src/login/logind-utmp.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2015 Daniel Mack
   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 <string.h>
  24 #include <unistd.h>
  25 #include <pwd.h>
  26
  27 #include "sd-messages.h"
  28 #include "strv.h"
  29 #include "special.h"
  30 #include "unit-name.h"
  31 #include "audit.h"
  32 #include "bus-util.h"
  33 #include "bus-error.h"
  34 #include "bus-common-errors.h"
  35 #include "logind.h"
  36 #include "formats-util.h"
  37 #include "utmp-wtmp.h"
  38
  39 _const_ static usec_t when_wall(usec_t n, usec_t elapse) {
  40
  41         usec_t left;
  42         unsigned int i;
  43         static const int wall_timers[] = {
  44                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
  45                 25, 40, 55, 70, 100, 130, 150, 180,
  46         };
  47
  48         /* If the time is already passed, then don't announce */
  49         if (n >= elapse)
  50                 return 0;
  51
  52         left = elapse - n;
  53
  54         for (i = 1; i < ELEMENTSOF(wall_timers); i++)
  55                 if (wall_timers[i] * USEC_PER_MINUTE >= left)
  56                         return left - wall_timers[i-1] * USEC_PER_MINUTE;
  57
  58         return left % USEC_PER_HOUR;
  59 }
  60
  61 bool logind_wall_tty_filter(const char *tty, void *userdata) {
  62
  63         Manager *m = userdata;
  64
  65         assert(m);
  66
  67         if (!startswith(tty, "/dev/"))
  68                 return true;
  69
  70         return !streq(tty + 5, m->scheduled_shutdown_tty);
  71 }
  72
  73 static int warn_wall(Manager *m, usec_t n) {
  74         char date[FORMAT_TIMESTAMP_MAX] = {};
  75         _cleanup_free_ char *l = NULL;
  76         usec_t left;
  77         int r;
  78
  79         assert(m);
  80
  81         if (!m->enable_wall_messages)
  82                 return 0;
  83
  84         left = m->scheduled_shutdown_timeout > n;
  85
  86         r = asprintf(&l, "%s%sThe system is going down for %s %s%s!",
  87                      strempty(m->wall_message),
  88                      isempty(m->wall_message) ? "" : "\n",
  89                      m->scheduled_shutdown_type,
  90                      left ? "at " : "NOW",
  91                      left ? format_timestamp(date, sizeof(date), m->scheduled_shutdown_timeout) : "");
  92         if (r < 0) {
  93                 log_oom();
  94                 return 0;
  95         }
  96
  97         utmp_wall(l, lookup_uid(m->scheduled_shutdown_uid),
  98                   m->scheduled_shutdown_tty, logind_wall_tty_filter, m);
  99
 100         return 1;
 101 }
 102
 103 static int wall_message_timeout_handler(
 104                         sd_event_source *s,
 105                         uint64_t usec,
 106                         void *userdata) {
 107
 108         Manager *m = userdata;
 109         usec_t n, next;
 110         int r;
 111
 112         assert(m);
 113         assert(s == m->wall_message_timeout_source);
 114
 115         n = now(CLOCK_REALTIME);
 116
 117         r = warn_wall(m, n);
 118         if (r == 0)
 119                 return 0;
 120
 121         next = when_wall(n, m->scheduled_shutdown_timeout);
 122         if (next > 0) {
 123                 r = sd_event_source_set_time(s, n + next);
 124                 if (r < 0)
 125                         return log_error_errno(r, "sd_event_source_set_time() failed. %m\n");
 126
 127                 r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
 128                 if (r < 0)
 129                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m\n");
 130         }
 131
 132         return 0;
 133 }
 134
 135 int manager_setup_wall_message_timer(Manager *m) {
 136
 137         usec_t n, elapse;
 138         int r;
 139
 140         assert(m);
 141
 142         n = now(CLOCK_REALTIME);
 143         elapse = m->scheduled_shutdown_timeout;
 144
 145         /* wall message handling */
 146
 147         if (isempty(m->scheduled_shutdown_type)) {
 148                 warn_wall(m, n);
 149                 return 0;
 150         }
 151
 152         if (elapse < n)
 153                 return 0;
 154
 155         /* Warn immediately if less than 15 minutes are left */
 156         if (elapse - n < 15 * USEC_PER_MINUTE) {
 157                 r = warn_wall(m, n);
 158                 if (r == 0)
 159                         return 0;
 160         }
 161
 162         elapse = when_wall(n, elapse);
 163         if (elapse == 0)
 164                 return 0;
 165
 166         if (m->wall_message_timeout_source) {
 167                 r = sd_event_source_set_time(m->wall_message_timeout_source, n + elapse);
 168                 if (r < 0)
 169                         return log_error_errno(r, "sd_event_source_set_time() failed. %m\n");
 170
 171                 r = sd_event_source_set_enabled(m->wall_message_timeout_source, SD_EVENT_ONESHOT);
 172                 if (r < 0)
 173                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m\n");
 174         } else {
 175                 r = sd_event_add_time(m->event, &m->wall_message_timeout_source,
 176                                       CLOCK_REALTIME, n + elapse, 0, wall_message_timeout_handler, m);
 177                 if (r < 0)
 178                         return log_error_errno(r, "sd_event_add_time() failed. %m\n");
 179         }
 180
 181         return 0;
 182 }