libfdt: Several cleanups to parameter checking

This patch makes a couple of small cleanups to parameter checking of
libfdt functions.

	- In several functions which take a node offset, we use an
idiom involving fdt_next_tag() first to check that we have indeed been
given a node offset.  This patch adds a helper function
_fdt_check_node_offset() to encapsulate this usage of fdt_next_tag().

	- In fdt_rw.c in several places we have the expanded version
of the RW_CHECK_HEADER() macro for no particular reason.  This patch
replaces those instances with an invocation of the macro; that's what
it's for.

	- In fdt_sw.c we rename the check_header_sw() function to
sw_check_header() to match the analgous function in fdt_rw.c, and we
provide an SW_CHECK_HEADER() wrapper macro as RW_CHECK_HEADER()
functions in fdt_rw.c

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 8 insertions, 18 deletions

diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index 11d80d2fa2..69af7bb843 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -161,16 +161,12 @@ int fdt_path_offset(const void *fdt, const char *path)
 
 const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
 {
-	const struct fdt_node_header *nh;
+	const struct fdt_node_header *nh = _fdt_offset_ptr(fdt, nodeoffset);
 	int err;
 
-	if ((err = fdt_check_header(fdt)) != 0)
-		goto fail;
-
-	err = -FDT_ERR_BADOFFSET;
-	nh = fdt_offset_ptr(fdt, nodeoffset, sizeof(*nh));
-	if (!nh || (fdt32_to_cpu(nh->tag) != FDT_BEGIN_NODE))
-		goto fail;
+	if (((err = fdt_check_header(fdt)) != 0)
+	    || ((err = _fdt_check_node_offset(fdt, nodeoffset)) < 0))
+			goto fail;
 
 	if (len)
 		*len = strlen(nh->name);
@@ -193,17 +189,11 @@ const struct fdt_property *fdt_get_property(const void *fdt,
 	int offset, nextoffset;
 	int err;
 
-	if ((err = fdt_check_header(fdt)) != 0)
-		goto fail;
-
-	err = -FDT_ERR_BADOFFSET;
-	if (nodeoffset % FDT_TAGSIZE)
-		goto fail;
-
-	tag = fdt_next_tag(fdt, nodeoffset, &nextoffset);
-	if (tag != FDT_BEGIN_NODE)
-		goto fail;
+	if (((err = fdt_check_header(fdt)) != 0)
+	    || ((err = _fdt_check_node_offset(fdt, nodeoffset)) < 0))
+			goto fail;
 
+	nextoffset = err;
 	do {
 		offset = nextoffset;