hostname-util: add relax parameter to hostname_is_valid

Tests are modified to check behaviour with relax and without relax.
New tests are added for hostname_cleanup().
Tests are moved a new file (test-hostname-util) because there's
now a bunch of them.

New parameter is not used anywhere, except in tests, so there should
be no observable change.

14 files changed, 199 insertions, 91 deletions

diff --git a/.gitignore b/.gitignore
index 7659e7a645..a66c7e1775 100644
--- a/.gitignore
+++ b/.gitignore
@@ -197,6 +197,7 @@
 /test-firewall-util
 /test-hashmap
 /test-hostname
+/test-hostname-util
 /test-icmp6-rs
 /test-id128
 /test-inhibit
diff --git a/Makefile.am b/Makefile.am
index d21982285f..4f97da10c2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1393,6 +1393,7 @@ tests += \
 	test-utf8 \
 	test-ellipsize \
 	test-util \
+	test-hostname-util \
 	test-process-util \
 	test-terminal-util \
 	test-path-lookup \
@@ -1671,6 +1672,12 @@ test_util_SOURCES = \
 test_util_LDADD = \
 	libshared.la
 
+test_hostname_util_SOURCES = \
+	src/test/test-hostname-util.c
+
+test_hostname_util_LDADD = \
+	libshared.la
+
 test_process_util_SOURCES = \
 	src/test/test-process-util.c
 
diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c
index e336f269fa..21fae89fd0 100644
--- a/src/basic/hostname-util.c
+++ b/src/basic/hostname-util.c
@@ -61,14 +61,22 @@ static bool hostname_valid_char(char c) {
                 c == '.';
 }
 
-bool hostname_is_valid(const char *s) {
+/**
+ * Check if s looks like a valid host name or fqdn. This does not do
+ * full DNS validation, but only checks if the name is composed of
+ * allowed characters and the length is not above the maximum allowed
+ * by Linux (c.f. dns_name_is_valid()). Trailing dot is allowed if
+ * relax is true and at least two components are present in the name.
+ */
+bool hostname_is_valid(const char *s, bool relax) {
         const char *p;
         bool dot;
+        unsigned dots = 0;
 
         if (isempty(s))
                 return false;
 
-        /* Doesn't accept empty hostnames, hostnames with trailing or
+        /* Doesn't accept empty hostnames, hostnames with
          * leading dots, and hostnames with multiple dots in a
          * sequence. Also ensures that the length stays below
          * HOST_NAME_MAX. */
@@ -79,6 +87,7 @@ bool hostname_is_valid(const char *s) {
                                 return false;
 
                         dot = true;
+                        dots ++;
                 } else {
                         if (!hostname_valid_char(*p))
                                 return false;
@@ -87,7 +96,7 @@ bool hostname_is_valid(const char *s) {
                 }
         }
 
-        if (dot)
+        if (dot && (dots < 2 || !relax))
                 return false;
 
         if (p-s > HOST_NAME_MAX)
diff --git a/src/basic/hostname-util.h b/src/basic/hostname-util.h
index 0c4763cf5a..ecae3a267c 100644
--- a/src/basic/hostname-util.h
+++ b/src/basic/hostname-util.h
@@ -29,7 +29,7 @@ bool hostname_is_set(void);
 
 char* gethostname_malloc(void);
 
-bool hostname_is_valid(const char *s) _pure_;
+bool hostname_is_valid(const char *s, bool relax) _pure_;
 char* hostname_cleanup(char *s, bool lowercase);
 
 bool is_localhost(const char *hostname);
diff --git a/src/basic/util.c b/src/basic/util.c
index 7896be8788..f81bf4e31e 100644
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -2997,7 +2997,7 @@ char* strshorten(char *s, size_t l) {
 
 bool machine_name_is_valid(const char *s) {
 
-        if (!hostname_is_valid(s))
+        if (!hostname_is_valid(s, false))
                 return false;
 
         /* Machine names should be useful hostnames, but also be
diff --git a/src/basic/util.h b/src/basic/util.h
index c2e5cc610b..5c0130d265 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -858,6 +858,11 @@ int unquote_first_word(const char **p, char **ret, UnquoteFlags flags);
 int unquote_first_word_and_warn(const char **p, char **ret, UnquoteFlags flags, const char *unit, const char *filename, unsigned line, const char *rvalue);
 int unquote_many_words(const char **p, UnquoteFlags flags, ...) _sentinel_;
 
+static inline void free_and_replace(char **s, char *v) {
+        free(*s);
+        *s = v;
+}
+
 int free_and_strdup(char **p, const char *s);
 
 #define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)
diff --git a/src/firstboot/firstboot.c b/src/firstboot/firstboot.c
index 3805b29437..43669d28bf 100644
--- a/src/firstboot/firstboot.c
+++ b/src/firstboot/firstboot.c
@@ -386,7 +386,7 @@ static int prompt_hostname(void) {
                         break;
                 }
 
-                if (!hostname_is_valid(h)) {
+                if (!hostname_is_valid(h, false)) {
                         log_error("Specified hostname invalid.");
                         continue;
                 }
@@ -780,14 +780,12 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
 
                 case ARG_HOSTNAME:
-                        if (!hostname_is_valid(optarg)) {
+                        if (!hostname_is_valid(optarg, false)) {
                                 log_error("Host name %s is not valid.", optarg);
                                 return -EINVAL;
                         }
 
-                        free(arg_hostname);
-                        arg_hostname = strdup(optarg);
-                        if (!arg_hostname)
+                        if (free_and_strdup(&arg_hostname, optarg) < 0)
                                 return log_oom();
 
                         break;
diff --git a/src/hostname/hostnamed.c b/src/hostname/hostnamed.c
index e52b872a8c..a78516c8b5 100644
--- a/src/hostname/hostnamed.c
+++ b/src/hostname/hostnamed.c
@@ -424,7 +424,7 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
         if (isempty(name))
                 name = "localhost";
 
-        if (!hostname_is_valid(name))
+        if (!hostname_is_valid(name, false))
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", name);
 
         if (streq_ptr(name, c->data[PROP_HOSTNAME]))
@@ -501,7 +501,7 @@ static int method_set_static_hostname(sd_bus_message *m, void *userdata, sd_bus_
         } else {
                 char *h;
 
-                if (!hostname_is_valid(name))
+                if (!hostname_is_valid(name, false))
                         return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid static hostname '%s'", name);
 
                 h = strdup(name);
diff --git a/src/import/pull-dkr.c b/src/import/pull-dkr.c
index 67ca1ce8e4..53d5174f33 100644
--- a/src/import/pull-dkr.c
+++ b/src/import/pull-dkr.c
@@ -721,7 +721,7 @@ static int dkr_pull_job_on_header(PullJob *j, const char *header, size_t sz)  {
                         return log_oom();
 
                 STRV_FOREACH(k, l) {
-                        if (!hostname_is_valid(*k)) {
+                        if (!hostname_is_valid(*k, false)) {
                                 log_error("Registry hostname is not valid.");
                                 strv_free(l);
                                 return -EBADMSG;
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index 54417b3af3..43f7566f65 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -553,11 +553,10 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const uint8_t *option,
                 if (e)
                         *e = 0;
 
-                if (!hostname_is_valid(hostname) || is_localhost(hostname))
+                if (!hostname_is_valid(hostname, false) || is_localhost(hostname))
                         break;
 
-                free(lease->hostname);
-                lease->hostname = hostname;
+                free_and_replace(&lease->hostname, hostname);
                 hostname = NULL;
 
                 break;
diff --git a/src/locale/localed.c b/src/locale/localed.c
index 88756542fd..3b511bfaf4 100644
--- a/src/locale/localed.c
+++ b/src/locale/localed.c
@@ -99,11 +99,6 @@ static const char* nonempty(const char *s) {
         return isempty(s) ? NULL : s;
 }
 
-static void free_and_replace(char **s, char *v) {
-        free(*s);
-        *s = v;
-}
-
 static bool startswith_comma(const char *s, const char *prefix) {
         const char *t;
 
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index d8f42621af..e3ac70ff33 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -838,7 +838,7 @@ int config_parse_hostname(const char *unit,
         if (r < 0)
                 return r;
 
-        if (!hostname_is_valid(hn)) {
+        if (!hostname_is_valid(hn, false)) {
                 log_syntax(unit, LOG_ERR, filename, line, EINVAL, "hostname is not valid, ignoring assignment: %s", rvalue);
 
                 free(hn);
diff --git a/src/test/test-hostname-util.c b/src/test/test-hostname-util.c
new file mode 100644
index 0000000000..2357ab5758
--- /dev/null
+++ b/src/test/test-hostname-util.c
@@ -0,0 +1,163 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+  Copyright 2013 Thomas H.P. Andersen
+  Copyright 2015 Zbigniew Jędrzejewski-Szmek
+
+  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 "util.h"
+#include "fileio.h"
+#include "hostname-util.h"
+
+static void test_hostname_is_valid(void) {
+        assert_se(hostname_is_valid("foobar", false));
+        assert_se(hostname_is_valid("foobar.com", false));
+        assert_se(!hostname_is_valid("foobar.com.", false));
+        assert_se(hostname_is_valid("fooBAR", false));
+        assert_se(hostname_is_valid("fooBAR.com", false));
+        assert_se(!hostname_is_valid("fooBAR.", false));
+        assert_se(!hostname_is_valid("fooBAR.com.", false));
+        assert_se(!hostname_is_valid("fööbar", false));
+        assert_se(!hostname_is_valid("", false));
+        assert_se(!hostname_is_valid(".", false));
+        assert_se(!hostname_is_valid("..", false));
+        assert_se(!hostname_is_valid("foobar.", false));
+        assert_se(!hostname_is_valid(".foobar", false));
+        assert_se(!hostname_is_valid("foo..bar", false));
+        assert_se(!hostname_is_valid("foo.bar..", false));
+        assert_se(!hostname_is_valid("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", false));
+
+        assert_se(hostname_is_valid("foobar", true));
+        assert_se(hostname_is_valid("foobar.com", true));
+        assert_se(hostname_is_valid("foobar.com.", true));
+        assert_se(hostname_is_valid("fooBAR", true));
+        assert_se(hostname_is_valid("fooBAR.com", true));
+        assert_se(!hostname_is_valid("fooBAR.", true));
+        assert_se(hostname_is_valid("fooBAR.com.", true));
+        assert_se(!hostname_is_valid("fööbar", true));
+        assert_se(!hostname_is_valid("", true));
+        assert_se(!hostname_is_valid(".", true));
+        assert_se(!hostname_is_valid("..", true));
+        assert_se(!hostname_is_valid("foobar.", true));
+        assert_se(!hostname_is_valid(".foobar", true));
+        assert_se(!hostname_is_valid("foo..bar", true));
+        assert_se(!hostname_is_valid("foo.bar..", true));
+        assert_se(!hostname_is_valid("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", true));
+}
+
+static void test_hostname_cleanup(void) {
+        char *s;
+
+        s = strdupa("foobar");
+        assert_se(streq(hostname_cleanup(s, false), "foobar"));
+        s = strdupa("foobar.com");
+        assert_se(streq(hostname_cleanup(s, false), "foobar.com"));
+        s = strdupa("foobar.com.");
+        assert_se(streq(hostname_cleanup(s, false), "foobar.com"));
+        s = strdupa("fooBAR");
+        assert_se(streq(hostname_cleanup(s, false), "fooBAR"));
+        s = strdupa("fooBAR.com");
+        assert_se(streq(hostname_cleanup(s, false), "fooBAR.com"));
+        s = strdupa("fooBAR.");
+        assert_se(streq(hostname_cleanup(s, false), "fooBAR"));
+        s = strdupa("fooBAR.com.");
+        assert_se(streq(hostname_cleanup(s, false), "fooBAR.com"));
+        s = strdupa("fööbar");
+        assert_se(streq(hostname_cleanup(s, false), "fbar"));
+        s = strdupa("");
+        assert_se(isempty(hostname_cleanup(s, false)));
+        s = strdupa(".");
+        assert_se(isempty(hostname_cleanup(s, false)));
+        s = strdupa("..");
+        assert_se(isempty(hostname_cleanup(s, false)));
+        s = strdupa("foobar.");
+        assert_se(streq(hostname_cleanup(s, false), "foobar"));
+        s = strdupa(".foobar");
+        assert_se(streq(hostname_cleanup(s, false), "foobar"));
+        s = strdupa("foo..bar");
+        assert_se(streq(hostname_cleanup(s, false), "foo.bar"));
+        s = strdupa("foo.bar..");
+        assert_se(streq(hostname_cleanup(s, false), "foo.bar"));
+        s = strdupa("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
+        assert_se(streq(hostname_cleanup(s, false), "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"));
+}
+
+static void test_read_hostname_config(void) {
+        char path[] = "/tmp/hostname.XXXXXX";
+        char *hostname;
+        int fd;
+
+        fd = mkostemp_safe(path, O_RDWR|O_CLOEXEC);
+        assert(fd > 0);
+        close(fd);
+
+        /* simple hostname */
+        write_string_file(path, "foo", WRITE_STRING_FILE_CREATE);
+        assert_se(read_hostname_config(path, &hostname) == 0);
+        assert_se(streq(hostname, "foo"));
+        free(hostname);
+        hostname = NULL;
+
+        /* with comment */
+        write_string_file(path, "# comment\nfoo", WRITE_STRING_FILE_CREATE);
+        assert_se(read_hostname_config(path, &hostname) == 0);
+        assert_se(hostname);
+        assert_se(streq(hostname, "foo"));
+        free(hostname);
+        hostname = NULL;
+
+        /* with comment and extra whitespace */
+        write_string_file(path, "# comment\n\n foo ", WRITE_STRING_FILE_CREATE);
+        assert_se(read_hostname_config(path, &hostname) == 0);
+        assert_se(hostname);
+        assert_se(streq(hostname, "foo"));
+        free(hostname);
+        hostname = NULL;
+
+        /* cleans up name */
+        write_string_file(path, "!foo/bar.com", WRITE_STRING_FILE_CREATE);
+        assert_se(read_hostname_config(path, &hostname) == 0);
+        assert_se(hostname);
+        assert_se(streq(hostname, "foobar.com"));
+        free(hostname);
+        hostname = NULL;
+
+        /* no value set */
+        hostname = (char*) 0x1234;
+        write_string_file(path, "# nothing here\n", WRITE_STRING_FILE_CREATE);
+        assert_se(read_hostname_config(path, &hostname) == -ENOENT);
+        assert_se(hostname == (char*) 0x1234);  /* does not touch argument on error */
+
+        /* nonexisting file */
+        assert_se(read_hostname_config("/non/existing", &hostname) == -ENOENT);
+        assert_se(hostname == (char*) 0x1234);  /* does not touch argument on error */
+
+        unlink(path);
+}
+
+int main(int argc, char *argv[]) {
+        log_parse_environment();
+        log_open();
+
+        test_hostname_is_valid();
+        test_hostname_cleanup();
+        test_read_hostname_config();
+
+        return 0;
+}
diff --git a/src/test/test-util.c b/src/test/test-util.c
index f43433baa1..9ad912d20f 100644
--- a/src/test/test-util.c
+++ b/src/test/test-util.c
@@ -38,7 +38,6 @@
 #include "conf-parser.h"
 #include "virt.h"
 #include "process-util.h"
-#include "hostname-util.h"
 #include "signal-util.h"
 
 static void test_streq_ptr(void) {
@@ -833,72 +832,6 @@ static void test_memdup_multiply(void) {
         free(dup);
 }
 
-static void test_hostname_is_valid(void) {
-        assert_se(hostname_is_valid("foobar"));
-        assert_se(hostname_is_valid("foobar.com"));
-        assert_se(!hostname_is_valid("fööbar"));
-        assert_se(!hostname_is_valid(""));
-        assert_se(!hostname_is_valid("."));
-        assert_se(!hostname_is_valid(".."));
-        assert_se(!hostname_is_valid("foobar."));
-        assert_se(!hostname_is_valid(".foobar"));
-        assert_se(!hostname_is_valid("foo..bar"));
-        assert_se(!hostname_is_valid("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"));
-}
-
-static void test_read_hostname_config(void) {
-        char path[] = "/tmp/hostname.XXXXXX";
-        char *hostname;
-        int fd;
-
-        fd = mkostemp_safe(path, O_RDWR|O_CLOEXEC);
-        assert(fd > 0);
-        close(fd);
-
-        /* simple hostname */
-        write_string_file(path, "foo", WRITE_STRING_FILE_CREATE);
-        assert_se(read_hostname_config(path, &hostname) == 0);
-        assert_se(streq(hostname, "foo"));
-        free(hostname);
-        hostname = NULL;
-
-        /* with comment */
-        write_string_file(path, "# comment\nfoo", WRITE_STRING_FILE_CREATE);
-        assert_se(read_hostname_config(path, &hostname) == 0);
-        assert_se(hostname);
-        assert_se(streq(hostname, "foo"));
-        free(hostname);
-        hostname = NULL;
-
-        /* with comment and extra whitespace */
-        write_string_file(path, "# comment\n\n foo ", WRITE_STRING_FILE_CREATE);
-        assert_se(read_hostname_config(path, &hostname) == 0);
-        assert_se(hostname);
-        assert_se(streq(hostname, "foo"));
-        free(hostname);
-        hostname = NULL;
-
-        /* cleans up name */
-        write_string_file(path, "!foo/bar.com", WRITE_STRING_FILE_CREATE);
-        assert_se(read_hostname_config(path, &hostname) == 0);
-        assert_se(hostname);
-        assert_se(streq(hostname, "foobar.com"));
-        free(hostname);
-        hostname = NULL;
-
-        /* no value set */
-        hostname = (char*) 0x1234;
-        write_string_file(path, "# nothing here\n", WRITE_STRING_FILE_CREATE);
-        assert_se(read_hostname_config(path, &hostname) == -ENOENT);
-        assert_se(hostname == (char*) 0x1234);  /* does not touch argument on error */
-
-        /* nonexisting file */
-        assert_se(read_hostname_config("/non/existing", &hostname) == -ENOENT);
-        assert_se(hostname == (char*) 0x1234);  /* does not touch argument on error */
-
-        unlink(path);
-}
-
 static void test_u64log2(void) {
         assert_se(u64log2(0) == 0);
         assert_se(u64log2(8) == 3);
@@ -2124,8 +2057,6 @@ int main(int argc, char *argv[]) {
         test_foreach_word();
         test_foreach_word_quoted();
         test_memdup_multiply();
-        test_hostname_is_valid();
-        test_read_hostname_config();
         test_u64log2();
         test_protect_errno();
         test_parse_size();