luci-base: implement session handling in luci.model.uci

Introduce luci.model.uci.set_session_id() and luci.model.uci.get_session_id()
to set and get the effective session ID respectively.

When a session ID is set, it is sent as `ubus_rpc_session` attribute to rpcd,
causing it to use per-session change directories, isolating LuCI changes from
the global system uci state.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

2 files changed, 193 insertions, 156 deletions

diff --git a/modules/luci-base/luasrc/model/uci.lua b/modules/luci-base/luasrc/model/uci.lua
index 0e3950c0b..fc2a605b3 100644
--- a/modules/luci-base/luasrc/model/uci.lua
+++ b/modules/luci-base/luasrc/model/uci.lua
@@ -32,6 +32,15 @@ local ERRSTR = {
 	"Connection failed"
 }
 
+local session_id = nil
+
+local function call(cmd, args)
+	if type(args) == "table" and session_id then
+		args.ubus_rpc_session = session_id
+	end
+	return util.ubus("uci", cmd, args)
+end
+
 
 function cursor()
 	return _M
@@ -54,6 +63,10 @@ function get_savedir(self)
 	return "/tmp/.uci"
 end
 
+function get_session_id(self)
+	return session_id
+end
+
 function set_confdir(self, directory)
 	return false
 end
@@ -62,6 +75,11 @@ function set_savedir(self, directory)
 	return false
 end
 
+function set_session_id(self, id)
+	session_id = id
+	return true
+end
+
 
 function load(self, config)
 	return true
@@ -77,7 +95,7 @@ end
 
 
 function changes(self, config)
-	local rv = util.ubus("uci", "changes", { config = config })
+	local rv = call("changes", { config = config })
 	local res = {}
 
 	if type(rv) == "table" and type(rv.changes) == "table" then
@@ -116,12 +134,12 @@ end
 
 
 function revert(self, config)
-	local _, err = util.ubus("uci", "revert", { config = config })
+	local _, err = call("revert", { config = config })
 	return (err == nil), ERRSTR[err]
 end
 
 function commit(self, config)
-	local _, err = util.ubus("uci", "commit", { config = config })
+	local _, err = call("commit", { config = config })
 	return (err == nil), ERRSTR[err]
 end
 
@@ -133,7 +151,7 @@ function apply(self, configs, command)
 
 	if type(configs) == "table" then
 		for _, config in ipairs(configs) do
-			util.ubus("service", "event", {
+			call("service", "event", {
 				type = "config.change",
 				data = { package = config }
 			})
@@ -145,7 +163,7 @@ end
 
 function foreach(self, config, stype, callback)
 	if type(callback) == "function" then
-		local rv, err = util.ubus("uci", "get", {
+		local rv, err = call("get", {
 			config = config,
 			type   = stype
 		})
@@ -186,7 +204,7 @@ local function _get(self, operation, config, section, option)
 	if section == nil then
 		return nil
 	elseif type(option) == "string" and option:byte(1) ~= 46 then
-		local rv, err = util.ubus("uci", operation, {
+		local rv, err = call(operation, {
 			config  = config,
 			section = section,
 			option  = option
@@ -220,7 +238,7 @@ function get_state(self, ...)
 end
 
 function get_all(self, config, section)
-	local rv, err = util.ubus("uci", "get", {
+	local rv, err = call("get", {
 		config  = config,
 		section = section
 	})
@@ -271,7 +289,7 @@ end
 
 
 function section(self, config, stype, name, values)
-	local rv, err = util.ubus("uci", "add", {
+	local rv, err = call("add", {
 		config = config,
 		type   = stype,
 		name   = name,
@@ -297,7 +315,7 @@ function set(self, config, section, option, value)
 		local sname, err = self:section(config, option, section)
 		return (not not sname), err
 	else
-		local _, err = util.ubus("uci", "set", {
+		local _, err = call("set", {
 			config  = config,
 			section = section,
 			values  = { [option] = value }
@@ -319,7 +337,7 @@ function set_list(self, config, section, option, value)
 end
 
 function tset(self, config, section, values)
-	local _, err = util.ubus("uci", "set", {
+	local _, err = call("set", {
 		config  = config,
 		section = section,
 		values  = values
@@ -353,7 +371,7 @@ function reorder(self, config, section, index)
 		return false, "Invalid argument"
 	end
 
-	local _, err = util.ubus("uci", "order", {
+	local _, err = call("order", {
 		config   = config,
 		sections = sections
 	})
@@ -363,7 +381,7 @@ end
 
 
 function delete(self, config, section, option)
-	local _, err = util.ubus("uci", "delete", {
+	local _, err = call("delete", {
 		config  = config,
 		section = section,
 		option  = option
@@ -374,13 +392,13 @@ end
 function delete_all(self, config, stype, comparator)
 	local _, err
 	if type(comparator) == "table" then
-		_, err = util.ubus("uci", "delete", {
+		_, err = call("delete", {
 			config = config,
 			type   = stype,
 			match  = comparator
 		})
 	elseif type(comparator) == "function" then
-		local rv = util.ubus("uci", "get", {
+		local rv = call("get", {
 			config = config,
 			type   = stype
 		})
@@ -389,7 +407,7 @@ function delete_all(self, config, stype, comparator)
 			local sname, section
 			for sname, section in pairs(rv.values) do
 				if comparator(section) then
-					_, err = util.ubus("uci", "delete", {
+					_, err = call("delete", {
 						config  = config,
 						section = sname
 					})
@@ -397,7 +415,7 @@ function delete_all(self, config, stype, comparator)
 			end
 		end
 	elseif comparator == nil then
-		_, err = util.ubus("uci", "delete", {
+		_, err = call("delete", {
 			config  = config,
 			type    = stype
 		})
diff --git a/modules/luci-base/luasrc/model/uci.luadoc b/modules/luci-base/luasrc/model/uci.luadoc
index 49093c793..ef89d09b9 100644
--- a/modules/luci-base/luasrc/model/uci.luadoc
+++ b/modules/luci-base/luasrc/model/uci.luadoc
@@ -14,224 +14,226 @@ module "luci.model.uci"
 ---[[
 Create a new UCI-Cursor.
 
-@class function
-@name cursor
-@return	UCI-Cursor
+@class				function
+@name				cursor
+@return				UCI-Cursor
 ]]
 
 ---[[
 Create a new Cursor initialized to the state directory.
 
-@class function
-@name cursor_state
-@return UCI cursor
+@class				function
+@name				cursor_state
+@return				UCI cursor
 ]]
 
 ---[[
 Applies UCI configuration changes
 
-@class function
-@name Cursor.apply
-@param configlist		List of UCI configurations
-@param command			Don't apply only return the command
+@class				function
+@name				Cursor.apply
+@param configlist	List of UCI configurations
+@param command		Don't apply only return the command
 ]]
 
 ---[[
 Delete all sections of a given type that match certain criteria.
 
-@class function
-@name Cursor.delete_all
+@class				function
+@name				Cursor.delete_all
 @param config		UCI config
 @param type			UCI section type
-@param comparator	Function that will be called for each section and
-returns a boolean whether to delete the current section (optional)
+@param comparator	Function that will be called for each section and returns
+					a boolean whether to delete the current section (optional)
 ]]
 
 ---[[
 Create a new section and initialize it with data.
 
-@class function
-@name Cursor.section
-@param config	UCI config
-@param type		UCI section type
-@param name		UCI section name (optional)
-@param values	Table of key - value pairs to initialize the section with
-@return			Name of created section
+@class				function
+@name				Cursor.section
+@param config		UCI config
+@param type			UCI section type
+@param name			UCI section name (optional)
+@param values		Table of key - value pairs to initialize the section with
+@return				Name of created section
 ]]
 
 ---[[
 Updated the data of a section using data from a table.
 
-@class function
-@name Cursor.tset
-@param config	UCI config
-@param section	UCI section name (optional)
-@param values	Table of key - value pairs to update the section with
+@class				function
+@name				Cursor.tset
+@param config		UCI config
+@param section		UCI section name (optional)
+@param values		Table of key - value pairs to update the section with
 ]]
 
 ---[[
 Get a boolean option and return it's value as true or false.
 
-@class function
-@name Cursor.get_bool
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option
-@return			Boolean
+@class				function
+@name				Cursor.get_bool
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option
+@return				Boolean
 ]]
 
 ---[[
 Get an option or list and return values as table.
 
-@class function
-@name Cursor.get_list
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option
-@return		table.  If the option was not found, you will simply get
---		an empty table.
+@class				function
+@name				Cursor.get_list
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option
+@return table.  	If the option was not found, you will simply get an empty
+					table.
 ]]
 
 ---[[
 Get the given option from the first section with the given type.
 
-@class function
-@name Cursor.get_first
-@param config	UCI config
-@param type		UCI section type
-@param option	UCI option (optional)
-@param default	Default value (optional)
-@return			UCI value
+@class				function
+@name				Cursor.get_first
+@param config		UCI config
+@param type			UCI section type
+@param option		UCI option (optional)
+@param default		Default value (optional)
+@return				UCI value
 ]]
 
 ---[[
 Set given values as list. Setting a list option to an empty list
 has the same effect as deleting the option.
 
-@class function
-@name Cursor.set_list
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option
-@param value	value or table. Raw values will become a single item table.
-@return			Boolean whether operation succeeded
+@class				function
+@name				Cursor.set_list
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option
+@param value		Value or table. Non-table values will be set as single
+					item UCI list.
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
-Create a sub-state of this cursor. The sub-state is tied to the parent
+Create a sub-state of this cursor.
 
-curser, means it the parent unloads or loads configs, the sub state will
-do so as well.
-@class function
-@name Cursor.substate
-@return			UCI state cursor tied to the parent cursor
+The sub-state is tied to the parent curser, means it the parent unloads or
+loads configs, the sub state will do so as well.
+
+@class				function
+@name				Cursor.substate
+@return				UCI state cursor tied to the parent cursor
 ]]
 
 ---[[
 Add an anonymous section.
 
-@class function
-@name Cursor.add
-@param config	UCI config
-@param type		UCI section type
-@return			Name of created section
+@class				function
+@name				Cursor.add
+@param config		UCI config
+@param type			UCI section type
+@return				Name of created section
 ]]
 
 ---[[
 Get a table of saved but uncommitted changes.
 
-@class function
-@name Cursor.changes
-@param config	UCI config
-@return			Table of changes
-@see Cursor.save
+@class				function
+@name				Cursor.changes
+@param config		UCI config
+@return				Table of changes
+@see				Cursor.save
 ]]
 
 ---[[
 Commit saved changes.
 
-@class function
-@name Cursor.commit
-@param config	UCI config
-@return			Boolean whether operation succeeded
-@see Cursor.revert
-@see Cursor.save
+@class				function
+@name				Cursor.commit
+@param config		UCI config
+@return				Boolean whether operation succeeded
+@see				Cursor.revert
+@see				Cursor.save
 ]]
 
 ---[[
 Deletes a section or an option.
 
-@class function
-@name Cursor.delete
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option (optional)
-@return			Boolean whether operation succeeded
+@class				function
+@name				Cursor.delete
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option (optional)
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
 Call a function for every section of a certain type.
 
-@class function
-@name Cursor.foreach
-@param config	UCI config
-@param type		UCI section type
-@param callback	Function to be called
-@return			Boolean whether operation succeeded
+@class				function
+@name				Cursor.foreach
+@param config		UCI config
+@param type			UCI section type
+@param callback		Function to be called
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
 Get a section type or an option
 
-@class function
-@name Cursor.get
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option (optional)
-@return			UCI value
+@class				function
+@name				Cursor.get
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option (optional)
+@return				UCI value
 ]]
 
 ---[[
 Get all sections of a config or all values of a section.
 
-@class function
-@name Cursor.get_all
-@param config	UCI config
-@param section	UCI section name (optional)
-@return			Table of UCI sections or table of UCI values
+@class				function
+@name				Cursor.get_all
+@param config		UCI config
+@param section		UCI section name (optional)
+@return				Table of UCI sections or table of UCI values
 ]]
 
 ---[[
 Manually load a config.
 
-@class function
-@name Cursor.load
-@param config	UCI config
-@return			Boolean whether operation succeeded
-@see Cursor.save
-@see Cursor.unload
+@class				function
+@name				Cursor.load
+@param config		UCI config
+@return				Boolean whether operation succeeded
+@see				Cursor.save
+@see				Cursor.unload
 ]]
 
 ---[[
 Revert saved but uncommitted changes.
 
-@class function
-@name Cursor.revert
-@param config	UCI config
-@return			Boolean whether operation succeeded
-@see Cursor.commit
-@see Cursor.save
+@class				function
+@name				Cursor.revert
+@param config		UCI config
+@return				Boolean whether operation succeeded
+@see				Cursor.commit
+@see				Cursor.save
 ]]
 
 ---[[
 Saves changes made to a config to make them committable.
 
-@class function
-@name Cursor.save
-@param config	UCI config
-@return			Boolean whether operation succeeded
-@see Cursor.load
-@see Cursor.unload
+@class				function
+@name				Cursor.save
+@param config		UCI config
+@return				Boolean whether operation succeeded
+@see				Cursor.load
+@see				Cursor.unload
 ]]
 
 ---[[
@@ -243,57 +245,74 @@ then a named section of the given type is created.
 When invoked with four arguments `config`, `sectionname`, `optionname` and
 `optionvalue` then the value of the specified option is set to the given value.
 
-@class function
-@name Cursor.set
-@param config	UCI config
-@param section	UCI section name
-@param option	UCI option or UCI section type
+@class				function
+@name				Cursor.set
+@param config		UCI config
+@param section		UCI section name
+@param option		UCI option or UCI section type
 @param value		UCI value or nothing if you want to create a section
-@return			Boolean whether operation succeeded
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
 Get the configuration directory.
 
-@class function
-@name Cursor.get_confdir
-@return			Configuration directory
+@class				function
+@name				Cursor.get_confdir
+@return				Configuration directory
 ]]
 
 ---[[
 Get the directory for uncomitted changes.
 
-@class function
-@name Cursor.get_savedir
-@return			Save directory
+@class				function
+@name				Cursor.get_savedir
+@return				Save directory
+]]
+
+---[[
+Get the effective session ID.
+
+@class				function
+@name				Cursor.get_session_id
+@return				String containing the session ID
 ]]
 
 ---[[
 Set the configuration directory.
 
-@class function
-@name Cursor.set_confdir
+@class				function
+@name				Cursor.set_confdir
 @param directory	UCI configuration directory
-@return			Boolean whether operation succeeded
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
 Set the directory for uncommited changes.
 
-@class function
-@name Cursor.set_savedir
+@class				function
+@name				Cursor.set_savedir
 @param directory	UCI changes directory
-@return			Boolean whether operation succeeded
+@return				Boolean whether operation succeeded
+]]
+
+---[[
+Set the effective session ID.
+
+@class				function
+@name				Cursor.set_session_id
+@param id			String containing the session ID to set
+@return				Boolean whether operation succeeded
 ]]
 
 ---[[
 Discard changes made to a config.
 
-@class function
-@name Cursor.unload
-@param config	UCI config
-@return			Boolean whether operation succeeded
-@see Cursor.load
-@see Cursor.save
+@class				function
+@name				Cursor.unload
+@param config		UCI config
+@return				Boolean whether operation succeeded
+@see				Cursor.load
+@see				Cursor.save
 ]]