From fcbc246e9f02cc780970defbcfa01767b7e3a3c6 Mon Sep 17 00:00:00 2001
From: Ned Deily <nad@acm.org>
Date: Fri, 22 Aug 2014 13:32:49 -0700
Subject: [PATCH] Issue #21166: Prevent possible segfaults and other random
 failures of python --generate-posix-vars in pybuilddir.txt build target by
 ensuring that pybuilddir.txt is always regenerated when configure is run and
 that the newly built skeleton python does not inadvertently import modules
 from previously installed instances.

---
 Makefile.pre.in | 12 +++++++++++-
 Misc/NEWS       |  3 +++
 configure       |  3 +++
 configure.ac    |  3 +++
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/Makefile.pre.in b/Makefile.pre.in
index 3b4e21edaea..c0f0c7b5a7a 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -546,8 +546,18 @@ platform: $(BUILDPYTHON) pybuilddir.txt
 # Create build directory and generate the sysconfig build-time data there.
 # pybuilddir.txt contains the name of the build dir and is used for
 # sys.path fixup -- see Modules/getpath.c.
+# Since this step runs before shared modules are built, try to avoid bootstrap
+# problems by creating a dummy pybuildstr.txt just to allow interpreter
+# initialization to succeed.  It will be overwritten by generate-posix-vars
+# or removed in case of failure.
 pybuilddir.txt: $(BUILDPYTHON)
-	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -m sysconfig --generate-posix-vars
+	@echo "none" > ./pybuilddir.txt
+	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -m sysconfig --generate-posix-vars ;\
+	if test $$? -ne 0 ; then \
+		echo "generate-posix-vars failed" ; \
+		rm -f ./pybuilddir.txt ; \
+		exit 1 ; \
+	fi
 
 # Build the shared modules
 # Under GNU make, MAKEFLAGS are sorted and normalized; the 's' for
diff --git a/Misc/NEWS b/Misc/NEWS
index 9396ac906f4..97d42db153c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -242,6 +242,9 @@ Build
 
 - Issue #21811: Anticipated fixes to support OS X versions > 10.9.
 
+- Issue #21166: Prevent possible segfaults and other random failures of
+  python --generate-posix-vars in pybuilddir.txt build target.
+
 IDLE
 ----
 
diff --git a/configure b/configure
index 73792038507..139d391d0c6 100755
--- a/configure
+++ b/configure
@@ -2950,6 +2950,9 @@ case $host_os in *\ *) host_os=`echo "$host_os" | sed 's/ /-/g'`;; esac
 
 
 
+# pybuilddir.txt will be created by --generate-posix-vars in the Makefile
+rm -f pybuilddir.txt
+
 if test "$cross_compiling" = yes; then
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for python interpreter for cross build" >&5
 $as_echo_n "checking for python interpreter for cross build... " >&6; }
diff --git a/configure.ac b/configure.ac
index 418e16ffa5d..9698ea0221e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,9 @@ AC_CANONICAL_HOST
 AC_SUBST(build)
 AC_SUBST(host)
 
+# pybuilddir.txt will be created by --generate-posix-vars in the Makefile
+rm -f pybuilddir.txt
+
 if test "$cross_compiling" = yes; then
     AC_MSG_CHECKING([for python interpreter for cross build])
     if test -z "$PYTHON_FOR_BUILD"; then