#!/usr/libexec/flua

-- SPDX-License-Identifier: BSD-2-Clause-FreeBSD
--
-- Copyright(c) 2020 The FreeBSD Foundation.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions
-- are met:
-- 1. Redistributions of source code must retain the above copyright
--    notice, this list of conditions and the following disclaimer.
-- 2. Redistributions in binary form must reproduce the above copyright
--    notice, this list of conditions and the following disclaimer in the
--    documentation and/or other materials provided with the distribution.
--
-- THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
-- ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-- ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-- OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-- SUCH DAMAGE.

-- $FreeBSD$

function main(args)
	if #args == 0 then usage() end
	local filename
	local printall, checkonly, pkgonly =
	    #args == 1, false, false
	local dcount, dsize, fuid, fgid, fid =
	    false, false, false, false, false
	local verbose = false
	local w_notagdirs = false

	local i = 1
	while i <= #args do
		if args[i] == '-h' then
			usage(true)
		elseif args[i] == '-a' then
			printall = true
		elseif args[i] == '-c' then
			printall = false
			checkonly = true
		elseif args[i] == '-p' then
			printall = false
			pkgonly = true
			while i < #args do
				i = i+1
				if args[i] == '-count' then
					dcount = true
				elseif args[i] == '-size' then
					dsize = true
				elseif args[i] == '-fsetuid' then
					fuid = true
				elseif args[i] == '-fsetgid' then
					fgid = true
				elseif args[i] == '-fsetid' then
					fid = true
				else
					i = i-1
					break
				end
			end
		elseif args[i] == '-v' then
			verbose = true
		elseif args[i] == '-Wcheck-notagdir' then
			w_notagdirs = true
		elseif args[i]:match('^%-') then
			io.stderr:write('Unknown argument '..args[i]..'.\n')
			usage()
		else
			filename = args[i]
		end
		i = i+1
	end

	if filename == nil then
		io.stderr:write('Missing filename.\n')
		usage()
	end

	local sess = Analysis_session(filename, verbose, w_notagdirs)

	if printall then
		io.write('--- PACKAGE REPORTS ---\n')
		io.write(sess.pkg_report_full())
		io.write('--- LINTING REPORTS ---\n')
		print_lints(sess)
	elseif checkonly then
		print_lints(sess)
	elseif pkgonly then
		io.write(sess.pkg_report_simple(dcount, dsize, {
			fuid and sess.pkg_issetuid or nil,
			fgid and sess.pkg_issetgid or nil,
			fid and sess.pkg_issetid or nil
		}))
	else
		io.stderr:write('This text should not be displayed.')
		usage()
	end
end

--- @param man boolean
function usage(man)
	local sn = 'Usage: '..arg[0].. ' [-h] [-a | -c | -p [-count] [-size] [-f...]] [-W...] metalog-path \n'
	if man then
		io.write('\n')
		io.write(sn)
		io.write(
[[

The script reads METALOG file created by pkgbase (make packages) and generates
reports about the installed system and issues.  It accepts an mtree file in a
format that's returned by `mtree -c | mtree -C`

  Options:
  -a         prints all scan results. this is the default option if no option
             is provided.
  -c         lints the file and gives warnings/errors, including duplication
             and conflicting metadata
      -Wcheck-notagdir    entries with dir type and no tags will be also
                          included the first time they appear
  -p         list all package names found in the file as exactly specified by
             `tags=package=...`
      -count       display the number of files of the package
      -size        display the size of the package
      -fsetgid     only include packages with setgid files
      -fsetuid     only include packages with setuid files
      -fsetid      only include packages with setgid or setuid files
  -v          verbose mode
  -h          help page

]])
		os.exit()
	else
		io.stderr:write(sn)
		os.exit(1)
	end
end

--- @param sess Analysis_session
function print_lints(sess)
	local dupwarn, duperr = sess.dup_report()
	io.write(dupwarn)
	io.write(duperr)
	local inodewarn, inodeerr = sess.inode_report()
	io.write(inodewarn)
	io.write(inodeerr)
end

--- @param t table
function sortedPairs(t)
	local sortedk = {}
	for k in next, t do sortedk[#sortedk+1] = k end
	table.sort(sortedk)
	local i = 0
	return function()
		i = i + 1
		return sortedk[i], t[sortedk[i]]
	end
end

--- @param t table <T, U>
--- @param f function <U -> U>
function table_map(t, f)
	local res = {}
	for k, v in pairs(t) do res[k] = f(v) end
	return res
end

--- @class MetalogRow
-- a table contaning file's info, from a line content from METALOG file
-- all fields in the table are strings
-- sample output:
--	{
--		filename = ./usr/share/man/man3/inet6_rthdr_segments.3.gz
--		lineno = 5
--		attrs = {
--			gname = 'wheel'
--			uname = 'root'
--			mode = '0444'
--			size = '1166'
--			time = nil
--			type = 'file'
--			tags = 'package=clibs,debug'
--		}
--	}
--- @param line string
function MetalogRow(line, lineno)
	local res, attrs = {}, {}
	local filename, rest = line:match('^(%S+) (.+)$')
	-- mtree file has space escaped as '\\040', not affecting splitting
	-- string by space
	for attrpair in rest:gmatch('[^ ]+') do
		local k, v = attrpair:match('^(.-)=(.+)')
		attrs[k] = v
	end
	res.filename = filename
	res.linenum = lineno
	res.attrs = attrs
	return res
end

-- check if an array of MetalogRows are equivalent. if not, the first field
-- that's different is returned secondly
--- @param rows MetalogRow[]
--- @param ignore_name boolean
--- @param ignore_tags boolean
function metalogrows_all_equal(rows, ignore_name, ignore_tags)
	local __eq = function(l, o)
		if not ignore_name and l.filename ~= o.filename then
			return false, 'filename'
		end
		-- ignoring linenum in METALOG file as it's not relavant
		for k in pairs(l.attrs) do
			if ignore_tags and k == 'tags' then goto continue end
			if l.attrs[k] ~= o.attrs[k] and o.attrs[k] ~= nil then
				return false, k
			end
			::continue::
		end
		return true
	end
	for _, v in ipairs(rows) do
		local bol, offby = __eq(v, rows[1])
		if not bol then return false, offby end
	end
	return true
end

--- @param tagstr string
function pkgname_from_tag(tagstr)
	local ext, pkgname, pkgend = '', '', ''
	for seg in tagstr:gmatch('[^,]+') do
		if seg:match('package=') then
			pkgname = seg:sub(9)
		elseif seg == 'development' or seg == 'profile'
			or seg == 'debug' or seg == 'docs' then
			pkgend = seg
		else
			ext = ext == '' and seg or ext..'-'..seg
		end
	end
	pkgname = pkgname
		..(ext == '' and '' or '-'..ext)
		..(pkgend == '' and '' or '-'..pkgend)
	return pkgname
end

--- @class Analysis_session
--- @param metalog string
--- @param verbose boolean
--- @param w_notagdirs boolean turn on to also check directories
function Analysis_session(metalog, verbose, w_notagdirs)
	local files = {} -- map<string, MetalogRow[]>
	-- set is map<elem, bool>. if bool is true then elem exists
	local pkgs = {} -- map<string, set<string>>
	----- used to keep track of files not belonging to a pkg. not used so
	----- it is commented with -----
	-----local nopkg = {} --            set<string>
	--- @public
	local swarn = {}
	--- @public
	local serrs = {}

	-- returns number of files in package and size of package
	-- nil is  returned upon errors
	--- @param pkgname string
	local function pkg_size(pkgname)
		local filecount, sz = 0, 0
		for filename in pairs(pkgs[pkgname]) do
			local rows = files[filename]
			-- normally, there should be only one row per filename
			-- if these rows are equal, there should be warning, but it
			-- does not affect size counting. if not, it is an error
			if #rows > 1 and not metalogrows_all_equal(rows) then
				return nil
			end
			local row = rows[1]
			if row.attrs.type == 'file' then
				sz = sz + tonumber(row.attrs.size)
			end
			filecount = filecount + 1
		end
		return filecount, sz
	end

	--- @param pkgname string
	--- @param mode number
	local function pkg_ismode(pkgname, mode)
		for filename in pairs(pkgs[pkgname]) do
			for _, row in ipairs(files[filename]) do
				if tonumber(row.attrs.mode, 8) & mode ~= 0 then
					return true
				end
			end
		end
		return false
	end

	--- @param pkgname string
	--- @public
	local function pkg_issetuid(pkgname)
		return pkg_ismode(pkgname, 2048)
	end

	--- @param pkgname string
	--- @public
	local function pkg_issetgid(pkgname)
		return pkg_ismode(pkgname, 1024)
	end

	--- @param pkgname string
	--- @public
	local function pkg_issetid(pkgname)
		return pkg_issetuid(pkgname) or pkg_issetgid(pkgname)
	end

	-- sample return:
	-- { [*string]: { count=1, size=2, issetuid=true, issetgid=true } }
	local function pkg_report_helper_table()
		local res = {}
		for pkgname in pairs(pkgs) do
			res[pkgname] = {}
			res[pkgname].count,
			res[pkgname].size = pkg_size(pkgname)
			res[pkgname].issetuid = pkg_issetuid(pkgname)
			res[pkgname].issetgid = pkg_issetgid(pkgname)
		end
		return res
	end

	-- returns a string describing package scan report
	--- @public
	local function pkg_report_full()
		local sb = {}
		for pkgname, v in sortedPairs(pkg_report_helper_table()) do
			sb[#sb+1] = 'Package '..pkgname..':'
			if v.issetuid or v.issetgid then
				sb[#sb+1] = ''..table.concat({
					v.issetuid and ' setuid' or '',
					v.issetgid and ' setgid' or '' }, '')
			end
			sb[#sb+1] = '\n  number of files: '..(v.count or '?')
				..'\n  total size: '..(v.size or '?')
			sb[#sb+1] = '\n'
		end
		return table.concat(sb, '')
	end

	--- @param have_count boolean
	--- @param have_size boolean
	--- @param filters function[]
	--- @public
	-- returns a string describing package size report.
	-- sample: "mypackage 2 2048"* if both booleans are true
	local function pkg_report_simple(have_count, have_size, filters)
		filters = filters or {}
		local sb = {}
		for pkgname, v in sortedPairs(pkg_report_helper_table()) do
			local pred = true
			-- doing a foldl to all the function results with (and)
			for _, f in pairs(filters) do pred = pred and f(pkgname) end
			if pred then
				sb[#sb+1] = pkgname..table.concat({
					have_count and (' '..(v.count or '?')) or '',
					have_size and (' '..(v.size or '?')) or ''}, '')
					..'\n'
			end
		end
		return table.concat(sb, '')
	end

	-- returns a string describing duplicate file warnings,
	-- returns a string describing duplicate file errors
	--- @public
	local function dup_report()
		local warn, errs = {}, {}
		for filename, rows in sortedPairs(files) do
			if #rows == 1 then goto continue end
			local iseq, offby = metalogrows_all_equal(rows)
			if iseq then -- repeated line, just a warning
				warn[#warn+1] = 'warning: '..filename
					..' repeated with same meta: line '
					..table.concat(
						table_map(rows, function(e) return e.linenum end), ',')
				warn[#warn+1] = '\n'
			elseif not metalogrows_all_equal(rows, false, true) then
			-- same filename (possibly different tags), different metadata, an error
				errs[#errs+1] = 'error: '..filename
					..' exists in multiple locations and with different meta: line '
					..table.concat(
						table_map(rows, function(e) return e.linenum end), ',')
					..'. off by "'..offby..'"'
				errs[#errs+1] = '\n'
			end
			::continue::
		end
		return table.concat(warn, ''), table.concat(errs, '')
	end

	-- returns a string describing warnings of found hard links
	-- returns a string describing errors of found hard links
	--- @public
	local function inode_report()
		-- obtain inodes of filenames
		local attributes = require('lfs').attributes
		local inm = {} -- map<number, string[]>
		local unstatables = {} -- string[]
		for filename in pairs(files) do
			-- i only took the first row of a filename,
			-- and skip links and folders
			if files[filename][1].attrs.type ~= 'file' then
				goto continue
			end
			-- make ./xxx become /xxx so that we can stat
			filename = filename:sub(2)
			local fs = attributes(filename)
			if fs == nil then
				unstatables[#unstatables+1] = filename
				goto continue
			end
			local inode = fs.ino
			inm[inode] = inm[inode] or {}
			-- add back the dot prefix
			table.insert(inm[inode], '.'..filename)
			::continue::
		end

		local warn, errs = {}, {}
		for _, filenames in pairs(inm) do
			if #filenames == 1 then goto continue end
			-- i only took the first row of a filename
			local rows = table_map(filenames, function(e)
				return files[e][1]
			end)
			local iseq, offby = metalogrows_all_equal(rows, true, true)
			if not iseq then
				errs[#errs+1] = 'error: '
					..'entries point to the same inode but have different meta: '
					..table.concat(filenames, ',')..' in line '
					..table.concat(
						table_map(rows, function(e) return e.linenum end), ',')
					..'. off by "'..offby..'"'
				errs[#errs+1] = '\n'
			end
			::continue::
		end

		if #unstatables > 0 then
			warn[#warn+1] = verbose and
				'note: skipped checking inodes: '..table.concat(unstatables, ',')..'\n'
				or
				'note: skipped checking inodes for '..#unstatables..' entries\n'
		end

		return table.concat(warn, ''), table.concat(errs, '')
	end

	do
	local fp, errmsg, errcode = io.open(metalog, 'r')
	if fp == nil then
		io.stderr:write('cannot open '..metalog..': '..errmsg..': '..errcode..'\n')
		os.exit(1)
	end

	-- scan all lines and put file data into the dictionaries
	local firsttimes = {} -- set<string>
	local lineno = 0
	for line in fp:lines() do
		-----local isinpkg = false
		lineno = lineno + 1
		-- skip lines beginning with #
		if line:match('^%s*#') then goto continue end
		-- skip blank lines
		if line:match('^%s*$') then goto continue end

		local data = MetalogRow(line, lineno)
		-- entries with dir and no tags... ignore for the first time
		if not w_notagdirs and
			data.attrs.tags == nil and data.attrs.type == 'dir'
			and not firsttimes[data.filename] then
			firsttimes[data.filename] = true
			goto continue
		end

		files[data.filename] = files[data.filename] or {}
		table.insert(files[data.filename], data)

		if data.attrs.tags ~= nil then
			pkgname = pkgname_from_tag(data.attrs.tags)
			pkgs[pkgname] = pkgs[pkgname] or {}
			pkgs[pkgname][data.filename] = true
			------isinpkg = true
		end
		-----if not isinpkg then nopkg[data.filename] = true end
		::continue::
	end

	fp:close()
	end

	return {
		warn = swarn,
		errs = serrs,
		pkg_issetuid = pkg_issetuid,
		pkg_issetgid = pkg_issetgid,
		pkg_issetid = pkg_issetid,
		pkg_report_full = pkg_report_full,
		pkg_report_simple = pkg_report_simple,
		dup_report = dup_report,
		inode_report = inode_report
	}
end

main(arg)