/*
 * Copyright 2007, Ingo Weinhold, bonefish@cs.tu-berlin.de.
 * Copyright 2002-2007, Axel Dörfler, axeld@pinc-software.de.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
 * Distributed under the terms of the NewOS License.
 */


#include "vfs_boot.h"
#include "vfs_net_boot.h"

#include <vfs.h>
#include <file_cache.h>
#include <KPath.h>
#include <syscalls.h>
#include <boot/kernel_args.h>
#include <util/KMessage.h>
#include <util/Stack.h>

#include <disk_device_manager/KDiskDevice.h>
#include <disk_device_manager/KDiskDeviceManager.h>
#include <disk_device_manager/KPartitionVisitor.h>
#include <DiskDeviceTypes.h>

#include <OS.h>
#include <fs_info.h>

#include <stdio.h>


//#define TRACE_VFS
#ifdef TRACE_VFS
#	define TRACE(x) dprintf x
#else
#	define TRACE(x) ;
#endif


typedef Stack<KPartition *> PartitionStack;

static struct {
	const char *path;
	const char *target;
} sPredefinedLinks[] = {
	{"/system", "/boot/beos/system"},
	{"/bin", "/boot/beos/bin"},
	{"/etc", "/boot/beos/etc"},
	{"/var", "/boot/var"},
	{"/tmp", "/boot/var/tmp"},
	{NULL}
};

// This can be used by other code to see if there is a boot file system already
dev_t gBootDevice = -1;


/*!	No image was chosen - prefer disks with names like "Haiku", or "System"
 */
int
compare_image_boot(const void *_a, const void *_b)
{
	KPartition *a = *(KPartition **)_a;
	KPartition *b = *(KPartition **)_b;

	if (a->ContentName() != NULL) {
		if (b->ContentName() == NULL)
			return 1;
	} else if (b->ContentName() != NULL) {
		return -1;
	} else
		return 0;

	int compare = strcmp(a->ContentName(), b->ContentName());
	if (!compare)
		return 0;

	if (!strcasecmp(a->ContentName(), "Haiku"))
		return 1;
	if (!strcasecmp(b->ContentName(), "Haiku"))
		return -1;
	if (!strncmp(a->ContentName(), "System", 6))
		return 1;
	if (!strncmp(b->ContentName(), "System", 6))
		return -1;

	return compare;	
}


/*!	The system was booted from CD - prefer CDs over other entries. If there
	is no CD, fall back to the standard mechanism (as implemented by
	compare_image_boot().
*/
static int
compare_cd_boot(const void *_a, const void *_b)
{
	KPartition *a = *(KPartition **)_a;
	KPartition *b = *(KPartition **)_b;

	bool aIsCD = a->Type() != NULL && !strcmp(a->Type(), kPartitionTypeDataSession);
	bool bIsCD = b->Type() != NULL && !strcmp(b->Type(), kPartitionTypeDataSession);

	int compare = (int)aIsCD - (int)bIsCD;
	if (compare != 0)
		return compare;

	return compare_image_boot(_a, _b);
}


/*!	Computes a check sum for the specified block.
	The check sum is the sum of all data in that block interpreted as an
	array of uint32 values.
	Note, this must use the same method as the one used in
	boot/platform/bios_ia32/devices.cpp (or similar solutions).
*/
static uint32
compute_check_sum(KDiskDevice *device, off_t offset)
{
	char buffer[512];
	ssize_t bytesRead = read_pos(device->FD(), offset, buffer, sizeof(buffer));
	if (bytesRead < B_OK)
		return 0;

	if (bytesRead < (ssize_t)sizeof(buffer))
		memset(buffer + bytesRead, 0, sizeof(buffer) - bytesRead);

	uint32 *array = (uint32 *)buffer;
	uint32 sum = 0;

	for (uint32 i = 0; i < (bytesRead + sizeof(uint32) - 1) / sizeof(uint32); i++) {
		sum += array[i];
	}

	return sum;
}


// #pragma mark - BootMethod


BootMethod::BootMethod(const KMessage& bootVolume, int32 method)
	:
	fBootVolume(bootVolume),
	fMethod(method)
{
}


BootMethod::~BootMethod()
{
}


status_t
BootMethod::Init()
{
	return B_OK;
}


// #pragma mark - DiskBootMethod


class DiskBootMethod : public BootMethod {
public:
	DiskBootMethod(const KMessage& bootVolume, int32 method)
		: BootMethod(bootVolume, method)
	{
	}

	virtual bool IsBootDevice(KDiskDevice* device, bool strict);
	virtual bool IsBootPartition(KPartition* partition, bool& foundForSure);
	virtual void SortPartitions(KPartition** partitions, int32 count);
};


bool
DiskBootMethod::IsBootDevice(KDiskDevice* device, bool strict)
{
	disk_identifier *disk;
	int32 diskIdentifierSize;
	if (fBootVolume.FindData(BOOT_VOLUME_DISK_IDENTIFIER, B_RAW_TYPE,
			(const void**)&disk, &diskIdentifierSize) != B_OK) {
		dprintf("DiskBootMethod::IsBootDevice(): no disk identifier!\n");
		return false;
	}

	TRACE(("boot device: bus %ld, device %ld\n", disk->bus_type,
		disk->device_type));

	switch (disk->bus_type) {
		case PCI_BUS:
		case LEGACY_BUS:
			// TODO: implement this! (and then enable this feature in the boot loader)
			// (we need a way to get the device_node of a device, then)
			break;

		case UNKNOWN_BUS:
			// nothing to do here
			break;
	}

	switch (disk->device_type) {
		case UNKNOWN_DEVICE:
			// test if the size of the device matches
			// (the BIOS might have given us the wrong value here, though)
			if (strict && device->Size() != disk->device.unknown.size)
				return false;

			// check if the check sums match, too
			for (int32 i = 0; i < NUM_DISK_CHECK_SUMS; i++) {
				if (disk->device.unknown.check_sums[i].offset == -1)
					continue;

				if (compute_check_sum(device,
						disk->device.unknown.check_sums[i].offset)
							!= disk->device.unknown.check_sums[i].sum) {
					return false;
				}
			}
			break;

		case ATA_DEVICE:
		case ATAPI_DEVICE:
		case SCSI_DEVICE:
		case USB_DEVICE:
		case FIREWIRE_DEVICE:
		case FIBRE_DEVICE:
			// TODO: implement me!
			break;
	}

	return true;
}


bool
DiskBootMethod::IsBootPartition(KPartition* partition, bool& foundForSure)
{
	if (!fBootVolume.GetBool(BOOT_VOLUME_BOOTED_FROM_IMAGE, false)) {
		// the simple case: we can just boot from the selected boot
		// device
		if (partition->Offset() == fBootVolume.GetInt64(
				BOOT_VOLUME_PARTITION_OFFSET, 0)) {
			foundForSure = true;
			return true;
		}
	} else {
		// for now, we will just collect all BFS volumes
		if (fMethod == BOOT_METHOD_CD
			&& fBootVolume.GetBool(BOOT_VOLUME_USER_SELECTED, false)
			&& partition->Type() != NULL
			&& strcmp(partition->Type(), kPartitionTypeDataSession)) {
			return false;
		}

		if (partition->ContentType() != NULL
			&& !strcmp(partition->ContentType(), "Be File System")) {
			return true;
		}
	}

	return false;
}


void
DiskBootMethod::SortPartitions(KPartition** partitions, int32 count)
{
	qsort(partitions, count, sizeof(KPartition *),
		fMethod == BOOT_METHOD_CD ? compare_cd_boot : compare_image_boot);
}


// #pragma mark -


/*!	Make the boot partition (and probably others) available. 
	The partitions that are a boot candidate a put into the /a partitions
	stack. If the user selected a boot device, there is will only be one
	entry in this stack; if not, the most likely is put up first.
	The boot code should then just try them one by one.
*/
static status_t
get_boot_partitions(kernel_args *args, PartitionStack &partitions)
{
	const KMessage& bootVolume = args->boot_volume;

	dprintf("get_boot_partitions(): boot volume message:\n");
	KMessageField field;
	while (bootVolume.GetNextField(&field) == B_OK) {
		type_code type = field.TypeCode();
		uint32 bigEndianType = B_HOST_TO_BENDIAN_INT32(type);
		dprintf("field: \"%s\", type: %.4s (0x%lx):\n", field.Name(),
			(char*)&bigEndianType, type);

		if (field.CountElements() == 0)
			dprintf("\n");

		int32 size;
		for (int i = 0; const void* data = field.ElementAt(i, &size); i++) {
			dprintf("  [%2d] ", i);
			bool isIntType = false;
			int64 intData = 0;
			switch (type) {
				case B_BOOL_TYPE:
					dprintf("%s\n", (*(bool*)data ? "true" : "false"));
					break;
				case B_INT8_TYPE:
					isIntType = true;
					intData = *(int8*)data;
					break;
				case B_INT16_TYPE:
					isIntType = true;
					intData = *(int16*)data;
					break;
				case B_INT32_TYPE:
					isIntType = true;
					intData = *(int32*)data;
					break;
				case B_INT64_TYPE:
					isIntType = true;
					intData = *(int64*)data;
					break;
				case B_STRING_TYPE:
					dprintf("\"%s\"\n", (char*)data);
					break;
				default:
					dprintf("data: \"%p\", %ld bytes\n", (char*)data, size);
					break;
			}
			if (isIntType)
				dprintf("%lld (0x%llx)\n", intData, intData);
		}
	}


	// create boot method
	int32 bootMethodType = bootVolume.GetInt32(BOOT_METHOD,
		BOOT_METHOD_DEFAULT);
dprintf("get_boot_partitions(): boot method type: %ld\n", bootMethodType);
	BootMethod* bootMethod = NULL;
	switch (bootMethodType) {
		case BOOT_METHOD_NET:
			bootMethod = new(nothrow) NetBootMethod(bootVolume, bootMethodType);
			break;

		case BOOT_METHOD_HARD_DISK:
		case BOOT_METHOD_CD:
		default:
			bootMethod = new(nothrow) DiskBootMethod(bootVolume,
				bootMethodType);
			break;
	}

	status_t status = bootMethod != NULL ? bootMethod->Init() : B_NO_MEMORY;
	if (status != B_OK)
		return status;

	KDiskDeviceManager::CreateDefault();
	KDiskDeviceManager *manager = KDiskDeviceManager::Default();

	status = manager->InitialDeviceScan();
	if (status != B_OK) {
		dprintf("KDiskDeviceManager::InitialDeviceScan() failed: %s\n",
			strerror(status));
		return status;
	}

	if (1 /* dump devices and partitions */) {
		KDiskDevice *device;
		int32 cookie = 0;
		while ((device = manager->NextDevice(&cookie)) != NULL) {
			device->Dump(true, 0);
		}
	}

	struct BootPartitionVisitor : KPartitionVisitor {
		BootPartitionVisitor(BootMethod* bootMethod, PartitionStack &stack)
			: fPartitions(stack),
			  fBootMethod(bootMethod)
		{
		}

		virtual bool VisitPre(KPartition *partition)
		{
			if (!partition->ContainsFileSystem())
				return false;

			bool foundForSure = false;
			if (fBootMethod->IsBootPartition(partition, foundForSure))
				fPartitions.Push(partition);

			// if found for sure, we can terminate the search
			return foundForSure;
		}

		private:
			PartitionStack	&fPartitions;
			BootMethod*		fBootMethod;
	} visitor(bootMethod, partitions);

	bool strict = true;

	while (true) {
		KDiskDevice *device;
		int32 cookie = 0;
		while ((device = manager->NextDevice(&cookie)) != NULL) {
			if (!bootMethod->IsBootDevice(device, strict))
				continue;

			if (device->VisitEachDescendant(&visitor) != NULL)
				break;
		}

		if (!partitions.IsEmpty() || !strict)
			break;

		// we couldn't find any potential boot devices, try again less strict
		strict = false;
	}

	// sort partition list (e.g.. when booting from CD, CDs should come first in
	// the list)
	if (!args->boot_volume.GetBool(BOOT_VOLUME_USER_SELECTED, false))
		bootMethod->SortPartitions(partitions.Array(), partitions.CountItems());

	return B_OK;
}


//	#pragma mark -


status_t
vfs_bootstrap_file_systems(void)
{
	status_t status;

	// bootstrap the root filesystem
	status = _kern_mount("/", NULL, "rootfs", 0, NULL, 0);
	if (status < B_OK)
		panic("error mounting rootfs!\n");

	_kern_setcwd(-1, "/");

	// bootstrap the devfs
	_kern_create_dir(-1, "/dev", 0755);
	status = _kern_mount("/dev", NULL, "devfs", 0, NULL, 0);
	if (status < B_OK)
		panic("error mounting devfs\n");

	// bootstrap the pipefs
	_kern_create_dir(-1, "/pipe", 0755);
	status = _kern_mount("/pipe", NULL, "pipefs", 0, NULL, 0);
	if (status < B_OK)
		panic("error mounting pipefs\n");

	// create directory for the boot volume
	_kern_create_dir(-1, "/boot", 0755);

	// create some standard links on the rootfs

	for (int32 i = 0; sPredefinedLinks[i].path != NULL; i++) {
		_kern_create_symlink(-1, sPredefinedLinks[i].path,
			sPredefinedLinks[i].target, 0);
			// we don't care if it will succeed or not
	}

	return B_OK;
}


void
vfs_mount_boot_file_system(kernel_args *args)
{
	PartitionStack partitions;
	status_t status = get_boot_partitions(args, partitions);
	if (status < B_OK) {
		panic("get_boot_partitions failed!");
	}
	if (partitions.IsEmpty()) {
		panic("did not find any boot partitions!");
	}

	KPartition *bootPartition;
	while (partitions.Pop(&bootPartition)) {
		KPath path;
		if (bootPartition->GetPath(&path) != B_OK)
			panic("could not get boot device!\n");

		TRACE(("trying to mount boot partition: %s\n", path.Path()));
		gBootDevice = _kern_mount("/boot", path.Path(), NULL, 0, NULL, 0);
		if (gBootDevice >= B_OK)
			break;
	}

	if (gBootDevice < B_OK)
		panic("could not mount boot device!\n");

	// create link for the name of the boot device

	fs_info info;
	if (_kern_read_fs_info(gBootDevice, &info) == B_OK) {
		char path[B_FILE_NAME_LENGTH + 1];
		snprintf(path, sizeof(path), "/%s", info.volume_name);

		_kern_create_symlink(-1, path, "/boot", 0);
	}

	file_cache_init_post_boot_device();

	// search for other disk systems
	KDiskDeviceManager *manager = KDiskDeviceManager::Default();
	manager->RescanDiskSystems();
	manager->InitialDeviceScan();
		// TODO: later, the DDM should notice when there are new
		// partitions/devices available
}