src/shared/fileio-label.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sys/stat.h>
   4
   5 #include "fileio-label.h"
   6 #include "fileio.h"
   7 #include "selinux-util.h"
   8
   9 int write_string_file_atomic_label_ts(const char *fn, const char *line, struct timespec *ts) {
  10         int r;
  11
  12         r = mac_selinux_create_file_prepare(fn, S_IFREG);
  13         if (r < 0)
  14                 return r;
  15
  16         r = write_string_file_ts(fn, line, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC, ts);
  17
  18         mac_selinux_create_file_clear();
  19
  20         return r;
  21 }
  22
  23 int create_shutdown_run_nologin_or_warn(void) {
  24         int r;
  25
  26         /* This is used twice: once in systemd-user-sessions.service, in order to block logins when we
  27          * actually go down, and once in systemd-logind.service when shutdowns are scheduled, and logins are
  28          * to be turned off a bit in advance. We use the same wording of the message in both cases.
  29          *
  30          * Traditionally, there was only /etc/nologin, and we managed that. Then, in PAM 1.1
  31          * support for /run/nologin was added as alternative
  32          * (https://github.com/linux-pam/linux-pam/commit/e9e593f6ddeaf975b7fe8446d184e6bc387d450b).
  33          * 13 years later we stopped managing /etc/nologin, leaving it for the administrator to manage.
  34          */
  35
  36         r = write_string_file_atomic_label("/run/nologin",
  37                                            "System is going down. Unprivileged users are not permitted to log in anymore. "
  38                                            "For technical details, see pam_nologin(8).");
  39         if (r < 0)
  40                 return log_error_errno(r, "Failed to create /run/nologin: %m");
  41
  42         return 0;
  43 }