src/login/logind-utmp.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2015 Daniel Mack
   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 <pwd.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include "sd-messages.h"
  26
  27 #include "alloc-util.h"
  28 #include "audit-util.h"
  29 #include "bus-common-errors.h"
  30 #include "bus-error.h"
  31 #include "bus-util.h"
  32 #include "formats-util.h"
  33 #include "logind.h"
  34 #include "special.h"
  35 #include "strv.h"
  36 #include "unit-name.h"
  37 #include "user-util.h"
  38 #include "utmp-wtmp.h"
  39
  40 _const_ static usec_t when_wall(usec_t n, usec_t elapse) {
  41
  42         usec_t left;
  43         unsigned int i;
  44         static const int wall_timers[] = {
  45                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
  46                 25, 40, 55, 70, 100, 130, 150, 180,
  47         };
  48
  49         /* If the time is already passed, then don't announce */
  50         if (n >= elapse)
  51                 return 0;
  52
  53         left = elapse - n;
  54
  55         for (i = 1; i < ELEMENTSOF(wall_timers); i++)
  56                 if (wall_timers[i] * USEC_PER_MINUTE >= left)
  57                         return left - wall_timers[i-1] * USEC_PER_MINUTE;
  58
  59         return left % USEC_PER_HOUR;
  60 }
  61
  62 bool logind_wall_tty_filter(const char *tty, void *userdata) {
  63
  64         Manager *m = userdata;
  65
  66         assert(m);
  67
  68         if (!startswith(tty, "/dev/") || !m->scheduled_shutdown_tty)
  69                 return true;
  70
  71         return !streq(tty + 5, m->scheduled_shutdown_tty);
  72 }
  73
  74 static int warn_wall(Manager *m, usec_t n) {
  75         char date[FORMAT_TIMESTAMP_MAX] = {};
  76         _cleanup_free_ char *l = NULL;
  77         usec_t left;
  78         int r;
  79
  80         assert(m);
  81
  82         if (!m->enable_wall_messages)
  83                 return 0;
  84
  85         left = m->scheduled_shutdown_timeout > n;
  86
  87         r = asprintf(&l, "%s%sThe system is going down for %s %s%s!",
  88                      strempty(m->wall_message),
  89                      isempty(m->wall_message) ? "" : "\n",
  90                      m->scheduled_shutdown_type,
  91                      left ? "at " : "NOW",
  92                      left ? format_timestamp(date, sizeof(date), m->scheduled_shutdown_timeout) : "");
  93         if (r < 0) {
  94                 log_oom();
  95                 return 0;
  96         }
  97
  98         utmp_wall(l, uid_to_name(m->scheduled_shutdown_uid),
  99                   m->scheduled_shutdown_tty, logind_wall_tty_filter, m);
 100
 101         return 1;
 102 }
 103
 104 static int wall_message_timeout_handler(
 105                         sd_event_source *s,
 106                         uint64_t usec,
 107                         void *userdata) {
 108
 109         Manager *m = userdata;
 110         usec_t n, next;
 111         int r;
 112
 113         assert(m);
 114         assert(s == m->wall_message_timeout_source);
 115
 116         n = now(CLOCK_REALTIME);
 117
 118         r = warn_wall(m, n);
 119         if (r == 0)
 120                 return 0;
 121
 122         next = when_wall(n, m->scheduled_shutdown_timeout);
 123         if (next > 0) {
 124                 r = sd_event_source_set_time(s, n + next);
 125                 if (r < 0)
 126                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 127
 128                 r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
 129                 if (r < 0)
 130                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 131         }
 132
 133         return 0;
 134 }
 135
 136 int manager_setup_wall_message_timer(Manager *m) {
 137
 138         usec_t n, elapse;
 139         int r;
 140
 141         assert(m);
 142
 143         n = now(CLOCK_REALTIME);
 144         elapse = m->scheduled_shutdown_timeout;
 145
 146         /* wall message handling */
 147
 148         if (isempty(m->scheduled_shutdown_type)) {
 149                 warn_wall(m, n);
 150                 return 0;
 151         }
 152
 153         if (elapse < n)
 154                 return 0;
 155
 156         /* Warn immediately if less than 15 minutes are left */
 157         if (elapse - n < 15 * USEC_PER_MINUTE) {
 158                 r = warn_wall(m, n);
 159                 if (r == 0)
 160                         return 0;
 161         }
 162
 163         elapse = when_wall(n, elapse);
 164         if (elapse == 0)
 165                 return 0;
 166
 167         if (m->wall_message_timeout_source) {
 168                 r = sd_event_source_set_time(m->wall_message_timeout_source, n + elapse);
 169                 if (r < 0)
 170                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 171
 172                 r = sd_event_source_set_enabled(m->wall_message_timeout_source, SD_EVENT_ONESHOT);
 173                 if (r < 0)
 174                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 175         } else {
 176                 r = sd_event_add_time(m->event, &m->wall_message_timeout_source,
 177                                       CLOCK_REALTIME, n + elapse, 0, wall_message_timeout_handler, m);
 178                 if (r < 0)
 179                         return log_error_errno(r, "sd_event_add_time() failed. %m");
 180         }
 181
 182         return 0;
 183 }