Upstream-Status: Submitted [https://github.com/jbruchon/dev86/pull/23]
Signed-off-by: Ross Burton <ross.burton@arm.com>

From f507ee398ae20e4e97f01dfbd9a8709a90bc760f Mon Sep 17 00:00:00 2001
From: Ross Burton <ross.burton@arm.com>
Date: Fri, 29 Apr 2022 16:44:08 +0100
Subject: [PATCH] cpp: fix race writing token.h files

The rules for token1.h and token2.h both write to a temporary file tmp.h
before renaming to token1.h or token2.h. However, in a parallel build
these will execute at the same time and race.

  gperf -aptTc -N is_ctok -H hash1 token1.tok > tmp.h
  gperf -aptTc -k1,3 -N is_ckey -H hash2 token2.tok > tmp.h
  mv tmp.h token1.h
  mv tmp.h token2.h
  mv: cannot stat 'tmp.h': No such file or directory

By using gperf --output-file, the race is avoided entirely.

Upstream-Status: Inappropriate [embedded specific]

---
 cpp/Makefile | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/cpp/Makefile b/cpp/Makefile
index 0ea43cc..743694f 100644
--- a/cpp/Makefile
+++ b/cpp/Makefile
@@ -20,9 +20,7 @@ token1.o: token1.h
 token2.o: token2.h
 
 token1.h: token1.tok
-	gperf -aptTc -N is_ctok -H hash1 token1.tok > tmp.h
-	mv tmp.h token1.h
+	gperf -aptTc -N is_ctok -H hash1 --output-file $@ $<
 
 token2.h: token2.tok
-	gperf -aptTc -k1,3 -N is_ckey -H hash2 token2.tok > tmp.h
-	mv tmp.h token2.h
+	gperf -aptTc -k1,3 -N is_ckey -H hash2 --output-file $@ $<
-- 
2.25.1

