1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2015 Lennart Poettering
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.
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.
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/>.
23 #include <sys/utsname.h>
25 //#include "fd-util.h"
27 #include "hostname-util.h"
28 #include "string-util.h"
31 /// UNNEEDED by elogind
33 bool hostname_is_set(void) {
36 assert_se(uname(&u) >= 0);
38 if (isempty(u.nodename))
41 /* This is the built-in kernel default host name */
42 if (streq(u.nodename, "(none)"))
48 char* gethostname_malloc(void) {
51 assert_se(uname(&u) >= 0);
53 if (isempty(u.nodename) || streq(u.nodename, "(none)"))
54 return strdup(u.sysname);
56 return strdup(u.nodename);
60 static bool hostname_valid_char(char c) {
62 (c >= 'a' && c <= 'z') ||
63 (c >= 'A' && c <= 'Z') ||
64 (c >= '0' && c <= '9') ||
71 * Check if s looks like a valid host name or FQDN. This does not do
72 * full DNS validation, but only checks if the name is composed of
73 * allowed characters and the length is not above the maximum allowed
74 * by Linux (c.f. dns_name_is_valid()). Trailing dot is allowed if
75 * allow_trailing_dot is true and at least two components are present
76 * in the name. Note that due to the restricted charset and length
77 * this call is substantially more conservative than
78 * dns_domain_is_valid().
80 bool hostname_is_valid(const char *s, bool allow_trailing_dot) {
88 /* Doesn't accept empty hostnames, hostnames with
89 * leading dots, and hostnames with multiple dots in a
90 * sequence. Also ensures that the length stays below
93 for (p = s, dot = true; *p; p++) {
101 if (!hostname_valid_char(*p))
108 if (dot && (n_dots < 2 || !allow_trailing_dot))
111 if (p-s > HOST_NAME_MAX) /* Note that HOST_NAME_MAX is 64 on
112 * Linux, but DNS allows domain names
113 * up to 255 characters */
119 /// UNNEEDED by elogind
121 char* hostname_cleanup(char *s) {
127 for (p = s, d = s, dot = true; *p; p++) {
134 } else if (hostname_valid_char(*p)) {
146 strshorten(s, HOST_NAME_MAX);
152 bool is_localhost(const char *hostname) {
155 /* This tries to identify local host and domain names
156 * described in RFC6761 plus the redhatism of .localdomain */
158 return strcaseeq(hostname, "localhost") ||
159 strcaseeq(hostname, "localhost.") ||
160 strcaseeq(hostname, "localdomain.") ||
161 strcaseeq(hostname, "localdomain") ||
162 endswith_no_case(hostname, ".localhost") ||
163 endswith_no_case(hostname, ".localhost.") ||
164 endswith_no_case(hostname, ".localdomain") ||
165 endswith_no_case(hostname, ".localdomain.");
168 /// UNNEEDED by elogind
170 bool is_gateway_hostname(const char *hostname) {
173 /* This tries to identify the valid syntaxes for the our
174 * synthetic "gateway" host. */
177 strcaseeq(hostname, "gateway") ||
178 strcaseeq(hostname, "gateway.");
181 int sethostname_idempotent(const char *s) {
182 char buf[HOST_NAME_MAX + 1] = {};
186 if (gethostname(buf, sizeof(buf)) < 0)
192 if (sethostname(s, strlen(s)) < 0)
198 int read_hostname_config(const char *path, char **hostname) {
199 _cleanup_fclose_ FILE *f = NULL;
206 f = fopen(path, "re");
210 /* may have comments, ignore them */
211 FOREACH_LINE(l, f, return -errno) {
213 if (l[0] != '\0' && l[0] != '#') {
214 /* found line with value */
215 name = hostname_cleanup(l);
224 /* no non-empty line found */