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 "format-util.h"
  33 #include "logind.h"
  34 #include "path-util.h"
  35 #include "special.h"
  36 #include "strv.h"
  37 #include "unit-name.h"
  38 #include "user-util.h"
  39 #include "utmp-wtmp.h"
  40
  41 _const_ static usec_t when_wall(usec_t n, usec_t elapse) {
  42
  43         usec_t left;
  44         unsigned int i;
  45         static const int wall_timers[] = {
  46                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
  47                 25, 40, 55, 70, 100, 130, 150, 180,
  48         };
  49
  50         /* If the time is already passed, then don't announce */
  51         if (n >= elapse)
  52                 return 0;
  53
  54         left = elapse - n;
  55
  56         for (i = 1; i < ELEMENTSOF(wall_timers); i++)
  57                 if (wall_timers[i] * USEC_PER_MINUTE >= left)
  58                         return left - wall_timers[i-1] * USEC_PER_MINUTE;
  59
  60         return left % USEC_PER_HOUR;
  61 }
  62
  63 bool logind_wall_tty_filter(const char *tty, void *userdata) {
  64         Manager *m = userdata;
  65         const char *p;
  66
  67         assert(m);
  68
  69         if (!m->scheduled_shutdown_tty)
  70                 return true;
  71
  72         p = path_startswith(tty, "/dev/");
  73         if (!p)
  74                 return true;
  75
  76         return !streq(p, m->scheduled_shutdown_tty);
  77 }
  78
  79 static int warn_wall(Manager *m, usec_t n) {
  80         char date[FORMAT_TIMESTAMP_MAX] = {};
  81         _cleanup_free_ char *l = NULL;
  82         usec_t left;
  83         int r;
  84
  85         assert(m);
  86
  87         if (!m->enable_wall_messages)
  88                 return 0;
  89
  90         left = m->scheduled_shutdown_timeout > n;
  91
  92         r = asprintf(&l, "%s%sThe system is going down for %s %s%s!",
  93                      strempty(m->wall_message),
  94                      isempty(m->wall_message) ? "" : "\n",
  95                      m->scheduled_shutdown_type,
  96                      left ? "at " : "NOW",
  97                      left ? format_timestamp(date, sizeof(date), m->scheduled_shutdown_timeout) : "");
  98         if (r < 0) {
  99                 log_oom();
 100                 return 0;
 101         }
 102
 103         utmp_wall(l, uid_to_name(m->scheduled_shutdown_uid),
 104                   m->scheduled_shutdown_tty, logind_wall_tty_filter, m);
 105
 106         return 1;
 107 }
 108
 109 static int wall_message_timeout_handler(
 110                         sd_event_source *s,
 111                         uint64_t usec,
 112                         void *userdata) {
 113
 114         Manager *m = userdata;
 115         usec_t n, next;
 116         int r;
 117
 118         assert(m);
 119         assert(s == m->wall_message_timeout_source);
 120
 121         n = now(CLOCK_REALTIME);
 122
 123         r = warn_wall(m, n);
 124         if (r == 0)
 125                 return 0;
 126
 127         next = when_wall(n, m->scheduled_shutdown_timeout);
 128         if (next > 0) {
 129                 r = sd_event_source_set_time(s, n + next);
 130                 if (r < 0)
 131                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 132
 133                 r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
 134                 if (r < 0)
 135                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 136         }
 137
 138         return 0;
 139 }
 140
 141 int manager_setup_wall_message_timer(Manager *m) {
 142
 143         usec_t n, elapse;
 144         int r;
 145
 146         assert(m);
 147
 148         n = now(CLOCK_REALTIME);
 149         elapse = m->scheduled_shutdown_timeout;
 150
 151         /* wall message handling */
 152
 153         if (isempty(m->scheduled_shutdown_type)) {
 154                 warn_wall(m, n);
 155                 return 0;
 156         }
 157
 158         if (elapse < n)
 159                 return 0;
 160
 161         /* Warn immediately if less than 15 minutes are left */
 162         if (elapse - n < 15 * USEC_PER_MINUTE) {
 163                 r = warn_wall(m, n);
 164                 if (r == 0)
 165                         return 0;
 166         }
 167
 168         elapse = when_wall(n, elapse);
 169         if (elapse == 0)
 170                 return 0;
 171
 172         if (m->wall_message_timeout_source) {
 173                 r = sd_event_source_set_time(m->wall_message_timeout_source, n + elapse);
 174                 if (r < 0)
 175                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 176
 177                 r = sd_event_source_set_enabled(m->wall_message_timeout_source, SD_EVENT_ONESHOT);
 178                 if (r < 0)
 179                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 180         } else {
 181                 r = sd_event_add_time(m->event, &m->wall_message_timeout_source,
 182                                       CLOCK_REALTIME, n + elapse, 0, wall_message_timeout_handler, m);
 183                 if (r < 0)
 184                         return log_error_errno(r, "sd_event_add_time() failed. %m");
 185         }
 186
 187         return 0;
 188 }