libfdt/fdt.c

/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 *
 * libfdt is dual licensed: you can use it either under the terms of
 * the GPL, or the BSD license, at your option.
 *
 *  a) This library 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 library 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 library; if not, write to the Free
 *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 *     MA 02110-1301 USA
 *
 * Alternatively,
 *
 *  b) 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 "libfdt_env.h"

#include <fdt.h>
#include <libfdt.h>

#include "libfdt_internal.h"

int fdt_check_header(const void *fdt)
{
	if (fdt_magic(fdt) == FDT_MAGIC) {
		/* Complete tree */
		if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
			return -FDT_ERR_BADVERSION;
		if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
			return -FDT_ERR_BADVERSION;
	} else if (fdt_magic(fdt) == SW_MAGIC) {
		/* Unfinished sequential-write blob */
		if (fdt_size_dt_struct(fdt) == 0)
			return -FDT_ERR_BADSTATE;
	} else {
		return -FDT_ERR_BADMAGIC;
	}

	return 0;
}

const void *fdt_offset_ptr(const void *fdt, int offset, int len)
{
	const void *p;

	if (fdt_version(fdt) >= 0x11)
		if (((offset + len) < offset)
		    || ((offset + len) > fdt_size_dt_struct(fdt)))
			return NULL;

	p = _fdt_offset_ptr(fdt, offset);

	if (p + len < p)
		return NULL;
	return p;
}

uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset)
{
	const uint32_t *tagp, *lenp;
	uint32_t tag;
	const char *p;

	if (offset % FDT_TAGSIZE)
		return -1;

	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
	if (! tagp)
		return FDT_END; /* premature end */
	tag = fdt32_to_cpu(*tagp);
	offset += FDT_TAGSIZE;

	switch (tag) {
	case FDT_BEGIN_NODE:
		/* skip name */
		do {
			p = fdt_offset_ptr(fdt, offset++, 1);
		} while (p && (*p != '\0'));
		if (! p)
			return FDT_END;
		break;
	case FDT_PROP:
		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
		if (! lenp)
			return FDT_END;
		/* skip name offset, length and value */
		offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
		break;
	}

	if (nextoffset)
		*nextoffset = ALIGN(offset, FDT_TAGSIZE);

	return tag;
}

int fdt_next_node(const void *fdt, int offset, int *depth)
{
	int nextoffset = 0;
	uint32_t tag;

	if (offset >= 0) {
		tag = fdt_next_tag(fdt, offset, &nextoffset);
		if (tag != FDT_BEGIN_NODE)
			return -FDT_ERR_BADOFFSET;
	}

	do {
		offset = nextoffset;
		tag = fdt_next_tag(fdt, offset, &nextoffset);

		switch (tag) {
		case FDT_PROP:
		case FDT_NOP:
			break;

		case FDT_BEGIN_NODE:
			if (depth)
				(*depth)++;
			break;

		case FDT_END_NODE:
			if (depth)
				(*depth)--;
			break;

		case FDT_END:
			return -FDT_ERR_NOTFOUND;

		default:
			return -FDT_ERR_BADSTRUCTURE;
		}
	} while (tag != FDT_BEGIN_NODE);

	return offset;
}

const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
{
	int len = strlen(s) + 1;
	const char *last = strtab + tabsize - len;
	const char *p;

	for (p = strtab; p <= last; p++)
		if (memeq(p, s, len))
			return p;
	return NULL;
}

int fdt_move(const void *fdt, void *buf, int bufsize)
{
	int err = fdt_check_header(fdt);

	if (err)
		return err;

	if (fdt_totalsize(fdt) > bufsize)
		return -FDT_ERR_NOSPACE;

	memmove(buf, fdt, fdt_totalsize(fdt));
	return 0;
}