scripts/env2string.awk

   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
  16 BEGIN {
  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
  23 NF {
  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
  73 END {
  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 }