src/login/logind-utmp.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2015 Daniel Mack
   6 ***/
   7
   8 #include <errno.h>
   9 #include <pwd.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12
  13 #include "sd-messages.h"
  14
  15 #include "alloc-util.h"
  16 #include "audit-util.h"
  17 #include "bus-common-errors.h"
  18 #include "bus-error.h"
  19 #include "bus-util.h"
  20 #include "format-util.h"
  21 #include "logind.h"
  22 #include "path-util.h"
  23 #include "special.h"
  24 #include "strv.h"
  25 #include "unit-name.h"
  26 #include "user-util.h"
  27 #include "utmp-wtmp.h"
  28
  29 _const_ static usec_t when_wall(usec_t n, usec_t elapse) {
  30
  31         usec_t left;
  32         unsigned int i;
  33         static const int wall_timers[] = {
  34                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
  35                 25, 40, 55, 70, 100, 130, 150, 180,
  36         };
  37
  38         /* If the time is already passed, then don't announce */
  39         if (n >= elapse)
  40                 return 0;
  41
  42         left = elapse - n;
  43
  44         for (i = 1; i < ELEMENTSOF(wall_timers); i++)
  45                 if (wall_timers[i] * USEC_PER_MINUTE >= left)
  46                         return left - wall_timers[i-1] * USEC_PER_MINUTE;
  47
  48         return left % USEC_PER_HOUR;
  49 }
  50
  51 bool logind_wall_tty_filter(const char *tty, void *userdata) {
  52         Manager *m = userdata;
  53         const char *p;
  54
  55         assert(m);
  56
  57         if (!m->scheduled_shutdown_tty)
  58                 return true;
  59
  60         p = path_startswith(tty, "/dev/");
  61         if (!p)
  62                 return true;
  63
  64         return !streq(p, m->scheduled_shutdown_tty);
  65 }
  66
  67 static int warn_wall(Manager *m, usec_t n) {
  68         char date[FORMAT_TIMESTAMP_MAX] = {};
  69         _cleanup_free_ char *l = NULL;
  70         usec_t left;
  71         int r;
  72
  73         assert(m);
  74
  75         if (!m->enable_wall_messages)
  76                 return 0;
  77
  78         left = m->scheduled_shutdown_timeout > n;
  79
  80         r = asprintf(&l, "%s%sThe system is going down for %s %s%s!",
  81                      strempty(m->wall_message),
  82                      isempty(m->wall_message) ? "" : "\n",
  83                      m->scheduled_shutdown_type,
  84                      left ? "at " : "NOW",
  85                      left ? format_timestamp(date, sizeof(date), m->scheduled_shutdown_timeout) : "");
  86         if (r < 0) {
  87                 log_oom();
  88                 return 0;
  89         }
  90
  91         utmp_wall(l, uid_to_name(m->scheduled_shutdown_uid),
  92                   m->scheduled_shutdown_tty, logind_wall_tty_filter, m);
  93
  94         return 1;
  95 }
  96
  97 static int wall_message_timeout_handler(
  98                         sd_event_source *s,
  99                         uint64_t usec,
 100                         void *userdata) {
 101
 102         Manager *m = userdata;
 103         usec_t n, next;
 104         int r;
 105
 106         assert(m);
 107         assert(s == m->wall_message_timeout_source);
 108
 109         n = now(CLOCK_REALTIME);
 110
 111         r = warn_wall(m, n);
 112         if (r == 0)
 113                 return 0;
 114
 115         next = when_wall(n, m->scheduled_shutdown_timeout);
 116         if (next > 0) {
 117                 r = sd_event_source_set_time(s, n + next);
 118                 if (r < 0)
 119                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 120
 121                 r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
 122                 if (r < 0)
 123                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 124         }
 125
 126         return 0;
 127 }
 128
 129 int manager_setup_wall_message_timer(Manager *m) {
 130
 131         usec_t n, elapse;
 132         int r;
 133
 134         assert(m);
 135
 136         n = now(CLOCK_REALTIME);
 137         elapse = m->scheduled_shutdown_timeout;
 138
 139         /* wall message handling */
 140
 141         if (isempty(m->scheduled_shutdown_type)) {
 142                 warn_wall(m, n);
 143                 return 0;
 144         }
 145
 146         if (elapse < n)
 147                 return 0;
 148
 149         /* Warn immediately if less than 15 minutes are left */
 150         if (elapse - n < 15 * USEC_PER_MINUTE) {
 151                 r = warn_wall(m, n);
 152                 if (r == 0)
 153                         return 0;
 154         }
 155
 156         elapse = when_wall(n, elapse);
 157         if (elapse == 0)
 158                 return 0;
 159
 160         if (m->wall_message_timeout_source) {
 161                 r = sd_event_source_set_time(m->wall_message_timeout_source, n + elapse);
 162                 if (r < 0)
 163                         return log_error_errno(r, "sd_event_source_set_time() failed. %m");
 164
 165                 r = sd_event_source_set_enabled(m->wall_message_timeout_source, SD_EVENT_ONESHOT);
 166                 if (r < 0)
 167                         return log_error_errno(r, "sd_event_source_set_enabled() failed. %m");
 168         } else {
 169                 r = sd_event_add_time(m->event, &m->wall_message_timeout_source,
 170                                       CLOCK_REALTIME, n + elapse, 0, wall_message_timeout_handler, m);
 171                 if (r < 0)
 172                         return log_error_errno(r, "sd_event_add_time() failed. %m");
 173         }
 174
 175         return 0;
 176 }