src/login/logind-utmp.c

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