[boot] added MS-DOS file extraction from diskcopy.dll

* diskcopy.dll contains a resource ('BINFILE') that is a 1.4MB
  floppy image of a bootable MS-DOS disk (FAT12)
* we can extract these files and use them for bootable USB

.msvc/rufus_2010.vcxproj

@@ -143,11 +143,13 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="..\msdos.c" />
     <ClCompile Include="..\rufus.c" />
     <ClCompile Include="..\stdlg.c" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\msapi_utf8.h" />
+    <ClInclude Include="..\msdos.h" />
     <ClInclude Include="..\rufus.h" />
     <ClInclude Include="..\license.h" />
     <ClInclude Include="..\sys_types.h" />

.msvc/rufus_2010.vcxproj.filters

@@ -21,6 +21,9 @@
     <ClCompile Include="..\stdlg.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\msdos.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\rufus.h">
@@ -35,6 +38,9 @@
     <ClInclude Include="..\sys_types.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\msdos.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\rufus.ico">

.msvc/rufus_sources

@@ -25,4 +25,5 @@ SXS_APPLICATION_MANIFEST=common_controls_and_elevation.manifest
 
 SOURCES=rufus.c \
         stdlg.c \
+        msdos.c \
         rufus.rc

Makefile

@@ -6,7 +6,7 @@ STRIP  = strip
 CFLAGS = -std=gnu99 -Wall -Wundef -Wunused -Wstrict-prototypes -Werror-implicit-function-declaration -Wno-pointer-sign -Wshadow -O2 -Wl,--subsystem,windows -DWINVER=0x501 -D_WIN32_IE=0x501
 LIBS   = -lsetupapi -lole32 -lgdi32
 
-RUFUS_SRC = rufus.c stdlg.c
+RUFUS_SRC = rufus.c stdlg.c msdos.c
 
 .PHONY: all clean
 

msdos.c

@@ -0,0 +1,145 @@
+/*
+ * Rufus: The Resourceful USB Formatting Utility
+ * MS-DOS boot file extraction, from the FAT12 floppy image in diskcopy.dll
+ * Copyright (c) 2011 Pete Batard <pete@akeo.ie>
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Memory leaks detection - define _CRTDBG_MAP_ALLOC as preprocessor macro */
+#ifdef _CRTDBG_MAP_ALLOC
+#include <stdlib.h>
+#include <crtdbg.h>
+#endif
+
+#include <windows.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "rufus.h"
+#include "msdos.h"
+
+static BYTE* DiskImage;
+static size_t DiskImageSize;
+
+/* Extract the file identified by FAT RootDir index 'entry' to 'path' */
+static BOOL ExtractFAT(int entry, const char* path)
+{
+	FILE* fd;
+	char filename[MAX_PATH];
+	size_t i, pos;
+	size_t filestart;
+	size_t filesize;
+	size_t FATFile = FAT12_ROOTDIR_OFFSET + entry*FAT12_ROOTDIR_ENTRY_SIZE;
+
+	if ((path == NULL) || ((safe_strlen(path) + 14) > sizeof(filename))) {
+		uprintf("invalid path supplied for MS-DOS FAT extraction\n");
+		return FALSE;
+	}
+	strcpy(filename, path);
+	pos = strlen(path);
+	filename[pos++] = '\\';
+
+	for(i=0; i<8; i++) {
+		if (DiskImage[FATFile + i] == ' ')
+			break;
+		filename[pos++] = DiskImage[FATFile + i];
+	}
+	filename[pos++] = '.';
+	for (i=8; i<11; i++) {
+		if (DiskImage[FATFile + i] == ' ')
+			break;
+		filename[pos++] = DiskImage[FATFile + i];
+	}
+	filename[pos] = 0;
+	GET_ULONG_LE(filesize, DiskImage, FATFile + FAT12_ROOTDIR_FILESIZE);
+	GET_USHORT_LE(filestart, DiskImage, FATFile + FAT12_ROOTDIR_FIRSTCLUSTER);
+	filestart += FAT12_CLUSTER_OFFSET;
+	filestart *= FAT12_CLUSTER_SIZE;
+	if ((filestart + filesize) > DiskImageSize) {
+		uprintf("FAT File %s would be out of bounds\n", filename);
+		return FALSE;
+	}
+
+	fd = fopen(filename, "wb");
+	if (fd == NULL) {
+		uprintf("Unable to create file '%s'.\n", filename);
+		return FALSE;
+	}
+
+	if (fwrite(&DiskImage[filestart], 1, filesize, fd) != filesize) {
+		uprintf("Couldn't write file '%s'.\n", filename);
+		fclose(fd);
+		return FALSE;
+	}
+	fclose(fd);
+
+	uprintf("Succesfully wrote '%s' (%d bytes)\n", filename, filesize);
+
+	// TODO: MSDOS.SYS and IO.SYS should have 'rahs' attributes
+	return TRUE;
+}
+
+/* Extract the MS-DOS files contained in the FAT12 1.4MB floppy
+   image included as resource "BINFILE" in diskcopy.dll */
+BOOL ExtractMSDOS(const char* path)
+{
+	char dllname[MAX_PATH] = "C:\\Windows\\System32";
+	int i, j;
+	HMODULE hDLL;
+	HRSRC hDiskImage;
+
+	// TODO: optionally extract some more, including "deleted" entries
+	char* extractlist[] = {"MSDOS   SYS", "COMMAND COM", "IO      SYS"};
+
+	GetSystemDirectoryA(dllname, sizeof(dllname));
+	safe_strcat(dllname, sizeof(dllname), "\\diskcopy.dll");
+	hDLL = LoadLibraryA(dllname);
+	if (hDLL == NULL) {
+		uprintf("Unable to open %s: %s\n", dllname, WindowsErrorString());
+		return FALSE;
+	}
+	hDiskImage = FindResourceA(hDLL, MAKEINTRESOURCEA(1), "BINFILE");
+	if (hDiskImage == NULL) {
+		uprintf("Unable to locate disk image in %s: %s\n", dllname, WindowsErrorString());
+		FreeLibrary(hDLL);
+		return FALSE;
+	}
+	DiskImage = (BYTE*)LockResource(LoadResource(hDLL, hDiskImage));
+	if (DiskImage == NULL) {
+		uprintf("Unable to access disk image in %s: %s\n", dllname, WindowsErrorString());
+		FreeLibrary(hDLL);
+		return FALSE;
+	}
+	DiskImageSize = (size_t)SizeofResource(hDLL, hDiskImage);
+	// Sanity check
+	if (DiskImageSize < 700*1024) {
+		uprintf("MS-DOS disk image is too small (%d bytes)\n", dllname, DiskImageSize);
+		FreeLibrary(hDLL);
+		return FALSE;
+	}
+
+	for (i=0; i<FAT12_ROOTDIR_NB_ENTRIES; i++) {
+		if (DiskImage[FAT12_ROOTDIR_OFFSET + i*FAT12_ROOTDIR_ENTRY_SIZE] == FAT12_DELETED_ENTRY)
+			continue;
+		for (j=0; j<ARRAYSIZE(extractlist); j++) {
+			if (memcmp(extractlist[j], &DiskImage[FAT12_ROOTDIR_OFFSET + i*FAT12_ROOTDIR_ENTRY_SIZE], 8+3) == 0) {
+				ExtractFAT(i, path);
+			}
+		}
+	}
+
+	FreeLibrary(hDLL);
+	return TRUE;
+}

msdos.h

@@ -0,0 +1,50 @@
+/*
+ * Rufus: The Resourceful USB Formatting Utility
+ * MS-DOS boot file extraction, from the FAT12 floppy image in diskcopy.dll
+ * Copyright (c) 2011 Pete Batard <pete@akeo.ie>
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* http://www.c-jump.com/CIS24/Slides/FAT/lecture.html */
+#define FAT12_ROOTDIR_OFFSET        0x2600
+#define FAT12_ROOTDIR_ENTRY_SIZE    0x20
+#define FAT12_ROOTDIR_NB_ENTRIES    0xE0
+#define FAT12_ROOTDIR_FIRSTCLUSTER  0x1A		// No need for high word on a 1.44 MB media
+#define FAT12_ROOTDIR_FILESIZE      0x1C
+#define FAT12_DELETED_ENTRY         0xE5
+
+/* Ideally, we'd read those from the FAT Boot Sector, but we have
+   a pretty good idea of what they are for a 1.44 MB floppy image */
+#define FAT12_CLUSTER_SIZE          0x200	// = sector size
+#define FAT12_DATA_START            0x4200
+#define FAT12_CLUSTER_OFFSET        ((FAT12_DATA_START/FAT12_CLUSTER_SIZE)-2)	// First cluster in data area is #2
+
+#ifndef GET_ULONG_LE
+#define GET_ULONG_LE(n,b,i)                     \
+{                                               \
+    (n) = ( (ULONG) (b)[(i)    ]       )        \
+        | ( (ULONG) (b)[(i) + 1] <<  8 )        \
+        | ( (ULONG) (b)[(i) + 2] << 16 )        \
+        | ( (ULONG) (b)[(i) + 3] << 24 );       \
+}
+#endif
+
+#ifndef GET_USHORT_LE
+#define GET_USHORT_LE(n,b,i)                    \
+{                                               \
+    (n) = ( (USHORT) (b)[(i)    ]       )       \
+        | ( (USHORT) (b)[(i) + 1] <<  8 );      \
+}
+#endif