From: Matt Helsley <matthltc@us.ibm.com>
Date: Sun, 8 Mar 2009 16:09:27 +0000 (+0100)
Subject: liblxc: Handle missing PR_CAPBSET_DROP definition
X-Git-Tag: lxc_0_6_1~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=656994bbfabe378c8e9e5b40ce93eac074a0f7e4;p=thirdparty%2Flxc.git

liblxc: Handle missing PR_CAPBSET_DROP definition

On distros with older headers liblxc fails to build because PR_CAPBSET_DROP is
not defined by including /usr/include/sys/prctl.h. This adds an autoconf
test and, if not present, defines it. When prctl() is called on systems that
do not support PR_CAPBSET_DROP we should expect EINVAL. This case is already
handled by the liblxc code so no further changes are needed.

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
---

diff --git a/configure.in b/configure.in
index 46c01a100..7bc788257 100644
--- a/configure.in
+++ b/configure.in
@@ -27,6 +27,9 @@ AC_CHECK_HEADERS([linux/netlink.h linux/genetlink.h], [], AC_MSG_ERROR([netlink
 AC_CHECK_HEADERS([sys/capability.h], [], AC_MSG_ERROR([please install libcap-devel.]),
 [#include <sys/capability.h>])
 
+# Some systems lack PR_CAPBSET_DROP definition => HAVE_DECL_PR_CAPBSET_DROP
+AC_CHECK_DECLS([PR_CAPBSET_DROP], [], [], [#include <sys/prctl.h>])
+
 AC_CHECK_HEADERS([sys/signalfd.h])
 
 AC_PROG_GCC_TRADITIONAL
diff --git a/src/lxc/start.c b/src/lxc/start.c
index e0c381bc7..cb3226100 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -48,6 +48,10 @@
 extern int signalfd (int fd, const sigset_t *mask, int flags);
 #endif
 
+#if !HAVE_DECL_PR_CAPBSET_DROP
+#define PR_CAPBSET_DROP 24
+#endif
+
 #include "error.h"
 #include "af_unix.h"
 #include "mainloop.h"