[lxc-devel] [PATCH 6/8] Check for non-posix utmpxname in configure

[Natanael Copa]

utmpx.h is specified in POSIX but utmpxname is not so we check for
utmpxname in configure script.

This fixes the following compile error with musl libc:
lxcutmp.c: In function 'utmp_get_runlevel':
lxcutmp.c:249:2: error: implicit declaration of function 'utmpxname' [-Werror=implicit-function-declaration]
  if (!access(path, F_OK) && !utmpxname(path))
    ^

Signed-off-by: Natanael Copa <ncopa at alpinelinux.org>
---
 configure.ac      |  2 +-
 src/lxc/lxcutmp.c | 31 +++++++++++++++++++------------
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/configure.ac b/configure.ac
index f6c95c1..c9d1f06 100644
--- a/configure.ac
+++ b/configure.ac
@@ -521,7 +521,7 @@ AC_CHECK_FUNCS([setns pivot_root sethostname unshare rand_r confstr])
 AC_CHECK_LIB(pthread, main)
 AC_CHECK_FUNCS(pthread_atfork)
 AC_CHECK_LIB(util, openpty)
-AC_CHECK_FUNCS([openpty hasmntopt setmntent endmntent])
+AC_CHECK_FUNCS([openpty hasmntopt setmntent endmntent utmpxname])
 AC_CHECK_FUNCS([getline],
 	AM_CONDITIONAL(HAVE_GETLINE, true)
 	AC_DEFINE(HAVE_GETLINE,1,[Have getline]),
diff --git a/src/lxc/lxcutmp.c b/src/lxc/lxcutmp.c
index 6c9e6f2..15dd71c 100644
--- a/src/lxc/lxcutmp.c
+++ b/src/lxc/lxcutmp.c
@@ -68,6 +68,10 @@ static int timerfd_settime (int __ufd, int __flags,
 #endif
 #ifdef HAVE_UTMPX_H
 #include <utmpx.h>
+#ifndef HAVE_UTMPXNAME
+#include <utmp.h>
+#endif
+
 #else
 #include <utmp.h>
 
@@ -75,18 +79,6 @@ static int timerfd_settime (int __ufd, int __flags,
 #define RUN_LVL 1
 #endif
 
-static int utmpxname(const char *file) {
-	int result;
-	result = utmpname(file);
-
-#ifdef IS_BIONIC
-	/* Yeah bionic is that weird */
-	result = result - 1;
-#endif
-
-	return result;
-}
-
 static void setutxent(void) {
 	return setutent();
 }
@@ -104,6 +96,21 @@ static void endutxent (void) {
 #endif
 }
 #endif
+
+#ifndef HAVE_UTMPXNAME
+static int utmpxname(const char *file) {
+	int result;
+	result = utmpname(file);
+
+#ifdef IS_BIONIC
+	/* Yeah bionic is that weird */
+	result = result - 1;
+#endif
+
+	return result;
+}
+#endif
+
 #undef __USE_GNU
 
 /* This file watches the /var/run/utmp file in the container
-- 
1.8.5.3