hostname-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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 #define LINE_MAX 4096
  34
  35 #if defined(TARGET_FEDORA)
  36 #define FILENAME "/etc/sysconfig/network"
  37 #elif defined(TARGET_SUSE)
  38 #define FILENAME "/etc/HOSTNAME"
  39 #elif defined(TARGET_DEBIAN)
  40 #define FILENAME "/etc/hostname"
  41 #elif defined(TARGET_ARCH)
  42 #define FILENAME "/etc/rc.conf"
  43 #elif defined(TARGET_GENTOO)
  44 #define FILENAME "/etc/conf.d/hostname"
  45 #endif
  46
  47 static char* strip_bad_chars(char *s) {
  48         char *p, *d;
  49
  50         for (p = s, d = s; *p; p++)
  51                 if ((*p >= 'a' && *p <= 'z') ||
  52                     (*p >= 'A' && *p <= 'Z') ||
  53                     (*p >= '0' && *p <= '9') ||
  54                     *p == '-' ||
  55                     *p == '_')
  56                         *(d++) = *p;
  57
  58         *d = 0;
  59
  60         return s;
  61 }
  62
  63 static int read_hostname(char **hn) {
  64
  65 #if defined(TARGET_FEDORA) || defined(TARGET_ARCH) || defined(TARGET_GENTOO)
  66         int r;
  67         FILE *f;
  68
  69         assert(hn);
  70
  71         if (!(f = fopen(FILENAME, "re")))
  72                 return -errno;
  73
  74         for (;;) {
  75                 char line[LINE_MAX];
  76                 char *s, *k;
  77
  78                 if (!fgets(line, sizeof(line), f)) {
  79                         if (feof(f))
  80                                 break;
  81
  82                         r = -errno;
  83                         goto finish;
  84                 }
  85
  86                 s = strstrip(line);
  87
  88                 if (!startswith_no_case(s, "HOSTNAME="))
  89                         continue;
  90
  91                 if (!(k = strdup(s+9))) {
  92                         r = -ENOMEM;
  93                         goto finish;
  94                 }
  95
  96                 strip_bad_chars(k);
  97
  98                 if (k[0] == 0) {
  99                         free(k);
 100                         r = -ENOENT;
 101                         goto finish;
 102                 }
 103
 104                 *hn = k;
 105                 break;
 106         }
 107
 108         r = 0;
 109
 110 finish:
 111         fclose(f);
 112         return r;
 113
 114 #elif defined(TARGET_SUSE) || defined(TARGET_DEBIAN)
 115         int r;
 116         char *s, *k;
 117
 118         assert(hn);
 119
 120         if ((r = read_one_line_file(FILENAME, &s)) < 0)
 121                 return r;
 122
 123         k = strdup(strstrip(s));
 124         free(s);
 125
 126         if (!k)
 127                 return -ENOMEM;
 128
 129         strip_bad_chars(k);
 130
 131         if (k[0] == 0) {
 132                 free(k);
 133                 return -ENOENT;
 134         }
 135
 136         *hn = k;
 137
 138 #else
 139 #warning "Don't know how to read the hostname"
 140
 141         return -ENOENT;
 142 #endif
 143
 144         return 0;
 145 }
 146
 147 int hostname_setup(void) {
 148         int r;
 149         char *hn;
 150
 151         if ((r = read_hostname(&hn)) < 0) {
 152                 if (r != -ENOENT)
 153                         log_warning("Failed to read configured hostname: %s", strerror(-r));
 154
 155                 return r;
 156         }
 157
 158         r = sethostname(hn, strlen(hn)) < 0 ? -errno : 0;
 159
 160         if (r < 0)
 161                 log_warning("Failed to set hostname to <%s>: %s", hn, strerror(-r));
 162         else
 163                 log_info("Set hostname to <%s>.", hn);
 164
 165         free(hn);
 166
 167         return r;
 168 }