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 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_MEEGO) || 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         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) || defined(TARGET_MEEGO) || defined(TARGET_MAGEIA)
  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)
 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 }