src/update-utmp/update-utmp.c

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