1.\" 2.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3.\" 4.\" Copyright (c) 2017 Kyle Kneitinger 5.\" All rights reserved. 6.\" Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org> 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd August 12, 2018 32.Dt LIBBE 3 33.Os 34.Sh NAME 35.Nm libbe 36.Nd library for creating, destroying and modifying ZFS boot environments 37.Sh LIBRARY 38.Lb libbe 39.Sh SYNOPSIS 40.In be.h 41.Ft "libbe_handle_t *hdl" Ns 42.Fn libbe_init void 43.Pp 44.Ft void 45.Fn libbe_close "libbe_handle_t *hdl" 46.Pp 47.Ft const char * Ns 48.Fn be_active_name "libbe_handle_t *hdl" 49.Pp 50.Ft const char * Ns 51.Fn be_active_path "libbe_handle_t *hdl" 52.Pp 53.Ft const char * Ns 54.Fn be_nextboot_name "libbe_handle_t *hdl" 55.Pp 56.Ft const char * Ns 57.Fn be_nextboot_path "libbe_handle_t *hdl" 58.Pp 59.Ft const char * Ns 60.Fn be_root_path "libbe_handle_t *hdl" 61.Pp 62.Ft int 63.Fn be_create "libbe_handle_t *hdl" "const char *be_name" 64.Pp 65.Ft int 66.Fn be_create_from_existing "libbe_handle_t *hdl" "const char *be_name" "const char *be_origin" 67.Pp 68.Ft int 69.Fn be_create_from_existing_snap "libbe_handle_t *hdl" "const char *be_name" "const char *snap" 70.Pp 71.Ft int 72.Fn be_rename "libbe_handle_t *hdl" "const char *be_old" "const char *be_new" 73.Pp 74.Ft int 75.Fn be_activate "libbe_handle_t *hdl" "const char *be_name" "bool temporary" 76.Ft int 77.Fn be_destroy "libbe_handle_t *hdl" "const char *be_name" "int options" 78.Pp 79.Ft void 80.Fn be_nicenum "uint64_t num" "char *buf" "size_t bufsz" 81.Pp 82.\" TODO: Write up of mount options 83.\" typedef enum { 84.\" BE_MNT_FORCE = 1 << 0, 85.\" BE_MNT_DEEP = 1 << 1, 86.\" } be_mount_opt_t 87.Ft int 88.Fn be_mount "libbe_handle_t *hdl" "char *be_name" "char *mntpoint" "int flags" "char *result" 89.Pp 90.Ft int 91.Fn be_mounted_at "libbe_handle_t *hdl" "const char *path" "nvlist_t *details" 92.Pp 93.Ft int 94.Fn be_unmount "libbe_handle_t *hdl" "char *be_name" "int flags" 95.Pp 96.Ft int 97.Fn libbe_errno "libbe_handle_t *hdl" 98.Pp 99.Ft const char * Ns 100.Fn libbe_error_description "libbe_handle_t *hdl" 101.Pp 102.Ft void 103.Fn libbe_print_on_error "libbe_handle_t *hdl" "bool doprint" 104.Pp 105.Ft int 106.Fn be_root_concat "libbe_handle_t *hdl" "const char *be_name" "char *result" 107.Pp 108.Ft int 109.Fn be_validate_name "libbe_handle_t *hdl" "const char *be_name" 110.Pp 111.Ft int 112.Fn be_validate_snap "libbe_handle_t *hdl" "const char *snap" 113.Pp 114.Ft bool 115.Fn be_exists "libbe_handle_t *hdl" "char *be_name" 116.Pp 117.Ft int 118.Fn be_export "libbe_handle_t *hdl" "const char *be_name" "int fd" 119.Pp 120.Ft int 121.Fn be_import "libbe_handle_t *hdl" "const char *be_name" "int fd" 122.Pp 123.Ft int 124.Fn be_prop_list_alloc "nvlist_t **prop_list" 125.Pp 126.Ft int 127.Fn be_get_bootenv_props "libbe_handle_t *hdl" "nvlist_t *be_list" 128.Pp 129.Ft int 130.Fn be_get_dataset_props "libbe_handle_t *hdl" "const char *ds_name" "nvlist_t *props" 131.Pp 132.Ft int 133.Fn be_get_dataset_snapshots "libbe_handle_t *hdl" "const char *ds_name" "nvlist_t *snap_list" 134.Pp 135.Ft void 136.Fn be_prop_list_free "nvlist_t *prop_list" 137.Sh DESCRIPTION 138.Nm 139interfaces with libzfs to provide a set of functions for various operations 140regarding ZFS boot environments including "deep" boot environments in which 141a boot environments has child datasets. 142.Pp 143A context structure is passed to each function, allowing for a small amount 144of state to be retained, such as errors from previous operations. 145.Nm 146may be configured to print the corresponding error message to 147.Dv stderr 148when an error is encountered with 149.Fn libbe_print_on_error . 150.Pp 151All functions returning an 152.Vt int 153return 0 on success, or a 154.Nm 155errno otherwise as described in 156.Sx DIAGNOSTICS . 157.Pp 158The 159.Fn libbe_init 160function initializes 161.Nm , 162returning a 163.Vt "libbe_handle_t *" 164on success, or 165.Dv NULL 166on error. 167An error may occur if: 168.Bl -column 169.It /boot and / are not on the same filesystem and device, 170.It libzfs fails to initialize, 171.It The system has not been properly booted with a ZFS boot 172environment, 173.It Nm 174fails to open the zpool the active boot environment resides on, or 175.It Nm 176fails to locate the boot environment that is currently mounted. 177.El 178.Pp 179The 180.Fn libbe_close 181function frees all resources previously acquired in 182.Fn libbe_init , 183invalidating the handle in the process. 184.Pp 185The 186.Fn be_active_name 187function returns the name of the currently booted boot environment, 188.Pp 189The 190.Fn be_active_path 191function returns the full path of the currently booted boot environment. 192.Pp 193The 194.Fn be_nextboot_name 195function returns the name of the boot environment that will be active on reboot. 196.Pp 197The 198.Fn be_nextboot_path 199function returns the full path of the boot environment that will be 200active on reboot. 201.Pp 202The 203.Fn be_root_path 204function returns the boot environment root path. 205.Pp 206The 207.Fn be_create 208function creates a boot environment with the given name. 209It will be created from a snapshot of the currently booted boot environment. 210.Pp 211The 212.Fn be_create_from_existing 213function creates a boot environment with the given name from the name of an 214existing boot environment. 215A snapshot will be made of the base boot environment, and the new boot 216environment will be created from that. 217.Pp 218The 219.Fn be_create_from_existing_snap 220function creates a boot environment with the given name from an existing 221snapshot. 222.Pp 223The 224.Fn be_rename 225function renames a boot environment. 226.Pp 227The 228.Fn be_activate 229function makes a boot environment active on the next boot. 230If the 231.Fa temporary 232flag is set, then it will be active for the next boot only, as done by 233.Xr zfsbootcfg 8 . 234Next boot functionality is currently only available when booting in x86 BIOS 235mode. 236.Pp 237The 238.Fn be_destroy 239function will recursively destroy the given boot environment. 240It will not destroy a mounted boot environment unless the 241.Dv BE_DESTROY_FORCE 242option is set in 243.Fa options . 244.Pp 245The 246.Fn be_nicenum 247function will format 248.Fa name 249in a traditional ZFS humanized format, similar to 250.Xr humanize_number 3 . 251This function effectively proxies 252.Fn zfs_nicenum 253from libzfs. 254.Pp 255The 256.Fn be_mount 257function will mount the given boot environment. 258If 259.Fa mountpoint 260is 261.Dv NULL , 262a mount point will be generated in 263.Pa /tmp 264using 265.Xr mkdtemp 3 . 266If 267.Fa result 268is not 269.Dv NULL , 270the final mount point will be copied into it. 271Setting the 272.Dv BE_MNT_FORCE 273flag will pass 274.Dv MNT_FORCE 275to the underlying 276.Xr mount 2 277call. 278.Pp 279The 280.Fn be_mounted_at 281function will check if there is a boot environment mounted at the given 282.Fa path . 283If 284.Fa details 285is not 286.Dv NULL , 287it will be populated with a list of the mounted dataset's properties. 288This list of properties matches the properties collected by 289.Fn be_get_bootenv_props . 290.Pp 291The 292.Fn be_unmount 293function will unmount the given boot environment. 294Setting the 295.Dv BE_MNT_FORCE 296flag will pass 297.Dv MNT_FORCE 298to the underlying 299.Xr mount 2 300call. 301.Pp 302The 303.Fn libbe_errno 304function returns the 305.Nm 306errno. 307.Pp 308The 309.Fn libbe_error_description 310function returns a string description of the currently set 311.Nm 312errno. 313.Pp 314The 315.Fn libbe_print_on_error 316function will change whether or not 317.Nm 318prints the description of any encountered error to 319.Dv stderr , 320based on 321.Fa doprint . 322.Pp 323The 324.Fn be_root_concat 325function will concatenate the boot environment root and the given boot 326environment name into 327.Fa result . 328.Pp 329The 330.Fn be_validate_name 331function will validate the given boot environment name. 332.Pp 333The 334.Fn be_validate_snap 335function will validate the given snapshot name. 336The snapshot must have a valid name, exist, and have a mountpoint of 337.Pa / . 338This function does not set the internal library error state. 339.Pp 340The 341.Fn be_exists 342function will check whether the given boot environment exists and has a 343mountpoint of 344.Pa / . 345.Pp 346The 347.Fn be_export 348function will export the given boot environment to the file specified by 349.Fa fd . 350A snapshot will be created of the boot environment prior to export. 351.Pp 352The 353.Fn be_import 354function will import the boot environment in the file specified by 355.Fa fd , 356and give it the name 357.Fa be_name . 358.Pp 359The 360.Fn be_prop_list_alloc 361function allocates a property list suitable for passing to 362.Fn be_get_bootenv_props , 363.Fn be_get_dataset_props , 364or 365.Fn be_get_dataset_snapshots . 366It should be freed later by 367.Fa be_prop_list_free . 368.Pp 369The 370.Fn be_get_bootenv_props 371function will populate 372.Fa be_list 373with 374.Vt nvpair_t 375of boot environment names paired with an 376.Vt nvlist_t 377of their properties. 378The following properties are currently collected as appropriate: 379.Bl -column "Returned name" 380.It Sy Returned name Ta Sy Description 381.It dataset Ta - 382.It name Ta Boot environment name 383.It mounted Ta Current mount point 384.It mountpoint Ta Do mountpoint Dc property 385.It origin Ta Do origin Dc property 386.It creation Ta Do creation Dc property 387.It active Ta Currently booted environment 388.It used Ta Literal Do used Dc property 389.It usedds Ta Literal Do usedds Dc property 390.It usedsnap Ta Literal Do usedrefreserv Dc property 391.It referenced Ta Literal Do referenced Dc property 392.It nextboot Ta Active on next boot 393.El 394.Pp 395Only the 396.Dq dataset , 397.Dq name , 398.Dq active , 399and 400.Dq nextboot 401returned values will always be present. 402All other properties may be omitted if not available. 403.Pp 404The 405.Fn be_get_dataset_props 406function will get properties of the specified dataset. 407.Fa props 408is populated directly with a list of the properties as returned by 409.Fn be_get_bootenv_props . 410.Pp 411The 412.Fn be_get_dataset_snapshots 413function will retrieve all snapshots of the given dataset. 414.Fa snap_list 415will be populated with a list of 416.Vt nvpair_t 417exactly as specified by 418.Fn be_get_bootenv_props . 419.Pp 420The 421.Fn be_prop_list_free 422function will free the property list. 423.Sh DIAGNOSTICS 424Upon error, one of the following values will be returned. 425.\" TODO: make each entry on its own line. 426.Bd -ragged -offset indent 427BE_ERR_SUCCESS, 428BE_ERR_INVALIDNAME, 429BE_ERR_EXISTS, 430BE_ERR_NOENT, 431BE_ERR_PERMS, 432BE_ERR_DESTROYACT, 433BE_ERR_DESTROYMNT, 434BE_ERR_BADPATH, 435BE_ERR_PATHBUSY, 436BE_ERR_PATHLEN, 437BE_ERR_INVORIGIN, 438BE_ERR_NOORIGIN, 439BE_ERR_MOUNTED, 440BE_ERR_NOMOUNT, 441BE_ERR_ZFSOPEN, 442BE_ERR_ZFSCLONE, 443BE_ERR_IO, 444BE_ERR_NOPOOL, 445BE_ERR_NOMEM, 446BE_ERR_UNKNOWN 447.Ed 448.Sh SEE ALSO 449.Xr be 1 450.Sh HISTORY 451.Nm 452and its corresponding command, 453.Xr bectl 8 , 454were written as a 2017 Google Summer of Code project with Allan Jude serving 455as a mentor. 456Later work was done by 457.An Kyle Evans Aq Mt kevans@FreeBSD.org . 458