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>

liblxc: Handle missing PR_CAPBSET_DROP definition
656994bb · Matt Helsley · Daniel Lezcano · 54b1eb68 · 656994bb · 656994bb
Commit 656994bb authored Mar 08, 2009 by Matt Helsley Committed by Daniel Lezcano Mar 08, 2009
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configure.in configure.in +3 -0

start.c src/lxc/start.c +4 -0

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--- 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

--- 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"