1 files changed, 160 insertions, 0 deletions
diff --git a/src/shared/hostname-util.c b/src/shared/hostname-util.c
new file mode 100644
index 0000000000..2998fdf2c7
--- /dev/null
+++ b/src/shared/hostname-util.c
@@ -0,0 +1,160 @@
+/*-*- 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;
+}