From 426be813048c87951c441d5b6b8c8020a2e801cd Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Mon, 23 Aug 2010 15:26:13 -0700
Subject: [PATCH] Handle SIGPIPE when unpack() extracts tar files through a pipe.

When checking ${PIPESTATUS[@]} for extraction of tar files in unpack(),
use a new assert_tar_extract() function which behaves the same as the
existing assert() function except that it tolerates pipe writers being
killed by SIGPIPE.
---
 bin/ebuild.sh             |    4 ++--
 bin/isolated-functions.sh |   29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/bin/ebuild.sh b/bin/ebuild.sh
index 84a83fe..d69408e 100755
--- a/bin/ebuild.sh
+++ b/bin/ebuild.sh
@@ -348,7 +348,7 @@ unpack() {
 		_unpack_tar() {
 			if [ "${y}" == "tar" ]; then
 				$1 -dc "$srcdir$x" | tar xof -
-				assert "$myfail"
+				assert_tar_extract "$myfail"
 			else
 				$1 -dc "${srcdir}${x}" > ${x%.*} || die "$myfail"
 			fi
@@ -364,7 +364,7 @@ unpack() {
 				;;
 			tbz|tbz2)
 				bzip2 -dc "$srcdir$x" | tar xof -
-				assert "$myfail"
+				assert_tar_extract "$myfail"
 				;;
 			ZIP|zip|jar)
 				unzip -qo "${srcdir}${x}" || die "$myfail"
diff --git a/bin/isolated-functions.sh b/bin/isolated-functions.sh
index 53312db..d0df9b1 100644
--- a/bin/isolated-functions.sh
+++ b/bin/isolated-functions.sh
@@ -15,6 +15,35 @@ assert() {
 	done
 }
 
+assert_tar_extract() {
+	# When extracting a tar file like this:
+	#
+	#     bzip2 -dc foo.tar.bz2 | tar xof -
+	#
+	# For some tar files (see bug #309001), tar will
+	# close its stdin pipe when the decompressor still has
+	# remaining data to be written to its stdout pipe. This
+	# causes the decompressor to be killed by SIGPIPE. In
+	# this case, we want to ignore pipe writers killed by
+	# SIGPIPE, and trust the exit status of tar. We borrow
+	# WIFSIGNALED and WTERMSIG bitwise operations from
+	# glibc's bits/waitstatus.h.
+
+	local x pipestatus=${PIPESTATUS[*]}
+	for x in $pipestatus ; do
+		if [[ $x -ne 0 ]] ; then
+			# WIFSIGNALED(status)
+			(( ( ( ( x & 0x7f ) + 1 ) >> 1 ) > 0 )) || die "$@"
+
+			# WTERMSIG(status) == SIGPIPE
+			(( ( x & 0x7f ) == 13 )) || die "$@"
+		fi
+	done
+
+	# Require normal success for the last process (tar).
+	[[ $x -eq 0 ]] || die "$@"
+}
+
 shopt -s extdebug
 
 # dump_trace([number of funcs on stack to skip],
-- 
1.7.1.1