corecfg: add "system.timezone" setting to the system settings

overlord/configstate/configcore/handlers.go

@@ -85,6 +85,9 @@ func init() {
 	// journal.persistent
 	addFSOnlyHandler(validateJournalSettings, handleJournalConfiguration, coreOnly)
 
+	// system.timezone
+	addFSOnlyHandler(validateTimezoneSettings, handleTimezoneConfiguration, coreOnly)
+
 	sysconfig.ApplyFilesystemOnlyDefaultsImpl = func(rootDir string, defaults map[string]interface{}, options *sysconfig.FilesystemOnlyApplyOptions) error {
 		return filesystemOnlyApply(rootDir, plainCoreConfig(defaults), options)
 	}

overlord/configstate/configcore/timezone.go

@@ -0,0 +1,86 @@
+// -*- Mode: Go; indent-tabs-mode: t -*-
+
+/*
+ * Copyright (C) 2020 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package configcore
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+
+	"github.com/snapcore/snapd/osutil"
+	"github.com/snapcore/snapd/overlord/configstate/config"
+)
+
+func init() {
+	// add supported configuration of this module
+	supportedConfigurations["core.system.timezone"] = true
+}
+
+var validTimezone = regexp.MustCompile(`^[a-zA-Z0-9+_-]+(/[a-zA-Z0-9+_-]+)?(/[a-zA-Z0-9+_-]+)?$`).MatchString
+
+func validateTimezoneSettings(tr config.ConfGetter) error {
+	timezone, err := coreCfg(tr, "system.timezone")
+	if err != nil {
+		return err
+	}
+	if timezone == "" {
+		return nil
+	}
+	if !validTimezone(timezone) {
+		return fmt.Errorf("cannot set timezone %q: name not valid", timezone)
+	}
+
+	return nil
+}
+
+func handleTimezoneConfiguration(tr config.ConfGetter, opts *fsOnlyContext) error {
+	output, err := coreCfg(tr, "system.timezone")
+	if err != nil {
+		return nil
+	}
+	// nothing to do
+	if output == "" {
+		return nil
+	}
+	// runtime system
+	if opts == nil {
+		output, err := exec.Command("timedatectl", "set-timezone", output).CombinedOutput()
+		if err != nil {
+			return fmt.Errorf("cannot set timezone: %v", osutil.OutputErr(output, err))
+		}
+	} else {
+		// important to use /etc/writable/
+		localtimePath := filepath.Join(opts.RootDir, "/etc/writable/localtime")
+		if err := os.MkdirAll(filepath.Dir(localtimePath), 0755); err != nil {
+			return err
+		}
+		if err := os.Symlink(filepath.Join("/usr/share/zoneinfo", output), localtimePath); err != nil {
+			return err
+		}
+		timezonePath := filepath.Join(opts.RootDir, "/etc/writable/timezone")
+		if err := osutil.AtomicWriteFile(timezonePath, []byte(output+"\n"), 0644, 0); err != nil {
+			return fmt.Errorf("cannot write timezone: %v", err)
+		}
+	}
+
+	return nil
+}

overlord/configstate/configcore/timezone_test.go

@@ -0,0 +1,102 @@
+// -*- Mode: Go; indent-tabs-mode: t -*-
+
+/*
+ * Copyright (C) 2020 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package configcore_test
+
+import (
+	"os"
+	"path/filepath"
+
+	. "gopkg.in/check.v1"
+
+	"github.com/snapcore/snapd/dirs"
+	"github.com/snapcore/snapd/overlord/configstate/configcore"
+	"github.com/snapcore/snapd/release"
+	"github.com/snapcore/snapd/testutil"
+)
+
+type timezoneSuite struct {
+	configcoreSuite
+}
+
+var _ = Suite(&timezoneSuite{})
+
+func (s *timezoneSuite) SetUpTest(c *C) {
+	s.configcoreSuite.SetUpTest(c)
+
+	err := os.MkdirAll(filepath.Join(dirs.GlobalRootDir, "/etc/"), 0755)
+	c.Assert(err, IsNil)
+}
+
+func (s *timezoneSuite) TestConfigureTimezoneInvalid(c *C) {
+	invalidTimezones := []string{
+		"no-#", "no-ä", "no/tripple/slash/",
+	}
+
+	for _, tz := range invalidTimezones {
+		err := configcore.Run(&mockConf{
+			state: s.state,
+			conf: map[string]interface{}{
+				"system.timezone": tz,
+			},
+		})
+		c.Assert(err, ErrorMatches, `cannot set timezone.*`)
+	}
+}
+
+func (s *timezoneSuite) TestConfigureTimezoneIntegration(c *C) {
+	restore := release.MockOnClassic(false)
+	defer restore()
+
+	mockedTimedatectl := testutil.MockCommand(c, "timedatectl", "")
+	defer mockedTimedatectl.Restore()
+
+	validTimezones := []string{
+		"UTC", "Europe/Malta", "US/Indiana-Starke", "Africa/Sao_Tome",
+		"America/Argentina/Cordoba", "America/Argentina/La_Rioja",
+		"Etc/GMT+1", "CST6CDT", "GMT0", "GMT-0", "PST8PDT",
+	}
+
+	for _, tz := range validTimezones {
+		err := configcore.Run(&mockConf{
+			state: s.state,
+			conf: map[string]interface{}{
+				"system.timezone": tz,
+			},
+		})
+		c.Assert(err, IsNil)
+		c.Check(mockedTimedatectl.Calls(), DeepEquals, [][]string{
+			{"timedatectl", "set-timezone", tz},
+		})
+		mockedTimedatectl.ForgetCalls()
+	}
+}
+
+func (s *timezoneSuite) TestFilesystemOnlyApply(c *C) {
+	conf := configcore.PlainCoreConfig(map[string]interface{}{
+		"system.timezone": "Europe/Berlin",
+	})
+	tmpDir := c.MkDir()
+	c.Assert(configcore.FilesystemOnlyApply(tmpDir, conf, nil), IsNil)
+
+	c.Check(filepath.Join(tmpDir, "/etc/writable/timezone"), testutil.FileEquals, "Europe/Berlin\n")
+	p, err := os.Readlink(filepath.Join(tmpDir, "/etc/writable/localtime"))
+	c.Assert(err, IsNil)
+	c.Check(p, Equals, "/usr/share/zoneinfo/Europe/Berlin")
+}

tests/core/snap-set-core-config/task.yaml

@@ -29,7 +29,10 @@ restore: |
         systemctl enable rsyslog.service
         systemctl start rsyslog.service
     fi
-
+    if [ -e current-timezone ]; then
+        timedatectl set-timezone "$(cat current-timezone)"
+    fi
+ 
     rm -f /etc/systemd/login.conf.d/00-snap-core.conf
 
 execute: |
@@ -134,3 +137,9 @@ execute: |
     snap unset system system.kernel.printk.console-loglevel
     not test -e /etc/sysctl.d/99-snapd.conf
     sysctl -n kernel.printk|MATCH "^4\s+"
+
+    echo "setting the timezone works"
+    cat /etc/timezone > current-timezone
+    snap set system system.timezone=Europe/Malta
+    MATCH "Europe/Malta" /etc/timezone
+    test "$(readlink -f /etc/localtime)" = "/usr/share/zoneinfo/Europe/Malta"

tests/nested/manual/core-early-config/defaults.yaml

@@ -3,3 +3,5 @@ defaults:
     service:
       rsyslog:
         disable: true
+    system:
+      timezone: Europe/Malta

tests/nested/manual/core-early-config/task.yaml

@@ -61,3 +61,7 @@ execute: |
     # early config is witnessed by install hook of the pc gadget
     execute_remote "cat /var/snap/pc/common/debug.txt" | MATCH "/dev/null"
     execute_remote "test -L /etc/systemd/system/rsyslog.service"
+
+    # timezone is set
+    execute_remote "cat /etc/timezone" | MATCH "Europe/Malta"
+    execute_remote "readlink -f /etc/localtime" | MATCH "Europe/Malta"