From d6707da4597fc798f4e400fa770001a7c7b7b538 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Tue, 4 Dec 2018 21:13:17 +0100
Subject: [PATCH] build system: protect digest calls from re-entry

The code for Ruby's Digest module seems to be racy
wrt. multi-threading. See e.g.
https://github.com/aws/aws-sdk-ruby/issues/525 for details.
---
 Rakefile                         | 1 +
 rake.d/digest.rb                 | 7 +++++++
 rake.d/format_string_verifier.rb | 4 +---
 3 files changed, 9 insertions(+), 3 deletions(-)
 create mode 100644 rake.d/digest.rb

diff --git a/Rakefile b/Rakefile
index cdaccb728..4c003f4e2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -47,6 +47,7 @@ $build_system_modules = {}
 $have_gtest           = (c(:GTEST_TYPE) == "system") || (c(:GTEST_TYPE) == "internal")
 $gtest_apps           = []
 
+require_relative "rake.d/digest"
 require_relative "rake.d/helpers"
 require_relative "rake.d/target"
 require_relative "rake.d/application"
diff --git a/rake.d/digest.rb b/rake.d/digest.rb
new file mode 100644
index 000000000..ed3cf945d
--- /dev/null
+++ b/rake.d/digest.rb
@@ -0,0 +1,7 @@
+require "digest"
+
+$digest_mutex = Mutex.new
+
+def sha1_hexdigest data
+  $digest_mutex.synchronize { Digest::SHA1.hexdigest(data) }
+end
diff --git a/rake.d/format_string_verifier.rb b/rake.d/format_string_verifier.rb
index 17cb1005d..86c477050 100755
--- a/rake.d/format_string_verifier.rb
+++ b/rake.d/format_string_verifier.rb
@@ -1,7 +1,5 @@
 #!/usr/bin/env ruby
 
-require "digest"
-
 class FormatStringVerifier
   def verify file_name
     language  = file_name.gsub(%r{.*/|\.po$}, '')
@@ -35,7 +33,7 @@ class FormatStringVerifier
           reject(&:nil?).
           each do |msgid|
             format_types.each do |type|
-              sha1 = Digest::SHA1.hexdigest "#{type}:#{msgid}:#{msgstr}"
+              sha1 = sha1_hexdigest "#{type}:#{msgid}:#{msgstr}"
 
               next if to_ignore.key?(language) && to_ignore[language].include?(sha1)