event, &m->wall_message_timeout_source,
 168                                       CLOCK_REALTIME, n + elapse, 0, wall_message_timeout_handler, m);
 169                 if (r < 0)
 170                         return log_error_errno(r, "sd_event_add_time() failed. %m");
 171         }
 172
 173         return 0;
 174 }