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 #if 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 "process-util.h"
  37 #include "special.h"
  38 #include "strv.h"
  39 #include "unit-name.h"
  40 #include "util.h"
  41 #include "utmp-wtmp.h"
  42
  43 typedef struct Context {
  44         sd_bus *bus;
  45 #if HAVE_AUDIT
  46         int audit_fd;
  47 #endif
  48 } Context;
  49
  50 static usec_t get_startup_time(Context *c) {
  51         _cleanup_(sd_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_errno(r, "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_GRAPHICAL_TARGET  },
  84                 { '3', SPECIAL_MULTI_USER_TARGET },
  85                 { '1', SPECIAL_RESCUE_TARGET     },
  86         };
  87
  88         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  89         int r;
  90         unsigned i;
  91
  92         assert(c);
  93
  94         for (i = 0; i < ELEMENTSOF(table); i++) {
  95                 _cleanup_free_ char *state = NULL, *path = NULL;
  96
  97                 path = unit_dbus_path_from_name(table[i].special);
  98                 if (!path)
  99                         return log_oom();
 100
 101                 r = sd_bus_get_property_string(
 102                                 c->bus,
 103                                 "org.freedesktop.systemd1",
 104                                 path,
 105                                 "org.freedesktop.systemd1.Unit",
 106                                 "ActiveState",
 107                                 &error,
 108                                 &state);
 109                 if (r < 0)
 110                         return log_warning_errno(r, "Failed to get state: %s", bus_error_message(&error, r));
 111
 112                 if (STR_IN_SET(state, "active", "reloading"))
 113                         return table[i].runlevel;
 114         }
 115
 116         return 0;
 117 }
 118
 119 static int on_reboot(Context *c) {
 120         int r = 0, q;
 121         usec_t t;
 122
 123         assert(c);
 124
 125         /* We finished start-up, so let's write the utmp
 126          * record and send the audit msg */
 127
 128 #if HAVE_AUDIT
 129         if (c->audit_fd >= 0)
 130                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_BOOT, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 131                     errno != EPERM) {
 132                         r = log_error_errno(errno, "Failed to send audit message: %m");
 133                 }
 134 #endif
 135
 136         /* If this call fails it will return 0, which
 137          * utmp_put_reboot() will then fix to the current time */
 138         t = get_startup_time(c);
 139
 140         q = utmp_put_reboot(t);
 141         if (q < 0) {
 142                 log_error_errno(q, "Failed to write utmp record: %m");
 143                 r = q;
 144         }
 145
 146         return r;
 147 }
 148
 149 static int on_shutdown(Context *c) {
 150         int r = 0, q;
 151
 152         assert(c);
 153
 154         /* We started shut-down, so let's write the utmp
 155          * record and send the audit msg */
 156
 157 #if HAVE_AUDIT
 158         if (c->audit_fd >= 0)
 159                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_SHUTDOWN, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 160                     errno != EPERM) {
 161                         r = log_error_errno(errno, "Failed to send audit message: %m");
 162                 }
 163 #endif
 164
 165         q = utmp_put_shutdown();
 166         if (q < 0) {
 167                 log_error_errno(q, "Failed to write utmp record: %m");
 168                 r = q;
 169         }
 170
 171         return r;
 172 }
 173
 174 static int on_runlevel(Context *c) {
 175         int r = 0, q, previous, runlevel;
 176
 177         assert(c);
 178
 179         /* We finished changing runlevel, so let's write the
 180          * utmp record and send the audit msg */
 181
 182         /* First, get last runlevel */
 183         q = utmp_get_runlevel(&previous, NULL);
 184
 185         if (q < 0) {
 186                 if (!IN_SET(q, -ESRCH, -ENOENT))
 187                         return log_error_errno(q, "Failed to get current runlevel: %m");
 188
 189                 previous = 0;
 190         }
 191
 192         /* Secondly, get new runlevel */
 193         runlevel = get_current_runlevel(c);
 194
 195         if (runlevel < 0)
 196                 return runlevel;
 197
 198         if (previous == runlevel)
 199                 return 0;
 200
 201 #if HAVE_AUDIT
 202         if (c->audit_fd >= 0) {
 203                 _cleanup_free_ char *s = NULL;
 204
 205                 if (asprintf(&s, "old-level=%c new-level=%c",
 206                              previous > 0 ? previous : 'N',
 207                              runlevel > 0 ? runlevel : 'N') < 0)
 208                         return log_oom();
 209
 210                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_RUNLEVEL, s, "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 && errno != EPERM)
 211                         r = log_error_errno(errno, "Failed to send audit message: %m");
 212         }
 213 #endif
 214
 215         q = utmp_put_runlevel(runlevel, previous);
 216         if (q < 0 && !IN_SET(q, -ESRCH, -ENOENT)) {
 217                 log_error_errno(q, "Failed to write utmp record: %m");
 218                 r = q;
 219         }
 220
 221         return r;
 222 }
 223
 224 int main(int argc, char *argv[]) {
 225         Context c = {
 226 #if HAVE_AUDIT
 227                 .audit_fd = -1
 228 #endif
 229         };
 230         int r;
 231
 232         if (getppid() != 1) {
 233                 log_error("This program should be invoked by init only.");
 234                 return EXIT_FAILURE;
 235         }
 236
 237         if (argc != 2) {
 238                 log_error("This program requires one argument.");
 239                 return EXIT_FAILURE;
 240         }
 241
 242         log_set_target(LOG_TARGET_AUTO);
 243         log_parse_environment();
 244         log_open();
 245
 246         umask(0022);
 247
 248 #if HAVE_AUDIT
 249         /* If the kernel lacks netlink or audit support,
 250          * don't worry about it. */
 251         c.audit_fd = audit_open();
 252         if (c.audit_fd < 0 && !IN_SET(errno, EAFNOSUPPORT, EPROTONOSUPPORT))
 253                 log_error_errno(errno, "Failed to connect to audit log: %m");
 254 #endif
 255         r = bus_connect_system_systemd(&c.bus);
 256         if (r < 0) {
 257                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 258                 r = -EIO;
 259                 goto finish;
 260         }
 261
 262         log_debug("systemd-update-utmp running as pid "PID_FMT, getpid_cached());
 263
 264         if (streq(argv[1], "reboot"))
 265                 r = on_reboot(&c);
 266         else if (streq(argv[1], "shutdown"))
 267                 r = on_shutdown(&c);
 268         else if (streq(argv[1], "runlevel"))
 269                 r = on_runlevel(&c);
 270         else {
 271                 log_error("Unknown command %s", argv[1]);
 272                 r = -EINVAL;
 273         }
 274
 275         log_debug("systemd-update-utmp stopped as pid "PID_FMT, getpid_cached());
 276
 277 finish:
 278 #if HAVE_AUDIT
 279         if (c.audit_fd >= 0)
 280                 audit_close(c.audit_fd);
 281 #endif
 282
 283         sd_bus_flush_close_unref(c.bus);
 284         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 285 }