nuageinit: implement resolv_conf support

Add support for the 'resolv_conf' cloud-config key which writes
directly to /etc/resolv.conf.

libexec/nuageinit/nuage.lua

@@ -837,6 +837,37 @@ local function add_fstab_entry(root, device, mount_point, fstype, options, dump_
 	return true
 end
 
+local function write_resolv_conf(root, config)
+	local path = root .. "/etc/resolv.conf"
+	local f = io.open(path, "w")
+	if not f then
+		warnmsg("unable to open " .. path .. " for writing")
+		return
+	end
+	if config.domain then
+		f:write("domain " .. config.domain .. "\n")
+	end
+	if config.searchdomains then
+		f:write("search " .. table.concat(config.searchdomains, " ") .. "\n")
+	end
+	if config.sortlist then
+		f:write("sortlist " .. table.concat(config.sortlist, " ") .. "\n")
+	end
+	if config.options then
+		local opts = {}
+		for k, v in pairs(config.options) do
+			table.insert(opts, k .. ":" .. v)
+		end
+		f:write("options " .. table.concat(opts, " ") .. "\n")
+	end
+	if config.nameservers then
+		for _, ns in ipairs(config.nameservers) do
+			f:write("nameserver " .. ns .. "\n")
+		end
+	end
+	f:close()
+end
+
 local function remove_fstab_entry(root, mount_point)
 	local fstab_path = root .. "/etc/fstab"
 	local f = io.open(fstab_path, "r")
@@ -891,6 +922,7 @@ local n = {
 	addfile = addfile,
 	add_fstab_entry = add_fstab_entry,
 	remove_fstab_entry = remove_fstab_entry,
+	write_resolv_conf = write_resolv_conf,
 }
 
 return n

libexec/nuageinit/nuageinit

@@ -531,6 +531,11 @@ local function disable_root(obj)
 	end
 end
 
+local function resolv_conf(obj)
+	if obj.resolv_conf == nil then return end
+	nuage.write_resolv_conf(root, obj.resolv_conf)
+end
+
 local function mounts(obj)
 	if obj.mounts == nil then return end
 	for _, m in ipairs(obj.mounts) do
@@ -870,6 +875,7 @@ elseif line == "#cloud-config" then
 		ssh_deletekeys,
 		ssh_keys,
 		network_config,
+		resolv_conf,
 		disable_root,
 		ssh_pwauth,
 		runcmd,

libexec/nuageinit/nuageinit.7

@@ -195,6 +195,23 @@ The pass number for
 .Xr fsck 8 ,
 defaults to 0.
 .El
+.It Ic resolv_conf
+An object configuring the content of
+.Pa /etc/resolv.conf .
+.Pp
+The following keys are recognized:
+.Bl -tag -width "nameservers"
+.It nameservers
+A list of IP addresses for DNS name servers.
+.It searchdomains
+A list of search domains.
+.It domain
+A single domain name.
+.It sortlist
+A list of IP/netmask sortlist entries.
+.It options
+A dictionary of resolver options.
+.El
 .It Ic timezone
 Sets the system timezone based on the value provided.
 .Pp

libexec/nuageinit/tests/nuageinit.sh

@@ -35,6 +35,7 @@ atf_test_case config2_userdata_disable_root
 atf_test_case config2_userdata_bootcmd
 atf_test_case config2_userdata_manage_etc_hosts
 atf_test_case config2_userdata_mounts
+atf_test_case config2_userdata_resolv_conf
 atf_test_case config2_userdata_fqdn_and_hostname
 atf_test_case config2_userdata_write_files
 
@@ -1140,6 +1141,36 @@ EOF
 	true
 }
 
+config2_userdata_resolv_conf_head()
+{
+	atf_set "require.user" root
+}
+config2_userdata_resolv_conf_body()
+{
+	mkdir -p media/nuageinit
+	setup_test_adduser
+	printf "{}" > media/nuageinit/meta_data.json
+	cat > media/nuageinit/user_data <<EOF
+#cloud-config
+resolv_conf:
+  nameservers:
+    - 9.9.9.9
+    - 149.112.112.112
+  searchdomains:
+    - example.com
+    - test.local
+  domain: mydomain.local
+  options:
+    timeout: "1"
+    attempts: "2"
+  sortlist:
+    - 192.168.1.0/255.255.255.0
+EOF
+	atf_check -o empty /usr/libexec/nuageinit "${PWD}"/media/nuageinit config-2
+	atf_check -o inline:"domain mydomain.local\nsearch example.com test.local\nsortlist 192.168.1.0/255.255.255.0\noptions timeout:1 attempts:2\nnameserver 9.9.9.9\nnameserver 149.112.112.112\n" cat etc/resolv.conf
+	true
+}
+
 config2_userdata_fqdn_and_hostname_body()
 {
 	mkdir -p media/nuageinit
@@ -1190,6 +1221,7 @@ atf_init_test_cases()
 	atf_add_test_case config2_userdata_bootcmd
 	atf_add_test_case config2_userdata_manage_etc_hosts
 	atf_add_test_case config2_userdata_mounts
+	atf_add_test_case config2_userdata_resolv_conf
 	atf_add_test_case config2_userdata_fqdn_and_hostname
 	atf_add_test_case config2_userdata_write_files
 }