Re: [B.A.T.M.A.N.] [PATCH 2/2] alfred: Bundle a lua script for autogenerating bat-hosts file

Simon Wunderlich
2013-10-14T17:52:34Z

> Provide a lua script that uses alfred to propagate and collect all
> interface mac + names, then generate a /tmp/bat-hosts file.
> If there's already a (probably hand-made) /etc/bat-hosts it won't overwrite
> it but if there's none, it will symlink /etc/bat-hosts -> /tmp/bat-hosts
>
> Signed-off-by: Gui Iribarren <gui@altermundi.net>
> Thanks-to: Joshua Head <joshua.head@outlook.com>

Thanks a lot, this sounds like a really good idea! As this will be part of the
openwrt package, I'd like to ask to make the bat-hosts.lua script optional and
selectable (like you can turn on/off vis). I'll do the same for other
(optional) services like gps.

Also, do you need any additional dependencies for lua?

Thanks,
Simon
> ---
> alfred/Makefile | 2 +
> alfred/files/bat-hosts.lua | 107
> ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 109
> insertions(+)
> create mode 100644 alfred/files/bat-hosts.lua
>
> diff --git a/alfred/Makefile b/alfred/Makefile
> index db9c71f..7027192 100644
> --- a/alfred/Makefile
> +++ b/alfred/Makefile
> @@ -74,6 +74,8 @@ define Package/alfred/install
> $(INSTALL_BIN) ./files/alfred.init $(1)/etc/init.d/alfred
> $(INSTALL_DIR) $(1)/etc/config
> $(INSTALL_DATA) ./files/alfred.config $(1)/etc/config/alfred
> + $(INSTALL_DIR) $(1)/etc/alfred
> + $(INSTALL_BIN) ./files/bat-hosts.lua $(1)/etc/alfred/bat-hosts.lua
> endef
>
> $(eval $(call BuildPackage,alfred))
> diff --git a/alfred/files/bat-hosts.lua b/alfred/files/bat-hosts.lua
> new file mode 100644
> index 0000000..19f2cad
> --- /dev/null
> +++ b/alfred/files/bat-hosts.lua
> @@ -0,0 +1,107 @@
> +#!/usr/bin/lua
> +
> +local type_id = 64 -- bat-hosts
> +
> +function get_hostname()
> + local hostfile = io.open("/proc/sys/kernel/hostname", "r")
> + local ret_string = hostfile:read("*a")
> + ret_string = string.gsub(ret_string, "\n", "")
> + hostfile:close()
> + return ret_string
> +end
> +
> +function get_interfaces_names()
> + local ret = {}
> +
> + for name in io.popen("ls -1 /sys/class/net/"):lines() do
> + table.insert(ret, name)
> + end
> +
> + return ret
> +end
> +
> +function get_interface_address(name)
> + local addressfile = io.open("/sys/class/net/"..name.."/address", "r")
> + local ret_string = addressfile:read("*a")
> + ret_string = string.gsub(ret_string, "\n", "")
> + addressfile:close()
> + return ret_string
> +end
> +
> +
> +local function generate_bat_hosts()
> +-- get hostname and interface macs/names
> +-- then return a table containing valid bat-hosts lines
> + local n, i
> + local ifaces, ret = {}, {}
> +
> + local hostname = get_hostname()
> +
> + for n, i in ipairs(get_interfaces_names()) do
> + local address = get_interface_address(i)
> + ifaces[address] = i
> + end
> +
> + for mac, iname in pairs(ifaces) do
> + if mac:match("^%x%x:%x%x:%x%x:%x%x:%x%x:%x%x$") and not
> mac:match("00:00:00:00:00:00") then + table.insert(ret, mac.."
> "..hostname.."_"..iname.."\n")
> + end
> + end
> +
> + return ret
> +end
> +
> +local function publish_bat_hosts()
> +-- pass a raw chunk of data to alfred
> + local fd = io.popen("alfred -s " .. type_id, "w")
> + if fd then
> + local ret = generate_bat_hosts()
> + if ret then
> + fd:write(table.concat(ret))
> + end
> + fd:close()
> + end
> +end
> +
> +local function receive_bat_hosts()
> +-- read raw chunks from alfred, convert them to a nested table and call
> write_bat_hosts + local fd = io.popen("alfred -r " .. type_id)
> + --[[ this command returns something like
> + { "54:e6:fc:b9:cb:37", "00:11:22:33:44:55
> ham_wlan0\x0a00:22:33:22:33:22 ham_eth0\x0a" }, + {
> "90:f6:52:bb:ec:57", "00:22:33:22:33:23 spam\x0a" },
> + ]]--
> +
> + if fd then
> + local output = fd:read("*a")
> + if output then
> + assert(loadstring("rows = {" .. output .. "}"))()
> + write_bat_hosts(rows)
> + end
> + fd:close()
> + end
> +end
> +
> +local function write_bat_hosts(rows)
> + local content = { "### File generated by alfred-bat-hosts\n" }
> +
> + -- merge the chunks from all nodes, de-escaping newlines
> + for _, row in ipairs(rows) do
> + local node, value = unpack(row)
> + table.insert(content, "# Node ".. node .. "\n")
> + table.insert(content, value:gsub("\x0a", "\n") .. "\n")
> + end
> +
> + -- write parsed content down to disk
> + local fd = io.open("/tmp/bat-hosts", "w")
> + if fd then
> + fd:write(table.concat(content))
> + fd:close()
> + end
> +
> + -- try to make a symlink in /etc pointing to /tmp,
> + -- if it exists, ln will do nothing.
> + os.execute("ln -ns /tmp/bat-hosts /etc/bat-hosts 2>/dev/null")
> +end
> +
> +publish_bat_hosts()
> +receive_bat_hosts()