src/core/hostname-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24
  25 #include "alloc-util.h"
  26 #include "fileio.h"
  27 #include "hostname-setup.h"
  28 #include "hostname-util.h"
  29 #include "log.h"
  30 #include "macro.h"
  31 #include "string-util.h"
  32 #include "util.h"
  33
  34 int hostname_setup(void) {
  35         _cleanup_free_ char *b = NULL;
  36         bool enoent = false;
  37         const char *hn;
  38         int r;
  39
  40         r = read_etc_hostname(NULL, &b);
  41         if (r < 0) {
  42                 if (r == -ENOENT)
  43                         enoent = true;
  44                 else
  45                         log_warning_errno(r, "Failed to read configured hostname: %m");
  46
  47                 hn = NULL;
  48         } else
  49                 hn = b;
  50
  51         if (isempty(hn)) {
  52                 /* Don't override the hostname if it is already set
  53                  * and not explicitly configured */
  54                 if (hostname_is_set())
  55                         return 0;
  56
  57                 if (enoent)
  58                         log_info("No hostname configured.");
  59
  60                 hn = FALLBACK_HOSTNAME;
  61         }
  62
  63         r = sethostname_idempotent(hn);
  64         if (r < 0)
  65                 return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
  66
  67         log_info("Set hostname to <%s>.", hn);
  68         return 0;
  69 }