/*
 * Rufus: The Reliable USB Formatting Utility
 * Drive access function calls
 * 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/>.
 */
#ifdef _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#endif

#include <windows.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

#include "msapi_utf8.h"
#include "rufus.h"
#include "resource.h"

/*
 * Globals
 */
RUFUS_DRIVE_INFO SelectedDrive;

/*
 * Open a drive or volume with optional write and lock access
 * Returns INVALID_HANDLE_VALUE (/!\ which is DIFFERENT from NULL /!\) on failure.
 * This call is quite risky (left unchecked, inadvertently passing 0 as index would
 * return a handle to C:, which we might then proceed to unknowingly repartition!),
 * so we apply the following mitigation factors:
 * - Valid indexes must belong to a specific range [DRIVE_INDEX_MIN; DRIVE_INDEX_MAX]
 * - When opening for write access, we lock the volume. If that fails, which would
 *   typically be the case on C:\ or any other drive in use, we report failure
 * - We report the full path of any drive that was successfully opened for write acces
 */
HANDLE GetDriveHandle(DWORD DriveIndex, char* DriveLetter, BOOL bWriteAccess, BOOL bLockDrive)
{
	BOOL r;
	DWORD size;
	HANDLE hDrive = INVALID_HANDLE_VALUE;
	STORAGE_DEVICE_NUMBER_REDEF device_number = {0};
	char drives[26*4];	/* "D:\", "E:\", etc. */
	char *drive = drives;
	char logical_drive[] = "\\\\.\\#:";
	char physical_drive[24];

	if ((DriveIndex < DRIVE_INDEX_MIN) || (DriveIndex > DRIVE_INDEX_MAX)) {
		uprintf("WARNING: Bad index value. Please check the code!\n");
	}
	DriveIndex -= DRIVE_INDEX_MIN;

	// If no drive letter is requested, open a phyical drive
	if (DriveLetter == NULL) {
		safe_sprintf(physical_drive, sizeof(physical_drive), "\\\\.\\PHYSICALDRIVE%d", DriveIndex);
		hDrive = CreateFileA(physical_drive, GENERIC_READ|(bWriteAccess?GENERIC_WRITE:0),
			FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, 0);
		if (hDrive == INVALID_HANDLE_VALUE) {
			uprintf("Could not open drive %s: %s\n", physical_drive, WindowsErrorString());
			goto out;
		}
		if (bWriteAccess) {
			uprintf("Caution: Opened %s drive for write access\n", physical_drive);
		}
	} else {
		*DriveLetter = ' ';
		size = GetLogicalDriveStringsA(sizeof(drives), drives);
		if (size == 0) {
			uprintf("GetLogicalDriveStrings failed: %s\n", WindowsErrorString());
			goto out;
		}
		if (size > sizeof(drives)) {
			uprintf("GetLogicalDriveStrings: buffer too small (required %d vs %d)\n", size, sizeof(drives));
			goto out;
		}

		hDrive = INVALID_HANDLE_VALUE;
		for ( ;*drive; drive += safe_strlen(drive)+1) {
			if (!isalpha(*drive))
				continue;
			*drive = (char)toupper((int)*drive);
			if (*drive < 'C') {
				continue;
			}
			safe_sprintf(logical_drive, sizeof(logical_drive), "\\\\.\\%c:", drive[0]);
			hDrive = CreateFileA(logical_drive, GENERIC_READ|(bWriteAccess?GENERIC_WRITE:0),
				FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, 0);
			if (hDrive == INVALID_HANDLE_VALUE) {
				uprintf("Warning: could not open drive %c: %s\n", drive[0], WindowsErrorString());
				continue;
			}

			r = DeviceIoControl(hDrive, IOCTL_STORAGE_GET_DEVICE_NUMBER, NULL,
				0, &device_number, sizeof(device_number), &size, NULL);
			if ((!r) || (size <= 0)) {
				uprintf("IOCTL_STORAGE_GET_DEVICE_NUMBER failed for device %s: %s\n",
					logical_drive, WindowsErrorString());
			} else if (device_number.DeviceNumber == DriveIndex) {
				break;
			}
			safe_closehandle(hDrive);
		}
		if (hDrive == INVALID_HANDLE_VALUE) {
			goto out;
		}
		if (bWriteAccess) {
			uprintf("Caution: Opened %s drive for write access\n", logical_drive);
		}
		*DriveLetter = *drive?*drive:' ';
	}

	if ((bLockDrive) && (!DeviceIoControl(hDrive, FSCTL_LOCK_VOLUME, NULL, 0, NULL, 0, &size, NULL))) {
		uprintf("Could not get exclusive access to %s: %s\n", logical_drive, WindowsErrorString());
		safe_closehandle(hDrive);
		goto out;
	}

out:
	return hDrive;
}

/*
 * Return the drive letter and volume label
 */
BOOL GetDriveLabel(DWORD DriveIndex, char* letter, char** label)
{
	HANDLE hDrive;
	char DrivePath[] = "#:\\";
	static char volume_label[MAX_PATH+1];

	*label = STR_NO_LABEL;

	hDrive = GetDriveHandle(DriveIndex, DrivePath, FALSE, FALSE);
	if (hDrive == INVALID_HANDLE_VALUE)
		return FALSE;
	safe_closehandle(hDrive);
	*letter = DrivePath[0];

	if (GetVolumeInformationA(DrivePath, volume_label, sizeof(volume_label),
		NULL, NULL, NULL, NULL, 0) && *volume_label) {
		*label = volume_label;
	}

	return TRUE;
}