From 30bdadf032d1c210bae6e2785277afe030d9baf4 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Sat, 29 Mar 2014 14:55:01 +0000
Subject: [PATCH] builder: Disable internal parallel xzcat on RHEL 6.

---
 builder/pxzcat-c.c | 28 +++++++++++++++++++---------
 configure.ac       |  8 +++++++-
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/builder/pxzcat-c.c b/builder/pxzcat-c.c
index f905b31f9..941599581 100644
--- a/builder/pxzcat-c.c
+++ b/builder/pxzcat-c.c
@@ -36,6 +36,10 @@
 
 #include "ignore-value.h"
 
+#if HAVE_LIBLZMA
+#include <lzma.h>
+#endif
+
 #ifdef HAVE_CAML_UNIXSUPPORT_H
 #include <caml/unixsupport.h>
 #else
@@ -43,18 +47,24 @@
 extern void unix_error (int errcode, char * cmdname, value arg) Noreturn;
 #endif
 
-#ifdef HAVE_LIBLZMA
-#include <lzma.h>
-
-static void pxzcat (value filenamev, value outputfilev, unsigned nr_threads);
+#if defined (HAVE_LIBLZMA) && \
+  defined (HAVE_LZMA_INDEX_STREAM_FLAGS) && \
+  defined (HAVE_LZMA_INDEX_STREAM_PADDING)
+#define PARALLEL_XZCAT 1
+#else
+#define PARALLEL_XZCAT 0
 #endif
 
+#if PARALLEL_XZCAT
+static void pxzcat (value filenamev, value outputfilev, unsigned nr_threads);
+#endif /* PARALLEL_XZCAT */
+
 value
 virt_builder_pxzcat (value inputfilev, value outputfilev)
 {
   CAMLparam2 (inputfilev, outputfilev);
 
-#ifdef HAVE_LIBLZMA
+#if PARALLEL_XZCAT
 
   /* Parallel implementation of xzcat (pxzcat). */
   /* XXX Make number of threads configurable? */
@@ -73,7 +83,7 @@ virt_builder_pxzcat (value inputfilev, value outputfilev)
    */
   pxzcat (inputfilev, outputfilev, nr_threads);
 
-#else
+#else /* !PARALLEL_XZCAT */
 
   /* Fallback: use regular xzcat. */
   int fd;
@@ -105,12 +115,12 @@ virt_builder_pxzcat (value inputfilev, value outputfilev)
   if (!WIFEXITED (status) || WEXITSTATUS (status) != 0)
     caml_failwith (XZCAT " program failed, see earlier error messages");
 
-#endif
+#endif /* !PARALLEL_XZCAT */
 
   CAMLreturn (Val_unit);
 }
 
-#ifdef HAVE_LIBLZMA
+#if PARALLEL_XZCAT
 
 #define DEBUG 0
 
@@ -649,4 +659,4 @@ worker_thread (void *vp)
   return &state->status;
 }
 
-#endif /* HAVE_LIBLZMA */
+#endif /* PARALLEL_XZCAT */
diff --git a/configure.ac b/configure.ac
index 5b13c1d9c..7e1c06812 100644
--- a/configure.ac
+++ b/configure.ac
@@ -677,10 +677,16 @@ test "x$XZCAT" = "xno" && AC_MSG_ERROR([xzcat must be installed])
 AC_DEFINE_UNQUOTED([XZCAT],["$XZCAT"],[Name of xzcat program.])
 
 dnl liblzma can be used by virt-builder (optional).
-PKG_CHECK_MODULES([LIBLZMA], [liblzma],[
+PKG_CHECK_MODULES([LIBLZMA], [liblzma], [
     AC_SUBST([LIBLZMA_CFLAGS])
     AC_SUBST([LIBLZMA_LIBS])
     AC_DEFINE([HAVE_LIBLZMA],[1],[liblzma found at compile time.])
+
+    dnl Old lzma in RHEL 6 didn't have some APIs we need.
+    old_LIBS="$LIBS"
+    LIBS="$LIBS $LIBLZMA_LIBS"
+    AC_CHECK_FUNCS([lzma_index_stream_flags lzma_index_stream_padding])
+    LIBS="$old_LIBS"
 ],
 [AC_MSG_WARN([liblzma not found, virt-builder will be slower])])