Bring over illumos ZFS FMA logic -- phase 1

This first phase brings over the ZFS SLM module, zfs_mod.c, to handle
auto operations in response to disk events. Disk event monitoring is
provided from libudev and generates the expected payload schema for
zfs_mod. This work leverages the recently added devid and phys_path
strings in the vdev label.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #4673

cmd/zed/agents/zfs_agents.h

@@ -0,0 +1,57 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License Version 1.0 (CDDL-1.0).
+ * You can obtain a copy of the license from the top-level file
+ * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
+ * You may not use this file except in compliance with the license.
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2016, Intel Corporation.
+ */
+
+#ifndef	ZFS_AGENTS_H
+#define	ZFS_AGENTS_H
+
+#include <libzfs.h>
+#include <libnvpair.h>
+
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/*
+ * Agents from ZFS FMA and syseventd - linked directly into ZED daemon binary
+ */
+
+/*
+ * ZFS Sysevent Linkable Module (SLM)
+ */
+extern int zfs_slm_init(libzfs_handle_t *zfs_hdl);
+extern void zfs_slm_fini(void);
+extern void zfs_slm_event(const char *, const char *, nvlist_t *);
+
+/*
+ * ZFS FMA Retire Agent
+ */
+extern int zfs_retire_init(libzfs_handle_t *zfs_hdl);
+extern void zfs_retire_fini(void);
+extern void zfs_retire_recv(nvlist_t *nvl, const char *class);
+
+/*
+ * ZFS FMA Diagnosis Engine
+ */
+extern int zfs_diagnosis_init(libzfs_handle_t *zfs_hdl);
+extern void zfs_diagnosis_fini(void);
+extern void zfs_diagnosis_recv(nvlist_t *nvl, const char *class);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* !ZFS_AGENTS_H */