Index: projects/bectl/lib/libbe/be.h
===================================================================
--- projects/bectl/lib/libbe/be.h	(revision 336728)
+++ projects/bectl/lib/libbe/be.h	(revision 336729)
@@ -1,118 +1,119 @@
 /*
  * be.h
  *
  * Copyright (c) 2017 Kyle J. Kneitinger <kyle@kneit.in>
  * All rights reserved.
  *
  * 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 REGENTS 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 REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * 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
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #ifndef _LIBBE_H
 #define _LIBBE_H
 
 #include <libnvpair.h>
 #include <stdbool.h>
 
 #define BE_MAXPATHLEN    512
 
 typedef struct libbe_handle libbe_handle_t;
 
 typedef enum be_error {
 	BE_ERR_SUCCESS = 0,     /* No error */
 	BE_ERR_INVALIDNAME,     /* invalid boot env name */
 	BE_ERR_EXISTS,          /* boot env name already taken */
 	BE_ERR_NOENT,           /* boot env doesn't exist */
 	BE_ERR_PERMS,           /* insufficient permissions */
 	BE_ERR_DESTROYACT,      /* cannot destroy active boot env */
 	BE_ERR_DESTROYMNT,      /* destroying a mounted be requires force */
 	BE_ERR_PATHLEN,         /* provided name exceeds maximum length limit */
 	BE_ERR_INVORIGIN,       /* snapshot origin's mountpoint is not '/' */
 	BE_ERR_NOORIGIN,        /* could not open snapshot's origin */
 	BE_ERR_MOUNTED,         /* boot environment is already mounted */
 	BE_ERR_NOMOUNT,         /* boot environment is not mounted */
 	BE_ERR_ZFSOPEN,         /* calling zfs_open() failed */
 	BE_ERR_ZFSCLONE,        /* error when calling zfs_clone to create be */
 	BE_ERR_UNKNOWN,         /* unknown error */
 } be_error_t;
 
 
 /* Library handling functions: be.c */
 libbe_handle_t *libbe_init(void);
 void libbe_close(libbe_handle_t *);
 
 /* Bootenv information functions: be_info.c */
 const char *be_active_name(libbe_handle_t *);
 const char *be_active_path(libbe_handle_t *);
 const char *be_nextboot_name(libbe_handle_t *);
 const char *be_nextboot_path(libbe_handle_t *);
 const char *be_root_path(libbe_handle_t *);
 
 int be_get_bootenv_props(libbe_handle_t *, nvlist_t *);
 int be_prop_list_alloc(nvlist_t **be_list);
 void be_prop_list_free(nvlist_t *be_list);
 
 int be_activate(libbe_handle_t *, char *, bool);
 
 /* Bootenv creation functions */
 int be_create(libbe_handle_t *, char *);
 int be_create_from_existing(libbe_handle_t *, const char *, const char *);
 int be_create_from_existing_snap(libbe_handle_t *, const char *, const char *);
 int be_snapshot(libbe_handle_t *, const char *, const char *, bool, char *);
 
 /* Bootenv manipulation functions */
 int be_rename(libbe_handle_t *, char *, char *);
 
 /* Bootenv removal functions */
 
 typedef enum {
 	BE_DESTROY_FORCE = 1 << 0,
 } be_destroy_opt_t;
 
 int be_destroy(libbe_handle_t *, char *, int);
 
 /* Bootenv mounting functions: be_access.c */
 
 typedef enum {
 	BE_MNT_FORCE		= 1 << 0,
 		BE_MNT_DEEP	= 1 << 1,
 } be_mount_opt_t;
 
 int be_mount(libbe_handle_t *, char *, char *, int, char *);
 int be_unmount(libbe_handle_t *, char *, int);
+int be_mounted_at(libbe_handle_t *, const char *path, nvlist_t *);
 
 /* Error related functions: be_error.c */
 int libbe_errno(libbe_handle_t *);
 const char *libbe_error_description(libbe_handle_t *);
 void libbe_print_on_error(libbe_handle_t *, bool);
 
 /* Utility Functions */
 int be_root_concat(libbe_handle_t *, const char *, char *);
 int be_validate_name(libbe_handle_t * __unused, const char *);
 int be_validate_snap(libbe_handle_t *, const char *);
 bool be_exists(libbe_handle_t *, char *);
 
 int be_export(libbe_handle_t *, char *, int fd);
 int be_import(libbe_handle_t *, char *, int fd);
 
 int be_add_child(libbe_handle_t *, char *, bool);
 
 #endif  /* _LIBBE_H */
Index: projects/bectl/lib/libbe/be_access.c
===================================================================
--- projects/bectl/lib/libbe/be_access.c	(revision 336728)
+++ projects/bectl/lib/libbe/be_access.c	(revision 336729)
@@ -1,121 +1,184 @@
 /*
  * be_access.c
  *
  * Copyright (c) 2017 Kyle J. Kneitinger <kyle@kneit.in>
  * All rights reserved.
  *
  * 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 REGENTS 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 REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * 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
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include "be.h"
 #include "be_impl.h"
 
+struct be_mountcheck_info {
+	const char *path;
+	char *name;
+};
+
+static int
+be_mountcheck_cb(zfs_handle_t *zfs_hdl, void *data)
+{
+	struct be_mountcheck_info *info;
+	char *mountpoint;
+
+	if (data == NULL)
+		return (1);
+	info = (struct be_mountcheck_info *)data;
+	if (!zfs_is_mounted(zfs_hdl, &mountpoint))
+		return (0);
+	if (strcmp(mountpoint, info->path) == 0) {
+		info->name = strdup(zfs_get_name(zfs_hdl));
+		return (1);
+	}
+	return (0);
+}
+
+/*
+ * usage
+ */
+int
+be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
+{
+	char be[BE_MAXPATHLEN + 1];
+	zfs_handle_t *root_hdl;
+	struct be_mountcheck_info info;
+	prop_data_t propinfo;
+
+	bzero(&be, BE_MAXPATHLEN + 1);
+	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
+	    ZFS_TYPE_FILESYSTEM)) == NULL)
+		return (BE_ERR_ZFSOPEN);
+
+	info.path = path;
+	info.name = NULL;
+	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
+	zfs_close(root_hdl);
+
+	if (info.name != NULL) {
+		if (details != NULL) {
+			if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
+			    ZFS_TYPE_FILESYSTEM)) == NULL) {
+				free(info.name);
+				return (BE_ERR_ZFSOPEN);
+			}
+
+			propinfo.lbh = lbh;
+			propinfo.list = details;
+			prop_list_builder_cb(root_hdl, &propinfo);
+			zfs_close(root_hdl);
+		}
+		free(info.name);
+		return (0);
+	}
+	return (1);
+}
+
 /*
  * usage
  */
 int
 be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
     char *result_loc)
 {
 	char be[BE_MAXPATHLEN];
 	char mnt_temp[BE_MAXPATHLEN];
 	char *path;
 	int mntflags;
 	int err;
 
 	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
 		return (set_error(lbh, err));
 
 	if (!be_exists(lbh, bootenv))
 		return (set_error(lbh, BE_ERR_NOENT));
 
 	if (is_mounted(lbh->lzh, be, &path))
 		return (set_error(lbh, BE_ERR_MOUNTED));
 
 	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
 
 	/* Create mountpoint if it is not specified */
 	if (mountpoint == NULL) {
 		strcpy(mnt_temp, "/tmp/be_mount.XXXX");
 		if (mkdtemp(mnt_temp) == NULL)
 			/* XXX TODO: create error for this */
 			return (set_error(lbh, BE_ERR_UNKNOWN));
 	}
 
 	char opt = '\0';
 	if ((err = zmount(be, (mountpoint == NULL) ? mnt_temp : mountpoint,
 	    mntflags, __DECONST(char *, MNTTYPE_ZFS), NULL, 0, &opt, 1)) != 0)
 		/*
 		 * XXX TODO: zmount returns the nmount error, look into what
 		 * kind of errors we can report from that
 		 */
 		return (set_error(lbh, BE_ERR_UNKNOWN));
 
 	if (result_loc != NULL)
 		strcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint);
 
 	return (BE_ERR_SUCCESS);
 }
 
 
 /*
  * usage
  */
 int
 be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
 {
 	int err, mntflags;
 	char be[BE_MAXPATHLEN];
 	struct statfs *mntbuf;
 	int mntsize;
 	char *mntpath;
 
 	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
 		return (set_error(lbh, err));
 
 	if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0)
 		/* XXX TODO correct error */
 		return (set_error(lbh, BE_ERR_NOMOUNT));
 
 	mntpath = NULL;
 	for (int i = 0; i < mntsize; ++i) {
 		/* 0x000000de is the type number of zfs */
 		if (mntbuf[i].f_type != 0x000000de)
 			continue;
 
 		if (strcmp(mntbuf[i].f_mntfromname, be) == 0) {
 			mntpath = mntbuf[i].f_mntonname;
 			break;
 		}
 	}
 
 	if (mntpath == NULL)
 		return (set_error(lbh, BE_ERR_NOMOUNT));
 
 	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
 
 	if ((err = unmount(mntpath, mntflags)) != 0)
 		/* XXX TODO correct error */
 		return (set_error(lbh, BE_ERR_NOMOUNT));
 
 	return (set_error(lbh, BE_ERR_SUCCESS));
 }
Index: projects/bectl/lib/libbe/be_impl.h
===================================================================
--- projects/bectl/lib/libbe/be_impl.h	(revision 336728)
+++ projects/bectl/lib/libbe/be_impl.h	(revision 336729)
@@ -1,61 +1,68 @@
 /*
  * be_impl.h
  *
  * Copyright (c) 2017 Kyle J. Kneitinger <kyle@kneit.in>
  * All rights reserved.
  *
  * 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 REGENTS 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 REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * 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
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #ifndef _LIBBE_IMPL_H
 #define _LIBBE_IMPL_H
 
 #include <libzfs.h>
 
 #include "be.h"
 
-
 struct libbe_handle {
 	libzfs_handle_t *lzh;
 	zpool_handle_t *active_phandle;
 	char root[BE_MAXPATHLEN];
 	char rootfs[BE_MAXPATHLEN];
 	char bootfs[BE_MAXPATHLEN];
 	be_error_t error;
 	bool print_on_err;
 };
 
 struct libbe_deep_clone {
 	libbe_handle_t *lbh;
 	const char *bename;
 	const char *snapname;
 	const char *be_root;
 };
 
 struct libbe_dccb {
 	zfs_handle_t *zhp;
 	nvlist_t *props;
 };
+
+typedef struct prop_data {
+	nvlist_t *list;
+	libbe_handle_t *lbh;
+} prop_data_t;
+
+int prop_list_builder_cb(zfs_handle_t *, void *);
+int prop_list_builder(prop_data_t *);
 
 int set_error(libbe_handle_t *, be_error_t);
 
 #endif  /* _LIBBE_IMPL_H */
Index: projects/bectl/lib/libbe/be_info.c
===================================================================
--- projects/bectl/lib/libbe/be_info.c	(revision 336728)
+++ projects/bectl/lib/libbe/be_info.c	(revision 336729)
@@ -1,252 +1,244 @@
 /*
  * be_info.c
  *
  * Copyright (c) 2017 Kyle J. Kneitinger <kyle@kneit.in>
  * All rights reserved.
  *
  * 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 REGENTS 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 REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * 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
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include "be.h"
 #include "be_impl.h"
 
-typedef struct prop_data {
-	nvlist_t *list;
-	libbe_handle_t *lbh;
-} prop_data_t;
-
-static int prop_list_builder_cb(zfs_handle_t *, void *);
-static int prop_list_builder(prop_data_t *);
-
 /*
  * Returns the name of the active boot environment
  */
 const char *
 be_active_name(libbe_handle_t *lbh)
 {
 
 	return (strrchr(lbh->rootfs, '/') + sizeof(char));
 }
 
 
 /*
  * Returns full path of the active boot environment
  */
 const char *
 be_active_path(libbe_handle_t *lbh)
 {
 
 	return (lbh->rootfs);
 }
 
 /*
  * Returns the name of the next active boot environment
  */
 const char *
 be_nextboot_name(libbe_handle_t *lbh)
 {
 
 	return (strrchr(lbh->bootfs, '/') + sizeof(char));
 }
 
 
 /*
  * Returns full path of the active boot environment
  */
 const char *
 be_nextboot_path(libbe_handle_t *lbh)
 {
 
 	return (lbh->bootfs);
 }
 
 
 /*
  * Returns the path of the boot environment root dataset
  */
 const char *
 be_root_path(libbe_handle_t *lbh)
 {
 
 	return (lbh->root);
 }
 
 
 /*
  * Populates dsnvl with one nvlist per bootenv dataset describing the properties
  * of that dataset that we've declared ourselves to care about.
  */
 int
 be_get_bootenv_props(libbe_handle_t *lbh, nvlist_t *dsnvl)
 {
 	prop_data_t data;
 
 	data.lbh = lbh;
 	data.list = dsnvl;
 	return (prop_list_builder(&data));
 }
 
 
 /*
  * Internal callback function used by zfs_iter_filesystems. For each dataset in
  * the bootenv root, populate an nvlist_t of its relevant properties.
  * TODO: should any other properties be included?
  */
-static int
+int
 prop_list_builder_cb(zfs_handle_t *zfs_hdl, void *data_p)
 {
 	char buf[512], *mountpoint;
 	prop_data_t *data;
 	libbe_handle_t *lbh;
 	nvlist_t *props;
 	const char *dataset, *name;
 	boolean_t mounted;
 
 	/*
 	 * XXX TODO:
 	 *      some system for defining constants for the nvlist keys
 	 *      error checking
 	 */
 	data = (prop_data_t *)data_p;
 	lbh = data->lbh;
 
 	nvlist_alloc(&props, NV_UNIQUE_NAME, KM_SLEEP);
 
 	dataset = zfs_get_name(zfs_hdl);
 	nvlist_add_string(props, "dataset", dataset);
 
 	name = strrchr(dataset, '/') + 1;
 	nvlist_add_string(props, "name", name);
 
 	mounted = zfs_is_mounted(zfs_hdl, &mountpoint);
 	nvlist_add_boolean_value(props, "mounted", mounted);
 
 	if (mounted)
 		nvlist_add_string(props, "mountpoint", mountpoint);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_ORIGIN, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "origin", buf);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_CREATION, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "creation", buf);
 
 	nvlist_add_boolean_value(props, "active",
 	    (strcmp(be_active_path(lbh), dataset) == 0));
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_USED, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "used", buf);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_USEDDS, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "usedds", buf);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_USEDSNAP, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "usedsnap", buf);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_USEDREFRESERV, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "usedrefreserv", buf);
 
 	if (zfs_prop_get(zfs_hdl, ZFS_PROP_REFERENCED, buf, 512,
 	    NULL, NULL, 0, 1))
 		nvlist_add_string(props, "referenced", buf);
 
 	nvlist_add_boolean_value(props, "nextboot",
 	    (strcmp(be_nextboot_path(lbh), dataset) == 0));
 
 	nvlist_add_nvlist(data->list, name, props);
 
 	return (0);
 }
 
 
 /*
  * Updates the properties of each bootenv in the libbe handle
  * XXX TODO: rename to be_proplist_update
  * XXX TODO: ensure that this is always consistent (run after adds, deletes,
  *       renames,etc
  */
-static int
+int
 prop_list_builder(prop_data_t *data)
 {
 	zfs_handle_t *root_hdl;
 
 	if ((root_hdl = zfs_open(data->lbh->lzh, data->lbh->root,
 	    ZFS_TYPE_FILESYSTEM)) == NULL)
 		return (BE_ERR_ZFSOPEN);
 
 	/* XXX TODO: some error checking here */
 	zfs_iter_filesystems(root_hdl, prop_list_builder_cb, data);
 
 	zfs_close(root_hdl);
 
 	return (0);
 }
 
 
 int
 be_prop_list_alloc(nvlist_t **be_list)
 {
 
 	return (nvlist_alloc(be_list, NV_UNIQUE_NAME, KM_SLEEP));
 }
 
 /*
  * frees property list and its children
  */
 void
 be_prop_list_free(nvlist_t *be_list)
 {
 	nvlist_t *prop_list;
 	nvpair_t *be_pair;
 
 	be_pair = nvlist_next_nvpair(be_list, NULL);
 	if (nvpair_value_nvlist(be_pair, &prop_list) == 0)
 		nvlist_free(prop_list);
 
 	while ((be_pair = nvlist_next_nvpair(be_list, be_pair)) != NULL) {
 		if (nvpair_value_nvlist(be_pair, &prop_list) == 0)
 			nvlist_free(prop_list);
 	}
 }
 
 
 /*
  * Usage
  */
 bool
 be_exists(libbe_handle_t *lbh, char *be)
 {
 	char buf[BE_MAXPATHLEN];
 
 	be_root_concat(lbh, be, buf);
 
 	/*
 	 * XXX TODO: check mountpoint prop and see if its /, AND that result
 	 * with below expression.
 	 */
 	return (zfs_dataset_exists(lbh->lzh, buf, ZFS_TYPE_DATASET));
 }
Index: projects/bectl/lib/libbe/libbe.3
===================================================================
--- projects/bectl/lib/libbe/libbe.3	(revision 336728)
+++ projects/bectl/lib/libbe/libbe.3	(revision 336729)
@@ -1,200 +1,203 @@
 .\"
 .\" Copyright (c) 2017 Kyle Kneitinger
 .\" All rights reserved.
 .\"
 .\" 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
 .\" 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
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\" This manual page is based on the mp(3X) manual page from Sun Release
 .\" 4.1, dated 7 September 1989.  It's an old, crufty, and relatively ugly
 .\" manual page, but it does document what appears to be the "traditional"
 .\" libmp interface.
 .\"
 .\" $FreeBSD$
 .\"
 .Dd July 25, 2018
 .Dt LIBBE 3
 .Os
 .Sh NAME
 .Nm libbe
 .Nd library for creating, destroying and modifying ZFS boot environments.
 .Sh SYNOPSIS
 .In be.h
 .Pp
 Function prototypes are given in the main body of the text.
 .Pp
 Applications using this interface must be linked with
 .Fl l Ns Ar be
 .Sh DESCRIPTION
 .Pp
 .Nm
 interfaces with libzfs to provide a set of functions for various operations
 regarding ZFS boot environments including "deep" boot environments in which
 a boot environments has child datasets.
 .Pp
 A context structure is passed to each function, allowing for a small amount
 of state to be retained, such as errors from previous operations.
 .\" TODO: describe break on err functionality
 .Pp
 .Ft "libbe_handle_t *" Ns
 .Fn libbe_init "void" ;
 .Pp
 .Ft void
 .Fn libbe_close "libbe_handle_t *" ;
 .Pp
 .Ft "const char *" Ns
 .Fn be_active_name "libbe_handle_t *" ;
 .Pp
 .Ft "const char *" Ns
 .Fn be_active_path "libbe_handle_t *" ;
 .Pp
 .Ft "const char *" Ns
 .Fn be_root_path "libbe_handle_t *" ;
 .Pp
 .Ft "nvlist_t *" Ns
 .Fn  libbe_handle_t "libbe_handle_t " ;
 .Pp
 .Ft int
 .Fn be_create "libbe_handle_t *, char *" ;
 .Pp
 .Ft int
 .Fn be_create_from_existing "libbe_handle_t *, const char *, const char *" ;
 .Pp
 .Ft int
 .Fn be_rename "libbe_handle_t *, char *, char *" ;
 .Pp
 .\" TODO: Write up of destroy options
 .\" typedef enum {
 .\"	BE_DESTROY_FORCE = 1 << 0,
 .\" } be_destroy_opt_t;
 .Ft int
 .Fn be_destroy "libbe_handle_t *, char *, int" ;
 .Pp
 .\" TODO: Write up of mount options
 .\" typedef enum {
 .\"	BE_MNT_FORCE		= 1 << 0,
 .\"	BE_MNT_DEEP		= 1 << 1,
 .\" } be_mount_opt_t;
 .Ft int
 .Fn be_mount "libbe_handle_t *, char *, char *, int" ;
 .Pp
 .Ft int
+.Fn be_mounted_at "libbe_handle_t *, const char *, nvlist_t" ;
+.Pp
+.Ft int
 .Fn be_unmount "libbe_handle_t *, char *, int" ;
 .Pp
 .Ft int
 .Fn libbe_errno "libbe_handle_t *" ;
 .Pp
 .Ft "const char *" Ns
 .Fn libbe_error_description "libbe_handle_t *" ;
 .Pp
 .Ft void
 .Fn libbe_print_on_error "libbe_handle_t *, bool" ;
 .Pp
 .Ft int
 .Fn be_root_concat "libbe_handle_t *, const char *, char *" ;
 .Pp
 .Ft int
 .Fn be_validate_name "libbe_handle_t *, const char *" ;
 .Pp
 .Ft int
 .Fn be_validate_snap "libbe_handle_t *, const char *" ;
 .Pp
 .Ft bool
 .Fn be_exists "libbe_handle_t *, char *" ;
 .Pp
 .Ft int
 .Fn be_export "libbe_handle_t *, char *, int fd" ;
 .Pp
 .Ft int
 .Fn be_import "libbe_handle_t *, char *, int fd" ;
 .Pp
 .Ft int
 .Fn be_add_child "libbe_handle_t *, char *, bool" ;
 .Pp
 .Ft int
 .Fn be_prop_list_alloc "nvlist_t **" ;
 .Pp
 .Ft int
 .Fn be_get_bootenv_props "libbe_handle_t *, nvlist_t *" ;
 .Pp
 .Ft void
 .Fn be_prop_list_free "nvlist_t *" ;
 .\" .Ft void
 .\" .Fn mp_mfree "MINT *mp" ;
 .\" .Bd -ragged -offset indent
 .\" .Fn mp_itom
 .\" returns an
 .\" .Vt MINT
 .\" with the value of
 .\" .Fa n .
 .\" .Fn mp_xtom
 .\" returns an
 .\" .Vt MINT
 .\" with the value of
 .\" .Fa s ,
 .\" which is treated to be in hexadecimal.
 .\" The return values from
 .\" .Fn mp_itom
 .\" and
 .\" .Fn mp_xtom
 .\" must be released with
 .\" .Fn mp_mfree
 .\" when they are no longer needed.
 .\" .Fn mp_mtox
 .\" returns a null-terminated hexadecimal string having the value of
 .\" .Fa mp ;
 .\" its return value must be released with
 .\" .Fn free
 .\" .Pq Xr free 3
 .\" when it is no longer needed.
 .\" .Ed
 .\" .Pp
 .Sh DIAGNOSTICS
 Upon error, one of the following values will be returned.
 .\" TODO: make each entry on its own line.
 .Bd -ragged -offset indent
 BE_ERR_SUCCESS,
 BE_ERR_INVALIDNAME,
 BE_ERR_EXISTS,
 BE_ERR_NOENT,
 BE_ERR_PERMS,
 BE_ERR_DESTROYACT,
 BE_ERR_DESTROYMNT,
 BE_ERR_PATHLEN,
 BE_ERR_INVORIGIN,
 BE_ERR_NOORIGIN,
 BE_ERR_MOUNTED,
 BE_ERR_NOMOUNT,
 BE_ERR_ZFSOPEN,
 BE_ERR_ZFSCLONE,
 BE_ERR_UNKNOWN
 .Ed
 .Sh SEE ALSO
 .Xr be 1 ,
 .Sh HISTORY
 .Nm
 and it's corresponding command,
 .Xr be 3 ,
 were written as a 2017 Google Summer of Code project with Allan Jude serving
 as a mentor.
 .\" TODO: update when implementation complete.
 .\" .Sh BUGS