Support 'r' format for printing raw bytes with fdtget

FT is sometimes used for storing raw data. That is quite common for
U-Boot FIT images.

Extracting such data is not trivial currently. Using type 's' (string)
will replace every 0x00 (NUL) with 0x20 (space). Using type 'x' will
print bytes but in xxd incompatible format.

This commit adds support for 'r' (raw) format. Example usage:
fdtget -t r firmware.itb /images/foo data > image.raw

Support for encoding isn't added as there isn't any clean way of passing
binary data as command line argument.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Message-Id: <20211209061420.29466-1-zajec5@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Documentation/manual.txt

@@ -712,7 +712,7 @@ The syntax of the fdtget command is:
 
 where options are:
 
-    <type>    s=string, i=int, u=unsigned, x=hex
+    <type>    s=string, i=int, u=unsigned, x=hex, r=raw
         Optional modifier prefix:
             hh or b=byte, h=2 byte, l=4 byte (default)
 

fdtget.c

@@ -97,6 +97,11 @@ static int show_data(struct display_info *disp, const char *data, int len)
 	if (len == 0)
 		return 0;
 
+	if (disp->type == 'r') {
+		fwrite(data, 1, len, stdout);
+		return 0;
+	}
+
 	is_string = (disp->type) == 's' ||
 		(!disp->type && util_is_printable_string(data, len));
 	if (is_string) {

fdtput.c

@@ -433,6 +433,8 @@ int main(int argc, char *argv[])
 			if (utilfdt_decode_type(optarg, &disp.type,
 					&disp.size))
 				usage("Invalid type string");
+			if (disp.type == 'r')
+				usage("Unsupported raw data type");
 			break;
 
 		case 'v':

tests/run_tests.sh

@@ -855,6 +855,8 @@ fdtget_tests () {
     run_fdtget_test 8000 -tx $dtb /cpus/PowerPC,970@1 d-cache-size
     run_fdtget_test "61 62 63 0" -tbx $dtb /randomnode tricky1
     run_fdtget_test "a b c d de ea ad be ef" -tbx $dtb /randomnode blob
+    run_fdtget_test "MyBoardName\0MyBoardFamilyName\0" -tr $dtb / compatible
+    run_fdtget_test "\x0a\x0b\x0c\x0d\xde\xea\xad\xbe\xef" -tr $dtb /randomnode blob
 
     # Here the property size is not a multiple of 4 bytes, so it should fail
     run_wrap_error_test $DTGET -tlx $dtb /randomnode mixed

tests/utilfdt_test.c

@@ -73,6 +73,9 @@ static void check_sizes(char *modifier, int expected_size)
 
 	*ptr = 's';
 	check(fmt, 's', -1);
+
+	*ptr = 'r';
+	check(fmt, 'r', -1);
 }
 
 static void test_utilfdt_decode_type(void)
@@ -90,7 +93,7 @@ static void test_utilfdt_decode_type(void)
 	/* try every other character */
 	checkfail("");
 	for (ch = ' '; ch < 127; ch++) {
-		if (!strchr("iuxs", ch)) {
+		if (!strchr("iuxsr", ch)) {
 			*fmt = ch;
 			fmt[1] = '\0';
 			checkfail(fmt);

util.c

@@ -353,11 +353,11 @@ int utilfdt_decode_type(const char *fmt, int *type, int *size)
 	}
 
 	/* we should now have a type */
-	if ((*fmt == '\0') || !strchr("iuxs", *fmt))
+	if ((*fmt == '\0') || !strchr("iuxsr", *fmt))
 		return -1;
 
 	/* convert qualifier (bhL) to byte size */
-	if (*fmt != 's')
+	if (*fmt != 's' && *fmt != 'r')
 		*size = qualifier == 'b' ? 1 :
 				qualifier == 'h' ? 2 :
 				qualifier == 'l' ? 4 : -1;

util.h

@@ -143,6 +143,7 @@ int utilfdt_write_err(const char *filename, const void *blob);
  *		i	signed integer
  *		u	unsigned integer
  *		x	hex
+ *		r	raw
  *
  * TODO: Implement ll modifier (8 bytes)
  * TODO: Implement o type (octal)
@@ -160,7 +161,7 @@ int utilfdt_decode_type(const char *fmt, int *type, int *size);
  */
 
 #define USAGE_TYPE_MSG \
-	"<type>\ts=string, i=int, u=unsigned, x=hex\n" \
+	"<type>\ts=string, i=int, u=unsigned, x=hex, r=raw\n" \
 	"\tOptional modifier prefix:\n" \
 	"\t\thh or b=byte, h=2 byte, l=4 byte (default)";