Index: tests/sys/audit/Makefile
===================================================================
--- tests/sys/audit/Makefile
+++ tests/sys/audit/Makefile
@@ -7,6 +7,7 @@
 ATF_TESTS_C+=	file-close
 ATF_TESTS_C+=	file-write
 ATF_TESTS_C+=	file-read
+ATF_TESTS_C+=	open
 
 SRCS.file-create+=	file-create.c
 SRCS.file-create+=	utils.c
@@ -18,6 +19,8 @@
 SRCS.file-write+=	utils.c
 SRCS.file-read+=	file-read.c
 SRCS.file-read+=	utils.c
+SRCS.open+=		open.c
+SRCS.open+=		utils.c
 
 TEST_METADATA+= timeout="30"
 TEST_METADATA+= required_user="root"
Index: tests/sys/audit/open.c
===================================================================
--- /dev/null
+++ tests/sys/audit/open.c
@@ -0,0 +1,191 @@
+/*-
+ * Copyright (c) 2018 Aniket Pandey
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Note: open(2) and openat(2) have 12 events each for various values of 'flag'
+ * Please see: contrib/openbsm/etc/audit_event#L261
+ *
+ * 270:AUE_OPENAT_R:openat(2) - read:fr
+ * 271:AUE_OPENAT_RC:openat(2) - read,creat:fc,fr,fa,fm
+ * 272:AUE_OPENAT_RT:openat(2) - read,trunc:fd,fr,fa,fm
+ * 273:AUE_OPENAT_RTC:openat(2) - read,creat,trunc:fc,fd,fr,fa,fm
+ * 274:AUE_OPENAT_W:openat(2) - write:fw
+ * 275:AUE_OPENAT_WC:openat(2) - write,creat:fc,fw,fa,fm
+ * 276:AUE_OPENAT_WT:openat(2) - write,trunc:fd,fw,fa,fm
+ * 277:AUE_OPENAT_WTC:openat(2) - write,creat,trunc:fc,fd,fw,fa,fm
+ * 278:AUE_OPENAT_RW:openat(2) - read,write:fr,fw
+ * 279:AUE_OPENAT_RWC:openat(2) - read,write,create:fc,fw,fr,fa,fm
+ * 280:AUE_OPENAT_RWT:openat(2) - read,write,trunc:fd,fw,fr,fa,fm
+ * 281:AUE_OPENAT_RWTC:openat(2) - read,write,creat,trunc:fc,fd,fw,fr,fa,fm
+ */
+
+#include <sys/syscall.h>
+
+#include <atf-c.h>
+#include <fcntl.h>
+
+#include "utils.h"
+
+static struct pollfd fds[1];
+static mode_t o_mode = 0777;
+static char extregex[80];
+static const char *path = "fileforaudit";
+static const char *errpath = "adirhasnoname/fileforaudit";
+
+/*
+ * Define test-cases for success and failure modes of both open(2) and openat(2)
+ */
+#define OPEN_AT_TC_DEFINE(mode, regex, flag, class) \
+ATF_TC_WITH_CLEANUP(open_ ## mode ## _success); \
+ATF_TC_HEAD(open_ ## mode ## _success, tc) \
+{ \
+	atf_tc_set_md_var(tc, "descr", "Tests the audit of a successful " \
+					"open(2) call for %s flag", #flag); \
+} \
+ATF_TC_BODY(open_ ## mode ## _success, tc) \
+{ \
+	snprintf(extregex, sizeof(extregex), \
+		"open.*%s.*fileforaudit.*return,success", regex); \
+	/* File needs to exist for successful open(2) invocation */ \
+	ATF_REQUIRE(open(path, O_CREAT, o_mode) != -1); \
+	FILE *pipefd = setup(fds, class); \
+	ATF_REQUIRE(syscall(SYS_open, path, flag) != -1); \
+	check_audit(fds, extregex, pipefd); \
+} \
+ATF_TC_CLEANUP(open_ ## mode ## _success, tc) \
+{ \
+	cleanup(); \
+} \
+ATF_TC_WITH_CLEANUP(open_ ## mode ## _failure); \
+ATF_TC_HEAD(open_ ## mode ## _failure, tc) \
+{ \
+	atf_tc_set_md_var(tc, "descr", "Tests the audit of an unsuccessful " \
+					"open(2) call for %s flag", #flag); \
+} \
+ATF_TC_BODY(open_ ## mode ## _failure, tc) \
+{ \
+	snprintf(extregex, sizeof(extregex), \
+		"open.*%s.*fileforaudit.*return,failure", regex); \
+	FILE *pipefd = setup(fds, class); \
+	ATF_REQUIRE_EQ(-1, syscall(SYS_open, errpath, flag)); \
+	check_audit(fds, extregex, pipefd); \
+} \
+ATF_TC_CLEANUP(open_ ## mode ## _failure, tc) \
+{ \
+	cleanup(); \
+} \
+ATF_TC_WITH_CLEANUP(openat_ ## mode ## _success); \
+ATF_TC_HEAD(openat_ ## mode ## _success, tc) \
+{ \
+	atf_tc_set_md_var(tc, "descr", "Tests the audit of a successful " \
+				"openat(2) call for %s flag", #flag); \
+} \
+ATF_TC_BODY(openat_ ## mode ## _success, tc) \
+{ \
+	snprintf(extregex, sizeof(extregex), \
+		"openat.*%s.*fileforaudit.*return,success", regex); \
+	/* File needs to exist for successful openat(2) invocation */ \
+	ATF_REQUIRE(open(path, O_CREAT, o_mode) != -1); \
+	FILE *pipefd = setup(fds, class); \
+	ATF_REQUIRE(openat(AT_FDCWD, path, flag) != -1); \
+	check_audit(fds, extregex, pipefd); \
+} \
+ATF_TC_CLEANUP(openat_ ## mode ## _success, tc) \
+{ \
+	cleanup(); \
+} \
+ATF_TC_WITH_CLEANUP(openat_ ## mode ## _failure); \
+ATF_TC_HEAD(openat_ ## mode ## _failure, tc) \
+{ \
+	atf_tc_set_md_var(tc, "descr", "Tests the audit of an unsuccessful " \
+				"openat(2) call for %s flag", #flag); \
+} \
+ATF_TC_BODY(openat_ ## mode ## _failure, tc) \
+{ \
+	snprintf(extregex, sizeof(extregex), \
+		"openat.*%s.*fileforaudit.*return,failure", regex); \
+	FILE *pipefd = setup(fds, class); \
+	ATF_REQUIRE_EQ(-1, openat(AT_FDCWD, errpath, flag)); \
+	check_audit(fds, extregex, pipefd); \
+} \
+ATF_TC_CLEANUP(openat_ ## mode ## _failure, tc) \
+{ \
+	cleanup(); \
+}
+
+/*
+ * Add both success and failure modes of open(2) and openat(2)
+ */
+#define OPEN_AT_TC_ADD(tp, mode) \
+do { \
+	ATF_TP_ADD_TC(tp, open_ ## mode ## _success); \
+	ATF_TP_ADD_TC(tp, open_ ## mode ## _failure); \
+	ATF_TP_ADD_TC(tp, openat_ ## mode ## _success); \
+	ATF_TP_ADD_TC(tp, openat_ ## mode ## _failure); \
+} while (0)
+
+
+/*
+ * Each of the 12 OPEN_AT_TC_DEFINE statement is a group of 4 test-cases
+ * corresponding to separate audit events for open(2) and openat(2)
+ */
+OPEN_AT_TC_DEFINE(read, "read", O_RDONLY, "fr")
+OPEN_AT_TC_DEFINE(read_creat, "read,creat", O_RDONLY | O_CREAT, "fr")
+OPEN_AT_TC_DEFINE(read_trunc, "read,trunc", O_RDONLY | O_TRUNC, "fr")
+OPEN_AT_TC_DEFINE(read_creat_trunc, "read,creat,trunc", O_RDONLY | O_CREAT
+	| O_TRUNC, "fr")
+OPEN_AT_TC_DEFINE(write, "write", O_WRONLY, "fw")
+OPEN_AT_TC_DEFINE(write_creat, "write,creat", O_WRONLY | O_CREAT, "fw")
+OPEN_AT_TC_DEFINE(write_trunc, "write,trunc", O_WRONLY | O_TRUNC, "fw")
+OPEN_AT_TC_DEFINE(write_creat_trunc, "write,creat,trunc", O_WRONLY | O_CREAT
+	| O_TRUNC, "fw")
+OPEN_AT_TC_DEFINE(read_write, "read,write", O_RDWR, "fr")
+OPEN_AT_TC_DEFINE(read_write_creat, "read,write,creat", O_RDWR | O_CREAT, "fw")
+OPEN_AT_TC_DEFINE(read_write_trunc, "read,write,trunc", O_RDWR | O_TRUNC, "fr")
+OPEN_AT_TC_DEFINE(read_write_creat_trunc, "read,write,creat,trunc", O_RDWR |
+	O_CREAT | O_TRUNC, "fw")
+
+
+ATF_TP_ADD_TCS(tp)
+{
+	OPEN_AT_TC_ADD(tp, read);
+	OPEN_AT_TC_ADD(tp, read_creat);
+	OPEN_AT_TC_ADD(tp, read_trunc);
+	OPEN_AT_TC_ADD(tp, read_creat_trunc);
+
+	OPEN_AT_TC_ADD(tp, write);
+	OPEN_AT_TC_ADD(tp, write_creat);
+	OPEN_AT_TC_ADD(tp, write_trunc);
+	OPEN_AT_TC_ADD(tp, write_creat_trunc);
+
+	OPEN_AT_TC_ADD(tp, read_write);
+	OPEN_AT_TC_ADD(tp, read_write_creat);
+	OPEN_AT_TC_ADD(tp, read_write_trunc);
+	OPEN_AT_TC_ADD(tp, read_write_creat_trunc);
+
+	return (atf_no_error());
+}