/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012 by Delphix. All rights reserved.
*/
/*
* The zfs plug-in routines for GRUB are:
*
* zfs_mount() - locates a valid uberblock of the root pool and reads
* in its MOS at the memory address MOS.
*
* zfs_open() - locates a plain file object by following the MOS
* and places its dnode at the memory address DNODE.
*
* zfs_read() - read in the data blocks pointed by the DNODE.
*
* ZFS_SCRATCH is used as a working area.
*
* (memory addr) MOS DNODE ZFS_SCRATCH
* | | |
* +-------V---------V----------V---------------+
* memory | | dnode | dnode | scratch |
* | | 512B | 512B | area |
* +--------------------------------------------+
*/
#ifdef FSYS_ZFS
#include "shared.h"
#include "filesys.h"
#include "fsys_zfs.h"
/* cache for a file block of the currently zfs_open()-ed file */
static void *file_buf = NULL;
static uint64_t file_start = 0;
static uint64_t file_end = 0;
/* cache for a dnode block */
static dnode_phys_t *dnode_buf = NULL;
static dnode_phys_t *dnode_mdn = NULL;
static uint64_t dnode_start = 0;
static uint64_t dnode_end = 0;
static uint64_t pool_guid = 0;
static uberblock_t current_uberblock;
static char *stackbase;
decomp_entry_t decomp_table[ZIO_COMPRESS_FUNCTIONS] =
{
{"inherit", 0}, /* ZIO_COMPRESS_INHERIT */
{"on", lzjb_decompress}, /* ZIO_COMPRESS_ON */
{"off", 0}, /* ZIO_COMPRESS_OFF */
{"lzjb", lzjb_decompress}, /* ZIO_COMPRESS_LZJB */
{"empty", 0} /* ZIO_COMPRESS_EMPTY */
};
static int zio_read_data(blkptr_t *bp, void *buf, char *stack);
/*
* Our own version of bcmp().
*/
static int
zfs_bcmp(const void *s1, const void *s2, size_t n)
{
const uchar_t *ps1 = s1;
const uchar_t *ps2 = s2;
if (s1 != s2 && n != 0) {
do {
if (*ps1++ != *ps2++)
return (1);
} while (--n != 0);
}
return (0);
}
/*
* Our own version of log2(). Same thing as highbit()-1.
*/
static int
zfs_log2(uint64_t num)
{
int i = 0;
while (num > 1) {
i++;
num = num >> 1;
}
return (i);
}
/* Checksum Functions */
static void
zio_checksum_off(const void *buf, uint64_t size, zio_cksum_t *zcp)
{
ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0);
}
/* Checksum Table and Values */
zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = {
{{NULL, NULL}, 0, 0, "inherit"},
{{NULL, NULL}, 0, 0, "on"},
{{zio_checksum_off, zio_checksum_off}, 0, 0, "off"},
{{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, "label"},
{{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, "gang_header"},
{{NULL, NULL}, 0, 0, "zilog"},
{{fletcher_2_native, fletcher_2_byteswap}, 0, 0, "fletcher2"},
{{fletcher_4_native, fletcher_4_byteswap}, 1, 0, "fletcher4"},
{{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 0, "SHA256"},
{{NULL, NULL}, 0, 0, "zilog2"},
};
/*
* zio_checksum_verify: Provides support for checksum verification.
*
* Fletcher2, Fletcher4, and SHA256 are supported.
*
* Return:
* -1 = Failure
* 0 = Success
*/
static int
zio_checksum_verify(blkptr_t *bp, char *data, int size)
{
zio_cksum_t zc = bp->blk_cksum;
uint32_t checksum = BP_GET_CHECKSUM(bp);
int byteswap = BP_SHOULD_BYTESWAP(bp);
zio_eck_t *zec = (zio_eck_t *)(data + size) - 1;
zio_checksum_info_t *ci = &zio_checksum_table[checksum];
zio_cksum_t actual_cksum, expected_cksum;
/* byteswap is not supported */
if (byteswap)
return (-1);
if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL)
return (-1);
if (ci->ci_eck) {
expected_cksum = zec->zec_cksum;
zec->zec_cksum = zc;
ci->ci_func[0](data, size, &actual_cksum);
zec->zec_cksum = expected_cksum;
zc = expected_cksum;
} else {
ci->ci_func[byteswap](data, size, &actual_cksum);
}
if ((actual_cksum.zc_word[0] - zc.zc_word[0]) |
(actual_cksum.zc_word[1] - zc.zc_word[1]) |
(actual_cksum.zc_word[2] - zc.zc_word[2]) |
(actual_cksum.zc_word[3] - zc.zc_word[3]))
return (-1);
return (0);
}
/*
* vdev_label_start returns the physical disk offset (in bytes) of
* label "l".
*/
static uint64_t
vdev_label_start(uint64_t psize, int l)
{
return (l * sizeof (vdev_label_t) + (l < VDEV_LABELS / 2 ?
0 : psize - VDEV_LABELS * sizeof (vdev_label_t)));
}
/*
* vdev_uberblock_compare takes two uberblock structures and returns an integer
* indicating the more recent of the two.
* Return Value = 1 if ub2 is more recent
* Return Value = -1 if ub1 is more recent
* The most recent uberblock is determined using its transaction number and
* timestamp. The uberblock with the highest transaction number is
* considered "newer". If the transaction numbers of the two blocks match, the
* timestamps are compared to determine the "newer" of the two.
*/
static int
vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2)
{
if (ub1->ub_txg < ub2->ub_txg)
return (-1);
if (ub1->ub_txg > ub2->ub_txg)
return (1);
if (ub1->ub_timestamp < ub2->ub_timestamp)
return (-1);
if (ub1->ub_timestamp > ub2->ub_timestamp)
return (1);
return (0);
}
/*
* Three pieces of information are needed to verify an uberblock: the magic
* number, the version number, and the checksum.
*
* Return:
* 0 - Success
* -1 - Failure
*/
static int
uberblock_verify(uberblock_t *uber, uint64_t ub_size, uint64_t offset)
{
blkptr_t bp;
BP_ZERO(&bp);
BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
BP_SET_BYTEORDER(&bp, ZFS_HOST_BYTEORDER);
ZIO_SET_CHECKSUM(&bp.blk_cksum, offset, 0, 0, 0);
if (zio_checksum_verify(&bp, (char *)uber, ub_size) != 0)
return (-1);
if (uber->ub_magic == UBERBLOCK_MAGIC &&
SPA_VERSION_IS_SUPPORTED(uber->ub_version))
return (0);
return (-1);
}
/*
* Find the best uberblock.
* Return:
* Success - Pointer to the best uberblock.
* Failure - NULL
*/
static uberblock_t *
find_bestub(char *ub_array, uint64_t ashift, uint64_t sector)
{
uberblock_t *ubbest = NULL;
uberblock_t *ubnext;
uint64_t offset, ub_size;
int i;
ub_size = VDEV_UBERBLOCK_SIZE(ashift);
for (i = 0; i < VDEV_UBERBLOCK_COUNT(ashift); i++) {
ubnext = (uberblock_t *)ub_array;
ub_array += ub_size;
offset = (sector << SPA_MINBLOCKSHIFT) +
VDEV_UBERBLOCK_OFFSET(ashift, i);
if (uberblock_verify(ubnext, ub_size, offset) != 0)
continue;
if (ubbest == NULL ||
vdev_uberblock_compare(ubnext, ubbest) > 0)
ubbest = ubnext;
}
return (ubbest);
}
/*
* Read a block of data based on the gang block address dva,
* and put its data in buf.
*
* Return:
* 0 - success
* 1 - failure
*/
static int
zio_read_gang(blkptr_t *bp, dva_t *dva, void *buf, char *stack)
{
zio_gbh_phys_t *zio_gb;
uint64_t offset, sector;
blkptr_t tmpbp;
int i;
zio_gb = (zio_gbh_phys_t *)stack;
stack += SPA_GANGBLOCKSIZE;
offset = DVA_GET_OFFSET(dva);
sector = DVA_OFFSET_TO_PHYS_SECTOR(offset);
/* read in the gang block header */
if (devread(sector, 0, SPA_GANGBLOCKSIZE, (char *)zio_gb) == 0) {
grub_printf("failed to read in a gang block header\n");
return (1);
}
/* self checksuming the gang block header */
BP_ZERO(&tmpbp);
BP_SET_CHECKSUM(&tmpbp, ZIO_CHECKSUM_GANG_HEADER);
BP_SET_BYTEORDER(&tmpbp, ZFS_HOST_BYTEORDER);
ZIO_SET_CHECKSUM(&tmpbp.blk_cksum, DVA_GET_VDEV(dva),
DVA_GET_OFFSET(dva), bp->blk_birth, 0);
if (zio_checksum_verify(&tmpbp, (char *)zio_gb, SPA_GANGBLOCKSIZE)) {
grub_printf("failed to checksum a gang block header\n");
return (1);
}
for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
if (zio_gb->zg_blkptr[i].blk_birth == 0)
continue;
if (zio_read_data(&zio_gb->zg_blkptr[i], buf, stack))
return (1);
buf += BP_GET_PSIZE(&zio_gb->zg_blkptr[i]);
}
return (0);
}
/*
* Read in a block of raw data to buf.
*
* Return:
* 0 - success
* 1 - failure
*/
static int
zio_read_data(blkptr_t *bp, void *buf, char *stack)
{
int i, psize;
psize = BP_GET_PSIZE(bp);
/* pick a good dva from the block pointer */
for (i = 0; i < SPA_DVAS_PER_BP; i++) {
uint64_t offset, sector;
if (bp->blk_dva[i].dva_word[0] == 0 &&
bp->blk_dva[i].dva_word[1] == 0)
continue;
if (DVA_GET_GANG(&bp->blk_dva[i])) {
if (zio_read_gang(bp, &bp->blk_dva[i], buf, stack) == 0)
return (0);
} else {
/* read in a data block */
offset = DVA_GET_OFFSET(&bp->blk_dva[i]);
sector = DVA_OFFSET_TO_PHYS_SECTOR(offset);
if (devread(sector, 0, psize, buf) != 0)
return (0);
}
}
return (1);
}
/*
* Read in a block of data, verify its checksum, decompress if needed,
* and put the uncompressed data in buf.
*
* Return:
* 0 - success
* errnum - failure
*/
static int
zio_read(blkptr_t *bp, void *buf, char *stack)
{
int lsize, psize, comp;
char *retbuf;
comp = BP_GET_COMPRESS(bp);
lsize = BP_GET_LSIZE(bp);
psize = BP_GET_PSIZE(bp);
if ((unsigned int)comp >= ZIO_COMPRESS_FUNCTIONS ||
(comp != ZIO_COMPRESS_OFF &&
decomp_table[comp].decomp_func == NULL)) {
grub_printf("compression algorithm not supported\n");
return (ERR_FSYS_CORRUPT);
}
if ((char *)buf < stack && ((char *)buf) + lsize > stack) {
grub_printf("not enough memory allocated\n");
return (ERR_WONT_FIT);
}
retbuf = buf;
if (comp != ZIO_COMPRESS_OFF) {
buf = stack;
stack += psize;
}
if (zio_read_data(bp, buf, stack) != 0) {
grub_printf("zio_read_data failed\n");
return (ERR_FSYS_CORRUPT);
}
if (zio_checksum_verify(bp, buf, psize) != 0) {
grub_printf("checksum verification failed\n");
return (ERR_FSYS_CORRUPT);
}
if (comp != ZIO_COMPRESS_OFF)
decomp_table[comp].decomp_func(buf, retbuf, psize, lsize);
return (0);
}
/*
* Get the block from a block id.
* push the block onto the stack.
*
* Return:
* 0 - success
* errnum - failure
*/
static int
dmu_read(dnode_phys_t *dn, uint64_t blkid, void *buf, char *stack)
{
int idx, level;
blkptr_t *bp_array = dn->dn_blkptr;
int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
blkptr_t *bp, *tmpbuf;
bp = (blkptr_t *)stack;
stack += sizeof (blkptr_t);
tmpbuf = (blkptr_t *)stack;
stack += 1<<dn->dn_indblkshift;
for (level = dn->dn_nlevels - 1; level >= 0; level--) {
idx = (blkid >> (epbs * level)) & ((1<<epbs)-1);
*bp = bp_array[idx];
if (level == 0)
tmpbuf = buf;
if (BP_IS_HOLE(bp)) {
grub_memset(buf, 0,
dn->dn_datablkszsec << SPA_MINBLOCKSHIFT);
break;
} else if (errnum = zio_read(bp, tmpbuf, stack)) {
return (errnum);
}
bp_array = tmpbuf;
}
return (0);
}
/*
* mzap_lookup: Looks up property described by "name" and returns the value
* in "value".
*
* Return:
* 0 - success
* errnum - failure
*/
static int
mzap_lookup(mzap_phys_t *zapobj, int objsize, const char *name,
uint64_t *value)
{
int i, chunks;
mzap_ent_phys_t *mzap_ent = zapobj->mz_chunk;
chunks = objsize / MZAP_ENT_LEN - 1;
for (i = 0; i < chunks; i++) {
if (grub_strcmp(mzap_ent[i].mze_name, name) == 0) {
*value = mzap_ent[i].mze_value;
return (0);
}
}
return (ERR_FSYS_CORRUPT);
}
static uint64_t
zap_hash(uint64_t salt, const char *name)
{
static uint64_t table[256];
const uint8_t *cp;
uint8_t c;
uint64_t crc = salt;
if (table[128] == 0) {
uint64_t *ct;
int i, j;
for (i = 0; i < 256; i++) {
for (ct = table + i, *ct = i, j = 8; j > 0; j--)
*ct = (*ct >> 1) ^ (-(*ct & 1) &
ZFS_CRC64_POLY);
}
}
if (crc == 0 || table[128] != ZFS_CRC64_POLY) {
errnum = ERR_FSYS_CORRUPT;
return (0);
}
for (cp = (const uint8_t *)name; (c = *cp) != '\0'; cp++)
crc = (crc >> 8) ^ table[(crc ^ c) & 0xFF];
/*
* Only use 28 bits, since we need 4 bits in the cookie for the
* collision differentiator. We MUST use the high bits, since
* those are the ones that we first pay attention to when
* choosing the bucket.
*/
crc &= ~((1ULL << (64 - 28)) - 1);
return (crc);
}
/*
* Only to be used on 8-bit arrays.
* array_len is actual len in bytes (not encoded le_value_length).
* buf is null-terminated.
*/
static int
zap_leaf_array_equal(zap_leaf_phys_t *l, int blksft, int chunk,
int array_len, const char *buf)
{
int bseen = 0;
while (bseen < array_len) {
struct zap_leaf_array *la =
&ZAP_LEAF_CHUNK(l, blksft, chunk).l_array;
int toread = MIN(array_len - bseen, ZAP_LEAF_ARRAY_BYTES);
if (chunk >= ZAP_LEAF_NUMCHUNKS(blksft))
return (0);
if (zfs_bcmp(la->la_array, buf + bseen, toread) != 0)
break;
chunk = la->la_next;
bseen += toread;
}
return (bseen == array_len);
}
/*
* Given a zap_leaf_phys_t, walk thru the zap leaf chunks to get the
* value for the property "name".
*
* Return:
* 0 - success
* errnum - failure
*/
static int
zap_leaf_lookup(zap_leaf_phys_t *l, int blksft, uint64_t h,
const char *name, uint64_t *value)
{
uint16_t chunk;
struct zap_leaf_entry *le;
/* Verify if this is a valid leaf block */
if (l->l_hdr.lh_block_type != ZBT_LEAF)
return (ERR_FSYS_CORRUPT);
if (l->l_hdr.lh_magic != ZAP_LEAF_MAGIC)
return (ERR_FSYS_CORRUPT);
for (chunk = l->l_hash[LEAF_HASH(blksft, h)];
chunk != CHAIN_END; chunk = le->le_next) {
if (chunk >= ZAP_LEAF_NUMCHUNKS(blksft))
return (ERR_FSYS_CORRUPT);
le = ZAP_LEAF_ENTRY(l, blksft, chunk);
/* Verify the chunk entry */
if (le->le_type != ZAP_CHUNK_ENTRY)
return (ERR_FSYS_CORRUPT);
if (le->le_hash != h)
continue;
if (zap_leaf_array_equal(l, blksft, le->le_name_chunk,
le->le_name_length, name)) {
struct zap_leaf_array *la;
uint8_t *ip;
if (le->le_int_size != 8 || le->le_value_length != 1)
return (ERR_FSYS_CORRUPT);
/* get the uint64_t property value */
la = &ZAP_LEAF_CHUNK(l, blksft,
le->le_value_chunk).l_array;
ip = la->la_array;
*value = (uint64_t)ip[0] << 56 | (uint64_t)ip[1] << 48 |
(uint64_t)ip[2] << 40 | (uint64_t)ip[3] << 32 |
(uint64_t)ip[4] << 24 | (uint64_t)ip[5] << 16 |
(uint64_t)ip[6] << 8 | (uint64_t)ip[7];
return (0);
}
}
return (ERR_FSYS_CORRUPT);
}
/*
* Fat ZAP lookup
*
* Return:
* 0 - success
* errnum - failure
*/
static int
fzap_lookup(dnode_phys_t *zap_dnode, zap_phys_t *zap,
const char *name, uint64_t *value, char *stack)
{
zap_leaf_phys_t *l;
uint64_t hash, idx, blkid;
int blksft = zfs_log2(zap_dnode->dn_datablkszsec << DNODE_SHIFT);
/* Verify if this is a fat zap header block */
if (zap->zap_magic != (uint64_t)ZAP_MAGIC ||
zap->zap_flags != 0)
return (ERR_FSYS_CORRUPT);
hash = zap_hash(zap->zap_salt, name);
if (errnum)
return (errnum);
/* get block id from index */
if (zap->zap_ptrtbl.zt_numblks != 0) {
/* external pointer tables not supported */
return (ERR_FSYS_CORRUPT);
}
idx = ZAP_HASH_IDX(hash, zap->zap_ptrtbl.zt_shift);
blkid = ((uint64_t *)zap)[idx + (1<<(blksft-3-1))];
/* Get the leaf block */
l = (zap_leaf_phys_t *)stack;
stack += 1<<blksft;
if ((1<<blksft) < sizeof (zap_leaf_phys_t))
return (ERR_FSYS_CORRUPT);
if (errnum = dmu_read(zap_dnode, blkid, l, stack))
return (errnum);
return (zap_leaf_lookup(l, blksft, hash, name, value));
}
/*
* Read in the data of a zap object and find the value for a matching
* property name.
*
* Return:
* 0 - success
* errnum - failure
*/
static int
zap_lookup(dnode_phys_t *zap_dnode, const char *name, uint64_t *val,
char *stack)
{
uint64_t block_type;
int size;
void *zapbuf;
/* Read in the first block of the zap object data. */
zapbuf = stack;
size = zap_dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
stack += size;
if ((errnum = dmu_read(zap_dnode, 0, zapbuf, stack)) != 0)
return (errnum);
block_type = *((uint64_t *)zapbuf);
if (block_type == ZBT_MICRO) {
return (mzap_lookup(zapbuf, size, name, val));
} else if (block_type == ZBT_HEADER) {
/* this is a fat zap */
return (fzap_lookup(zap_dnode, zapbuf, name,
val, stack));
}
return (ERR_FSYS_CORRUPT);
}
typedef struct zap_attribute {
int za_integer_length;
uint64_t za_num_integers;
uint64_t za_first_integer;
char *za_name;
} zap_attribute_t;
typedef int (zap_cb_t)(zap_attribute_t *za, void *arg, char *stack);
static int
zap_iterate(dnode_phys_t *zap_dnode, zap_cb_t *cb, void *arg, char *stack)
{
uint32_t size = zap_dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
zap_attribute_t za;
int i;
mzap_phys_t *mzp = (mzap_phys_t *)stack;
stack += size;
if ((errnum = dmu_read(zap_dnode, 0, mzp, stack)) != 0)
return (errnum);
/*
* Iteration over fatzap objects has not yet been implemented.
* If we encounter a pool in which there are more features for
* read than can fit inside a microzap (i.e., more than 2048
* features for read), we can add support for fatzap iteration.
* For now, fail.
*/
if (mzp->mz_block_type != ZBT_MICRO) {
grub_printf("feature information stored in fatzap, pool "
"version not supported\n");
return (1);
}
za.za_integer_length = 8;
za.za_num_integers = 1;
for (i = 0; i < size / MZAP_ENT_LEN - 1; i++) {
mzap_ent_phys_t *mzep = &mzp->mz_chunk[i];
int err;
za.za_first_integer = mzep->mze_value;
za.za_name = mzep->mze_name;
err = cb(&za, arg, stack);
if (err != 0)
return (err);
}
return (0);
}
/*
* Get the dnode of an object number from the metadnode of an object set.
*
* Input
* mdn - metadnode to get the object dnode
* objnum - object number for the object dnode
* buf - data buffer that holds the returning dnode
* stack - scratch area
*
* Return:
* 0 - success
* errnum - failure
*/
static int
dnode_get(dnode_phys_t *mdn, uint64_t objnum, uint8_t type, dnode_phys_t *buf,
char *stack)
{
uint64_t blkid, blksz; /* the block id this object dnode is in */
int epbs; /* shift of number of dnodes in a block */
int idx; /* index within a block */
dnode_phys_t *dnbuf;
blksz = mdn->dn_datablkszsec << SPA_MINBLOCKSHIFT;
epbs = zfs_log2(blksz) - DNODE_SHIFT;
blkid = objnum >> epbs;
idx = objnum & ((1<<epbs)-1);
if (dnode_buf != NULL && dnode_mdn == mdn &&
objnum >= dnode_start && objnum < dnode_end) {
grub_memmove(buf, &dnode_buf[idx], DNODE_SIZE);
VERIFY_DN_TYPE(buf, type);
return (0);
}
if (dnode_buf && blksz == 1<<DNODE_BLOCK_SHIFT) {
dnbuf = dnode_buf;
dnode_mdn = mdn;
dnode_start = blkid << epbs;
dnode_end = (blkid + 1) << epbs;
} else {
dnbuf = (dnode_phys_t *)stack;
stack += blksz;
}
if (errnum = dmu_read(mdn, blkid, (char *)dnbuf, stack))
return (errnum);
grub_memmove(buf, &dnbuf[idx], DNODE_SIZE);
VERIFY_DN_TYPE(buf, type);
return (0);
}
/*
* Check if this is a special file that resides at the top
* dataset of the pool. Currently this is the GRUB menu,
* boot signature and boot signature backup.
* str starts with '/'.
*/
static int
is_top_dataset_file(char *str)
{
char *tptr;
if ((tptr = grub_strstr(str, "menu.lst")) &&
(tptr[8] == '\0' || tptr[8] == ' ') &&
*(tptr-1) == '/')
return (1);
if (grub_strncmp(str, BOOTSIGN_DIR"/",
grub_strlen(BOOTSIGN_DIR) + 1) == 0)
return (1);
if (grub_strcmp(str, BOOTSIGN_BACKUP) == 0)
return (1);
return (0);
}
static int
check_feature(zap_attribute_t *za, void *arg, char *stack)
{
const char **names = arg;
int i;
if (za->za_first_integer == 0)
return (0);
for (i = 0; names[i] != NULL; i++) {
if (grub_strcmp(za->za_name, names[i]) == 0) {
return (0);
}
}
grub_printf("missing feature for read '%s'\n", za->za_name);
return (ERR_NEWER_VERSION);
}
/*
* Get the file dnode for a given file name where mdn is the meta dnode
* for this ZFS object set. When found, place the file dnode in dn.
* The 'path' argument will be mangled.
*
* Return:
* 0 - success
* errnum - failure
*/
static int
dnode_get_path(dnode_phys_t *mdn, char *path, dnode_phys_t *dn,
char *stack)
{
uint64_t objnum, version;
char *cname, ch;
if (errnum = dnode_get(mdn, MASTER_NODE_OBJ, DMU_OT_MASTER_NODE,
dn, stack))
return (errnum);
if (errnum = zap_lookup(dn, ZPL_VERSION_STR, &version, stack))
return (errnum);
if (version > ZPL_VERSION)
return (-1);
if (errnum = zap_lookup(dn, ZFS_ROOT_OBJ, &objnum, stack))
return (errnum);
if (errnum = dnode_get(mdn, objnum, DMU_OT_DIRECTORY_CONTENTS,
dn, stack))
return (errnum);
/* skip leading slashes */
while (*path == '/')
path++;
while (*path && !grub_isspace(*path)) {
/* get the next component name */
cname = path;
while (*path && !grub_isspace(*path) && *path != '/')
path++;
ch = *path;
*path = 0; /* ensure null termination */
if (errnum = zap_lookup(dn, cname, &objnum, stack))
return (errnum);
objnum = ZFS_DIRENT_OBJ(objnum);
if (errnum = dnode_get(mdn, objnum, 0, dn, stack))
return (errnum);
*path = ch;
while (*path == '/')
path++;
}
/* We found the dnode for this file. Verify if it is a plain file. */
VERIFY_DN_TYPE(dn, DMU_OT_PLAIN_FILE_CONTENTS);
return (0);
}
/*
* Get the default 'bootfs' property value from the rootpool.
*
* Return:
* 0 - success
* errnum -failure
*/
static int
get_default_bootfsobj(dnode_phys_t *mosmdn, uint64_t *obj, char *stack)
{
uint64_t objnum = 0;
dnode_phys_t *dn = (dnode_phys_t *)stack;
stack += DNODE_SIZE;
if (errnum = dnode_get(mosmdn, DMU_POOL_DIRECTORY_OBJECT,
DMU_OT_OBJECT_DIRECTORY, dn, stack))
return (errnum);
/*
* find the object number for 'pool_props', and get the dnode
* of the 'pool_props'.
*/
if (zap_lookup(dn, DMU_POOL_PROPS, &objnum, stack))
return (ERR_FILESYSTEM_NOT_FOUND);
if (errnum = dnode_get(mosmdn, objnum, DMU_OT_POOL_PROPS, dn, stack))
return (errnum);
if (zap_lookup(dn, ZPOOL_PROP_BOOTFS, &objnum, stack))
return (ERR_FILESYSTEM_NOT_FOUND);
if (!objnum)
return (ERR_FILESYSTEM_NOT_FOUND);
*obj = objnum;
return (0);
}
/*
* List of pool features that the grub implementation of ZFS supports for
* read. Note that features that are only required for write do not need
* to be listed here since grub opens pools in read-only mode.
*/
static const char *spa_feature_names[] = {
NULL
};
/*
* Checks whether the MOS features that are active are supported by this
* (GRUB's) implementation of ZFS.
*
* Return:
* 0: Success.
* errnum: Failure.
*/
static int
check_mos_features(dnode_phys_t *mosmdn, char *stack)
{
uint64_t objnum;
dnode_phys_t *dn;
uint8_t error = 0;
dn = (dnode_phys_t *)stack;
stack += DNODE_SIZE;
if ((errnum = dnode_get(mosmdn, DMU_POOL_DIRECTORY_OBJECT,
DMU_OT_OBJECT_DIRECTORY, dn, stack)) != 0)
return (errnum);
/*
* Find the object number for 'features_for_read' and retrieve its
* corresponding dnode. Note that we don't check features_for_write
* because GRUB is not opening the pool for write.
*/
if ((errnum = zap_lookup(dn, DMU_POOL_FEATURES_FOR_READ, &objnum,
stack)) != 0)
return (errnum);
if ((errnum = dnode_get(mosmdn, objnum, DMU_OTN_ZAP_METADATA,
dn, stack)) != 0)
return (errnum);
return (zap_iterate(dn, check_feature, spa_feature_names, stack));
}
/*
* Given a MOS metadnode, get the metadnode of a given filesystem name (fsname),
* e.g. pool/rootfs, or a given object number (obj), e.g. the object number
* of pool/rootfs.
*
* If no fsname and no obj are given, return the DSL_DIR metadnode.
* If fsname is given, return its metadnode and its matching object number.
* If only obj is given, return the metadnode for this object number.
*
* Return:
* 0 - success
* errnum - failure
*/
static int
get_objset_mdn(dnode_phys_t *mosmdn, char *fsname, uint64_t *obj,
dnode_phys_t *mdn, char *stack)
{
uint64_t objnum, headobj;
char *cname, ch;
blkptr_t *bp;
objset_phys_t *osp;
int issnapshot = 0;
char *snapname;
if (fsname == NULL && obj) {
headobj = *obj;
goto skip;
}
if (errnum = dnode_get(mosmdn, DMU_POOL_DIRECTORY_OBJECT,
DMU_OT_OBJECT_DIRECTORY, mdn, stack))
return (errnum);
if (errnum = zap_lookup(mdn, DMU_POOL_ROOT_DATASET, &objnum,
stack))
return (errnum);
if (errnum = dnode_get(mosmdn, objnum, DMU_OT_DSL_DIR, mdn, stack))
return (errnum);
if (fsname == NULL) {
headobj =
((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_head_dataset_obj;
goto skip;
}
/* take out the pool name */
while (*fsname && !grub_isspace(*fsname) && *fsname != '/')
fsname++;
while (*fsname && !grub_isspace(*fsname)) {
uint64_t childobj;
while (*fsname == '/')
fsname++;
cname = fsname;
while (*fsname && !grub_isspace(*fsname) && *fsname != '/')
fsname++;
ch = *fsname;
*fsname = 0;
snapname = cname;
while (*snapname && !grub_isspace(*snapname) && *snapname !=
'@')
snapname++;
if (*snapname == '@') {
issnapshot = 1;
*snapname = 0;
}
childobj =
((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_child_dir_zapobj;
if (errnum = dnode_get(mosmdn, childobj,
DMU_OT_DSL_DIR_CHILD_MAP, mdn, stack))
return (errnum);
if (zap_lookup(mdn, cname, &objnum, stack))
return (ERR_FILESYSTEM_NOT_FOUND);
if (errnum = dnode_get(mosmdn, objnum, DMU_OT_DSL_DIR,
mdn, stack))
return (errnum);
*fsname = ch;
if (issnapshot)
*snapname = '@';
}
headobj = ((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_head_dataset_obj;
if (obj)
*obj = headobj;
skip:
if (errnum = dnode_get(mosmdn, headobj, DMU_OT_DSL_DATASET, mdn, stack))
return (errnum);
if (issnapshot) {
uint64_t snapobj;
snapobj = ((dsl_dataset_phys_t *)DN_BONUS(mdn))->
ds_snapnames_zapobj;
if (errnum = dnode_get(mosmdn, snapobj,
DMU_OT_DSL_DS_SNAP_MAP, mdn, stack))
return (errnum);
if (zap_lookup(mdn, snapname + 1, &headobj, stack))
return (ERR_FILESYSTEM_NOT_FOUND);
if (errnum = dnode_get(mosmdn, headobj,
DMU_OT_DSL_DATASET, mdn, stack))
return (errnum);
if (obj)
*obj = headobj;
}
bp = &((dsl_dataset_phys_t *)DN_BONUS(mdn))->ds_bp;
osp = (objset_phys_t *)stack;
stack += sizeof (objset_phys_t);
if (errnum = zio_read(bp, osp, stack))
return (errnum);
grub_memmove((char *)mdn, (char *)&osp->os_meta_dnode, DNODE_SIZE);
return (0);
}
/*
* For a given XDR packed nvlist, verify the first 4 bytes and move on.
*
* An XDR packed nvlist is encoded as (comments from nvs_xdr_create) :
*
* encoding method/host endian (4 bytes)
* nvl_version (4 bytes)
* nvl_nvflag (4 bytes)
* encoded nvpairs:
* encoded size of the nvpair (4 bytes)
* decoded size of the nvpair (4 bytes)
* name string size (4 bytes)
* name string data (sizeof(NV_ALIGN4(string))
* data type (4 bytes)
* # of elements in the nvpair (4 bytes)
* data
* 2 zero's for the last nvpair
* (end of the entire list) (8 bytes)
*
* Return:
* 0 - success
* 1 - failure
*/
static int
nvlist_unpack(char *nvlist, char **out)
{
/* Verify if the 1st and 2nd byte in the nvlist are valid. */
if (nvlist[0] != NV_ENCODE_XDR || nvlist[1] != HOST_ENDIAN)
return (1);
*out = nvlist + 4;
return (0);
}
static char *
nvlist_array(char *nvlist, int index)
{
int i, encode_size;
for (i = 0; i < index; i++) {
/* skip the header, nvl_version, and nvl_nvflag */
nvlist = nvlist + 4 * 2;
while (encode_size = BSWAP_32(*(uint32_t *)nvlist))
nvlist += encode_size; /* goto the next nvpair */
nvlist = nvlist + 4 * 2; /* skip the ending 2 zeros - 8 bytes */
}
return (nvlist);
}
/*
* The nvlist_next_nvpair() function returns a handle to the next nvpair in the
* list following nvpair. If nvpair is NULL, the first pair is returned. If
* nvpair is the last pair in the nvlist, NULL is returned.
*/
static char *
nvlist_next_nvpair(char *nvl, char *nvpair)
{
char *cur, *prev;
int encode_size;
if (nvl == NULL)
return (NULL);
if (nvpair == NULL) {
/* skip over nvl_version and nvl_nvflag */
nvpair = nvl + 4 * 2;
} else {
/* skip to the next nvpair */
encode_size = BSWAP_32(*(uint32_t *)nvpair);
nvpair += encode_size;
}
/* 8 bytes of 0 marks the end of the list */
if (*(uint64_t *)nvpair == 0)
return (NULL);
return (nvpair);
}
/*
* This function returns 0 on success and 1 on failure. On success, a string
* containing the name of nvpair is saved in buf.
*/
static int
nvpair_name(char *nvp, char *buf, int buflen)
{
int len;
/* skip over encode/decode size */
nvp += 4 * 2;
len = BSWAP_32(*(uint32_t *)nvp);
if (buflen < len + 1)
return (1);
grub_memmove(buf, nvp + 4, len);
buf[len] = '\0';
return (0);
}
/*
* This function retrieves the value of the nvpair in the form of enumerated
* type data_type_t. This is used to determine the appropriate type to pass to
* nvpair_value().
*/
static int
nvpair_type(char *nvp)
{
int name_len, type;
/* skip over encode/decode size */
nvp += 4 * 2;
/* skip over name_len */
name_len = BSWAP_32(*(uint32_t *)nvp);
nvp += 4;
/* skip over name */
nvp = nvp + ((name_len + 3) & ~3); /* align */
type = BSWAP_32(*(uint32_t *)nvp);
return (type);
}
static int
nvpair_value(char *nvp, void *val, int valtype, int *nelmp)
{
int name_len, type, slen;
char *strval = val;
uint64_t *intval = val;
/* skip over encode/decode size */
nvp += 4 * 2;
/* skip over name_len */
name_len = BSWAP_32(*(uint32_t *)nvp);
nvp += 4;
/* skip over name */
nvp = nvp + ((name_len + 3) & ~3); /* align */
/* skip over type */
type = BSWAP_32(*(uint32_t *)nvp);
nvp += 4;
if (type == valtype) {
int nelm;
nelm = BSWAP_32(*(uint32_t *)nvp);
if (valtype != DATA_TYPE_BOOLEAN && nelm < 1)
return (1);
nvp += 4;
switch (valtype) {
case DATA_TYPE_BOOLEAN:
return (0);
case DATA_TYPE_STRING:
slen = BSWAP_32(*(uint32_t *)nvp);
nvp += 4;
grub_memmove(strval, nvp, slen);
strval[slen] = '\0';
return (0);
case DATA_TYPE_UINT64:
*intval = BSWAP_64(*(uint64_t *)nvp);
return (0);
case DATA_TYPE_NVLIST:
*(void **)val = (void *)nvp;
return (0);
case DATA_TYPE_NVLIST_ARRAY:
*(void **)val = (void *)nvp;
if (nelmp)
*nelmp = nelm;
return (0);
}
}
return (1);
}
static int
nvlist_lookup_value(char *nvlist, char *name, void *val, int valtype,
int *nelmp)
{
char *nvpair;
for (nvpair = nvlist_next_nvpair(nvlist, NULL);
nvpair != NULL;
nvpair = nvlist_next_nvpair(nvlist, nvpair)) {
int name_len = BSWAP_32(*(uint32_t *)(nvpair + 4 * 2));
char *nvp_name = nvpair + 4 * 3;
if ((grub_strncmp(nvp_name, name, name_len) == 0) &&
nvpair_type(nvpair) == valtype) {
return (nvpair_value(nvpair, val, valtype, nelmp));
}
}
return (1);
}
/*
* Check if this vdev is online and is in a good state.
*/
static int
vdev_validate(char *nv)
{
uint64_t ival;
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_OFFLINE, &ival,
DATA_TYPE_UINT64, NULL) == 0 ||
nvlist_lookup_value(nv, ZPOOL_CONFIG_FAULTED, &ival,
DATA_TYPE_UINT64, NULL) == 0 ||
nvlist_lookup_value(nv, ZPOOL_CONFIG_REMOVED, &ival,
DATA_TYPE_UINT64, NULL) == 0)
return (ERR_DEV_VALUES);
return (0);
}
/*
* Get a valid vdev pathname/devid from the boot device.
* The caller should already allocate MAXPATHLEN memory for bootpath and devid.
*/
static int
vdev_get_bootpath(char *nv, uint64_t inguid, char *devid, char *bootpath,
int is_spare)
{
char type[16];
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_TYPE, &type, DATA_TYPE_STRING,
NULL))
return (ERR_FSYS_CORRUPT);
if (grub_strcmp(type, VDEV_TYPE_DISK) == 0) {
uint64_t guid;
if (vdev_validate(nv) != 0)
return (ERR_NO_BOOTPATH);
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_GUID,
&guid, DATA_TYPE_UINT64, NULL) != 0)
return (ERR_NO_BOOTPATH);
if (guid != inguid)
return (ERR_NO_BOOTPATH);
/* for a spare vdev, pick the disk labeled with "is_spare" */
if (is_spare) {
uint64_t spare = 0;
(void) nvlist_lookup_value(nv, ZPOOL_CONFIG_IS_SPARE,
&spare, DATA_TYPE_UINT64, NULL);
if (!spare)
return (ERR_NO_BOOTPATH);
}
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_PHYS_PATH,
bootpath, DATA_TYPE_STRING, NULL) != 0)
bootpath[0] = '\0';
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_DEVID,
devid, DATA_TYPE_STRING, NULL) != 0)
devid[0] = '\0';
if (grub_strlen(bootpath) >= MAXPATHLEN ||
grub_strlen(devid) >= MAXPATHLEN)
return (ERR_WONT_FIT);
return (0);
} else if (grub_strcmp(type, VDEV_TYPE_MIRROR) == 0 ||
grub_strcmp(type, VDEV_TYPE_REPLACING) == 0 ||
(is_spare = (grub_strcmp(type, VDEV_TYPE_SPARE) == 0))) {
int nelm, i;
char *child;
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_CHILDREN, &child,
DATA_TYPE_NVLIST_ARRAY, &nelm))
return (ERR_FSYS_CORRUPT);
for (i = 0; i < nelm; i++) {
char *child_i;
child_i = nvlist_array(child, i);
if (vdev_get_bootpath(child_i, inguid, devid,
bootpath, is_spare) == 0)
return (0);
}
}
return (ERR_NO_BOOTPATH);
}
/*
* Check the disk label information and retrieve needed vdev name-value pairs.
*
* Return:
* 0 - success
* ERR_* - failure
*/
static int
check_pool_label(uint64_t sector, char *stack, char *outdevid,
char *outpath, uint64_t *outguid, uint64_t *outashift, uint64_t *outversion)
{
vdev_phys_t *vdev;
uint64_t pool_state, txg = 0;
char *nvlist, *nv, *features;
uint64_t diskguid;
sector += (VDEV_SKIP_SIZE >> SPA_MINBLOCKSHIFT);
/* Read in the vdev name-value pair list (112K). */
if (devread(sector, 0, VDEV_PHYS_SIZE, stack) == 0)
return (ERR_READ);
vdev = (vdev_phys_t *)stack;
stack += sizeof (vdev_phys_t);
if (nvlist_unpack(vdev->vp_nvlist, &nvlist))
return (ERR_FSYS_CORRUPT);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_STATE, &pool_state,
DATA_TYPE_UINT64, NULL))
return (ERR_FSYS_CORRUPT);
if (pool_state == POOL_STATE_DESTROYED)
return (ERR_FILESYSTEM_NOT_FOUND);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_NAME,
current_rootpool, DATA_TYPE_STRING, NULL))
return (ERR_FSYS_CORRUPT);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_TXG, &txg,
DATA_TYPE_UINT64, NULL))
return (ERR_FSYS_CORRUPT);
/* not an active device */
if (txg == 0)
return (ERR_NO_BOOTPATH);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_VERSION, outversion,
DATA_TYPE_UINT64, NULL))
return (ERR_FSYS_CORRUPT);
if (!SPA_VERSION_IS_SUPPORTED(*outversion))
return (ERR_NEWER_VERSION);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_VDEV_TREE, &nv,
DATA_TYPE_NVLIST, NULL))
return (ERR_FSYS_CORRUPT);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_GUID, &diskguid,
DATA_TYPE_UINT64, NULL))
return (ERR_FSYS_CORRUPT);
if (nvlist_lookup_value(nv, ZPOOL_CONFIG_ASHIFT, outashift,
DATA_TYPE_UINT64, NULL) != 0)
return (ERR_FSYS_CORRUPT);
if (vdev_get_bootpath(nv, diskguid, outdevid, outpath, 0))
return (ERR_NO_BOOTPATH);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_GUID, outguid,
DATA_TYPE_UINT64, NULL))
return (ERR_FSYS_CORRUPT);
if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_FEATURES_FOR_READ,
&features, DATA_TYPE_NVLIST, NULL) == 0) {
char *nvp;
char *name = stack;
stack += MAXNAMELEN;
for (nvp = nvlist_next_nvpair(features, NULL);
nvp != NULL;
nvp = nvlist_next_nvpair(features, nvp)) {
zap_attribute_t za;
if (nvpair_name(nvp, name, MAXNAMELEN) != 0)
return (ERR_FSYS_CORRUPT);
za.za_integer_length = 8;
za.za_num_integers = 1;
za.za_first_integer = 1;
za.za_name = name;
if (check_feature(&za, spa_feature_names, stack) != 0)
return (ERR_NEWER_VERSION);
}
}
return (0);
}
/*
* zfs_mount() locates a valid uberblock of the root pool and read in its MOS
* to the memory address MOS.
*
* Return:
* 1 - success
* 0 - failure
*/
int
zfs_mount(void)
{
char *stack, *ub_array;
int label = 0;
uberblock_t *ubbest;
objset_phys_t *osp;
char tmp_bootpath[MAXNAMELEN];
char tmp_devid[MAXNAMELEN];
uint64_t tmp_guid, ashift, version;
uint64_t adjpl = (uint64_t)part_length << SPA_MINBLOCKSHIFT;
int err = errnum; /* preserve previous errnum state */
/* if it's our first time here, zero the best uberblock out */
if (best_drive == 0 && best_part == 0 && find_best_root) {
grub_memset(¤t_uberblock, 0, sizeof (uberblock_t));
pool_guid = 0;
}
stackbase = ZFS_SCRATCH;
stack = stackbase;
ub_array = stack;
stack += VDEV_UBERBLOCK_RING;
osp = (objset_phys_t *)stack;
stack += sizeof (objset_phys_t);
adjpl = P2ALIGN(adjpl, (uint64_t)sizeof (vdev_label_t));
for (label = 0; label < VDEV_LABELS; label++) {
/*
* some eltorito stacks don't give us a size and
* we end up setting the size to MAXUINT, further
* some of these devices stop working once a single
* read past the end has been issued. Checking
* for a maximum part_length and skipping the backup
* labels at the end of the slice/partition/device
* avoids breaking down on such devices.
*/
if (part_length == MAXUINT && label == 2)
break;
uint64_t sector = vdev_label_start(adjpl,
label) >> SPA_MINBLOCKSHIFT;
/* Read in the uberblock ring (128K). */
if (devread(sector +
((VDEV_SKIP_SIZE + VDEV_PHYS_SIZE) >> SPA_MINBLOCKSHIFT),
0, VDEV_UBERBLOCK_RING, ub_array) == 0)
continue;
if (check_pool_label(sector, stack, tmp_devid,
tmp_bootpath, &tmp_guid, &ashift, &version))
continue;
if (pool_guid == 0)
pool_guid = tmp_guid;
if ((ubbest = find_bestub(ub_array, ashift, sector)) == NULL ||
zio_read(&ubbest->ub_rootbp, osp, stack) != 0)
continue;
VERIFY_OS_TYPE(osp, DMU_OST_META);
if (version >= SPA_VERSION_FEATURES &&
check_mos_features(&osp->os_meta_dnode, stack) != 0)
continue;
if (find_best_root && ((pool_guid != tmp_guid) ||
vdev_uberblock_compare(ubbest, &(current_uberblock)) <= 0))
continue;
/* Got the MOS. Save it at the memory addr MOS. */
grub_memmove(MOS, &osp->os_meta_dnode, DNODE_SIZE);
grub_memmove(¤t_uberblock, ubbest, sizeof (uberblock_t));
grub_memmove(current_bootpath, tmp_bootpath, MAXNAMELEN);
grub_memmove(current_devid, tmp_devid, grub_strlen(tmp_devid));
is_zfs_mount = 1;
return (1);
}
/*
* While some fs impls. (tftp) rely on setting and keeping
* global errnums set, others won't reset it and will break
* when issuing rawreads. The goal here is to simply not
* have zfs mount attempts impact the previous state.
*/
errnum = err;
return (0);
}
/*
* zfs_open() locates a file in the rootpool by following the
* MOS and places the dnode of the file in the memory address DNODE.
*
* Return:
* 1 - success
* 0 - failure
*/
int
zfs_open(char *filename)
{
char *stack;
dnode_phys_t *mdn;
file_buf = NULL;
stackbase = ZFS_SCRATCH;
stack = stackbase;
mdn = (dnode_phys_t *)stack;
stack += sizeof (dnode_phys_t);
dnode_mdn = NULL;
dnode_buf = (dnode_phys_t *)stack;
stack += 1<<DNODE_BLOCK_SHIFT;
/*
* menu.lst is placed at the root pool filesystem level,
* do not goto 'current_bootfs'.
*/
if (is_top_dataset_file(filename)) {
if (errnum = get_objset_mdn(MOS, NULL, NULL, mdn, stack))
return (0);
current_bootfs_obj = 0;
} else {
if (current_bootfs[0] == '\0') {
/* Get the default root filesystem object number */
if (errnum = get_default_bootfsobj(MOS,
¤t_bootfs_obj, stack))
return (0);
if (errnum = get_objset_mdn(MOS, NULL,
¤t_bootfs_obj, mdn, stack))
return (0);
} else {
if (errnum = get_objset_mdn(MOS, current_bootfs,
¤t_bootfs_obj, mdn, stack)) {
grub_memset(current_bootfs, 0, MAXNAMELEN);
return (0);
}
}
}
if (dnode_get_path(mdn, filename, DNODE, stack)) {
errnum = ERR_FILE_NOT_FOUND;
return (0);
}
/* get the file size and set the file position to 0 */
/*
* For DMU_OT_SA we will need to locate the SIZE attribute
* attribute, which could be either in the bonus buffer
* or the "spill" block.
*/
if (DNODE->dn_bonustype == DMU_OT_SA) {
sa_hdr_phys_t *sahdrp;
int hdrsize;
if (DNODE->dn_bonuslen != 0) {
sahdrp = (sa_hdr_phys_t *)DN_BONUS(DNODE);
} else {
if (DNODE->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
blkptr_t *bp = &DNODE->dn_spill;
void *buf;
buf = (void *)stack;
stack += BP_GET_LSIZE(bp);
/* reset errnum to rawread() failure */
errnum = 0;
if (zio_read(bp, buf, stack) != 0) {
return (0);
}
sahdrp = buf;
} else {
errnum = ERR_FSYS_CORRUPT;
return (0);
}
}
hdrsize = SA_HDR_SIZE(sahdrp);
filemax = *(uint64_t *)((char *)sahdrp + hdrsize +
SA_SIZE_OFFSET);
} else {
filemax = ((znode_phys_t *)DN_BONUS(DNODE))->zp_size;
}
filepos = 0;
dnode_buf = NULL;
return (1);
}
/*
* zfs_read reads in the data blocks pointed by the DNODE.
*
* Return:
* len - the length successfully read in to the buffer
* 0 - failure
*/
int
zfs_read(char *buf, int len)
{
char *stack;
int blksz, length, movesize;
if (file_buf == NULL) {
file_buf = stackbase;
stackbase += SPA_MAXBLOCKSIZE;
file_start = file_end = 0;
}
stack = stackbase;
/*
* If offset is in memory, move it into the buffer provided and return.
*/
if (filepos >= file_start && filepos+len <= file_end) {
grub_memmove(buf, file_buf + filepos - file_start, len);
filepos += len;
return (len);
}
blksz = DNODE->dn_datablkszsec << SPA_MINBLOCKSHIFT;
/*
* Entire Dnode is too big to fit into the space available. We
* will need to read it in chunks. This could be optimized to
* read in as large a chunk as there is space available, but for
* now, this only reads in one data block at a time.
*/
length = len;
while (length) {
/*
* Find requested blkid and the offset within that block.
*/
uint64_t blkid = filepos / blksz;
if (errnum = dmu_read(DNODE, blkid, file_buf, stack))
return (0);
file_start = blkid * blksz;
file_end = file_start + blksz;
movesize = MIN(length, file_end - filepos);
grub_memmove(buf, file_buf + filepos - file_start,
movesize);
buf += movesize;
length -= movesize;
filepos += movesize;
}
return (len);
}
/*
* No-Op
*/
int
zfs_embed(int *start_sector, int needed_sectors)
{
return (1);
}
#endif /* FSYS_ZFS */