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 "format-util.h"
  34 #include "log.h"
  35 #include "macro.h"
  36 #include "special.h"
  37 #include "strv.h"
  38 #include "unit-name.h"
  39 #include "util.h"
  40 #include "utmp-wtmp.h"
  41
  42 typedef struct Context {
  43         sd_bus *bus;
  44 #ifdef HAVE_AUDIT
  45         int audit_fd;
  46 #endif
  47 } Context;
  48
  49 static usec_t get_startup_time(Context *c) {
  50         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  51         usec_t t = 0;
  52         int r;
  53
  54         assert(c);
  55
  56         r = sd_bus_get_property_trivial(
  57                         c->bus,
  58                         "org.freedesktop.systemd1",
  59                         "/org/freedesktop/systemd1",
  60                         "org.freedesktop.systemd1.Manager",
  61                         "UserspaceTimestamp",
  62                         &error,
  63                         't', &t);
  64         if (r < 0) {
  65                 log_error_errno(r, "Failed to get timestamp: %s", bus_error_message(&error, r));
  66                 return 0;
  67         }
  68
  69         return t;
  70 }
  71
  72 static int get_current_runlevel(Context *c) {
  73         static const struct {
  74                 const int runlevel;
  75                 const char *special;
  76         } table[] = {
  77                 /* The first target of this list that is active or has
  78                  * a job scheduled wins. We prefer runlevels 5 and 3
  79                  * here over the others, since these are the main
  80                  * runlevels used on Fedora. It might make sense to
  81                  * change the order on some distributions. */
  82                 { '5', SPECIAL_GRAPHICAL_TARGET  },
  83                 { '3', SPECIAL_MULTI_USER_TARGET },
  84                 { '1', SPECIAL_RESCUE_TARGET     },
  85         };
  86
  87         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  88         int r;
  89         unsigned i;
  90
  91         assert(c);
  92
  93         for (i = 0; i < ELEMENTSOF(table); i++) {
  94                 _cleanup_free_ char *state = NULL, *path = NULL;
  95
  96                 path = unit_dbus_path_from_name(table[i].special);
  97                 if (!path)
  98                         return log_oom();
  99
 100                 r = sd_bus_get_property_string(
 101                                 c->bus,
 102                                 "org.freedesktop.systemd1",
 103                                 path,
 104                                 "org.freedesktop.systemd1.Unit",
 105                                 "ActiveState",
 106                                 &error,
 107                                 &state);
 108                 if (r < 0)
 109                         return log_warning_errno(r, "Failed to get state: %s", bus_error_message(&error, r));
 110
 111                 if (STR_IN_SET(state, "active", "reloading"))
 112                         return table[i].runlevel;
 113         }
 114
 115         return 0;
 116 }
 117
 118 static int on_reboot(Context *c) {
 119         int r = 0, q;
 120         usec_t t;
 121
 122         assert(c);
 123
 124         /* We finished start-up, so let's write the utmp
 125          * record and send the audit msg */
 126
 127 #ifdef HAVE_AUDIT
 128         if (c->audit_fd >= 0)
 129                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_BOOT, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 130                     errno != EPERM) {
 131                         r = log_error_errno(errno, "Failed to send audit message: %m");
 132                 }
 133 #endif
 134
 135         /* If this call fails it will return 0, which
 136          * utmp_put_reboot() will then fix to the current time */
 137         t = get_startup_time(c);
 138
 139         q = utmp_put_reboot(t);
 140         if (q < 0) {
 141                 log_error_errno(q, "Failed to write utmp record: %m");
 142                 r = q;
 143         }
 144
 145         return r;
 146 }
 147
 148 static int on_shutdown(Context *c) {
 149         int r = 0, q;
 150
 151         assert(c);
 152
 153         /* We started shut-down, so let's write the utmp
 154          * record and send the audit msg */
 155
 156 #ifdef HAVE_AUDIT
 157         if (c->audit_fd >= 0)
 158                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_SHUTDOWN, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 159                     errno != EPERM) {
 160                         r = log_error_errno(errno, "Failed to send audit message: %m");
 161                 }
 162 #endif
 163
 164         q = utmp_put_shutdown();
 165         if (q < 0) {
 166                 log_error_errno(q, "Failed to write utmp record: %m");
 167                 r = q;
 168         }
 169
 170         return r;
 171 }
 172
 173 static int on_runlevel(Context *c) {
 174         int r = 0, q, previous, runlevel;
 175
 176         assert(c);
 177
 178         /* We finished changing runlevel, so let's write the
 179          * utmp record and send the audit msg */
 180
 181         /* First, get last runlevel */
 182         q = utmp_get_runlevel(&previous, NULL);
 183
 184         if (q < 0) {
 185                 if (q != -ESRCH && q != -ENOENT)
 186                         return log_error_errno(q, "Failed to get current runlevel: %m");
 187
 188                 previous = 0;
 189         }
 190
 191         /* Secondly, get new runlevel */
 192         runlevel = get_current_runlevel(c);
 193
 194         if (runlevel < 0)
 195                 return runlevel;
 196
 197         if (previous == runlevel)
 198                 return 0;
 199
 200 #ifdef HAVE_AUDIT
 201         if (c->audit_fd >= 0) {
 202                 _cleanup_free_ char *s = NULL;
 203
 204                 if (asprintf(&s, "old-level=%c new-level=%c",
 205                              previous > 0 ? previous : 'N',
 206                              runlevel > 0 ? runlevel : 'N') < 0)
 207                         return log_oom();
 208
 209                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_RUNLEVEL, s, "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 && errno != EPERM)
 210                         r = log_error_errno(errno, "Failed to send audit message: %m");
 211         }
 212 #endif
 213
 214         q = utmp_put_runlevel(runlevel, previous);
 215         if (q < 0 && q != -ESRCH && q != -ENOENT) {
 216                 log_error_errno(q, "Failed to write utmp record: %m");
 217                 r = q;
 218         }
 219
 220         return r;
 221 }
 222
 223 int main(int argc, char *argv[]) {
 224         Context c = {
 225 #ifdef HAVE_AUDIT
 226                 .audit_fd = -1
 227 #endif
 228         };
 229         int r;
 230
 231         if (getppid() != 1) {
 232                 log_error("This program should be invoked by init only.");
 233                 return EXIT_FAILURE;
 234         }
 235
 236         if (argc != 2) {
 237                 log_error("This program requires one argument.");
 238                 return EXIT_FAILURE;
 239         }
 240
 241         log_set_target(LOG_TARGET_AUTO);
 242         log_parse_environment();
 243         log_open();
 244
 245         umask(0022);
 246
 247 #ifdef HAVE_AUDIT
 248         /* If the kernel lacks netlink or audit support,
 249          * don't worry about it. */
 250         c.audit_fd = audit_open();
 251         if (c.audit_fd < 0 && errno != EAFNOSUPPORT && errno != EPROTONOSUPPORT)
 252                 log_error_errno(errno, "Failed to connect to audit log: %m");
 253 #endif
 254         r = bus_connect_system_systemd(&c.bus);
 255         if (r < 0) {
 256                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 257                 r = -EIO;
 258                 goto finish;
 259         }
 260
 261         log_debug("systemd-update-utmp running as pid "PID_FMT, getpid());
 262
 263         if (streq(argv[1], "reboot"))
 264                 r = on_reboot(&c);
 265         else if (streq(argv[1], "shutdown"))
 266                 r = on_shutdown(&c);
 267         else if (streq(argv[1], "runlevel"))
 268                 r = on_runlevel(&c);
 269         else {
 270                 log_error("Unknown command %s", argv[1]);
 271                 r = -EINVAL;
 272         }
 273
 274         log_debug("systemd-update-utmp stopped as pid "PID_FMT, getpid());
 275
 276 finish:
 277 #ifdef HAVE_AUDIT
 278         if (c.audit_fd >= 0)
 279                 audit_close(c.audit_fd);
 280 #endif
 281
 282         sd_bus_flush_close_unref(c.bus);
 283         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 284 }