fdtgrep: Improve error handling with invalid device tree

This tool requires that the aliases node be the first node in the tree. But
when it is not, it does not handle things gracefully. In fact it crashes.

Fix this, and add a more helpful error message.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/tools/fdtgrep.c b/tools/fdtgrep.c
index 67aa41a24d..8d3fef4027 100644
--- a/tools/fdtgrep.c
+++ b/tools/fdtgrep.c
@@ -660,6 +660,8 @@ static int fdtgrep_find_regions(const void *fdt,
 		if (!ret)
 			count++;
 	}
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		return ret;
 
 	/* Find all the aliases and add those regions back in */
 	if (disp->add_aliases && count < max_regions) {
@@ -667,7 +669,11 @@ static int fdtgrep_find_regions(const void *fdt,
 
 		new_count = fdt_add_alias_regions(fdt, region, count,
 						  max_regions, &state);
-		if (new_count <= max_regions) {
+		if (new_count == -FDT_ERR_NOTFOUND) {
+			/* No alias node found */
+		} else if (new_count < 0) {
+			return new_count;
+		} else if (new_count <= max_regions) {
 			/*
 			* The alias regions will now be at the end of the list.
 			* Sort the regions by offset to get things into the
@@ -679,9 +685,6 @@ static int fdtgrep_find_regions(const void *fdt,
 		}
 	}
 
-	if (ret != -FDT_ERR_NOTFOUND)
-		return ret;
-
 	return count;
 }
 
@@ -807,6 +810,9 @@ static int do_fdtgrep(struct display_info *disp, const char *filename)
 				disp->flags);
 		if (count < 0) {
 			report_error("fdt_find_regions", count);
+			if (count == -FDT_ERR_BADLAYOUT)
+				fprintf(stderr,
+					"/aliases node must come before all other nodes\n");
 			return -1;
 		}
 		if (count <= max_regions)