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
   8 #include <errno.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11
  12 #include "alloc-util.h"
  13 #include "fileio.h"
  14 #include "hostname-setup.h"
  15 #include "hostname-util.h"
  16 #include "log.h"
  17 #include "macro.h"
  18 #include "string-util.h"
  19 #include "util.h"
  20
  21 int hostname_setup(void) {
  22         _cleanup_free_ char *b = NULL;
  23         bool enoent = false;
  24         const char *hn;
  25         int r;
  26
  27         r = read_etc_hostname(NULL, &b);
  28         if (r < 0) {
  29                 if (r == -ENOENT)
  30                         enoent = true;
  31                 else
  32                         log_warning_errno(r, "Failed to read configured hostname: %m");
  33
  34                 hn = NULL;
  35         } else
  36                 hn = b;
  37
  38         if (isempty(hn)) {
  39                 /* Don't override the hostname if it is already set
  40                  * and not explicitly configured */
  41                 if (hostname_is_set())
  42                         return 0;
  43
  44                 if (enoent)
  45                         log_info("No hostname configured.");
  46
  47                 hn = FALLBACK_HOSTNAME;
  48         }
  49
  50         r = sethostname_idempotent(hn);
  51         if (r < 0)
  52                 return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
  53
  54         log_info("Set hostname to <%s>.", hn);
  55         return 0;
  56 }