libfdt - library for manipulating device trees in flattened format

Initial revision, read-only and "in-place" (no memmove() required)
write operations only.

fdt_ro.c

@@ -0,0 +1,243 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+static int check_header(const struct fdt_header *fdt)
+{
+	if (fdt32_to_cpu(fdt->magic) != FDT_MAGIC)
+		return FDT_ERR_BADMAGIC;
+	if (fdt32_to_cpu(fdt->version) < FDT_FIRST_SUPPORTED_VERSION)
+		return FDT_ERR_BADVERSION;
+	if (fdt32_to_cpu(fdt->last_comp_version) > FDT_LAST_SUPPORTED_VERSION)
+		return FDT_ERR_BADVERSION;
+	return 0;
+}
+
+#define OFFSET_CHECK_HEADER(fdt) \
+	{ \
+		int err; \
+		if ((err = check_header(fdt)) != 0) \
+			return OFFSET_ERROR(err); \
+	}
+
+static int offset_streq(const struct fdt_header *fdt, int offset,
+			const char *s, int len)
+{
+	const char *p = fdt_offset_ptr(fdt, offset, len+1);
+
+	if (! p)
+		/* short match */
+		return 0;
+
+	if (memcmp(p, s, len) != 0)
+		return 0;
+
+	if (p[len] != '\0')
+		return 0;
+
+	return 1;
+}
+
+int fdt_property_offset(const struct fdt_header *fdt, int nodeoffset,
+			const char *name)
+{
+	int level = 0;
+	uint32_t tag;
+	struct fdt_property *prop;
+	int namestroff;
+	int offset, nextoffset;
+
+	OFFSET_CHECK_HEADER(fdt);
+
+	if (nodeoffset % FDT_TAGSIZE)
+		return OFFSET_ERROR(FDT_ERR_BADOFFSET);
+
+	tag = _fdt_next_tag(fdt, nodeoffset, &nextoffset);
+	if (tag != FDT_BEGIN_NODE)
+		return OFFSET_ERROR(FDT_ERR_BADOFFSET);
+
+	do {
+		offset = nextoffset;
+		if (offset % FDT_TAGSIZE)
+			return OFFSET_ERROR(FDT_ERR_INTERNAL);
+
+		tag = _fdt_next_tag(fdt, offset, &nextoffset);
+		switch (tag) {
+		case FDT_END:
+			return OFFSET_ERROR(FDT_ERR_TRUNCATED);
+
+		case FDT_BEGIN_NODE:
+			level++;
+			break;
+
+		case FDT_END_NODE:
+			level--;
+			break;
+
+		case FDT_PROP:
+			if (level != 0)
+				continue;
+
+			prop = fdt_offset_ptr_typed(fdt, offset, prop);
+			if (! prop)
+				return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
+			namestroff = fdt32_to_cpu(prop->nameoff);
+			if (fdt_string_cmp(fdt, namestroff, name) == 0)
+				/* Found it! */
+				return offset;
+			break;
+
+		case FDT_NOP:
+			break;
+
+		default:
+			return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
+		}
+	} while (level >= 0);
+
+	return OFFSET_ERROR(FDT_ERR_NOTFOUND);
+}
+
+int fdt_subnode_offset_namelen(const struct fdt_header *fdt, int parentoffset,
+			       const char *name, int namelen)
+{
+	int level = 0;
+	uint32_t tag;
+	int offset, nextoffset;
+
+	OFFSET_CHECK_HEADER(fdt);
+
+	tag = _fdt_next_tag(fdt, parentoffset, &nextoffset);
+	if (tag != FDT_BEGIN_NODE)
+		return OFFSET_ERROR(FDT_ERR_BADOFFSET);
+
+	do {
+		offset = nextoffset;
+		tag = _fdt_next_tag(fdt, offset, &nextoffset);
+
+		switch (tag) {
+		case FDT_END:
+			return OFFSET_ERROR(FDT_ERR_TRUNCATED);
+
+		case FDT_BEGIN_NODE:
+			level++;
+			if (level != 1)
+				continue;
+			if (offset_streq(fdt, offset+FDT_TAGSIZE, name, namelen))
+				/* Found it! */
+				return offset;
+			break;
+
+		case FDT_END_NODE:
+			level--;
+			break;
+
+		case FDT_PROP:
+		case FDT_NOP:
+			break;
+
+		default:
+			return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
+		}
+	} while (level >= 0);
+
+	return OFFSET_ERROR(FDT_ERR_NOTFOUND);
+}
+
+int fdt_subnode_offset(const struct fdt_header *fdt, int parentoffset,
+		       const char *name)
+{
+	return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
+}
+
+int fdt_path_offset(const struct fdt_header *fdt, const char *path)
+{
+	const char *end = path + strlen(path);
+	const char *p = path;
+	int offset = 0;
+
+	OFFSET_CHECK_HEADER(fdt);
+
+	if (*path != '/')
+		return OFFSET_ERROR(FDT_ERR_BADPATH);
+
+	while (*p) {
+		const char *q;
+
+		while (*p == '/')
+			p++;
+		if (! *p)
+			return OFFSET_ERROR(FDT_ERR_BADPATH);
+		q = strchr(p, '/');
+		if (! q)
+			q = end;
+
+		offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
+		if (fdt_offset_error(offset))
+			return offset;
+
+		p = q;
+	}
+
+	return offset;	
+}
+
+struct fdt_property *_fdt_getprop(const struct fdt_header *fdt, int nodeoffset,
+				  const char *name, int *lenp)
+{
+	int propoffset;
+	struct fdt_property *prop;
+	int err;
+	int len;
+
+	propoffset = fdt_property_offset(fdt, nodeoffset, name);
+	if ((err = fdt_offset_error(propoffset)))
+		return PTR_ERROR(err);
+
+	prop = fdt_offset_ptr(fdt, propoffset, sizeof(prop));
+	if (! prop)
+		return PTR_ERROR(FDT_ERR_BADSTRUCTURE);
+	len = fdt32_to_cpu(prop->len);
+	prop = fdt_offset_ptr(fdt, propoffset, sizeof(prop) + len);
+	if (! prop)
+		return PTR_ERROR(FDT_ERR_BADSTRUCTURE);
+
+	if (lenp)
+		*lenp = len;
+
+	return prop;
+}
+
+void *fdt_getprop(const struct fdt_header *fdt, int nodeoffset,
+		  const char *name, int *lenp)
+{
+	const struct fdt_property *prop;
+	int err;
+
+	prop = _fdt_getprop(fdt, nodeoffset, name, lenp);
+	if ((err = fdt_ptr_error(prop)))
+		return PTR_ERROR(err);
+
+	return prop->data;
+}