From eff82c45c589b42061344039d5f2efc8ad7c52df Mon Sep 17 00:00:00 2001
From: stefan <stefan@s00.xyz>
Date: Fri, 21 Apr 2023 19:53:04 -0400
Subject: libfdt port and the required libc functions

---
 lib/libfdt/fdt_check.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 lib/libfdt/fdt_check.c

(limited to 'lib/libfdt/fdt_check.c')

diff --git a/lib/libfdt/fdt_check.c b/lib/libfdt/fdt_check.c
new file mode 100644
index 0000000..e9ce6e9
--- /dev/null
+++ b/lib/libfdt/fdt_check.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ */
+#include <libfdt_env.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+int fdt_check_full(const void *fdt, size_t bufsize)
+{
+	int err;
+	int num_memrsv;
+	int offset, nextoffset = 0;
+	uint32_t tag;
+	unsigned int depth = 0;
+	const void *prop;
+	const char *propname;
+	bool expect_end = false;
+
+	if (bufsize < FDT_V1_SIZE)
+		return -FDT_ERR_TRUNCATED;
+	if (bufsize < fdt_header_size(fdt))
+		return -FDT_ERR_TRUNCATED;
+	err = fdt_check_header(fdt);
+	if (err != 0)
+		return err;
+	if (bufsize < fdt_totalsize(fdt))
+		return -FDT_ERR_TRUNCATED;
+
+	num_memrsv = fdt_num_mem_rsv(fdt);
+	if (num_memrsv < 0)
+		return num_memrsv;
+
+	while (1) {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+
+		if (nextoffset < 0)
+			return nextoffset;
+
+		/* If we see two root nodes, something is wrong */
+		if (expect_end && tag != FDT_END)
+			return -FDT_ERR_BADSTRUCTURE;
+
+		switch (tag) {
+		case FDT_NOP:
+			break;
+
+		case FDT_END:
+			if (depth != 0)
+				return -FDT_ERR_BADSTRUCTURE;
+			return 0;
+
+		case FDT_BEGIN_NODE:
+			depth++;
+			if (depth > INT_MAX)
+				return -FDT_ERR_BADSTRUCTURE;
+
+			/* The root node must have an empty name */
+			if (depth == 1) {
+				const char *name;
+				int len;
+
+				name = fdt_get_name(fdt, offset, &len);
+				if (!name)
+					return len;
+
+				if (*name || len)
+					return -FDT_ERR_BADSTRUCTURE;
+			}
+			break;
+
+		case FDT_END_NODE:
+			if (depth == 0)
+				return -FDT_ERR_BADSTRUCTURE;
+			depth--;
+			if (depth == 0)
+				expect_end = true;
+			break;
+
+		case FDT_PROP:
+			prop = fdt_getprop_by_offset(fdt, offset, &propname,
+						     &err);
+			if (!prop)
+				return err;
+			break;
+
+		default:
+			return -FDT_ERR_INTERNAL;
+		}
+	}
+}
-- 
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