luci-app-lxc: fix "plain-vanilla" integration, part 2

I've tried to get the lxc app in a more usable state. Tested with mips
and amd64 targets.

* check /etc/config/lxc in controller, not in cbi
* more controller cleanups
* remove unused 'fork_exec' function
* check path before container creation
* check space requirements before container creation
  * support new uci options 'min_space' and 'min_temp',
    default for both is 100000 KB
  * both options are configurable via LuCI CBI template
* write messages to log in case of an error
* validate the container name during creation,
  automatically remove invalid chars
* inform the user that only a stopped container can be destroyed
* add experimental ssl support (untested, disabled by default)

Signed-off-by: Dirk Brenken <dev@brenken.org>

1 files changed, 55 insertions, 57 deletions

diff --git a/applications/luci-app-lxc/luasrc/controller/lxc.lua b/applications/luci-app-lxc/luasrc/controller/lxc.lua
index e15915df5d..f14606ee81 100644
--- a/applications/luci-app-lxc/luasrc/controller/lxc.lua
+++ b/applications/luci-app-lxc/luasrc/controller/lxc.lua
@@ -14,73 +14,43 @@ Author: Petar Koretic <petar.koretic@sartura.hr>
 
 ]]--
 
+module("luci.controller.lxc", package.seeall)
+
 local uci  = require "luci.model.uci".cursor()
 local util = require "luci.util"
 local fs   = require "nixio"
 
-module("luci.controller.lxc", package.seeall)
-
-function fork_exec(command)
-	local pid = fs.fork()
-	if pid > 0 then
+function index()
+	if not nixio.fs.access("/etc/config/lxc") then
 		return
-	elseif pid == 0 then
-		-- change to root dir
-		fs.chdir("/")
-
-		-- patch stdin, out, err to /dev/null
-		local null = fs.open("/dev/null", "w+")
-		if null then
-			fs.dup(null, fs.stderr)
-			fs.dup(null, fs.stdout)
-			fs.dup(null, fs.stdin)
-			if null:fileno() > 2 then
-				null:close()
-			end
-		end
-
-		-- replace with target command
-		fs.exec("/bin/sh", "-c", command)
 	end
-end
 
-function index()
 	page = node("admin", "services", "lxc")
 	page.target = cbi("lxc")
 	page.title = _("LXC Containers")
 	page.order = 70
 
-	page = entry({"admin", "services", "lxc_create"}, call("lxc_create"), nil)
-	page.leaf = true
-
-	page = entry({"admin", "services", "lxc_action"}, call("lxc_action"), nil)
-	page.leaf = true
-
-	page = entry({"admin", "services", "lxc_get_downloadable"}, call("lxc_get_downloadable"), nil)
-	page.leaf = true
-
-	page = entry({"admin", "services", "lxc_configuration_get"}, call("lxc_configuration_get"), nil)
-	page.leaf = true
-
-	page = entry({"admin", "services", "lxc_configuration_set"}, call("lxc_configuration_set"), nil)
-	page.leaf = true
-
+	entry({"admin", "services", "lxc_create"}, call("lxc_create"), nil).leaf = true
+	entry({"admin", "services", "lxc_action"}, call("lxc_action"), nil).leaf = true
+	entry({"admin", "services", "lxc_get_downloadable"}, call("lxc_get_downloadable"), nil).leaf = true
+	entry({"admin", "services", "lxc_configuration_get"}, call("lxc_configuration_get"), nil).leaf = true
+	entry({"admin", "services", "lxc_configuration_set"}, call("lxc_configuration_set"), nil).leaf = true
 end
 
 function lxc_get_downloadable()
 	local target = lxc_get_arch_target()
 	local templates = {}
+	local ssl_status = lxc_get_ssl_status()
 
-	local f = io.popen('sh /usr/share/lxc/templates/lxc-download --list --no-validate --server %s 2>/dev/null'
-		% util.shellquote(uci:get("lxc", "lxc", "url")), 'r')
+	local f = io.popen('sh /usr/share/lxc/templates/lxc-download --list %s --server %s 2>/dev/null'
+		%{ ssl_status, util.shellquote(uci:get("lxc", "lxc", "url")) }, 'r')
 	local line
 	for line in f:lines() do
 		local dist, version, dist_target = line:match("^(%S+)%s+(%S+)%s+(%S+)%s+default%s+%S+$")
-		if dist and version and dist_target == target then
+		if dist and version and dist_target and dist_target == target then
 			templates[#templates+1] = "%s:%s" %{ dist, version }
 		end
 	end
-
 	f:close()
 
 	luci.http.prepare_content("application/json")
@@ -90,23 +60,26 @@ end
 function lxc_create(lxc_name, lxc_template)
 	luci.http.prepare_content("text/plain")
 
-	if not pcall(dofile, "/etc/openwrt_release") then
-		return luci.http.write("1")
+	local check = lxc_get_config_path()
+	if not check then
+		return
 	end
 
-	local lxc_dist, lxc_release = lxc_template:match("^(.+):(.+)$")
+	local ssl_status = lxc_get_ssl_status()
 
+	local src_err
+	local lxc_dist, lxc_release = lxc_template:match("^(.+):(.+)$")
 	luci.http.write(util.ubus("lxc", "create", {
 		name = lxc_name,
 		template = "download",
 		args = {
 			"--server", uci:get("lxc", "lxc", "url"),
-			"--no-validate",
 			"--dist", lxc_dist,
 			"--release", lxc_release,
-			"--arch", lxc_get_arch_target()
+			"--arch", lxc_get_arch_target(),
+			ssl_status
 		}
-	}))
+	}), src_err)
 end
 
 function lxc_action(lxc_action, lxc_name)
@@ -123,9 +96,25 @@ function lxc_get_config_path()
 
 	local ret = content:match('^%s*lxc.lxcpath%s*=%s*([^%s]*)')
 	if ret then
-		return ret .. "/"
+		if nixio.fs.access(ret) then
+			local min_space = tonumber(uci:get("lxc", "lxc", "min_space")) or 100000
+			local free_space = tonumber(util.exec("df " ..ret.. " | awk '{if(NR==2)print $4}'"))
+			if free_space and free_space >= min_space then
+				local min_temp = tonumber(uci:get("lxc", "lxc", "min_temp")) or 100000
+				local free_temp = tonumber(util.exec("df /tmp | awk '{if(NR==2)print $4}'"))
+				if free_temp and free_temp >= min_temp then
+					return ret .. "/"
+				else
+					util.perror("lxc error: not enough temporary space (< " ..min_temp.. " KB)")
+				end
+			else
+				util.perror("lxc error: not enough space (< " ..min_space.. " KB)")
+			end
+		else
+			util.perror("lxc error: directory not found")
+		end
 	else
-		return "/srv/lxc/"
+		util.perror("lxc error: config path is empty")
 	end
 end
 
@@ -143,14 +132,15 @@ function lxc_configuration_set(lxc_name)
 	luci.http.prepare_content("text/plain")
 
 	local lxc_configuration = luci.http.formvalue("lxc_configuration")
-
 	if lxc_configuration == nil then
-		return luci.http.write("1")
+		util.perror("lxc error: config formvalue is empty")
+		return
 	end
 
 	local f, err = io.open(lxc_get_config_path() .. lxc_name .. "/config","w+")
 	if not f then
-		return luci.http.write("2")
+		util.perror("lxc error: config file not found")
+		return
 	end
 
 	f:write(lxc_configuration)
@@ -168,13 +158,21 @@ function lxc_get_arch_target()
 		armv8  = "arm64",
 		x86_64 = "amd64"
 	}
-
 	local k, v
 	for k, v in pairs(target_map) do
-		if target:find(k) then
+		if target:find("^" ..k.. "$") then
 			return v
 		end
 	end
-
 	return target
 end
+
+function lxc_get_ssl_status()
+	local ssl_enabled = uci:get("lxc", "lxc", "ssl_enabled")
+	local ssl_status = "--no-validate"
+
+	if ssl_enabled and ssl_enabled == "1" then
+		ssl_status = ""
+	end
+	return ssl_status
+end