src/update-utmp/update-utmp.c

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