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