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Refactoring of function nvlist_find_value
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It's needed to allow iteration of nvlists in other functions.

Ported to GRUB2 from IllumOS changeset 13700    2889e2596bd6

Author: Christopher Siden <chris.siden@delphix.com>
Ported-by: Massimo Maggi <me@massimo-maggi.eu>
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@maxximino
maxximino committed Jan 26, 2013
1 parent 595d76e commit 5834403
Showing 1 changed file with 158 additions and 72 deletions.
230 changes: 158 additions & 72 deletions grub-core/fs/zfs/zfs.c
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Expand Up @@ -2,6 +2,7 @@
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2009,2010,2011 Free Software Foundation, Inc.
* Copyright 2010 Sun Microsystems, Inc.
* Copyright (c) 2012 by Delphix. All rights reserved.
*
* GRUB is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
Expand Down Expand Up @@ -767,6 +768,155 @@ fill_vdev_info (struct grub_zfs_data *data,
diskdesc, inserted, 0xffffffff);
}

/*
* 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)
*
*/

/*
* 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 const char *
nvlist_next_nvpair(const char *nvl, const char *nvpair)
{
const char *nvp;
int encode_size;
int name_len;
if (nvl == NULL)
return (NULL);

if (nvpair == NULL) {
/* skip over header, nvl_version and nvl_nvflag */
nvpair = nvl + 4 * 3;
} else {
/* skip to the next nvpair */
encode_size = grub_be_to_cpu32 (grub_get_unaligned32(nvpair));
nvpair += encode_size;
}
/* 8 bytes of 0 marks the end of the list */
if (*(grub_uint64_t*)nvpair == 0)
return (NULL);
/*consistency checks*/
if (nvpair + 4 * 3 >= nvl + VDEV_PHYS_SIZE)
{
grub_dprintf ("zfs", "nvlist overflow\n");
grub_error (GRUB_ERR_BAD_FS, "incorrect nvlist");
return (NULL);
}
encode_size = grub_be_to_cpu32 (grub_get_unaligned32(nvpair));

nvp = nvpair + 4*2;
name_len = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));
nvp += 4;

nvp = nvp + ((name_len + 3) & ~3); // align
if (nvp + 4 >= nvl + VDEV_PHYS_SIZE
|| encode_size < 0
|| nvp + 4 + encode_size > nvl + VDEV_PHYS_SIZE)
{
grub_dprintf ("zfs", "nvlist overflow\n");
grub_error (GRUB_ERR_BAD_FS, "incorrect nvlist");
return (NULL);
}
/* end consistency checks */

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(const char *nvp, char **buf, int* buflen)
{
int len;

/* skip over encode/decode size */
nvp += 4 * 2;

len = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));
nvp=nvp+4;

*buf=(char*)nvp;
*buflen=len;

return (0);
}
/*
* This function retrieves the value of the nvpair in the form of enumerated
* type data_type_t.
*/
static int
nvpair_type(const char *nvp)
{
int name_len, type;

/* skip over encode/decode size */
nvp += 4 * 2;

/* skip over name_len */
name_len = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));
nvp += 4;

/* skip over name */
nvp = nvp + ((name_len + 3) & ~3); /* align */

type = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));

return (type);
}
static int
nvpair_value(const char *nvp,char **val,
grub_size_t *size_out, grub_size_t *nelm_out)
{
int name_len,nelm,encode_size;

/* skip over encode/decode size */
encode_size = grub_be_to_cpu32 (grub_get_unaligned32(nvp));
nvp += 8;

/* skip over name_len */
name_len = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));
nvp += 4;

/* skip over name */
nvp = nvp + ((name_len + 3) & ~3); /* align */

/* skip over type */
nvp += 4;
nelm = grub_be_to_cpu32 (grub_get_unaligned32 (nvp));
nvp +=4;
if (nelm < 1)
{
grub_error (GRUB_ERR_BAD_FS, "empty nvpair");
return 0;
}
*val = (char *) nvp;
*size_out = encode_size;
if (nelm_out)
*nelm_out = nelm;

return 1;
}

/*
* Check the disk label information and retrieve needed vdev name-value pairs.
*
Expand Down Expand Up @@ -3064,34 +3214,14 @@ dnode_get_fullpath (const char *fullpath, struct subvolume *subvol,
return err;
}

/*
* 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)
*
*/

static int
nvlist_find_value (const char *nvlist_in, const char *name,
int valtype, char **val,
grub_size_t *size_out, grub_size_t *nelm_out)
{
int name_len, type, encode_size;
const char *nvpair, *nvp_name, *nvlist = nvlist_in;
int name_len, type ;
const char *nvpair=NULL,*nvlist=nvlist_in;
char *nvp_name;

/* Verify if the 1st and 2nd byte in the nvlist are valid. */
/* NOTE: independently of what endianness header announces all
Expand All @@ -3104,62 +3234,18 @@ nvlist_find_value (const char *nvlist_in, const char *name,
return 0;
}

/* skip the header, nvl_version, and nvl_nvflag */
nvlist = nvlist + 4 * 3;
/*
* Loop thru the nvpair list
* The XDR representation of an integer is in big-endian byte order.
*/
while ((encode_size = grub_be_to_cpu32 (grub_get_unaligned32 (nvlist))))
while ((nvpair=nvlist_next_nvpair(nvlist,nvpair)))
{
int nelm;

if (nvlist + 4 * 4 >= nvlist_in + VDEV_PHYS_SIZE)
nvpair_name(nvpair,&nvp_name,&name_len);
type = nvpair_type(nvpair);
if ((grub_strncmp (nvp_name, name, grub_strlen(name)) == 0) && type == valtype)
{
grub_dprintf ("zfs", "nvlist overflow\n");
grub_error (GRUB_ERR_BAD_FS, "incorrect nvlist");
return 0;
}

nvpair = nvlist + 4 * 2; /* skip the encode/decode size */

name_len = grub_be_to_cpu32 (grub_get_unaligned32 (nvpair));
nvpair += 4;

nvp_name = nvpair;
nvpair = nvpair + ((name_len + 3) & ~3); /* align */

if (nvpair + 8 >= nvlist_in + VDEV_PHYS_SIZE
|| encode_size < 0
|| nvpair + 8 + encode_size > nvlist_in + VDEV_PHYS_SIZE)
{
grub_dprintf ("zfs", "nvlist overflow\n");
grub_error (GRUB_ERR_BAD_FS, "incorrect nvlist");
return 0;
return nvpair_value(nvpair,val,size_out,nelm_out);
}

type = grub_be_to_cpu32 (grub_get_unaligned32 (nvpair));
nvpair += 4;

nelm = grub_be_to_cpu32 (grub_get_unaligned32 (nvpair));
if (nelm < 1)
{
grub_error (GRUB_ERR_BAD_FS, "empty nvpair");
return 0;
}

nvpair += 4;

if ((grub_strncmp (nvp_name, name, name_len) == 0) && type == valtype)
{
*val = (char *) nvpair;
*size_out = encode_size;
if (nelm_out)
*nelm_out = nelm;
return 1;
}

nvlist += encode_size; /* goto the next nvpair */
}
return 0;
}
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