src/login/logind-utmp.c

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