[lxc-devel] [PATCH 14/21] Make utmpx.h optional

[Stéphane Graber]

This adds code detecting the presence of utmpx.h and in its absence, turns the
utmp related functions into no-ops.

Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
---
 configure.ac   | 2 +-
 src/lxc/utmp.c | 7 +++++++
 src/lxc/utmp.h | 9 +++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 2905aee..5b7573a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -211,7 +211,7 @@ AM_CONDITIONAL([IS_BIONIC], [test "x$libc_type" = "xbionic"])
 AC_CHECK_DECLS([PR_CAPBSET_DROP], [], [], [#include <sys/prctl.h>])
 
 # Check for some headers
-AC_CHECK_HEADERS([sys/signalfd.h sys/personality.h sys/capability.h pty.h])
+AC_CHECK_HEADERS([sys/signalfd.h sys/personality.h sys/capability.h pty.h utmpx.h])
 
 # Check for some functions
 AC_CHECK_FUNCS([getline fgetln openpty setns pivot_root sethostname unshare])
diff --git a/src/lxc/utmp.c b/src/lxc/utmp.c
index a7b9b52..16d1b5d 100644
--- a/src/lxc/utmp.c
+++ b/src/lxc/utmp.c
@@ -21,6 +21,10 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+#include "config.h"
+
+#ifdef HAVE_UTMPX_H
+
 #include <stdio.h>
 #include <unistd.h>
 #include <errno.h>
@@ -37,6 +41,7 @@
 #include "mainloop.h"
 #include "lxc.h"
 #include "log.h"
+
 #define __USE_GNU
 #include <utmpx.h>
 #undef __USE_GNU
@@ -410,3 +415,5 @@ int lxc_utmp_del_timer(struct lxc_epoll_descr *descr,
 	else
 		return 0;
 }
+
+#endif
diff --git a/src/lxc/utmp.h b/src/lxc/utmp.h
index ac3eee4..ad4a8ab 100644
--- a/src/lxc/utmp.h
+++ b/src/lxc/utmp.h
@@ -21,8 +21,17 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+#include "config.h"
+
 struct lxc_handler;
 struct lxc_epoll_descr;
 
+#ifdef HAVE_UTMPX_H
 int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
 			  struct lxc_handler *handler);
+#else
+static inline int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
+			  struct lxc_handler *handler) {
+		return 0;
+}
+#endif
-- 
1.8.0