Added an option to prepend extracted images with a 32 KB SDK header.

Option is -N or --ndev.

NOTE: Only seems to work with Wii images at the moment. NDEV displays
the disc information from GameCube images, but then hangs.

Tested with SL and DL discs on the apploader.

doc/sdk_header.md: Initial SDK header documentation.

doc/sdk_header.md

@@ -0,0 +1,39 @@
+# GCM SDK Headers
+
+This document is Copyright (C) 2018 by David Korth.<br>
+Licensed under the GNU Free Documentation License v1.3.
+
+GCM images produced by the official GameCube and Wii SDKs have a 32 KB header.
+This header isn't present in images ripped using e.g. CleanRip, and it isn't
+recognized by the Dolphin emulator. It's also not present on RVT-H Reader HDDs.
+However, it **is** needed when using the official SDK tools, e.g. rvtwriter and
+the NDEV optical drive emulator.
+
+## Example Header
+
+The following header is from an swupdate image from one of the Wii SDKs:
+
+```
+00000000  ff ff 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00000820  00 00 00 00 00 00 00 00  00 00 00 00 00 00 e0 06  |................|
+00000830  00 00 6b 4f 00 00 00 00  00 00 00 00 00 00 00 00  |..kO............|
+00000840  00 00 00 00 01 00 00 00  00 00 00 00 00 00 00 00  |................|
+00000850  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00008000  52 41 42 41 30 31 00 00  00 00 00 00 00 00 00 00  |RABA01..........|
+```
+
+The header is mostly zeroes, except for these important DWORD values:
+* 0x0000: `FF FF 00 00`
+* 0x082C: `00 00 E0 06`
+* 0x0830: `00 00 6B 4F`
+
+The value at 0x0830 appears to be a checksum of some sort. If this header is
+prepended as-is to any generic Wii image and loaded onto an NDEV using ODEM,
+the NDEV will show a "Wrong disk" error. However, zeroing out this DWORD gets
+it working for all discs.
+
+Images built using `makeGCM` from the GameCube SDK always have a checksum of
+`0xAB0B`; however, the NDEV system locks up after displaying the disc info.

src/librvth/nhcd_structs.h

@@ -140,6 +140,10 @@ ASSERT_STRUCT(NHCD_BankTable, 512*9);
 // Block size.
 #define NHCD_BLOCK_SIZE		512
 
+// SDK header size.
+#define SDK_HEADER_SIZE_BYTES	32768
+#define SDK_HEADER_SIZE_LBA	(SDK_HEADER_SIZE_BYTES / NHCD_BLOCK_SIZE)
+
 #pragma pack()
 
 #ifdef __cplusplus

src/librvth/ref_file.c

@@ -81,9 +81,9 @@ static RefFile *ref_open_int(const TCHAR *filename, const TCHAR *mode)
 
 	// Initialize the reference count.
 	f->ref_count = 1;
-        // File writability depends on the mode.
+	// File writability depends on the mode.
 	// NOTE: Only checking the first character.
-        f->is_writable = (mode[0] == _T('w'));
+	f->is_writable = (mode[0] == _T('w'));
 	return f;
 
 fail:

src/librvth/rvth.c

@@ -434,7 +434,7 @@ const char *rvth_error(int err)
 	// for system-level issues. For anything weird encountered
 	// within an RVT-H HDD or GCN/Wii disc image, an
 	// RvtH_Errors code should be retured instead.
-	static const char *const errtbl[RVTH_ERROR_MAX] = {
+	static const char *const errtbl[] = {
 		// tr: RVTH_ERROR_SUCCESS
 		"Success",
 		// tr: RVTH_ERROR_UNRECOGNIZED_FILE
@@ -492,8 +492,13 @@ const char *rvth_error(int err)
 		"The second bank for the Dual-Layer image is not empty or deleted",
 		// tr: RVTH_ERROR_IMPORT_DL_NOT_CONTIGUOUS
 		"The two banks are not contiguous",
+
+		// NDEV option.
+
+		// tr: RVTH_ERROR_NDEV_GCN_NOT_SUPPORTED
+		"NDEV headers for GCN are currently unsupported.",
 	};
-	// TODO: static_assert()
+	static_assert(ARRAY_SIZE(errtbl) == RVTH_ERROR_MAX, "Missing error descriptions!");
 
 	if (err < 0) {
 		return strerror(-err);

src/librvth/rvth.h

@@ -69,6 +69,9 @@ typedef enum {
 	RVTH_ERROR_BANK2DL_NOT_EMPTY_OR_DELETED	= 25,	// The second bank for the Dual-Layer image is not empty or deleted.
 	RVTH_ERROR_IMPORT_DL_NOT_CONTIGUOUS	= 26,	// The two banks are not contiguous.
 
+	// NDEV option.
+	RVTH_ERROR_NDEV_GCN_NOT_SUPPORTED	= 27,	// NDEV headers for GCN are currently unsupported.
+
 	RVTH_ERROR_MAX
 } RvtH_Errors;
 
@@ -274,6 +277,15 @@ RvtH *rvth_create_gcm(const TCHAR *filename, uint32_t lba_len, int *pErr);
  */
 int rvth_copy_to_gcm(RvtH *rvth_dest, const RvtH *rvth_src, unsigned int bank_src, RvtH_Progress_Callback callback);
 
+/**
+ * RVT-H extraction flags.
+ */
+typedef enum {
+	// Prepend a 32k SDK header.
+	// Required for rvtwriter, NDEV ODEM, etc.
+	RVTH_EXTRACT_PREPEND_SDK_HEADER		= (1 << 0),
+} RvtH_Extract_Flags;
+
 /**
  * Extract a disc image from the RVT-H disk image.
  * Compatibility wrapper; this function calls rvth_create_gcm() and rvth_copy().
@@ -281,10 +293,12 @@ int rvth_copy_to_gcm(RvtH *rvth_dest, const RvtH *rvth_src, unsigned int bank_sr
  * @param bank		[in] Bank number. (0-7)
  * @param filename	[in] Destination filename.
  * @param recrypt_key	[in] Key for recryption. (-1 for default; otherwise, see RvtH_CryptoType_e)
+ * @param flags		[in] Flags. (See RvtH_Extract_Flags.)
  * @param callback	[in,opt] Progress callback.
  * @return Error code. (If negative, POSIX error; otherwise, see RvtH_Errors.)
  */
-int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int recrypt_key, RvtH_Progress_Callback callback);
+int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename,
+	int recrypt_key, uint32_t flags, RvtH_Progress_Callback callback);
 
 /**
  * Copy a bank from an RVT-H HDD or standalone disc image to an RVT-H system.

src/librvth/rvth_extract.c

@@ -276,12 +276,14 @@ end:
  * @param bank		[in] Bank number. (0-7)
  * @param filename	[in] Destination filename.
  * @param recrypt_key	[in] Key for recryption. (-1 for default; otherwise, see RvtH_CryptoType_e)
+ * @param flags		[in] Flags. (See RvtH_Extract_Flags.)
  * @param callback	[in,opt] Progress callback.
  * @return Error code. (If negative, POSIX error; otherwise, see RvtH_Errors.)
  */
-int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int recrypt_key, RvtH_Progress_Callback callback)
+int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename,
+	int recrypt_key, uint32_t flags, RvtH_Progress_Callback callback)
 {
-	RvtH *rvth_dest;
+	RvtH *rvth_dest = NULL;
 	RvtH_BankEntry *entry;
 	uint32_t gcm_lba_len;
 	bool unenc_to_enc;
@@ -313,7 +315,8 @@ int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int
 		if (!game_pte) {
 			// No game partition...
 			errno = EIO;
-			return RVTH_ERROR_NO_GAME_PARTITION;
+			ret = RVTH_ERROR_NO_GAME_PARTITION;
+			goto end;
 		}
 
 		// TODO: Read the partition header to determine the data offset.
@@ -330,6 +333,15 @@ int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int
 		gcm_lba_len = entry->lba_len;
 	}
 
+	if (flags & RVTH_EXTRACT_PREPEND_SDK_HEADER) {
+		if (entry->type == RVTH_BankType_GCN) {
+			// FIXME: Not supported.
+			return RVTH_ERROR_NDEV_GCN_NOT_SUPPORTED;
+		}
+		// Prepend 32k to the GCM.
+		gcm_lba_len += BYTES_TO_LBA(32768);
+	}
+
 	ret = 0;
 	rvth_dest = rvth_create_gcm(filename, gcm_lba_len, &ret);
 	if (!rvth_dest) {
@@ -337,7 +349,65 @@ int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int
 		if (ret == 0) {
 			ret = -EIO;
 		}
-		return ret;
+		goto end;
+	}
+
+	if (flags & RVTH_EXTRACT_PREPEND_SDK_HEADER) {
+		// Prepend 32k to the GCM.
+		size_t size;
+		Reader *const reader = rvth_dest->entries[0].reader;
+		uint8_t *sdk_header = calloc(1, SDK_HEADER_SIZE_BYTES);
+		if (!sdk_header) {
+			ret = -errno;
+			if (ret == 0) {
+				ret = -ENOMEM;
+			}
+			goto end;
+		}
+
+		// TODO: Get headers for GC1L and NN2L.
+		// TODO: Optimize by using 32-bit writes?
+		switch (entry->type) {
+			case RVTH_BankType_GCN:
+				// FIXME; GameCube GCM seems to use the same values,
+				// but it doesn't load with NDEV.
+				// Checksum field is always 0xAB0B.
+				// TODO: Delete the file?
+				rvth_close(rvth_dest);
+				return RVTH_ERROR_NDEV_GCN_NOT_SUPPORTED;
+			case RVTH_BankType_Wii_SL:
+			case RVTH_BankType_Wii_DL:
+				// 0x0000: FF FF 00 00
+				sdk_header[0x0000] = 0xFF;
+				sdk_header[0x0001] = 0xFF;
+				// 0x082C: 00 00 E0 06
+				sdk_header[0x082E] = 0xE0;
+				sdk_header[0x082F] = 0x06;
+				// TODO: Checksum at 0x0830? (If 00 00, seems to work for all discs.)
+				// 0x0844: 01 00 00 00
+				sdk_header[0x0844] = 0x01;
+				break;
+			default:
+				// Should not get here...
+				assert(!"Incorrect bank type.");
+				free(sdk_header);
+				goto end;
+		}
+
+		size = reader_write(reader, sdk_header, 0, SDK_HEADER_SIZE_LBA);
+		if (size != SDK_HEADER_SIZE_LBA) {
+			// Write error.
+			ret = -errno;
+			if (ret == 0) {
+				ret = -EIO;
+			}
+			goto end;
+		}
+		free(sdk_header);
+
+		// Remove the SDK header from the reader's offsets.
+		reader->lba_start += SDK_HEADER_SIZE_LBA;
+		reader->lba_len -= SDK_HEADER_SIZE_LBA;
 	}
 
 	// Copy the bank from the source image to the destination GCM.
@@ -354,7 +424,11 @@ int rvth_extract(const RvtH *rvth, unsigned int bank, const TCHAR *filename, int
 		}
 	}
 
-	rvth_close(rvth_dest);
+end:
+	// TODO: Delete the file on error?
+	if (rvth_dest) {
+		rvth_close(rvth_dest);
+	}
 	return ret;
 }
 

src/rvthtool/extract.c

@@ -77,9 +77,10 @@ static bool progress_callback(const RvtH_Progress_State *state)
  * @param s_bank	[in] Bank number (as a string). (If NULL, assumes bank 1.)
  * @param gcm_filename	[in] Filename for the extracted GCM image.
  * @param recrypt_key	[in] Key for recryption. (-1 for default)
+ * @param flags		[in] Flags. (See RvtH_Extract_Flags.)
  * @return 0 on success; non-zero on error.
  */
-int extract(const TCHAR *rvth_filename, const TCHAR *s_bank, const TCHAR *gcm_filename, int recrypt_key)
+int extract(const TCHAR *rvth_filename, const TCHAR *s_bank, const TCHAR *gcm_filename, int recrypt_key, uint32_t flags)
 {
 	RvtH *rvth;
 	TCHAR *endptr;
@@ -126,7 +127,7 @@ int extract(const TCHAR *rvth_filename, const TCHAR *s_bank, const TCHAR *gcm_fi
 	printf("Extracting Bank %u into '", bank+1);
 	_fputts(gcm_filename, stdout);
 	fputs("'...\n", stdout);
-	ret = rvth_extract(rvth, bank, gcm_filename, recrypt_key, progress_callback);
+	ret = rvth_extract(rvth, bank, gcm_filename, recrypt_key, flags, progress_callback);
 	if (ret == 0) {
 		printf("Bank %u extracted to '", bank+1);
 		_fputts(gcm_filename, stdout);

src/rvthtool/extract.h

@@ -22,6 +22,7 @@
 #define __RVTHTOOL_RVTHTOOL_EXTRACT_H__
 
 #include "librvth/tcharx.h"
+#include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -33,9 +34,10 @@ extern "C" {
  * @param s_bank	Bank number (as a string). (If NULL, assumes bank 1.)
  * @param gcm_filename	Filename for the extracted GCM image.
  * @param recrypt_key	[in] Key for recryption. (-1 for default)
+ * @param flags		[in] Flags. (See RvtH_Extract_Flags.)
  * @return 0 on success; non-zero on error.
  */
-int extract(const TCHAR *rvth_filename, const TCHAR *s_bank, const TCHAR *gcm_filename, int recrypt_key);
+int extract(const TCHAR *rvth_filename, const TCHAR *s_bank, const TCHAR *gcm_filename, int recrypt_key, uint32_t flags);
 
 /**
  * 'import' command.

src/rvthtool/main.c

@@ -125,6 +125,8 @@ static void print_help(const TCHAR *argv0)
 		"                            default, retail, korean, debug\n"
 		"                            Recrypting to retail will use fakesigning.\n"
 		"                            Importing to RVT-H will always use debug keys.\n"
+		"  -N, --ndev                Prepend extracted images with a 32 KB header\n"
+		"                            required by official SDK tools.\n"
 		"  -h, --help                Display this help and exit.\n"
 		"\n"
 		, stdout);
@@ -133,6 +135,7 @@ static void print_help(const TCHAR *argv0)
 int RVTH_CDECL _tmain(int argc, TCHAR *argv[])
 {
 	int ret;
+	uint32_t flags = 0;
 
 	// Key to use for recryption.
 	// -1 == default; no recryption, except when importing retail to RVT-H.
@@ -159,12 +162,13 @@ int RVTH_CDECL _tmain(int argc, TCHAR *argv[])
 	while (true) {
 		static const struct option long_options[] = {
 			{_T("recrypt"),	required_argument,	0, _T('k')},
+			{_T("ndev"),	no_argument,		0, _T('N')},
 			{_T("help"),	no_argument,		0, _T('h')},
 
 			{NULL, 0, 0, 0}
 		};
 
-		int c = getopt_long(argc, argv, _T("k:h"), long_options, NULL);
+		int c = getopt_long(argc, argv, _T("k:Nh"), long_options, NULL);
 		if (c == -1)
 			break;
 
@@ -190,6 +194,12 @@ int RVTH_CDECL _tmain(int argc, TCHAR *argv[])
 				}
 				break;
 
+			case 'N':
+				// Prepend the SDK header.
+				// TODO: Show error if not using 'extract'?
+				flags |= RVTH_EXTRACT_PREPEND_SDK_HEADER;
+				break;
+
 			case 'h':
 				print_help(argv[0]);
 				return EXIT_SUCCESS;
@@ -230,10 +240,10 @@ int RVTH_CDECL _tmain(int argc, TCHAR *argv[])
 			// Pass NULL as the bank number, which will be
 			// interpreted as bank 1 for single-disc images
 			// and an error for HDD images.
-			ret = extract(argv[optind+1], NULL, argv[optind+2], recrypt_key);
+			ret = extract(argv[optind+1], NULL, argv[optind+2], recrypt_key, flags);
 		} else {
 			// Three or more parameters specified.
-			ret = extract(argv[optind+1], argv[optind+2], argv[optind+3], recrypt_key);
+			ret = extract(argv[optind+1], argv[optind+2], argv[optind+3], recrypt_key, flags);
 		}
 	} else if (!_tcscmp(argv[optind], _T("import"))) {
 		// Import a bank.