freebsd-skq/sbin/zfsbootcfg/zfsbootcfg.c
Andriy Gapon 97371ba2a9 zfsbootcfg: a simple tool to set next boot (one time) options for zfsboot
(gpt)zfsboot will read one-time boot directives from a special ZFS pool
area.  The area was previously described as "Boot Block Header", but
currently it is know as Pad2, marked as reserved and is zeroed out on
pool creation.  The new code interprets data in this area, if any, using
the same format as boot.config.  The area is immediately wiped out.
Failure to parse the directives results in a reboot right after the
cleanup.  Otherwise the boot sequence proceeds as usual.

zfsbootcfg writes zfsboot arguments specified on its command line to the
Pad2 area of a disk identified by vfs.zfs.boot.primary_pool and
vfs.zfs.boot.primary_vdev kenv variables that are set by loader during
boot.  Please see the manual page for more.

Thanks to all who reviewed, contributed and made suggestions!  There are
many potential improvements to the feature, please see the review for
details.

Reviewed by:	wblock (docs)
Discussed with:	jhb, tsoome
MFC after:	3 weeks
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D7612
2016-10-29 14:09:32 +00:00

99 lines
2.9 KiB
C

/*-
* Copyright (c) 2016 Andriy Gapon <avg@FreeBSD.org>
* 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 ``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 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <kenv.h>
#include <libzfs.h>
/* Keep in sync with zfsboot.c. */
#define MAX_COMMAND_LEN 512
int main(int argc, const char * const *argv)
{
char buf[32];
libzfs_handle_t *hdl;
uint64_t pool_guid;
uint64_t vdev_guid;
int zfs_fd;
int len;
if (argc != 2) {
fprintf(stderr, "usage: zfsbootcfg <boot.config(5) options>\n");
return (1);
}
len = strlen(argv[1]);
if (len >= MAX_COMMAND_LEN) {
fprintf(stderr, "options string is too long\n");
return (1);
}
if (kenv(KENV_GET, "vfs.zfs.boot.primary_pool", buf, sizeof(buf)) <= 0) {
perror("can't get vfs.zfs.boot.primary_pool");
return (1);
}
pool_guid = strtoumax(buf, NULL, 10);
if (pool_guid == 0) {
perror("can't parse vfs.zfs.boot.primary_pool");
return (1);
}
if (kenv(KENV_GET, "vfs.zfs.boot.primary_vdev", buf, sizeof(buf)) <= 0) {
perror("can't get vfs.zfs.boot.primary_vdev");
return (1);
}
vdev_guid = strtoumax(buf, NULL, 10);
if (vdev_guid == 0) {
perror("can't parse vfs.zfs.boot.primary_vdev");
return (1);
}
if ((hdl = libzfs_init()) == NULL) {
(void) fprintf(stderr, "internal error: failed to "
"initialize ZFS library\n");
return (1);
}
if (zpool_nextboot(hdl, pool_guid, vdev_guid, argv[1]) != 0) {
perror("ZFS_IOC_NEXTBOOT failed");
libzfs_fini(hdl);
return (1);
}
libzfs_fini(hdl);
printf("zfs next boot options are successfully written\n");
return (0);
}