src/update-utmp/update-utmp.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <assert.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27
  28 #ifdef HAVE_AUDIT
  29 #include <libaudit.h>
  30 #endif
  31
  32 #include "sd-bus.h"
  33
  34 #include "log.h"
  35 #include "macro.h"
  36 #include "util.h"
  37 #include "special.h"
  38 #include "utmp-wtmp.h"
  39 #include "bus-util.h"
  40 #include "bus-error.h"
  41 #include "unit-name.h"
  42
  43 typedef struct Context {
  44         sd_bus *bus;
  45 #ifdef HAVE_AUDIT
  46         int audit_fd;
  47 #endif
  48 } Context;
  49
  50 static usec_t get_startup_time(Context *c) {
  51         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
  52         usec_t t = 0;
  53         int r;
  54
  55         assert(c);
  56
  57         r = sd_bus_get_property_trivial(
  58                         c->bus,
  59                         "org.freedesktop.systemd1",
  60                         "/org/freedesktop/systemd1",
  61                         "org.freedesktop.systemd1.Manager",
  62                         "UserspaceTimestamp",
  63                         &error,
  64                         't', &t);
  65         if (r < 0) {
  66                 log_error("Failed to get timestamp: %s", bus_error_message(&error, -r));
  67                 return 0;
  68         }
  69
  70         return t;
  71 }
  72
  73 static int get_current_runlevel(Context *c) {
  74         static const struct {
  75                 const int runlevel;
  76                 const char *special;
  77         } table[] = {
  78                 /* The first target of this list that is active or has
  79                  * a job scheduled wins. We prefer runlevels 5 and 3
  80                  * here over the others, since these are the main
  81                  * runlevels used on Fedora. It might make sense to
  82                  * change the order on some distributions. */
  83                 { '5', SPECIAL_RUNLEVEL5_TARGET },
  84                 { '3', SPECIAL_RUNLEVEL3_TARGET },
  85                 { '4', SPECIAL_RUNLEVEL4_TARGET },
  86                 { '2', SPECIAL_RUNLEVEL2_TARGET },
  87                 { '1', SPECIAL_RESCUE_TARGET },
  88         };
  89
  90         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
  91         int r;
  92         unsigned i;
  93
  94         assert(c);
  95
  96         for (i = 0; i < ELEMENTSOF(table); i++) {
  97                 _cleanup_free_ char *state = NULL, *path = NULL;
  98
  99                 path = unit_dbus_path_from_name(table[i].special);
 100                 if (!path)
 101                         return log_oom();
 102
 103                 r = sd_bus_get_property_string(
 104                                 c->bus,
 105                                 "org.freedesktop.systemd1",
 106                                 path,
 107                                 "org.freedesktop.systemd1.Unit",
 108                                 "ActiveState",
 109                                 &error,
 110                                 &state);
 111                 if (r < 0) {
 112                         log_warning("Failed to get state: %s", bus_error_message(&error, -r));
 113                         return r;
 114                 }
 115
 116                 if (streq(state, "active") || streq(state, "reloading"))
 117                         return table[i].runlevel;
 118         }
 119
 120         return 0;
 121 }
 122
 123 static int on_reboot(Context *c) {
 124         int r = 0, q;
 125         usec_t t;
 126
 127         assert(c);
 128
 129         /* We finished start-up, so let's write the utmp
 130          * record and send the audit msg */
 131
 132 #ifdef HAVE_AUDIT
 133         if (c->audit_fd >= 0)
 134                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_BOOT, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 135                     errno != EPERM) {
 136                         log_error_errno(errno, "Failed to send audit message: %m");
 137                         r = -errno;
 138                 }
 139 #endif
 140
 141         /* If this call fails it will return 0, which
 142          * utmp_put_reboot() will then fix to the current time */
 143         t = get_startup_time(c);
 144
 145         q = utmp_put_reboot(t);
 146         if (q < 0) {
 147                 log_error_errno(q, "Failed to write utmp record: %m");
 148                 r = q;
 149         }
 150
 151         return r;
 152 }
 153
 154 static int on_shutdown(Context *c) {
 155         int r = 0, q;
 156
 157         assert(c);
 158
 159         /* We started shut-down, so let's write the utmp
 160          * record and send the audit msg */
 161
 162 #ifdef HAVE_AUDIT
 163         if (c->audit_fd >= 0)
 164                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_SHUTDOWN, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 165                     errno != EPERM) {
 166                         log_error_errno(errno, "Failed to send audit message: %m");
 167                         r = -errno;
 168                 }
 169 #endif
 170
 171         q = utmp_put_shutdown();
 172         if (q < 0) {
 173                 log_error_errno(q, "Failed to write utmp record: %m");
 174                 r = q;
 175         }
 176
 177         return r;
 178 }
 179
 180 static int on_runlevel(Context *c) {
 181         int r = 0, q, previous, runlevel;
 182
 183         assert(c);
 184
 185         /* We finished changing runlevel, so let's write the
 186          * utmp record and send the audit msg */
 187
 188         /* First, get last runlevel */
 189         q = utmp_get_runlevel(&previous, NULL);
 190
 191         if (q < 0) {
 192                 if (q != -ESRCH && q != -ENOENT)
 193                         return log_error_errno(q, "Failed to get current runlevel: %m");
 194
 195                 previous = 0;
 196         }
 197
 198         /* Secondly, get new runlevel */
 199         runlevel = get_current_runlevel(c);
 200
 201         if (runlevel < 0)
 202                 return runlevel;
 203
 204         if (previous == runlevel)
 205                 return 0;
 206
 207 #ifdef HAVE_AUDIT
 208         if (c->audit_fd >= 0) {
 209                 _cleanup_free_ char *s = NULL;
 210
 211                 if (asprintf(&s, "old-level=%c new-level=%c",
 212                              previous > 0 ? previous : 'N',
 213                              runlevel > 0 ? runlevel : 'N') < 0)
 214                         return log_oom();
 215
 216                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_RUNLEVEL, s, "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 217                     errno != EPERM) {
 218                         log_error_errno(errno, "Failed to send audit message: %m");
 219                         r = -errno;
 220                 }
 221         }
 222 #endif
 223
 224         q = utmp_put_runlevel(runlevel, previous);
 225         if (q < 0 && q != -ESRCH && q != -ENOENT) {
 226                 log_error_errno(q, "Failed to write utmp record: %m");
 227                 r = q;
 228         }
 229
 230         return r;
 231 }
 232
 233 int main(int argc, char *argv[]) {
 234         Context c = {
 235 #ifdef HAVE_AUDIT
 236                 .audit_fd = -1
 237 #endif
 238         };
 239         int r;
 240
 241         if (getppid() != 1) {
 242                 log_error("This program should be invoked by init only.");
 243                 return EXIT_FAILURE;
 244         }
 245
 246         if (argc != 2) {
 247                 log_error("This program requires one argument.");
 248                 return EXIT_FAILURE;
 249         }
 250
 251         log_set_target(LOG_TARGET_AUTO);
 252         log_parse_environment();
 253         log_open();
 254
 255         umask(0022);
 256
 257 #ifdef HAVE_AUDIT
 258         /* If the kernel lacks netlink or audit support,
 259          * don't worry about it. */
 260         c.audit_fd = audit_open();
 261         if (c.audit_fd < 0 && errno != EAFNOSUPPORT && errno != EPROTONOSUPPORT)
 262                 log_error_errno(errno, "Failed to connect to audit log: %m");
 263 #endif
 264         r = bus_open_system_systemd(&c.bus);
 265         if (r < 0) {
 266                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 267                 r = -EIO;
 268                 goto finish;
 269         }
 270
 271         log_debug("systemd-update-utmp running as pid "PID_FMT, getpid());
 272
 273         if (streq(argv[1], "reboot"))
 274                 r = on_reboot(&c);
 275         else if (streq(argv[1], "shutdown"))
 276                 r = on_shutdown(&c);
 277         else if (streq(argv[1], "runlevel"))
 278                 r = on_runlevel(&c);
 279         else {
 280                 log_error("Unknown command %s", argv[1]);
 281                 r = -EINVAL;
 282         }
 283
 284         log_debug("systemd-update-utmp stopped as pid "PID_FMT, getpid());
 285
 286 finish:
 287 #ifdef HAVE_AUDIT
 288         if (c.audit_fd >= 0)
 289                 audit_close(c.audit_fd);
 290 #endif
 291
 292         if (c.bus)
 293                 sd_bus_unref(c.bus);
 294
 295         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 296 }