/*
 * Copyright (c) 2018 naehrwert
 * Copyright (c) 2018-2023 CTCaer
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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/>.
 */

#include <string.h>

#include <bdk.h>

#include "hos.h"
#include "pkg2.h"
#include "pkg2_ini_kippatch.h"

#include "../config.h"
#include <libs/compr/blz.h>
#include <libs/fatfs/ff.h>
#include "../storage/emummc.h"

//#define DPRINTF(...) gfx_printf(__VA_ARGS__)
#define DPRINTF(...)

extern hekate_config h_cfg;
extern const u8 package2_keyseed[];

u32 pkg2_newkern_ini1_info;
u32 pkg2_newkern_ini1_start;
u32 pkg2_newkern_ini1_end;

enum kip_offset_section
{
	KIP_TEXT    = 0,
	KIP_RODATA  = 1,
	KIP_DATA    = 2,
	KIP_BSS     = 3,
	KIP_UNKSEC1 = 4,
	KIP_UNKSEC2 = 5
};

#define KIP_PATCH_SECTION_SHIFT  (29)
#define KIP_PATCH_SECTION_MASK   (7 << KIP_PATCH_SECTION_SHIFT)
#define KIP_PATCH_OFFSET_MASK    (~KIP_PATCH_SECTION_MASK)
#define GET_KIP_PATCH_SECTION(x) (((x) >> KIP_PATCH_SECTION_SHIFT) & 7)
#define GET_KIP_PATCH_OFFSET(x)  ((x) & KIP_PATCH_OFFSET_MASK)
#define KPS(x)                   ((u32)(x) << KIP_PATCH_SECTION_SHIFT)

#include "pkg2_patches.inl"

static kip1_id_t *_kip_id_sets = _kip_ids;
static u32 _kip_id_sets_cnt = ARRAY_SIZE(_kip_ids);

void pkg2_get_ids(kip1_id_t **ids, u32 *entries)
{
	*ids = _kip_id_sets;
	*entries = _kip_id_sets_cnt;
}

static void parse_external_kip_patches()
{
	static bool ext_patches_parsed = false;

	if (ext_patches_parsed)
		return;

	LIST_INIT(ini_kip_sections);
	if (ini_patch_parse(&ini_kip_sections, "bootloader/patches.ini"))
	{
		// Copy ids into a new patchset.
		_kip_id_sets = calloc(sizeof(kip1_id_t), 256); // Max 256 kip ids.
		memcpy(_kip_id_sets, _kip_ids, sizeof(_kip_ids));

		// Parse patchsets and glue them together.
		LIST_FOREACH_ENTRY(ini_kip_sec_t, ini_psec, &ini_kip_sections, link)
		{
			kip1_id_t* curr_kip = NULL;
			bool found = false;
			for (u32 curr_kip_idx = 0; curr_kip_idx < _kip_id_sets_cnt + 1; curr_kip_idx++)
			{
				curr_kip = &_kip_id_sets[curr_kip_idx];

				// Check if reached the end of predefined list.
				if (!curr_kip->name)
					break;

				// Check if name and hash match.
				if (!strcmp(curr_kip->name, ini_psec->name) && !memcmp(curr_kip->hash, ini_psec->hash, 8))
				{
					found = true;
					break;
				}
			}

			if (!curr_kip)
				continue;

			// If not found, create a new empty entry.
			if (!found)
			{
				curr_kip->name = ini_psec->name;
				memcpy(curr_kip->hash, ini_psec->hash, 8);
				curr_kip->patchset = calloc(sizeof(kip1_patchset_t), 1);

				_kip_id_sets_cnt++;
			}

			kip1_patchset_t *patchsets = (kip1_patchset_t *)calloc(sizeof(kip1_patchset_t), 16); // Max 16 patchsets per kip.

			u32 curr_patchset_idx;
			for (curr_patchset_idx = 0; curr_kip->patchset[curr_patchset_idx].name != NULL; curr_patchset_idx++)
			{
				patchsets[curr_patchset_idx].name = curr_kip->patchset[curr_patchset_idx].name;
				patchsets[curr_patchset_idx].patches = curr_kip->patchset[curr_patchset_idx].patches;
			}

			curr_kip->patchset = patchsets;
			bool first_ext_patch = true;
			u32 curr_patch_idx = 0;

			// Parse patches and glue them together to a patchset.
			kip1_patch_t *patches = calloc(sizeof(kip1_patch_t), 32); // Max 32 patches per set.
			LIST_FOREACH_ENTRY(ini_patchset_t, pt, &ini_psec->pts, link)
			{
				if (first_ext_patch)
				{
					first_ext_patch = false;
					patchsets[curr_patchset_idx].name = pt->name;
					patchsets[curr_patchset_idx].patches = patches;
				}
				else if (strcmp(pt->name, patchsets[curr_patchset_idx].name))
				{
					// New patchset name found, create a new set.
					curr_patchset_idx++;
					curr_patch_idx = 0;
					patches = calloc(sizeof(kip1_patch_t), 32); // Max 32 patches per set.

					patchsets[curr_patchset_idx].name = pt->name;
					patchsets[curr_patchset_idx].patches = patches;
				}

				if (pt->length)
				{
					patches[curr_patch_idx].offset = pt->offset;
					patches[curr_patch_idx].length = pt->length;

					patches[curr_patch_idx].srcData = (char *)pt->srcData;
					patches[curr_patch_idx].dstData = (char *)pt->dstData;
				}
				else
					patches[curr_patch_idx].srcData = malloc(1); // Empty patches check. Keep everything else as 0.

				curr_patch_idx++;
			}
			curr_patchset_idx++;
			patchsets[curr_patchset_idx].name = NULL;
			patchsets[curr_patchset_idx].patches = NULL;
		}
	}

	ext_patches_parsed = true;
}

const pkg2_kernel_id_t *pkg2_identify(u8 *hash)
{
	for (u32 i = 0; i < ARRAY_SIZE(_pkg2_kernel_ids); i++)
	{
		if (!memcmp(hash, _pkg2_kernel_ids[i].hash, sizeof(_pkg2_kernel_ids[0].hash)))
			return &_pkg2_kernel_ids[i];
	}
	return NULL;
}

static u32 _pkg2_calc_kip1_size(pkg2_kip1_t *kip1)
{
	u32 size = sizeof(pkg2_kip1_t);
	for (u32 j = 0; j < KIP1_NUM_SECTIONS; j++)
		size += kip1->sections[j].size_comp;
	return size;
}

void pkg2_get_newkern_info(u8 *kern_data)
{
	u32 crt_start = 0;
	pkg2_newkern_ini1_info  = 0;
	pkg2_newkern_ini1_start = 0;

	u32 first_op = *(u32 *)kern_data;
	if ((first_op & 0xFE000000) == 0x14000000)
		crt_start = (first_op & 0x1FFFFFF) << 2;

	// Find static OP offset that is close to INI1 offset.
	u32 counter_ops = 0x100;
	while (counter_ops)
	{
		if (*(u32 *)(kern_data + crt_start + 0x100 - counter_ops) == PKG2_NEWKERN_GET_INI1_HEURISTIC)
		{
			// OP found. Add 12 for the INI1 info offset.
			pkg2_newkern_ini1_info = crt_start + 0x100 - counter_ops + 12;

			// On v2 kernel with dynamic crt there's a NOP after heuristic. Offset one op.
			if (crt_start)
				pkg2_newkern_ini1_info += 4;
			break;
		}

		counter_ops -= 4;
	}

	// Offset not found?
	if (!counter_ops)
		return;

	u32 info_op = *(u32 *)(kern_data + pkg2_newkern_ini1_info);
	pkg2_newkern_ini1_info += ((info_op & 0xFFFF) >> 3); // Parse ADR and PC.

	pkg2_newkern_ini1_start = *(u32 *)(kern_data + pkg2_newkern_ini1_info);
	pkg2_newkern_ini1_end   = *(u32 *)(kern_data + pkg2_newkern_ini1_info + 0x8);

	// On v2 kernel with dynamic crt, values are relative to value address.
	if (crt_start)
	{
		pkg2_newkern_ini1_start += pkg2_newkern_ini1_info;
		pkg2_newkern_ini1_end   += pkg2_newkern_ini1_info + 0x8;
	}
}

bool pkg2_parse_kips(link_t *info, pkg2_hdr_t *pkg2, bool *new_pkg2)
{
	u8 *ptr;
	// Check for new pkg2 type.
	if (!pkg2->sec_size[PKG2_SEC_INI1])
	{
		pkg2_get_newkern_info(pkg2->data);

		if (!pkg2_newkern_ini1_start)
			return false;

		ptr = pkg2->data + pkg2_newkern_ini1_start;
		*new_pkg2 = true;
	}
	else
		ptr = pkg2->data + pkg2->sec_size[PKG2_SEC_KERNEL];

	pkg2_ini1_t *ini1 = (pkg2_ini1_t *)ptr;
	ptr += sizeof(pkg2_ini1_t);

	for (u32 i = 0; i < ini1->num_procs; i++)
	{
		pkg2_kip1_t *kip1 = (pkg2_kip1_t *)ptr;
		pkg2_kip1_info_t *ki = (pkg2_kip1_info_t *)malloc(sizeof(pkg2_kip1_info_t));
		ki->kip1 = kip1;
		ki->size = _pkg2_calc_kip1_size(kip1);
		list_append(info, &ki->link);
		ptr += ki->size;
DPRINTF(" kip1 %d:%s @ %08X (%08X)\n", i, kip1->name, (u32)kip1, ki->size);
	}

	return true;
}

int pkg2_has_kip(link_t *info, u64 tid)
{
	LIST_FOREACH_ENTRY(pkg2_kip1_info_t, ki, info, link)
		if (ki->kip1->tid == tid)
			return 1;
	return 0;
}

void pkg2_replace_kip(link_t *info, u64 tid, pkg2_kip1_t *kip1)
{
	LIST_FOREACH_ENTRY(pkg2_kip1_info_t, ki, info, link)
	{
		if (ki->kip1->tid == tid)
		{
			ki->kip1 = kip1;
			ki->size = _pkg2_calc_kip1_size(kip1);
DPRINTF("replaced kip %s (new size %08X)\n", kip1->name, ki->size);
			return;
		}
	}
}

void pkg2_add_kip(link_t *info, pkg2_kip1_t *kip1)
{
	pkg2_kip1_info_t *ki = (pkg2_kip1_info_t *)malloc(sizeof(pkg2_kip1_info_t));
	ki->kip1 = kip1;
	ki->size = _pkg2_calc_kip1_size(kip1);
DPRINTF("added kip %s (size %08X)\n", kip1->name, ki->size);
	list_append(info, &ki->link);
}

void pkg2_merge_kip(link_t *info, pkg2_kip1_t *kip1)
{
	if (pkg2_has_kip(info, kip1->tid))
		pkg2_replace_kip(info, kip1->tid, kip1);
	else
		pkg2_add_kip(info, kip1);
}

int pkg2_decompress_kip(pkg2_kip1_info_t* ki, u32 sectsToDecomp)
{
	u32 compClearMask = ~sectsToDecomp;
	if ((ki->kip1->flags & compClearMask) == ki->kip1->flags)
		return 0; // Already decompressed, nothing to do.

	pkg2_kip1_t hdr;
	memcpy(&hdr, ki->kip1, sizeof(hdr));

	unsigned int newKipSize = sizeof(hdr);
	for (u32 sectIdx = 0; sectIdx < KIP1_NUM_SECTIONS; sectIdx++)
	{
		u32 sectCompBit = BIT(sectIdx);
		// For compressed, cant get actual decompressed size without doing it, so use safe "output size".
		if (sectIdx < 3 && (sectsToDecomp & sectCompBit) && (hdr.flags & sectCompBit))
			newKipSize += hdr.sections[sectIdx].size_decomp;
		else
			newKipSize += hdr.sections[sectIdx].size_comp;
	}

	pkg2_kip1_t* newKip = malloc(newKipSize);
	unsigned char* dstDataPtr = newKip->data;
	const unsigned char* srcDataPtr = ki->kip1->data;
	for (u32 sectIdx = 0; sectIdx < KIP1_NUM_SECTIONS; sectIdx++)
	{
		u32 sectCompBit = BIT(sectIdx);
		// Easy copy path for uncompressed or ones we dont want to uncompress.
		if (sectIdx >= 3 || !(sectsToDecomp & sectCompBit) || !(hdr.flags & sectCompBit))
		{
			unsigned int dataSize = hdr.sections[sectIdx].size_comp;
			if (dataSize == 0)
				continue;

			memcpy(dstDataPtr, srcDataPtr, dataSize);
			srcDataPtr += dataSize;
			dstDataPtr += dataSize;
			continue;
		}

		unsigned int compSize = hdr.sections[sectIdx].size_comp;
		unsigned int outputSize = hdr.sections[sectIdx].size_decomp;
		gfx_printf("Decomping '%s', sect %d, size %d..\n", (const char*)hdr.name, sectIdx, compSize);
		if (blz_uncompress_srcdest(srcDataPtr, compSize, dstDataPtr, outputSize) == 0)
		{
			gfx_con.mute = false;
			gfx_printf("%kERROR decomping sect %d of '%s'!%k\n", TXT_CLR_ERROR, sectIdx, (char*)hdr.name, TXT_CLR_DEFAULT);
			free(newKip);

			return 1;
		}
		else
		{
			DPRINTF("Done! Decompressed size is %d!\n", outputSize);
		}
		hdr.sections[sectIdx].size_comp = outputSize;
		srcDataPtr += compSize;
		dstDataPtr += outputSize;
	}

	hdr.flags &= compClearMask;
	memcpy(newKip, &hdr, sizeof(hdr));
	newKipSize = dstDataPtr-(unsigned char*)(newKip);

	free(ki->kip1);
	ki->kip1 = newKip;
	ki->size = newKipSize;

	return 0;
}

static int _kipm_inject(const char *kipm_path, char *target_name, pkg2_kip1_info_t* ki)
{
	if (!strncmp((const char *)ki->kip1->name, target_name, sizeof(ki->kip1->name)))
	{
		u32 size = 0;
		u8 *kipm_data = (u8 *)sd_file_read(kipm_path, &size);
		if (!kipm_data)
			return 1;

		u32 inject_size = size - sizeof(ki->kip1->caps);
		u8 *kip_patched_data = (u8 *)malloc(ki->size + inject_size);

		// Copy headers.
		memcpy(kip_patched_data, ki->kip1, sizeof(pkg2_kip1_t));

		pkg2_kip1_t *fs_kip = ki->kip1;
		ki->kip1 = (pkg2_kip1_t *)kip_patched_data;
		ki->size = ki->size + inject_size;

		// Patch caps.
		memcpy(&ki->kip1->caps, kipm_data, sizeof(ki->kip1->caps));
		// Copy our .text data.
		memcpy(&ki->kip1->data, kipm_data + sizeof(ki->kip1->caps), inject_size);

		u32 new_offset = 0;

		for (u32 currSectIdx = 0; currSectIdx < KIP1_NUM_SECTIONS - 2; currSectIdx++)
		{
			if (!currSectIdx) // .text.
			{
				memcpy(ki->kip1->data + inject_size, fs_kip->data, fs_kip->sections[0].size_comp);
				ki->kip1->sections[0].size_decomp += inject_size;
				ki->kip1->sections[0].size_comp += inject_size;
			}
			else // Others.
			{
				if (currSectIdx < 3)
					memcpy(ki->kip1->data + new_offset + inject_size, fs_kip->data + new_offset, fs_kip->sections[currSectIdx].size_comp);
				ki->kip1->sections[currSectIdx].offset += inject_size;
			}
			new_offset += fs_kip->sections[currSectIdx].size_comp;
		}

		// Patch PMC capabilities for 1.0.0.
		if (!emu_cfg.fs_ver)
		{
			for (u32 i = 0; i < 0x20; i++)
			{
				if (ki->kip1->caps[i] == 0xFFFFFFFF)
				{
					ki->kip1->caps[i] = 0x07000E7F;
					break;
				}
			}
		}

		free(kipm_data);
		return 0;
	}

	return 1;
}

const char* pkg2_patch_kips(link_t *info, char* patchNames)
{
	if (patchNames == NULL || patchNames[0] == 0)
		return NULL;

	static const u32 MAX_NUM_PATCHES_REQUESTED = sizeof(u32) * 8;
	char* patches[MAX_NUM_PATCHES_REQUESTED];

	u32 numPatches = 1;
	patches[0] = patchNames;
	{
		for (char* p = patchNames; *p != 0; p++)
		{
			if (*p == ',')
			{
				*p = 0;
				patches[numPatches++] = p + 1;
				if (numPatches >= MAX_NUM_PATCHES_REQUESTED)
					return "too_many_patches";
			}
			else if (*p >= 'A' && *p <= 'Z') // Convert to lowercase.
				*p += 0x20;
		}
	}

	u32 patchesApplied = 0; // Bitset over patches.
	for (u32 i = 0; i < numPatches; i++)
	{
		// Eliminate leading spaces.
		for (const char* p = patches[i]; *p != 0; p++)
		{
			if (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')
				patches[i]++;
			else
				break;
		}
		int valueLen = strlen(patches[i]);
		if (valueLen == 0)
			continue;

		// Eliminate trailing spaces.
		for (int chIdx = valueLen - 1; chIdx >= 0; chIdx--)
		{
			const char* p = patches[i] + chIdx;
			if (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')
				valueLen = chIdx;
			else
				break;
		}
		patches[i][valueLen] = 0;

		DPRINTF("Requested patch: '%s'\n", patches[i]);
	}

	// Parse external patches if needed.
	for (u32 i = 0; i < numPatches; i++)
	{
		if (strcmp(patches[i], "emummc") && strcmp(patches[i], "nogc"))
		{
			parse_external_kip_patches();
			break;
		}
	}

	u32 shaBuf[SE_SHA_256_SIZE / sizeof(u32)];
	LIST_FOREACH_ENTRY(pkg2_kip1_info_t, ki, info, link)
	{
		shaBuf[0] = 0; // sha256 for this kip not yet calculated.
		for (u32 currKipIdx = 0; currKipIdx < _kip_id_sets_cnt; currKipIdx++)
		{
			if (strncmp((const char*)ki->kip1->name, _kip_id_sets[currKipIdx].name, sizeof(ki->kip1->name)) != 0)
				continue;

			u32 bitsAffected = 0;
			kip1_patchset_t* currPatchset = _kip_id_sets[currKipIdx].patchset;
			while (currPatchset != NULL && currPatchset->name != NULL)
			{
				for (u32 i = 0; i < numPatches; i++)
				{
					// Continue if patch name does not match.
					if (strcmp(currPatchset->name, patches[i]) != 0)
						continue;

					bitsAffected = i + 1;
					break;
				}
				currPatchset++;
			}

			// Dont bother even hashing this KIP if we dont have any patches enabled for it.
			if (bitsAffected == 0)
				continue;

			if (shaBuf[0] == 0)
			{
				if (!se_calc_sha256_oneshot(shaBuf, ki->kip1, ki->size))
					memset(shaBuf, 0, sizeof(shaBuf));
			}

			if (memcmp(shaBuf, _kip_id_sets[currKipIdx].hash, sizeof(_kip_id_sets[0].hash)) != 0)
				continue;

			// Find out which sections are affected by the enabled patches, to know which to decompress.
			bitsAffected = 0;
			currPatchset = _kip_id_sets[currKipIdx].patchset;
			while (currPatchset != NULL && currPatchset->name != NULL)
			{
				if (currPatchset->patches != NULL)
				{
					for (u32 currEnabIdx = 0; currEnabIdx < numPatches; currEnabIdx++)
					{
						if (strcmp(currPatchset->name, patches[currEnabIdx]))
							continue;

						if (!strcmp(currPatchset->name, "emummc"))
							bitsAffected |= BIT(GET_KIP_PATCH_SECTION(currPatchset->patches->offset));

						for (const kip1_patch_t* currPatch=currPatchset->patches; currPatch != NULL && (currPatch->length != 0); currPatch++)
							bitsAffected |= BIT(GET_KIP_PATCH_SECTION(currPatch->offset));
					}
				}
				currPatchset++;
			}

			// Got patches to apply to this kip, have to decompress it.
			if (pkg2_decompress_kip(ki, bitsAffected))
				return (const char*)ki->kip1->name; // Failed to decompress.

			currPatchset = _kip_id_sets[currKipIdx].patchset;
			bool emummc_patch_selected = false;
			while (currPatchset != NULL && currPatchset->name != NULL)
			{
				for (u32 currEnabIdx = 0; currEnabIdx < numPatches; currEnabIdx++)
				{
					if (strcmp(currPatchset->name, patches[currEnabIdx]))
						continue;

					u32 appliedMask = BIT(currEnabIdx);

					if (!strcmp(currPatchset->name, "emummc"))
					{
						emummc_patch_selected = true;
						patchesApplied |= appliedMask;

						continue; // Patching is done later.
					}

					if (currPatchset->patches == NULL)
					{
						DPRINTF("Patch '%s' not necessary for %s\n", currPatchset->name, (const char*)ki->kip1->name);
						patchesApplied |= appliedMask;

						continue; // Continue in case it's double defined.
					}

					unsigned char* kipSectData = ki->kip1->data;
					for (u32 currSectIdx = 0; currSectIdx < KIP1_NUM_SECTIONS; currSectIdx++)
					{
						if (bitsAffected & BIT(currSectIdx))
						{
							gfx_printf("Applying '%s' on %s, sect %d\n", currPatchset->name, (const char*)ki->kip1->name, currSectIdx);
							for (const kip1_patch_t* currPatch = currPatchset->patches; currPatch != NULL && currPatch->srcData != NULL; currPatch++)
							{
								if (GET_KIP_PATCH_SECTION(currPatch->offset) != currSectIdx)
									continue;

								if (!currPatch->length)
								{
									gfx_con.mute = false;
									gfx_printf("%kPatch empty!%k\n", TXT_CLR_ERROR, TXT_CLR_DEFAULT);
									return currPatchset->name; // MUST stop here as it's not probably intended.
								}

								u32 currOffset = GET_KIP_PATCH_OFFSET(currPatch->offset);
								// If source does not match and is not already patched, throw an error.
								if ((memcmp(&kipSectData[currOffset], currPatch->srcData, currPatch->length) != 0) &&
									(memcmp(&kipSectData[currOffset], currPatch->dstData, currPatch->length) != 0))
								{
									gfx_con.mute = false;
									gfx_printf("%kPatch mismatch at 0x%x!%k\n", TXT_CLR_ERROR, currOffset, TXT_CLR_DEFAULT);
									return currPatchset->name; // MUST stop here as kip is likely corrupt.
								}
								else
								{
									DPRINTF("Patching %d bytes at offset 0x%x\n", currPatch->length, currOffset);
									memcpy(&kipSectData[currOffset], currPatch->dstData, currPatch->length);
								}
							}
						}
						kipSectData += ki->kip1->sections[currSectIdx].size_comp;
					}

					patchesApplied |= appliedMask;
					continue; // Continue in case it's double defined.
				}
				currPatchset++;
			}

			if (emummc_patch_selected && !strncmp(_kip_id_sets[currKipIdx].name, "FS", sizeof(ki->kip1->name)))
			{
				emummc_patch_selected = false;
				emu_cfg.fs_ver = currKipIdx;
				if (currKipIdx)
					emu_cfg.fs_ver--;
				if (currKipIdx > 17)
					emu_cfg.fs_ver -= 2;

				gfx_printf("Injecting emuMMC. FS ID: %d\n", emu_cfg.fs_ver);
				if (_kipm_inject("/bootloader/sys/emummc.kipm", "FS", ki))
					return "emummc";
			}
		}
	}

	for (u32 i = 0; i < numPatches; i++)
	{
		if ((patchesApplied & BIT(i)) == 0)
			return patches[i];
	}

	return NULL;
}

// Master key 7 encrypted with 8.  (7.0.0 with 8.1.0). AES-ECB
static const u8 mkey_vector_7xx[SE_KEY_128_SIZE] =
	{ 0xEA, 0x60, 0xB3, 0xEA, 0xCE, 0x8F, 0x24, 0x46, 0x7D, 0x33, 0x9C, 0xD1, 0xBC, 0x24, 0x98, 0x29 };

u8 pkg2_keyslot;
pkg2_hdr_t *pkg2_decrypt(void *data, u8 kb, bool is_exo)
{
	u8 *pdata = (u8 *)data;

	// Skip signature.
	pdata += 0x100;

	pkg2_hdr_t *hdr = (pkg2_hdr_t *)pdata;

	// Skip header.
	pdata += sizeof(pkg2_hdr_t);

	// Set pkg2 key slot to default. If 7.0.0 it will change to 9.
	pkg2_keyslot = 8;

	// Decrypt 7.0.0 pkg2 via 8.1.0 mkey on Erista.
	if (!h_cfg.t210b01 && kb == HOS_KB_VERSION_700)
	{
		u8 tmp_mkey[SE_KEY_128_SIZE];

		// Decrypt 7.0.0 encrypted mkey.
		se_aes_crypt_ecb(!is_exo ? 7 : 13, DECRYPT, tmp_mkey, SE_KEY_128_SIZE, mkey_vector_7xx, SE_KEY_128_SIZE);

		// Set and unwrap pkg2 key.
		se_aes_key_set(9, tmp_mkey, SE_KEY_128_SIZE);
		se_aes_unwrap_key(9, 9, package2_keyseed);

		pkg2_keyslot = 9;
	}

	// Decrypt header.
	se_aes_crypt_ctr(pkg2_keyslot, hdr, sizeof(pkg2_hdr_t), hdr, sizeof(pkg2_hdr_t), hdr);

	if (hdr->magic != PKG2_MAGIC)
		return NULL;

	// Decrypt sections.
	for (u32 i = 0; i < 4; i++)
	{
DPRINTF("sec %d has size %08X\n", i, hdr->sec_size[i]);
		if (!hdr->sec_size[i])
			continue;

		se_aes_crypt_ctr(pkg2_keyslot, pdata, hdr->sec_size[i], pdata, hdr->sec_size[i], &hdr->sec_ctr[i * SE_AES_IV_SIZE]);

		pdata += hdr->sec_size[i];
	}

	return hdr;
}

static u32 _pkg2_ini1_build(u8 *pdst, u8 *psec, pkg2_hdr_t *hdr, link_t *kips_info, bool new_pkg2)
{
	// Calculate INI1 size.
	u32 ini1_size = sizeof(pkg2_ini1_t);
	LIST_FOREACH_ENTRY(pkg2_kip1_info_t, ki, kips_info, link)
	{
		ini1_size += ki->size;
	}

	// Align size and set it.
	ini1_size = ALIGN(ini1_size, 4);

	// For new kernel if INI1 fits in the old one, use it.
	bool use_old_ini_region = psec && ini1_size <= (pkg2_newkern_ini1_end - pkg2_newkern_ini1_start);
	if (use_old_ini_region)
		pdst = psec + pkg2_newkern_ini1_start;

	// Set initial header and magic.
	pkg2_ini1_t *ini1 = (pkg2_ini1_t *)pdst;
	memset(ini1, 0, sizeof(pkg2_ini1_t));
	ini1->magic = INI1_MAGIC;
	ini1->size  = ini1_size;
	pdst += sizeof(pkg2_ini1_t);

	// Merge KIPs into INI1.
	LIST_FOREACH_ENTRY(pkg2_kip1_info_t, ki, kips_info, link)
	{
DPRINTF("adding kip1 '%s' @ %08X (%08X)\n", ki->kip1->name, (u32)ki->kip1, ki->size);
		memcpy(pdst, ki->kip1, ki->size);
		pdst += ki->size;
		ini1->num_procs++;
	}

	// Encrypt INI1 in its own section if old pkg2. Otherwise it gets embedded into Kernel.
	if (!new_pkg2)
	{
		hdr->sec_size[PKG2_SEC_INI1] = ini1_size;
		hdr->sec_off[PKG2_SEC_INI1] = 0x14080000;
		se_aes_crypt_ctr(8, ini1, ini1_size, ini1, ini1_size, &hdr->sec_ctr[PKG2_SEC_INI1 * SE_AES_IV_SIZE]);
	}
	else
	{
		hdr->sec_size[PKG2_SEC_INI1] = 0;
		hdr->sec_off[PKG2_SEC_INI1] = 0;
	}

	return !use_old_ini_region ? ini1_size : 0;
}

void pkg2_build_encrypt(void *dst, void *hos_ctxt, link_t *kips_info, bool is_exo)
{
	launch_ctxt_t * ctxt = (launch_ctxt_t *)hos_ctxt;
	u32 meso_magic = *(u32 *)(ctxt->kernel + 4);
	u32 kernel_size = ctxt->kernel_size;
	u8 kb = ctxt->pkg1_id->kb;
	u8 *pdst = (u8 *)dst;

	// Force new Package2 if Mesosphere.
	bool is_meso = (meso_magic & 0xF0FFFFFF) == ATM_MESOSPHERE;
	if (is_meso)
		ctxt->new_pkg2 = true;

	// Set key version. For Erista 7.0.0, use 8.1.0 because of a bug in Exo2?
	u8 key_ver = kb ? kb + 1 : 0;
	if (pkg2_keyslot == 9)
	{
		key_ver = HOS_KB_VERSION_810 + 1;
		pkg2_keyslot = 8;
	}

	// Signature.
	memset(pdst, 0, 0x100);
	pdst += 0x100;

	// Header.
	pkg2_hdr_t *hdr = (pkg2_hdr_t *)pdst;
	memset(hdr, 0, sizeof(pkg2_hdr_t));

	// Set initial header values.
	hdr->magic = PKG2_MAGIC;
	hdr->bl_ver = 0;
	hdr->pkg2_ver = 0xFF;

	if (!ctxt->new_pkg2)
		hdr->base = 0x10000000;
	else
		hdr->base = 0x60000;
DPRINTF("%s @ %08X (%08X)\n", is_meso ? "Mesosphere": "kernel",(u32)ctxt->kernel, kernel_size);

	pdst += sizeof(pkg2_hdr_t);

	// Kernel.
	memcpy(pdst, ctxt->kernel, kernel_size);
	if (!ctxt->new_pkg2)
		hdr->sec_off[PKG2_SEC_KERNEL] = 0x10000000;
	else
	{
		// Build INI1 for new Package2.
		u32 ini1_size = _pkg2_ini1_build(pdst + kernel_size, is_meso ? NULL : pdst, hdr, kips_info, true);
		hdr->sec_off[PKG2_SEC_KERNEL] = 0x60000;

		// Set new INI1 offset to kernel.
		u32 meso_meta_offset = *(u32 *)(pdst + 8);
		if (is_meso && (meso_magic & 0xF000000)) // MSS1.
			*(u32 *)(pdst + meso_meta_offset) = kernel_size - meso_meta_offset;
		else if (ini1_size)
			*(u32 *)(pdst + (is_meso ? 8 : pkg2_newkern_ini1_info)) = kernel_size;

		kernel_size += ini1_size;
	}
	hdr->sec_size[PKG2_SEC_KERNEL] = kernel_size;
	se_aes_crypt_ctr(pkg2_keyslot, pdst, kernel_size, pdst, kernel_size, &hdr->sec_ctr[PKG2_SEC_KERNEL * SE_AES_IV_SIZE]);
	pdst += kernel_size;
DPRINTF("kernel encrypted\n");

	// Build INI1 for old Package2.
	u32 ini1_size = 0;
	if (!ctxt->new_pkg2)
		ini1_size = _pkg2_ini1_build(pdst, NULL, hdr, kips_info, false);
DPRINTF("INI1 encrypted\n");

	if (!is_exo) // Not needed on Exosphere 1.0.0 and up.
	{
		// Calculate SHA256 over encrypted Kernel and INI1.
		u8 *pk2_hash_data = (u8 *)dst + 0x100 + sizeof(pkg2_hdr_t);
		se_calc_sha256_oneshot(&hdr->sec_sha256[SE_SHA_256_SIZE * PKG2_SEC_KERNEL],
			(void *)pk2_hash_data, hdr->sec_size[PKG2_SEC_KERNEL]);
		pk2_hash_data += hdr->sec_size[PKG2_SEC_KERNEL];
		se_calc_sha256_oneshot(&hdr->sec_sha256[SE_SHA_256_SIZE * PKG2_SEC_INI1],
			(void *)pk2_hash_data, hdr->sec_size[PKG2_SEC_INI1]);
	}

	// Encrypt header.
	*(u32 *)hdr->ctr = 0x100 + sizeof(pkg2_hdr_t) + kernel_size + ini1_size;
	hdr->ctr[4] = key_ver;
	se_aes_crypt_ctr(pkg2_keyslot, hdr, sizeof(pkg2_hdr_t), hdr, sizeof(pkg2_hdr_t), hdr);
	memset(hdr->ctr, 0 , SE_AES_IV_SIZE);
	*(u32 *)hdr->ctr = 0x100 + sizeof(pkg2_hdr_t) + kernel_size + ini1_size;
	hdr->ctr[4] = key_ver;
}