src/update-utmp/update-utmp.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2010 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9
  10 #if HAVE_AUDIT
  11 #include <libaudit.h>
  12 #endif
  13
  14 #include "sd-bus.h"
  15
  16 #include "alloc-util.h"
  17 #include "bus-error.h"
  18 #include "bus-util.h"
  19 #include "format-util.h"
  20 #include "log.h"
  21 #include "macro.h"
  22 #include "process-util.h"
  23 #include "special.h"
  24 #include "strv.h"
  25 #include "unit-name.h"
  26 #include "util.h"
  27 #include "utmp-wtmp.h"
  28
  29 typedef struct Context {
  30         sd_bus *bus;
  31 #if HAVE_AUDIT
  32         int audit_fd;
  33 #endif
  34 } Context;
  35
  36 static usec_t get_startup_time(Context *c) {
  37         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  38         usec_t t = 0;
  39         int r;
  40
  41         assert(c);
  42
  43         r = sd_bus_get_property_trivial(
  44                         c->bus,
  45                         "org.freedesktop.systemd1",
  46                         "/org/freedesktop/systemd1",
  47                         "org.freedesktop.systemd1.Manager",
  48                         "UserspaceTimestamp",
  49                         &error,
  50                         't', &t);
  51         if (r < 0) {
  52                 log_error_errno(r, "Failed to get timestamp: %s", bus_error_message(&error, r));
  53                 return 0;
  54         }
  55
  56         return t;
  57 }
  58
  59 static int get_current_runlevel(Context *c) {
  60         static const struct {
  61                 const int runlevel;
  62                 const char *special;
  63         } table[] = {
  64                 /* The first target of this list that is active or has
  65                  * a job scheduled wins. We prefer runlevels 5 and 3
  66                  * here over the others, since these are the main
  67                  * runlevels used on Fedora. It might make sense to
  68                  * change the order on some distributions. */
  69                 { '5', SPECIAL_GRAPHICAL_TARGET  },
  70                 { '3', SPECIAL_MULTI_USER_TARGET },
  71                 { '1', SPECIAL_RESCUE_TARGET     },
  72         };
  73
  74         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  75         int r;
  76         unsigned i;
  77
  78         assert(c);
  79
  80         for (i = 0; i < ELEMENTSOF(table); i++) {
  81                 _cleanup_free_ char *state = NULL, *path = NULL;
  82
  83                 path = unit_dbus_path_from_name(table[i].special);
  84                 if (!path)
  85                         return log_oom();
  86
  87                 r = sd_bus_get_property_string(
  88                                 c->bus,
  89                                 "org.freedesktop.systemd1",
  90                                 path,
  91                                 "org.freedesktop.systemd1.Unit",
  92                                 "ActiveState",
  93                                 &error,
  94                                 &state);
  95                 if (r < 0)
  96                         return log_warning_errno(r, "Failed to get state: %s", bus_error_message(&error, r));
  97
  98                 if (STR_IN_SET(state, "active", "reloading"))
  99                         return table[i].runlevel;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static int on_reboot(Context *c) {
 106         int r = 0, q;
 107         usec_t t;
 108
 109         assert(c);
 110
 111         /* We finished start-up, so let's write the utmp
 112          * record and send the audit msg */
 113
 114 #if HAVE_AUDIT
 115         if (c->audit_fd >= 0)
 116                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_BOOT, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 117                     errno != EPERM) {
 118                         r = log_error_errno(errno, "Failed to send audit message: %m");
 119                 }
 120 #endif
 121
 122         /* If this call fails it will return 0, which
 123          * utmp_put_reboot() will then fix to the current time */
 124         t = get_startup_time(c);
 125
 126         q = utmp_put_reboot(t);
 127         if (q < 0) {
 128                 log_error_errno(q, "Failed to write utmp record: %m");
 129                 r = q;
 130         }
 131
 132         return r;
 133 }
 134
 135 static int on_shutdown(Context *c) {
 136         int r = 0, q;
 137
 138         assert(c);
 139
 140         /* We started shut-down, so let's write the utmp
 141          * record and send the audit msg */
 142
 143 #if HAVE_AUDIT
 144         if (c->audit_fd >= 0)
 145                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_SHUTDOWN, "", "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 &&
 146                     errno != EPERM) {
 147                         r = log_error_errno(errno, "Failed to send audit message: %m");
 148                 }
 149 #endif
 150
 151         q = utmp_put_shutdown();
 152         if (q < 0) {
 153                 log_error_errno(q, "Failed to write utmp record: %m");
 154                 r = q;
 155         }
 156
 157         return r;
 158 }
 159
 160 static int on_runlevel(Context *c) {
 161         int r = 0, q, previous, runlevel;
 162
 163         assert(c);
 164
 165         /* We finished changing runlevel, so let's write the
 166          * utmp record and send the audit msg */
 167
 168         /* First, get last runlevel */
 169         q = utmp_get_runlevel(&previous, NULL);
 170
 171         if (q < 0) {
 172                 if (!IN_SET(q, -ESRCH, -ENOENT))
 173                         return log_error_errno(q, "Failed to get current runlevel: %m");
 174
 175                 previous = 0;
 176         }
 177
 178         /* Secondly, get new runlevel */
 179         runlevel = get_current_runlevel(c);
 180
 181         if (runlevel < 0)
 182                 return runlevel;
 183
 184         if (previous == runlevel)
 185                 return 0;
 186
 187 #if HAVE_AUDIT
 188         if (c->audit_fd >= 0) {
 189                 _cleanup_free_ char *s = NULL;
 190
 191                 if (asprintf(&s, "old-level=%c new-level=%c",
 192                              previous > 0 ? previous : 'N',
 193                              runlevel > 0 ? runlevel : 'N') < 0)
 194                         return log_oom();
 195
 196                 if (audit_log_user_comm_message(c->audit_fd, AUDIT_SYSTEM_RUNLEVEL, s, "systemd-update-utmp", NULL, NULL, NULL, 1) < 0 && errno != EPERM)
 197                         r = log_error_errno(errno, "Failed to send audit message: %m");
 198         }
 199 #endif
 200
 201         q = utmp_put_runlevel(runlevel, previous);
 202         if (q < 0 && !IN_SET(q, -ESRCH, -ENOENT)) {
 203                 log_error_errno(q, "Failed to write utmp record: %m");
 204                 r = q;
 205         }
 206
 207         return r;
 208 }
 209
 210 int main(int argc, char *argv[]) {
 211         Context c = {
 212 #if HAVE_AUDIT
 213                 .audit_fd = -1
 214 #endif
 215         };
 216         int r;
 217
 218         if (getppid() != 1) {
 219                 log_error("This program should be invoked by init only.");
 220                 return EXIT_FAILURE;
 221         }
 222
 223         if (argc != 2) {
 224                 log_error("This program requires one argument.");
 225                 return EXIT_FAILURE;
 226         }
 227
 228         log_set_target(LOG_TARGET_AUTO);
 229         log_parse_environment();
 230         log_open();
 231
 232         umask(0022);
 233
 234 #if HAVE_AUDIT
 235         /* If the kernel lacks netlink or audit support,
 236          * don't worry about it. */
 237         c.audit_fd = audit_open();
 238         if (c.audit_fd < 0 && !IN_SET(errno, EAFNOSUPPORT, EPROTONOSUPPORT))
 239                 log_error_errno(errno, "Failed to connect to audit log: %m");
 240 #endif
 241         r = bus_connect_system_systemd(&c.bus);
 242         if (r < 0) {
 243                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 244                 r = -EIO;
 245                 goto finish;
 246         }
 247
 248         log_debug("systemd-update-utmp running as pid "PID_FMT, getpid_cached());
 249
 250         if (streq(argv[1], "reboot"))
 251                 r = on_reboot(&c);
 252         else if (streq(argv[1], "shutdown"))
 253                 r = on_shutdown(&c);
 254         else if (streq(argv[1], "runlevel"))
 255                 r = on_runlevel(&c);
 256         else {
 257                 log_error("Unknown command %s", argv[1]);
 258                 r = -EINVAL;
 259         }
 260
 261         log_debug("systemd-update-utmp stopped as pid "PID_FMT, getpid_cached());
 262
 263 finish:
 264 #if HAVE_AUDIT
 265         if (c.audit_fd >= 0)
 266                 audit_close(c.audit_fd);
 267 #endif
 268
 269         sd_bus_flush_close_unref(c.bus);
 270         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 271 }