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https://github.com/nchevsky/systemrescue-zfs.git
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24529bbb58
Previously when loading a YAML config, it overrode single values on the second hierarchy level. But on all deeper levels new values were completely overwritten. This was inconsistent and poses a problem for config entries that use these levels, like the ca-trust or the in-development autoterminal. This change implements full merging of dictionaries on all levels to solve this. Values in files later in precedence overwrite previous values. If the the old and the new config values are both dictionaries, then the hierarchy levels are merged down recursively. You can remove a previously existing dict entry again in a later file by assigning it an empty value. Also fix handling of invalid YAMLs: ignore them instead of aborting execution
314 lines
13 KiB
Lua
Executable file
314 lines
13 KiB
Lua
Executable file
#!/usr/bin/env lua
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--
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-- Author: Francois Dupoux
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-- SPDX-License-Identifier: GPL-3.0-or-later
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--
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-- SystemRescue configuration processing script
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--
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-- This script uses the SystemRescue yaml configuration files and the options
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-- passed on the boot command line to override the default configuration.
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-- It processes yaml configuration files in the alphabetical order, and each option
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-- found in a file override the options defined earlier. Options passed on the
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-- boot command like take precedence over configuration options defined in files.
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-- At the end it writes the effective configuration to a JSON file which is meant
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-- to be ready by any initialisation script which needs to know the configuration.
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-- Shell scripts can read values from the JSON file using a command such as:
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-- jq --raw-output '.global.copytoram' /etc/sysrescue/sysrescue-effective-config.json
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-- This script requires the following lua packages to run on Arch Linux:
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-- sudo pacman -Sy lua lua-yaml lua-dkjson lua-http
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-- ==============================================================================
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-- Import modules
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-- ==============================================================================
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local lfs = require('lfs')
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local yaml = require('yaml')
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local json = require("dkjson")
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local request = require("http.request")
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-- ==============================================================================
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-- Utility functions
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-- ==============================================================================
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-- Read a file and return all its contents
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function read_file_contents(path)
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local file = io.open(path, "rb")
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if not file then
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return nil
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end
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local content = file:read("*a")
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file:close()
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return content
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end
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-- Return true if the item is present in the list or false otherwise
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function item_in_list(item, list)
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for _, curitem in ipairs(list) do
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if (curitem == item) then
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return true
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end
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end
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return false
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end
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-- Return the number of items in a table
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function get_table_size(mytable)
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size = 0
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for _ in pairs(mytable) do
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size = size + 1
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end
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return size
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end
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-- Return a list of files with a yaml extension found in the directory 'dirname'
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-- If 'filenames' is an empty list then it will return all files which have been found
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-- If 'filenames' is not empty then it will only return files with a name present in the list
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function list_config_files(dirname, filenames)
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local results = {}
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for curfile in lfs.dir(dirname) do
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fullpath = dirname.."/"..curfile
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filetype = lfs.attributes(fullpath, "mode")
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if (filetype == "file") and curfile:match(".[Yy][Aa][Mm][Ll]$") then
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if (get_table_size(filenames) == 0) or item_in_list(curfile, filenames) then
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table.insert(results, fullpath)
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end
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end
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end
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table.sort(results)
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return results
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end
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-- Attempt to find the option 'optname' on the boot command line and return its value
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-- If 'multiple' is false then it will return the value of the last occurence found or nil
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-- If 'multiple' is true then it will return a list of all values passed or an empty list
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function search_cmdline_option(optname, multiple)
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local result_single = nil
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local result_multiple = {}
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local cmdline = read_file_contents("/proc/cmdline")
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for curopt in cmdline:gmatch("%S+") do
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optmatch1 = string.match(curopt, "^"..optname.."$")
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_, _, optmatch2 = string.find(curopt, "^"..optname.."=([^%s]+)$")
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if (optmatch1 ~= nil) or (optmatch2 == 'y') or (optmatch2 == 'yes') or (optmatch2 == 'true') then
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result_single = true
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table.insert(result_multiple, true)
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elseif (optmatch2 == 'n') or (optmatch2 == 'no') or (optmatch2 == 'false') then
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result_single = false
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table.insert(result_multiple, false)
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elseif (optmatch2 ~= nil) then
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result_single = optmatch2
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table.insert(result_multiple, optmatch2)
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end
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end
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if multiple == true then
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return result_multiple
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else
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return result_single
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end
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end
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-- Process a block of yaml configuration and override the current configuration with new values
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function process_yaml_config(curconfig)
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if (curconfig == nil) or (type(curconfig) ~= "table") then
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io.stderr:write(string.format("This is not valid yaml (=no table), it will be ignored\n"))
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return false
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end
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merge_config_table(config, curconfig, "config")
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return true
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end
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-- Recursive merge of a config table
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-- config_table: references the current level within the global config
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-- new_table: the current level within the new yaml we want to merge right now
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-- leveltext: textual representation of the current level used for messages, split by "|"
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function merge_config_table(config_table, new_table, leveltext)
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for key, value in pairs(new_table) do
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-- loop through the current level of the new config
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if (config_table[key] == nil) then
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-- a key just existing in the new config, not in current config -> copy it
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print("- Merging "..leveltext.."|"..key.." into the config")
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config_table[key] = value
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else
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-- key of the new config also exisiting in the current config: check value type
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if (type(value) == "nil" or (type(value) == "string" and value == "")) then
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-- remove an existing table entry with an empty value
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print("- Removing "..leveltext.."|"..key)
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config_table[key] = nil
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elseif (type(value) == "table" and type(config_table[key]) == "table") then
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-- old and new values are tables: recurse
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merge_config_table(config_table[key], value, leveltext.."|"..key)
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else
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-- overwrite the old value
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print("- Overriding "..leveltext.."|"..key.." with the value from the yaml file")
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config_table[key] = value
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end
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end
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end
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end
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-- Download a file over http/https and return the contents of the file or nil if it fails
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function download_file(fileurl)
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local req_timeout = 10
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local req = request.new_from_uri(fileurl)
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local headers, stream = req:go(req_timeout)
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if headers == nil then
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io.stderr:write(string.format("Failed to download %s: Could not connect\n", fileurl))
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return nil
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end
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status = headers:get(":status")
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if status ~= '200' then
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io.stderr:write(string.format("Failed to download %s: Received HTTP code %s\n", fileurl, status))
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return nil
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end
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local body, err = stream:get_body_as_string()
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if not body and err then
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io.stderr:write(string.format("Failed to download %s: Error %s\n", fileurl, tostring(err)))
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return nil
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end
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return body
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end
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-- ==============================================================================
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-- Initialisation
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-- ==============================================================================
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errcnt = 0
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-- ==============================================================================
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-- We start with an empty global config
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-- the default config is usually in the first yaml file parsed (100-defaults.yaml)
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-- ==============================================================================
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config = { }
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-- ==============================================================================
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-- Merge one yaml file after the other in lexicographic order
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-- ==============================================================================
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print ("====> Merging configuration with values from yaml files ...")
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confdirs = {"/run/archiso/bootmnt/sysrescue.d", "/run/archiso/copytoram/sysrescue.d"}
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conffiles = search_cmdline_option("sysrescuecfg", true)
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-- Process local yaml configuration files
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for _, curdir in ipairs(confdirs) do
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if lfs.attributes(curdir, "mode") == "directory" then
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print("Searching for yaml configuration files in "..curdir.." ...")
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for _, curfile in ipairs(list_config_files(curdir, conffiles)) do
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print(string.format("Processing local yaml configuration file: %s ...", curfile))
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if pcall(function() curconfig = yaml.loadpath(curfile) end) then
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--print("++++++++++++++\n"..yaml.dump(curconfig).."++++++++++++++\n")
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if process_yaml_config(curconfig) == false then
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errcnt = errcnt + 1
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end
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else
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io.stderr:write(string.format("Failed parsing yaml, it will be ignored\n"))
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errcnt = errcnt + 1
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end
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end
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else
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print("Directory "..curdir.." was not found so it has been ignored")
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end
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end
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-- Process remote yaml configuration files
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print("Searching for remote yaml configuration files ...")
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for _, curfile in ipairs(conffiles) do
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if string.match(curfile, "^https?://") then
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print(string.format("Processing remote yaml configuration file: %s ...", curfile))
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local contents = download_file(curfile)
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if (contents == nil) then
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io.stderr:write(string.format("Error downloading or empty file received\n"))
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errcnt = errcnt + 1
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end
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if pcall(function() curconfig = yaml.load(contents) end) then
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if process_yaml_config(curconfig) == false then
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errcnt = errcnt + 1
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end
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else
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io.stderr:write(string.format("Failed parsing yaml, it will be ignored\n"))
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errcnt = errcnt + 1
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end
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end
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end
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-- ==============================================================================
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-- Override the configuration with values passed on the boot command line
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--
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-- NOTE: boot command line options are only for legacy compatibility and
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-- very common options. Consider carfully before adding new boot
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-- command line options. New features should by default just be
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-- configured through the yaml config.
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-- ==============================================================================
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cmdline_options = {
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['copytoram'] = "global",
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['checksum'] = "global",
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['loadsrm'] = "global",
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['dostartx'] = "global",
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['dovnc'] = "global",
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['noautologin'] = "global",
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['nofirewall'] = "global",
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['rootshell'] = "global",
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['rootpass'] = "global",
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['rootcryptpass'] = "global",
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['setkmap'] = "global",
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['vncpass'] = "global",
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['ar_disable'] = "autorun",
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['ar_nowait'] = "autorun",
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['ar_nodel'] = "autorun",
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['ar_ignorefail'] = "autorun",
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['ar_attempts'] = "autorun",
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['ar_source'] = "autorun",
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['ar_suffixes'] = "autorun"
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}
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print ("====> Overriding the configuration with options passed on the boot command line ...")
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for option, scope in pairs(cmdline_options) do
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optresult = search_cmdline_option(option, false)
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if optresult == true then
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print("- Option '"..option.."' has been enabled on the boot command line")
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config[scope][option] = optresult
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elseif optresult == false then
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print("- Option '"..option.."' has been disabled on the boot command line")
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config[scope][option] = optresult
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elseif optresult ~= nil then
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print("- Option '"..option.."' has been defined as '"..optresult.."' on the boot command line")
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config[scope][option] = optresult
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end
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end
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-- ==============================================================================
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-- Print the effective configuration
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-- ==============================================================================
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print ("====> Printing the effective configuration")
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local jsoncfgtxt = json.encode (config, { indent = true })
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print (jsoncfgtxt)
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-- ==============================================================================
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-- Write the effective configuration to a JSON file
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-- ==============================================================================
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print ("====> Writing the effective configuration to a JSON file ...")
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output_location = "/etc/sysrescue"
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output_filename = "sysrescue-effective-config.json"
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output_fullpath = output_location.."/"..output_filename
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lfs.mkdir(output_location)
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jsoncfgfile = io.open(output_fullpath, "w")
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if jsoncfgfile == nil then
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io.stderr:write(string.format("ERROR: Failed to create effective configuration file in %s\n", output_fullpath))
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os.exit(1)
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end
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jsoncfgfile:write(jsoncfgtxt)
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jsoncfgfile:close()
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os.execute("chmod 700 "..output_location)
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os.execute("chmod 600 "..output_fullpath)
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print ("Effective configuration has been written to "..output_fullpath)
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-- ==============================================================================
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-- Error handling
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-- ==============================================================================
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if errcnt == 0 then
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print ("SUCCESS: Have successfully completed the processing of the configuration")
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os.exit(0)
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else
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io.stderr:write(string.format("FAILURE: Have completed the processing of the configuration with %d errors\n", errcnt))
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os.exit(1)
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end
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