Merge pull request #2496 from pqarmitage/updates

Fix building on (unsupported) CentOS 7

configure.ac

@@ -693,7 +693,7 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
     signs="d"
     WARN_SIGN=""
   ])
-CFLAGS="$CFLAGS -Werror=format $WARN_SIGN"
+CFLAGS="$SAV_CFLAGS -Werror=format $WARN_SIGN"
 for field in t tv.tv_sec tv.tv_usec ts.tv_sec ts.tv_nsec; do
   for sign in $signs; do
     for len in "" l ll; do
@@ -1695,7 +1695,7 @@ AC_CHECK_LIB(magic, magic_open,
 AM_CONDITIONAL([MAGIC], [test $MAGIC -eq 1])
 unset LIBS
 
-dnl -- Check for the following variables introduced at various times into Linux
+dnl -- Check for the following definitions introduced at various times into Linux
 dnl --RTAX_QUICKACK		dnl -- Linux 3.11
 dnl --FRA_SUPPRESS_PREFIXLEN	dnl -- Linux 3.12
 dnl --FRA_SUPPRESS_IFGROUP	dnl -- Linux 3.12
@@ -1736,6 +1736,19 @@ for flag in IFA_FLAGS; do
   fi
 done
 
+dnl -- Linux 3.15
+AC_CHECK_DECLS([F_OFD_SETLK], [], [],
+  [[
+    #include <unistd.h>
+    #include <fcntl.h>
+  ]])
+for flag in F_OFD_SETLK; do
+  AS_VAR_COPY([decl_var], [ac_cv_have_decl_$flag])
+  if test ${decl_var} = yes; then
+    add_system_opt[${flag}]
+  fi
+done
+
 dnl - Introduced in Linux 5.18
 AC_CHECK_DECLS([IFA_PROTO], [], [], [[#include <linux/if_addr.h>]])
 for flag in IFA_PROTO; do

keepalived/core/pidfile.c

@@ -158,7 +158,9 @@ create_pidfile(pidfile_t *pidf)
 	struct stat st, fd_st;
 	int error;
 	int ret;
+#if HAVE_DECL_F_OFD_SETLK == 1
 	struct flock fl = { .l_type = F_WRLCK, .l_whence = SEEK_SET, .l_start = 0, .l_len = 0 };
+#endif
 
 	for (;;) {
 		/* We want to create the file with permissions rw-r--r-- */
@@ -177,6 +179,7 @@ create_pidfile(pidfile_t *pidf)
 			return true;
 		}
 
+#if HAVE_DECL_F_OFD_SETLK == 1
 		fl.l_pid = 0;
 		while ((ret = fcntl(pidf->fd, F_OFD_SETLK, &fl)) && errno == EINTR);
 		if (ret) {
@@ -187,6 +190,7 @@ create_pidfile(pidfile_t *pidf)
 
 			break;
 		}
+#endif
 
 		/* Make sure the file has not been removed/moved */
 		if (stat(pidf->path, &st)) {