src/user-sessions/user-sessions.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 <unistd.h>
  22
  23 #include "fileio.h"
  24 #include "fileio-label.h"
  25 #include "log.h"
  26 #include "selinux-util.h"
  27 #include "string-util.h"
  28 #include "util.h"
  29
  30 int main(int argc, char*argv[]) {
  31
  32         if (argc != 2) {
  33                 log_error("This program requires one argument.");
  34                 return EXIT_FAILURE;
  35         }
  36
  37         log_set_target(LOG_TARGET_AUTO);
  38         log_parse_environment();
  39         log_open();
  40
  41         umask(0022);
  42
  43         mac_selinux_init();
  44
  45         if (streq(argv[1], "start")) {
  46                 int r = 0;
  47
  48                 if (unlink("/run/nologin") < 0 && errno != ENOENT)
  49                         r = log_error_errno(errno,
  50                                             "Failed to remove /run/nologin file: %m");
  51
  52                 if (unlink("/etc/nologin") < 0 && errno != ENOENT) {
  53                         /* If the file doesn't exist and /etc simply
  54                          * was read-only (in which case unlink()
  55                          * returns EROFS even if the file doesn't
  56                          * exist), don't complain */
  57
  58                         if (errno != EROFS || access("/etc/nologin", F_OK) >= 0) {
  59                                 log_error_errno(errno, "Failed to remove /etc/nologin file: %m");
  60                                 return EXIT_FAILURE;
  61                         }
  62                 }
  63
  64                 if (r < 0)
  65                         return EXIT_FAILURE;
  66
  67         } else if (streq(argv[1], "stop")) {
  68                 int r;
  69
  70                 r = write_string_file_atomic_label("/run/nologin", "System is going down.");
  71                 if (r < 0) {
  72                         log_error_errno(r, "Failed to create /run/nologin: %m");
  73                         return EXIT_FAILURE;
  74                 }
  75
  76         } else {
  77                 log_error("Unknown verb %s.", argv[1]);
  78                 return EXIT_FAILURE;
  79         }
  80
  81         mac_selinux_finish();
  82
  83         return EXIT_SUCCESS;
  84 }