src/update-utmp/update-utmp.c

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