src/core/hostname-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <unistd.h>
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27
  28 #include "hostname-setup.h"
  29 #include "macro.h"
  30 #include "util.h"
  31 #include "log.h"
  32
  33 #if defined(TARGET_FEDORA) || defined(TARGET_ALTLINUX) || defined(TARGET_MANDRIVA) || defined(TARGET_MAGEIA)
  34 #define FILENAME "/etc/sysconfig/network"
  35 #elif defined(TARGET_SUSE) || defined(TARGET_SLACKWARE)
  36 #define FILENAME "/etc/HOSTNAME"
  37 #elif defined(TARGET_ARCH)
  38 #define FILENAME "/etc/rc.conf"
  39 #elif defined(TARGET_GENTOO)
  40 #define FILENAME "/etc/conf.d/hostname"
  41 #endif
  42
  43 static int read_and_strip_hostname(const char *path, char **hn) {
  44         char *s;
  45         int r;
  46
  47         assert(path);
  48         assert(hn);
  49
  50         r = read_one_line_file(path, &s);
  51         if (r < 0)
  52                 return r;
  53
  54         hostname_cleanup(s);
  55
  56         if (isempty(s)) {
  57                 free(s);
  58                 return -ENOENT;
  59         }
  60
  61         *hn = s;
  62
  63         return 0;
  64 }
  65
  66 static int read_distro_hostname(char **hn) {
  67
  68 #if defined(TARGET_FEDORA) || defined(TARGET_ARCH) || defined(TARGET_GENTOO) || defined(TARGET_ALTLINUX) || defined(TARGET_MANDRIVA) || defined(TARGET_MAGEIA)
  69         int r;
  70         FILE *f;
  71
  72         assert(hn);
  73
  74         f = fopen(FILENAME, "re");
  75         if (!f)
  76                 return -errno;
  77
  78         for (;;) {
  79                 char line[LINE_MAX];
  80                 char *s, *k;
  81
  82                 if (!fgets(line, sizeof(line), f)) {
  83                         if (feof(f))
  84                                 break;
  85
  86                         r = -errno;
  87                         goto finish;
  88                 }
  89
  90                 s = strstrip(line);
  91
  92                 if (!startswith_no_case(s, "HOSTNAME="))
  93                         continue;
  94
  95                 k = strdup(s+9);
  96                 if (!k) {
  97                         r = -ENOMEM;
  98                         goto finish;
  99                 }
 100
 101                 hostname_cleanup(k);
 102
 103                 if (isempty(k)) {
 104                         free(k);
 105                         r = -ENOENT;
 106                         goto finish;
 107                 }
 108
 109                 *hn = k;
 110                 r = 0;
 111                 goto finish;
 112         }
 113
 114         r = -ENOENT;
 115
 116 finish:
 117         fclose(f);
 118         return r;
 119
 120 #elif defined(TARGET_SUSE) || defined(TARGET_SLACKWARE)
 121         return read_and_strip_hostname(FILENAME, hn);
 122 #else
 123         return -ENOENT;
 124 #endif
 125 }
 126
 127 static int read_hostname(char **hn) {
 128         int r;
 129
 130         assert(hn);
 131
 132         /* First, try to load the generic hostname configuration file,
 133          * that we support on all distributions */
 134
 135         r = read_and_strip_hostname("/etc/hostname", hn);
 136         if (r < 0) {
 137                 if (r == -ENOENT)
 138                         return read_distro_hostname(hn);
 139
 140                 return r;
 141         }
 142
 143         return 0;
 144 }
 145
 146 int hostname_setup(void) {
 147         int r;
 148         char *b = NULL;
 149         const char *hn = NULL;
 150         bool enoent = false;
 151
 152         r = read_hostname(&b);
 153         if (r < 0) {
 154                 hn = NULL;
 155
 156                 if (r == -ENOENT)
 157                         enoent = true;
 158                 else
 159                         log_warning("Failed to read configured hostname: %s", strerror(-r));
 160         } else
 161                 hn = b;
 162
 163         if (isempty(hn)) {
 164                 /* Don't override the hostname if it is already set
 165                  * and not explicitly configured */
 166                 if (hostname_is_set())
 167                         goto finish;
 168
 169                 if (enoent)
 170                         log_info("No hostname configured.");
 171
 172                 hn = "localhost";
 173         }
 174
 175         if (sethostname(hn, strlen(hn)) < 0) {
 176                 log_warning("Failed to set hostname to <%s>: %m", hn);
 177                 r = -errno;
 178         } else
 179                 log_info("Set hostname to <%s>.", hn);
 180
 181 finish:
 182         free(b);
 183
 184         return r;
 185 }