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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/utsname.h>
#include <ctype.h>
#include "util.h"
#include "hostname-util.h"
bool hostname_is_set(void) {
struct utsname u;
assert_se(uname(&u) >= 0);
if (isempty(u.nodename))
return false;
/* This is the built-in kernel default host name */
if (streq(u.nodename, "(none)"))
return false;
return true;
}
char* gethostname_malloc(void) {
struct utsname u;
assert_se(uname(&u) >= 0);
if (isempty(u.nodename) || streq(u.nodename, "(none)"))
return strdup(u.sysname);
return strdup(u.nodename);
}
static bool hostname_valid_char(char c) {
return
(c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
c == '-' ||
c == '_' ||
c == '.';
}
bool hostname_is_valid(const char *s) {
const char *p;
bool dot;
if (isempty(s))
return false;
/* Doesn't accept empty hostnames, hostnames with trailing or
* leading dots, and hostnames with multiple dots in a
* sequence. Also ensures that the length stays below
* HOST_NAME_MAX. */
for (p = s, dot = true; *p; p++) {
if (*p == '.') {
if (dot)
return false;
dot = true;
} else {
if (!hostname_valid_char(*p))
return false;
dot = false;
}
}
if (dot)
return false;
if (p-s > HOST_NAME_MAX)
return false;
return true;
}
char* hostname_cleanup(char *s, bool lowercase) {
char *p, *d;
bool dot;
assert(s);
for (p = s, d = s, dot = true; *p; p++) {
if (*p == '.') {
if (dot)
continue;
*(d++) = '.';
dot = true;
} else if (hostname_valid_char(*p)) {
*(d++) = lowercase ? tolower(*p) : *p;
dot = false;
}
}
if (dot && d > s)
d[-1] = 0;
else
*d = 0;
strshorten(s, HOST_NAME_MAX);
return s;
}
bool is_localhost(const char *hostname) {
assert(hostname);
/* This tries to identify local host and domain names
* described in RFC6761 plus the redhatism of .localdomain */
return streq(hostname, "localhost") ||
streq(hostname, "localhost.") ||
streq(hostname, "localdomain.") ||
streq(hostname, "localdomain") ||
endswith(hostname, ".localhost") ||
endswith(hostname, ".localhost.") ||
endswith(hostname, ".localdomain") ||
endswith(hostname, ".localdomain.");
}
int sethostname_idempotent(const char *s) {
char buf[HOST_NAME_MAX + 1] = {};
assert(s);
if (gethostname(buf, sizeof(buf)) < 0)
return -errno;
if (streq(buf, s))
return 0;
if (sethostname(s, strlen(s)) < 0)
return -errno;
return 1;
}
int read_hostname_config(const char *path, char **hostname) {
_cleanup_fclose_ FILE *f = NULL;
char l[LINE_MAX];
char *name = NULL;
assert(path);
assert(hostname);
f = fopen(path, "re");
if (!f)
return -errno;
/* may have comments, ignore them */
FOREACH_LINE(l, f, return -errno) {
truncate_nl(l);
if (l[0] != '\0' && l[0] != '#') {
/* found line with value */
name = hostname_cleanup(l, false);
name = strdup(name);
if (!name)
return -ENOMEM;
break;
}
}
if (!name)
/* no non-empty line found */
return -ENOENT;
*hostname = name;
return 0;
}
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