113 lines
3.1 KiB
Lua
113 lines
3.1 KiB
Lua
#!/usr/bin/lua
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local type_id = 64 -- bat-hosts
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function get_hostname()
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local hostfile = io.open("/proc/sys/kernel/hostname", "r")
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local ret_string = hostfile:read()
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hostfile:close()
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return ret_string
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end
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function get_interfaces_names()
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local ret = {}
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for name in io.popen("ls -1 /sys/class/net/"):lines() do
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table.insert(ret, name)
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end
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return ret
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end
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function get_interface_address(name)
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local addressfile = io.open("/sys/class/net/"..name.."/address", "r")
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local ret_string = addressfile:read()
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addressfile:close()
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return ret_string
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end
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local function generate_bat_hosts()
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-- get hostname and interface macs/names
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-- then return a table containing valid bat-hosts lines
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local n, i
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local ifaces, ret = {}, {}
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local hostname = get_hostname()
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for n, i in ipairs(get_interfaces_names()) do
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local address = get_interface_address(i)
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if not ifaces[address] then ifaces[address] = i end
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end
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for mac, iname in pairs(ifaces) do
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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
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table.insert(ret, mac.." "..hostname.."_"..iname.."\n")
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end
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end
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return ret
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end
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local function publish_bat_hosts()
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-- pass a raw chunk of data to alfred
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local fd = io.popen("alfred -s " .. type_id, "w")
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if fd then
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local ret = generate_bat_hosts()
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if ret then
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fd:write(table.concat(ret))
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end
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fd:close()
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end
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end
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local function write_bat_hosts(rows)
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local content = { "### /tmp/bat-hosts generated by alfred-bat-hosts\n",
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"### /!\\ This file is overwritten every 5 minutes /!\\\n",
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"### (To keep manual changes, replace /etc/bat-hosts symlink with a static file)\n" }
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-- merge the chunks from all nodes, de-escaping newlines
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for _, row in ipairs(rows) do
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local node, value = unpack(row)
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table.insert(content, "# Node ".. node .. "\n")
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table.insert(content, value:gsub("\x0a", "\n") .. "\n")
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end
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-- write parsed content down to disk
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local fd = io.open("/tmp/bat-hosts", "w")
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if fd then
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fd:write(table.concat(content))
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fd:close()
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end
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-- try to make a symlink in /etc pointing to /tmp,
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-- if it exists, ln will do nothing.
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os.execute("ln -ns /tmp/bat-hosts /etc/bat-hosts 2>/dev/null")
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end
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local function receive_bat_hosts()
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-- read raw chunks from alfred, convert them to a nested table and call write_bat_hosts
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-- "alfred -r" can fail in slave nodes (returns empty stdout), so:
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-- check output is not null before writing /tmp/bat-hosts, and retry 3 times before giving up.
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for n = 1, 3 do
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local fd = io.popen("alfred -r " .. type_id)
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--[[ this command returns something like
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{ "54:e6:fc:b9:cb:37", "00:11:22:33:44:55 ham_wlan0\x0a00:22:33:22:33:22 ham_eth0\x0a" },
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{ "90:f6:52:bb:ec:57", "00:22:33:22:33:23 spam\x0a" },
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]]--
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if fd then
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local output = fd:read("*a")
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fd:close()
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if output and output ~= "" then
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assert(loadstring("rows = {" .. output .. "}"))()
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write_bat_hosts(rows)
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break
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end
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end
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end
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end
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publish_bat_hosts()
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receive_bat_hosts()
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