1# SPDX-License-Identifier: GPL-2.0+
2#
3# Copyright 2021 Google, Inc
4#
5# SPDX-License-Identifier:	GPL-2.0+
6#
7# Awk script to parse a text file containing an environment and convert it
8# to a C string which can be compiled into U-Boot.
9
10# The resulting output is:
11#
12#   #define CONFIG_EXTRA_ENV_TEXT "<environment here>"
13#
14# If the input is empty, this script outputs a comment instead.
15
16BEGIN {
17	# env holds the env variable we are currently processing
18	env = "";
19	ORS = ""
20}
21
22# Skip empty lines, as these are generated by the clang preprocessor
23NF {
24	do_output = 0
25
26	# Quote quotes
27	gsub("\"", "\\\"")
28
29	# Avoid using the non-POSIX third parameter to match(), by splitting
30	# the work into several steps.
31	has_var = match($0, "^([^ \t=][^ =]*)=(.*)$")
32
33	# Is this the start of a new environment variable?
34	if (has_var) {
35		if (length(env) != 0) {
36			# Record the value of the variable now completed
37			vars[var] = env
38			do_output = 1
39		}
40
41		# Collect the variable name. The value follows the '='
42		match($0, "^([^ \t=][^ =]*)=")
43		var = substr($0, 1, RLENGTH - 1)
44		env = substr($0, RLENGTH + 1)
45
46		# Deal with += which concatenates the new string to the existing
47		# variable. Again we are careful to use POSIX match()
48		if (length(env) != 0 && match(var, "^(.*)[+]$")) {
49			plusname = substr(var, RSTART, RLENGTH - 1)
50			# Allow var\+=val to indicate that the variable name is
51			# var+ and this is not actually a concatenation
52			if (substr(plusname, length(plusname)) == "\\") {
53				# Drop the backslash
54				sub(/\\[+]$/, "+", var)
55			} else {
56				var = plusname
57				env = vars[var] env
58			}
59		}
60	} else {
61		# Change newline to space
62		gsub(/^[ \t]+/, "")
63
64		# Don't keep leading spaces generated by the previous blank line
65		if (length(env) == 0) {
66			env = $0
67		} else {
68			env = env " " $0
69		}
70	}
71}
72
73END {
74	# Record the value of the variable now completed. If the variable is
75	# empty it is not set.
76	if (length(env) != 0) {
77		vars[var] = env
78		do_output = 1
79	}
80
81	if (do_output) {
82		printf("%s", "#define CONFIG_EXTRA_ENV_TEXT \"")
83
84		# Print out all the variables by alphabetic order, if using
85		# gawk. This allows test_env_test.py to work on both awk (where
86		# this next line does nothing)
87		PROCINFO["sorted_in"] = "@ind_str_asc"
88		for (var in vars) {
89			env = vars[var]
90			print var "=" vars[var] "\\0"
91		}
92		print "\"\n"
93	}
94}
95