src/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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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)
  34 #define FILENAME "/etc/sysconfig/network"
  35 #elif defined(TARGET_SUSE) || defined(TARGET_SLACKWARE) || defined(TARGET_FRUGALWARE)
  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         if ((r = read_one_line_file(path, &s)) < 0)
  51                 return r;
  52
  53         hostname_cleanup(s);
  54
  55         if (isempty(s)) {
  56                 free(s);
  57                 return -ENOENT;
  58         }
  59
  60         *hn = s;
  61
  62         return 0;
  63 }
  64
  65 static int read_distro_hostname(char **hn) {
  66
  67 #if defined(TARGET_FEDORA) || defined(TARGET_ARCH) || defined(TARGET_GENTOO) || defined(TARGET_ALTLINUX) || defined(TARGET_MANDRIVA)
  68         int r;
  69         FILE *f;
  70
  71         assert(hn);
  72
  73         if (!(f = fopen(FILENAME, "re")))
  74                 return -errno;
  75
  76         for (;;) {
  77                 char line[LINE_MAX];
  78                 char *s, *k;
  79
  80                 if (!fgets(line, sizeof(line), f)) {
  81                         if (feof(f))
  82                                 break;
  83
  84                         r = -errno;
  85                         goto finish;
  86                 }
  87
  88                 s = strstrip(line);
  89
  90                 if (!startswith_no_case(s, "HOSTNAME="))
  91                         continue;
  92
  93                 if (!(k = strdup(s+9))) {
  94                         r = -ENOMEM;
  95                         goto finish;
  96                 }
  97
  98                 hostname_cleanup(k);
  99
 100                 if (isempty(k)) {
 101                         free(k);
 102                         r = -ENOENT;
 103                         goto finish;
 104                 }
 105
 106                 *hn = k;
 107                 r = 0;
 108                 goto finish;
 109         }
 110
 111         r = -ENOENT;
 112
 113 finish:
 114         fclose(f);
 115         return r;
 116
 117 #elif defined(TARGET_SUSE) || defined(TARGET_SLACKWARE) || defined(TARGET_FRUGALWARE)
 118         return read_and_strip_hostname(FILENAME, hn);
 119 #else
 120         return -ENOENT;
 121 #endif
 122 }
 123
 124 static int read_hostname(char **hn) {
 125         int r;
 126
 127         assert(hn);
 128
 129         /* First, try to load the generic hostname configuration file,
 130          * that we support on all distributions */
 131
 132         if ((r = read_and_strip_hostname("/etc/hostname", hn)) < 0) {
 133
 134                 if (r == -ENOENT)
 135                         return read_distro_hostname(hn);
 136
 137                 return r;
 138         }
 139
 140         return 0;
 141 }
 142
 143 int hostname_setup(void) {
 144         int r;
 145         char *b = NULL;
 146         const char *hn = NULL;
 147
 148         if ((r = read_hostname(&b)) < 0) {
 149                 if (r == -ENOENT)
 150                         log_info("No hostname configured.");
 151                 else
 152                         log_warning("Failed to read configured hostname: %s", strerror(-r));
 153
 154                 hn = NULL;
 155         } else
 156                 hn = b;
 157
 158         if (!hn) {
 159                 /* Don't override the hostname if it is unset and not
 160                  * explicitly configured */
 161
 162                 char *old_hostname = NULL;
 163
 164                 if ((old_hostname = gethostname_malloc())) {
 165                         bool already_set;
 166
 167                         already_set = old_hostname[0] != 0;
 168                         free(old_hostname);
 169
 170                         if (already_set)
 171                                 goto finish;
 172                 }
 173
 174                 hn = "localhost";
 175         }
 176
 177         if (sethostname(hn, strlen(hn)) < 0) {
 178                 log_warning("Failed to set hostname to <%s>: %m", hn);
 179                 r = -errno;
 180         } else
 181                 log_info("Set hostname to <%s>.", hn);
 182
 183 finish:
 184         free(b);
 185
 186         return r;
 187 }