[DTC] small ftdump cleanup patch

[Paul Gortmaker]

Here is a small patch to clean up the usage info and the error returns
for ftdump -- not sure what the future holds for ftdump vs. simply using
"dtc -I dtb -O dts someblob.dtb" ...

Paul.


diff --git a/ftdump.c b/ftdump.c
index 53343d7..49bc7cf 100644
--- a/ftdump.c
+++ b/ftdump.c
@@ -8,6 +8,8 @@
 #include <ctype.h>
 #include <netinet/in.h>
 #include <byteswap.h>
+#include <errno.h>
+#include <libgen.h>
 
 #include <fdt.h>
 
@@ -165,21 +167,22 @@ int main(int argc, char *argv[])
 	char buf[16384];	/* 16k max */
 	int size;
 
-	if (argc < 2) {
-		fprintf(stderr, "supply input filename\n");
-		return 5;
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s filename.dtb\n", basename(argv[0]));
+		fprintf(stderr, "\t-dump binary device tree blob contents.\n");
+		return EINVAL;
 	}
 
 	fp = fopen(argv[1], "rb");
 	if (fp == NULL) {
 		fprintf(stderr, "unable to open %s\n", argv[1]);
-		return 10;
+		return errno;
 	}
 
 	size = fread(buf, 1, sizeof(buf), fp);
 	if (size == sizeof(buf)) {	/* too large */
 		fprintf(stderr, "file too large\n");
-		return 10;
+		return EFBIG;
 	}
 
 	dump_blob(buf);