src/update-utmp/update-utmp.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11
  12 #if HAVE_AUDIT
  13 #include <libaudit.h>
  14 #endif
  15
  16 #include "sd-bus.h"
  17
  18 #include "alloc-util.h"
  19 #include "bus-error.h"
  20 #include "bus-util.h"
  21 #include "format-util.h"
  22 #include "log.h"
  23 #include "macro.h"
  24 #include "process-util.h"
  25 #include "special.h"
  26 #include "strv.h"
  27 #include "unit-name.h"
  28 #include "util.h"
  29 #include "utmp-wtmp.h"
  30
  31 typedef struct Context {
  32         sd_bus *bus;
  33 #if HAVE_AUDIT
  34         int audit_fd;
  35 #endif
  36 } Context;
  37
  38 static usec_t get_startup_time(Context *c) {
  39         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  40         usec_t t = 0;
  41         int r;
  42
  43         assert(c);
  44
  45         r = sd_bus_get_property_trivial(
  46                         c->bus,
  47                         "org.freedesktop.systemd1",
  48                         "/org/freedesktop/systemd1",
  49                         "org.freedesktop.systemd1.Manager",
  50                         "UserspaceTimestamp",
  51                         &error,
  52                         't', &t);
  53         if (r < 0) {
  54                 log_error_errno(r, "Failed to get timestamp: %s", bus_error_message(&error, r));
  55                 return 0;
  56         }
  57
  58         return t;
  59 }
  60
  61 static int get_current_runlevel(Context *c) {
  62         static const struct {
  63                 const int runlevel;
  64                 const char *special;
  65         } table[] = {
  66                 /* The first target of this list that is active or has
  67                  * a job scheduled wins. We prefer runlevels 5 and 3
  68                  * here over the others, since these are the main
  69                  * runlevels used on Fedora. It might make sense to
  70                  * change the order on some distributions. */
  71                 { '5', SPECIAL_GRAPHICAL_TARGET  },
  72                 { '3', SPECIAL_MULTI_USER_TARGET },
  73                 { '1', SPECIAL_RESCUE_TARGET     },
  74         };
  75
  76         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  77         int r;
  78         unsigned i;
  79
  80         assert(c);
  81
  82         for (i = 0; i < ELEMENTSOF(table); i++) {
  83                 _cleanup_free_ char *state = NULL, *path = NULL;
  84
  85                 path = unit_dbus_path_from_name(table[i].special);
  86                 if (!path)
  87                         return log_oom();
  88
  89                 r = sd_bus_get_property_string(
  90                                 c->bus,
  91                                 "org.freedesktop.systemd1",
  92                                 path,
  93                                 "org.freedesktop.systemd1.Unit",
  94                                 "ActiveState",
  95                                 &error,
  96                                 &state);
  97                 if (r < 0)
  98                         return log_warning_errno(r, "Failed to get state: %s", bus_error_message(&error, r));
  99
 100                 if (STR_IN_SET(state, "active", "reloading"))
 101                         return table[i].runlevel;
 102         }
 103
 104         return 0;
 105 }
 106
 107 static int on_reboot(Context *c) {
 108         int r = 0, q;
 109         usec_t t;
 110
 111         assert(c);
 112
 113         /* We finished start-up, so let's write the utmp
 114          * record and send the audit msg */
 115
 116 #if HAVE_AUDIT
 117         if (c->audit_fd >= 0)
 118                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_BOOT, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 119                     errno != EPERM) {
 120                         r = log_error_errno(errno, "Failed to send audit message: %m");
 121                 }
 122 #endif
 123
 124         /* If this call fails it will return 0, which
 125          * utmp_put_reboot() will then fix to the current time */
 126         t = get_startup_time(c);
 127
 128         q = utmp_put_reboot(t);
 129         if (q < 0) {
 130                 log_error_errno(q, "Failed to write utmp record: %m");
 131                 r = q;
 132         }
 133
 134         return r;
 135 }
 136
 137 static int on_shutdown(Context *c) {
 138         int r = 0, q;
 139
 140         assert(c);
 141
 142         /* We started shut-down, so let's write the utmp
 143          * record and send the audit msg */
 144
 145 #if HAVE_AUDIT
 146         if (c->audit_fd >= 0)
 147                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_SHUTDOWN, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 148                     errno != EPERM) {
 149                         r = log_error_errno(errno, "Failed to send audit message: %m");
 150                 }
 151 #endif
 152
 153         q = utmp_put_shutdown();
 154         if (q < 0) {
 155                 log_error_errno(q, "Failed to write utmp record: %m");
 156                 r = q;
 157         }
 158
 159         return r;
 160 }
 161
 162 static int on_runlevel(Context *c) {
 163         int r = 0, q, previous, runlevel;
 164
 165         assert(c);
 166
 167         /* We finished changing runlevel, so let's write the
 168          * utmp record and send the audit msg */
 169
 170         /* First, get last runlevel */
 171         q = utmp_get_runlevel(&previous, NULL);
 172
 173         if (q < 0) {
 174                 if (!IN_SET(q, -ESRCH, -ENOENT))
 175                         return log_error_errno(q, "Failed to get current runlevel: %m");
 176
 177                 previous = 0;
 178         }
 179
 180         /* Secondly, get new runlevel */
 181         runlevel = get_current_runlevel(c);
 182
 183         if (runlevel < 0)
 184                 return runlevel;
 185
 186         if (previous == runlevel)
 187                 return 0;
 188
 189 #if HAVE_AUDIT
 190         if (c->audit_fd >= 0) {
 191                 _cleanup_free_ char *s = NULL;
 192
 193                 if (asprintf(&s, "old-level=%c new-level=%c",
 194                              previous > 0 ? previous : 'N',
 195                              runlevel > 0 ? runlevel : 'N') < 0)
 196                         return log_oom();
 197
 198                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_RUNLEVEL, s, "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 && errno != EPERM)
 199                         r = log_error_errno(errno, "Failed to send audit message: %m");
 200         }
 201 #endif
 202
 203         q = utmp_put_runlevel(runlevel, previous);
 204         if (q < 0 && !IN_SET(q, -ESRCH, -ENOENT)) {
 205                 log_error_errno(q, "Failed to write utmp record: %m");
 206                 r = q;
 207         }
 208
 209         return r;
 210 }
 211
 212 int main(int argc, char *argv[]) {
 213         Context c = {
 214 #if HAVE_AUDIT
 215                 .audit_fd = -1
 216 #endif
 217         };
 218         int r;
 219
 220         if (getppid() != 1) {
 221                 log_error("This program should be invoked by init only.");
 222                 return EXIT_FAILURE;
 223         }
 224
 225         if (argc != 2) {
 226                 log_error("This program requires one argument.");
 227                 return EXIT_FAILURE;
 228         }
 229
 230         log_set_target(LOG_TARGET_AUTO);
 231         log_parse_environment();
 232         log_open();
 233
 234         umask(0022);
 235
 236 #if HAVE_AUDIT
 237         /* If the kernel lacks netlink or audit support,
 238          * don't worry about it. */
 239         c.audit_fd = audit_open();
 240         if (c.audit_fd < 0 && !IN_SET(errno, EAFNOSUPPORT, EPROTONOSUPPORT))
 241                 log_error_errno(errno, "Failed to connect to audit log: %m");
 242 #endif
 243         r = bus_connect_system_systemd(&c.bus);
 244         if (r < 0) {
 245                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 246                 r = -EIO;
 247                 goto finish;
 248         }
 249
 250         log_debug("systemd-update-utmp running as pid "PID_FMT, getpid_cached());
 251
 252         if (streq(argv[1], "reboot"))
 253                 r = on_reboot(&c);
 254         else if (streq(argv[1], "shutdown"))
 255                 r = on_shutdown(&c);
 256         else if (streq(argv[1], "runlevel"))
 257                 r = on_runlevel(&c);
 258         else {
 259                 log_error("Unknown command %s", argv[1]);
 260                 r = -EINVAL;
 261         }
 262
 263         log_debug("systemd-update-utmp stopped as pid "PID_FMT, getpid_cached());
 264
 265 finish:
 266 #if HAVE_AUDIT
 267         if (c.audit_fd >= 0)
 268                 audit_close(c.audit_fd);
 269 #endif
 270
 271         sd_bus_flush_close_unref(c.bus);
 272         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 273 }