[PATCH 2/7] libfdt: Allow control of checks in fdt.c

[Simon Glass <sjg@xxxxxxxxxxxx>]

This core file provides checks for the header and for traversal of the
device tree. Allow these checks to be disabled to reduce code size.

Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
---

 libfdt/fdt.c | 79 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 44 insertions(+), 35 deletions(-)

diff --git a/libfdt/fdt.c b/libfdt/fdt.c
index 179168e..fea49cb 100644
--- a/libfdt/fdt.c
+++ b/libfdt/fdt.c
@@ -71,38 +71,45 @@ int fdt_check_header(const void *fdt)
 
 	if (fdt_magic(fdt) != FDT_MAGIC)
 		return -FDT_ERR_BADMAGIC;
-	hdrsize = fdt_header_size(fdt);
-	if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
-	    || (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION))
-		return -FDT_ERR_BADVERSION;
-	if (fdt_version(fdt) < fdt_last_comp_version(fdt))
-		return -FDT_ERR_BADVERSION;
-
-	if ((fdt_totalsize(fdt) < hdrsize)
-	    || (fdt_totalsize(fdt) > INT_MAX))
-		return -FDT_ERR_TRUNCATED;
-
-	/* Bounds check memrsv block */
-	if (!check_off_(hdrsize, fdt_totalsize(fdt), fdt_off_mem_rsvmap(fdt)))
-		return -FDT_ERR_TRUNCATED;
-
-	/* Bounds check structure block */
-	if (fdt_version(fdt) < 17) {
+	if (_check1()) {
+		hdrsize = fdt_header_size(fdt);
+		if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
+		    || (fdt_last_comp_version(fdt) >
+			FDT_LAST_SUPPORTED_VERSION))
+			return -FDT_ERR_BADVERSION;
+		if (fdt_version(fdt) < fdt_last_comp_version(fdt))
+			return -FDT_ERR_BADVERSION;
+
+		if ((fdt_totalsize(fdt) < hdrsize)
+		    || (fdt_totalsize(fdt) > INT_MAX))
+			return -FDT_ERR_TRUNCATED;
+
+		/* Bounds check memrsv block */
 		if (!check_off_(hdrsize, fdt_totalsize(fdt),
-				fdt_off_dt_struct(fdt)))
+				fdt_off_mem_rsvmap(fdt)))
 			return -FDT_ERR_TRUNCATED;
-	} else {
+	}
+
+	if (_check2()) {
+		/* Bounds check structure block */
+		if (fdt_version(fdt) < 17) {
+			if (!check_off_(hdrsize, fdt_totalsize(fdt),
+					fdt_off_dt_struct(fdt)))
+				return -FDT_ERR_TRUNCATED;
+		} else {
+			if (!check_block_(hdrsize, fdt_totalsize(fdt),
+					  fdt_off_dt_struct(fdt),
+					  fdt_size_dt_struct(fdt)))
+				return -FDT_ERR_TRUNCATED;
+		}
+
+		/* Bounds check strings block */
 		if (!check_block_(hdrsize, fdt_totalsize(fdt),
-				  fdt_off_dt_struct(fdt),
-				  fdt_size_dt_struct(fdt)))
+				  fdt_off_dt_strings(fdt),
+				  fdt_size_dt_strings(fdt)))
 			return -FDT_ERR_TRUNCATED;
 	}
 
-	/* Bounds check strings block */
-	if (!check_block_(hdrsize, fdt_totalsize(fdt),
-			  fdt_off_dt_strings(fdt), fdt_size_dt_strings(fdt)))
-		return -FDT_ERR_TRUNCATED;
-
 	return 0;
 }
 
@@ -110,11 +117,12 @@ const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
 {
 	unsigned absoffset = offset + fdt_off_dt_struct(fdt);
 
-	if ((absoffset < offset)
-	    || ((absoffset + len) < absoffset)
-	    || (absoffset + len) > fdt_totalsize(fdt))
-		return NULL;
-
+	if (_check1()) {
+		if ((absoffset < offset)
+		    || ((absoffset + len) < absoffset)
+		    || (absoffset + len) > fdt_totalsize(fdt))
+			return NULL;
+	}
 	if (fdt_version(fdt) >= 0x11)
 		if (((offset + len) < offset)
 		    || ((offset + len) > fdt_size_dt_struct(fdt)))
@@ -132,7 +140,7 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 
 	*nextoffset = -FDT_ERR_TRUNCATED;
 	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
-	if (!tagp)
+	if (_check1() && !tagp)
 		return FDT_END; /* premature end */
 	tag = fdt32_to_cpu(*tagp);
 	offset += FDT_TAGSIZE;
@@ -144,13 +152,13 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 		do {
 			p = fdt_offset_ptr(fdt, offset++, 1);
 		} while (p && (*p != '\0'));
-		if (!p)
+		if (_check1() && !p)
 			return FDT_END; /* premature end */
 		break;
 
 	case FDT_PROP:
 		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
-		if (!lenp)
+		if (_check1() && !lenp)
 			return FDT_END; /* premature end */
 		/* skip-name offset, length and value */
 		offset += sizeof(struct fdt_property) - FDT_TAGSIZE
@@ -169,7 +177,8 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 		return FDT_END;
 	}
 
-	if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
+	if (_check1() &&
+	    !fdt_offset_ptr(fdt, startoffset, offset - startoffset))
 		return FDT_END; /* premature end */
 
 	*nextoffset = FDT_TAGALIGN(offset);
-- 
2.22.0.657.g960e92d24f-goog