Atmosphere/libraries/libstratosphere/source/fssystem/fssystem_bucket_tree.cpp

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/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* 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 <stratosphere.hpp>
namespace ams::fssystem {
namespace {
using Node = impl::BucketTreeNode<const s64 *>;
static_assert(sizeof(Node) == sizeof(BucketTree::NodeHeader));
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static_assert(util::is_pod<Node>::value);
constexpr inline s32 NodeHeaderSize = sizeof(BucketTree::NodeHeader);
class StorageNode {
private:
class Offset {
public:
using difference_type = s64;
private:
s64 offset;
s32 stride;
public:
constexpr Offset(s64 offset, s32 stride) : offset(offset), stride(stride) { /* ... */ }
constexpr Offset &operator++() { this->offset += this->stride; return *this; }
constexpr Offset operator++(int) { Offset ret(*this); this->offset += this->stride; return ret; }
constexpr Offset &operator--() { this->offset -= this->stride; return *this; }
constexpr Offset operator--(int) { Offset ret(*this); this->offset -= this->stride; return ret; }
constexpr difference_type operator-(const Offset &rhs) const { return (this->offset - rhs.offset) / this->stride; }
constexpr Offset operator+(difference_type ofs) const { return Offset(this->offset + ofs * this->stride, this->stride); }
constexpr Offset operator-(difference_type ofs) const { return Offset(this->offset - ofs * this->stride, this->stride); }
constexpr Offset &operator+=(difference_type ofs) { this->offset += ofs * this->stride; return *this; }
constexpr Offset &operator-=(difference_type ofs) { this->offset -= ofs * this->stride; return *this; }
constexpr bool operator==(const Offset &rhs) const { return this->offset == rhs.offset; }
constexpr bool operator!=(const Offset &rhs) const { return this->offset != rhs.offset; }
constexpr s64 Get() const { return this->offset; }
};
private:
const Offset start;
const s32 count;
s32 index;
public:
StorageNode(size_t size, s32 count) : start(NodeHeaderSize, static_cast<s32>(size)), count(count), index(-1) { /* ... */ }
StorageNode(s64 ofs, size_t size, s32 count) : start(NodeHeaderSize + ofs, static_cast<s32>(size)), count(count), index(-1) { /* ... */ }
s32 GetIndex() const { return this->index; }
void Find(const char *buffer, s64 virtual_address) {
s32 end = this->count;
auto pos = this->start;
while (end > 0) {
auto half = end / 2;
auto mid = pos + half;
s64 offset = 0;
std::memcpy(std::addressof(offset), buffer + mid.Get(), sizeof(s64));
if (offset <= virtual_address) {
pos = mid + 1;
end -= half + 1;
} else {
end = half;
}
}
this->index = static_cast<s32>(pos - this->start) - 1;
}
Result Find(fs::SubStorage &storage, s64 virtual_address) {
s32 end = this->count;
auto pos = this->start;
while (end > 0) {
auto half = end / 2;
auto mid = pos + half;
s64 offset = 0;
R_TRY(storage.Read(mid.Get(), std::addressof(offset), sizeof(s64)));
if (offset <= virtual_address) {
pos = mid + 1;
end -= half + 1;
} else {
end = half;
}
}
this->index = static_cast<s32>(pos - this->start) - 1;
return ResultSuccess();
}
};
}
void BucketTree::Header::Format(s32 entry_count) {
AMS_ASSERT(entry_count >= 0);
this->magic = Magic;
this->version = Version;
this->entry_count = entry_count;
this->reserved = 0;
}
Result BucketTree::Header::Verify() const {
R_UNLESS(this->magic == Magic, fs::ResultInvalidBucketTreeSignature());
R_UNLESS(this->entry_count >= 0, fs::ResultInvalidBucketTreeEntryCount());
R_UNLESS(this->version <= Version, fs::ResultUnsupportedVersion());
return ResultSuccess();
}
Result BucketTree::NodeHeader::Verify(s32 node_index, size_t node_size, size_t entry_size) const {
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R_UNLESS(this->index == node_index, fs::ResultInvalidBucketTreeNodeIndex());
R_UNLESS(entry_size != 0 && node_size >= entry_size + NodeHeaderSize, fs::ResultInvalidSize());
const size_t max_entry_count = (node_size - NodeHeaderSize) / entry_size;
R_UNLESS(this->count > 0 && static_cast<size_t>(this->count) <= max_entry_count, fs::ResultInvalidBucketTreeNodeEntryCount());
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R_UNLESS(this->offset >= 0, fs::ResultInvalidBucketTreeNodeOffset());
return ResultSuccess();
}
Result BucketTree::Initialize(IAllocator *allocator, fs::SubStorage node_storage, fs::SubStorage entry_storage, size_t node_size, size_t entry_size, s32 entry_count) {
/* Validate preconditions. */
AMS_ASSERT(allocator != nullptr);
AMS_ASSERT(entry_size >= sizeof(s64));
AMS_ASSERT(node_size >= entry_size + sizeof(NodeHeader));
AMS_ASSERT(NodeSizeMin <= node_size && node_size <= NodeSizeMax);
AMS_ASSERT(util::IsPowerOfTwo(node_size));
AMS_ASSERT(!this->IsInitialized());
/* Ensure valid entry count. */
R_UNLESS(entry_count > 0, fs::ResultInvalidArgument());
/* Allocate node. */
R_UNLESS(this->node_l1.Allocate(allocator, node_size), fs::ResultBufferAllocationFailed());
auto node_guard = SCOPE_GUARD { this->node_l1.Free(node_size); };
/* Read node. */
R_TRY(node_storage.Read(0, this->node_l1.Get(), node_size));
/* Verify node. */
R_TRY(this->node_l1->Verify(0, node_size, sizeof(s64)));
/* Validate offsets. */
const auto offset_count = GetOffsetCount(node_size);
const auto entry_set_count = GetEntrySetCount(node_size, entry_size, entry_count);
const auto * const node = this->node_l1.Get<Node>();
s64 start_offset;
if (offset_count < entry_set_count && node->GetCount() < offset_count) {
start_offset = *node->GetEnd();
} else {
start_offset = *node->GetBegin();
}
const auto end_offset = node->GetEndOffset();
R_UNLESS(0 <= start_offset && start_offset <= node->GetBeginOffset(), fs::ResultInvalidBucketTreeEntryOffset());
R_UNLESS(start_offset < end_offset, fs::ResultInvalidBucketTreeEntryOffset());
/* Set member variables. */
this->node_storage = node_storage;
this->entry_storage = entry_storage;
this->node_size = node_size;
this->entry_size = entry_size;
this->entry_count = entry_count;
this->offset_count = offset_count;
this->entry_set_count = entry_set_count;
this->start_offset = start_offset;
this->end_offset = end_offset;
/* Cancel guard. */
node_guard.Cancel();
return ResultSuccess();
}
void BucketTree::Initialize(size_t node_size, s64 end_offset) {
AMS_ASSERT(NodeSizeMin <= node_size && node_size <= NodeSizeMax);
AMS_ASSERT(util::IsPowerOfTwo(node_size));
AMS_ASSERT(end_offset > 0);
AMS_ASSERT(!this->IsInitialized());
this->node_size = node_size;
this->end_offset = end_offset;
}
void BucketTree::Finalize() {
if (this->IsInitialized()) {
this->node_storage = fs::SubStorage();
this->entry_storage = fs::SubStorage();
this->node_l1.Free(this->node_size);
this->node_size = 0;
this->entry_size = 0;
this->entry_count = 0;
this->offset_count = 0;
this->entry_set_count = 0;
this->start_offset = 0;
this->end_offset = 0;
}
}
Result BucketTree::Find(Visitor *visitor, s64 virtual_address) const {
AMS_ASSERT(visitor != nullptr);
AMS_ASSERT(this->IsInitialized());
R_UNLESS(virtual_address >= 0, fs::ResultInvalidOffset());
R_UNLESS(!this->IsEmpty(), fs::ResultOutOfRange());
R_TRY(visitor->Initialize(this));
return visitor->Find(virtual_address);
}
Result BucketTree::InvalidateCache() {
/* Invalidate the node storage cache. */
{
s64 storage_size;
R_TRY(this->node_storage.GetSize(std::addressof(storage_size)));
R_TRY(this->node_storage.OperateRange(fs::OperationId::Invalidate, 0, storage_size));
}
/* Refresh start/end offsets. */
{
/* Read node. */
R_TRY(node_storage.Read(0, this->node_l1.Get(), this->node_size));
/* Verify node. */
R_TRY(this->node_l1->Verify(0, this->node_size, sizeof(s64)));
/* Validate offsets. */
const auto * const node = this->node_l1.Get<Node>();
s64 start_offset;
if (offset_count < this->entry_set_count && node->GetCount() < this->offset_count) {
start_offset = *node->GetEnd();
} else {
start_offset = *node->GetBegin();
}
const auto end_offset = node->GetEndOffset();
R_UNLESS(0 <= start_offset && start_offset <= node->GetBeginOffset(), fs::ResultInvalidBucketTreeEntryOffset());
R_UNLESS(start_offset < end_offset, fs::ResultInvalidBucketTreeEntryOffset());
/* Set refreshed offsets. */
this->start_offset = start_offset;
this->end_offset = end_offset;
}
/* Invalidate the entry storage cache. */
{
s64 storage_size;
R_TRY(this->entry_storage.GetSize(std::addressof(storage_size)));
R_TRY(this->entry_storage.OperateRange(fs::OperationId::Invalidate, 0, storage_size));
}
return ResultSuccess();
}
Result BucketTree::Visitor::Initialize(const BucketTree *tree) {
AMS_ASSERT(tree != nullptr);
AMS_ASSERT(this->tree == nullptr || this->tree == tree);
if (this->entry == nullptr) {
this->entry = tree->GetAllocator()->Allocate(tree->entry_size);
R_UNLESS(this->entry != nullptr, fs::ResultBufferAllocationFailed());
this->tree = tree;
}
return ResultSuccess();
}
Result BucketTree::Visitor::MoveNext() {
R_UNLESS(this->IsValid(), fs::ResultOutOfRange());
/* Invalidate our index, and read the header for the next index. */
auto entry_index = this->entry_index + 1;
if (entry_index == this->entry_set.info.count) {
const auto entry_set_index = this->entry_set.info.index + 1;
R_UNLESS(entry_set_index < this->entry_set_count, fs::ResultOutOfRange());
this->entry_index = -1;
const auto end = this->entry_set.info.end;
const auto entry_set_size = this->tree->node_size;
const auto entry_set_offset = entry_set_index * static_cast<s64>(entry_set_size);
R_TRY(this->tree->entry_storage.Read(entry_set_offset, std::addressof(this->entry_set), sizeof(EntrySetHeader)));
R_TRY(this->entry_set.header.Verify(entry_set_index, entry_set_size, this->tree->entry_size));
R_UNLESS(this->entry_set.info.start == end && this->entry_set.info.start < this->entry_set.info.end, fs::ResultInvalidBucketTreeEntrySetOffset());
entry_index = 0;
} else {
this->entry_index = 1;
}
/* Read the new entry. */
const auto entry_size = this->tree->entry_size;
const auto entry_offset = impl::GetBucketTreeEntryOffset(this->entry_set.info.index, this->tree->node_size, entry_size, entry_index);
R_TRY(this->tree->entry_storage.Read(entry_offset, std::addressof(this->entry), entry_size));
/* Note that we changed index. */
this->entry_index = entry_index;
return ResultSuccess();
}
Result BucketTree::Visitor::MovePrevious() {
R_UNLESS(this->IsValid(), fs::ResultOutOfRange());
/* Invalidate our index, and read the heasder for the previous index. */
auto entry_index = this->entry_index;
if (entry_index == 0) {
R_UNLESS(this->entry_set.info.index > 0, fs::ResultOutOfRange());
this->entry_index = -1;
const auto start = this->entry_set.info.start;
const auto entry_set_size = this->tree->node_size;
const auto entry_set_index = this->entry_set.info.index - 1;
const auto entry_set_offset = entry_set_index * static_cast<s64>(entry_set_size);
R_TRY(this->tree->entry_storage.Read(entry_set_offset, std::addressof(this->entry_set), sizeof(EntrySetHeader)));
R_TRY(this->entry_set.header.Verify(entry_set_index, entry_set_size, this->tree->entry_size));
R_UNLESS(this->entry_set.info.end == start && this->entry_set.info.start < this->entry_set.info.end, fs::ResultInvalidBucketTreeEntrySetOffset());
entry_index = this->entry_set.info.count;
} else {
this->entry_index = -1;
}
--entry_index;
/* Read the new entry. */
const auto entry_size = this->tree->entry_size;
const auto entry_offset = impl::GetBucketTreeEntryOffset(this->entry_set.info.index, this->tree->node_size, entry_size, entry_index);
R_TRY(this->tree->entry_storage.Read(entry_offset, std::addressof(this->entry), entry_size));
/* Note that we changed index. */
this->entry_index = entry_index;
return ResultSuccess();
}
Result BucketTree::Visitor::Find(s64 virtual_address) {
AMS_ASSERT(this->tree != nullptr);
/* Get the node. */
const auto * const node = this->tree->node_l1.Get<Node>();
R_UNLESS(virtual_address < node->GetEndOffset(), fs::ResultOutOfRange());
/* Get the entry set index. */
s32 entry_set_index = -1;
if (this->tree->IsExistOffsetL2OnL1() && virtual_address < node->GetBeginOffset()) {
const auto start = node->GetEnd();
const auto end = node->GetBegin() + tree->offset_count;
auto pos = std::upper_bound(start, end, virtual_address);
R_UNLESS(start < pos, fs::ResultOutOfRange());
--pos;
entry_set_index = static_cast<s32>(pos - start);
} else {
const auto start = node->GetBegin();
const auto end = node->GetEnd();
auto pos = std::upper_bound(start, end, virtual_address);
R_UNLESS(start < pos, fs::ResultOutOfRange());
--pos;
if (this->tree->IsExistL2()) {
const auto node_index = static_cast<s32>(pos - start);
R_UNLESS(0 <= node_index && node_index < this->tree->offset_count, fs::ResultInvalidBucketTreeNodeOffset());
R_TRY(this->FindEntrySet(std::addressof(entry_set_index), virtual_address, node_index));
} else {
entry_set_index = static_cast<s32>(pos - start);
}
}
/* Validate the entry set index. */
R_UNLESS(0 <= entry_set_index && entry_set_index < this->tree->entry_set_count, fs::ResultInvalidBucketTreeNodeOffset());
/* Find the entry. */
R_TRY(this->FindEntry(virtual_address, entry_set_index));
/* Set count. */
this->entry_set_count = this->tree->entry_set_count;
return ResultSuccess();
}
Result BucketTree::Visitor::FindEntrySet(s32 *out_index, s64 virtual_address, s32 node_index) {
const auto node_size = this->tree->node_size;
PooledBuffer pool(node_size, 1);
if (node_size <= pool.GetSize()) {
return this->FindEntrySetWithBuffer(out_index, virtual_address, node_index, pool.GetBuffer());
} else {
pool.Deallocate();
return this->FindEntrySetWithoutBuffer(out_index, virtual_address, node_index);
}
}
Result BucketTree::Visitor::FindEntrySetWithBuffer(s32 *out_index, s64 virtual_address, s32 node_index, char *buffer) {
/* Calculate node extents. */
const auto node_size = this->tree->node_size;
const auto node_offset = (node_index + 1) * static_cast<s64>(node_size);
fs::SubStorage &storage = tree->node_storage;
/* Read the node. */
R_TRY(storage.Read(node_offset, buffer, node_size));
/* Validate the header. */
NodeHeader header;
std::memcpy(std::addressof(header), buffer, NodeHeaderSize);
R_TRY(header.Verify(node_index, node_size, sizeof(s64)));
/* Create the node, and find. */
StorageNode node(sizeof(s64), header.count);
node.Find(buffer, virtual_address);
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R_UNLESS(node.GetIndex() >= 0, fs::ResultInvalidBucketTreeVirtualOffset());
/* Return the index. */
*out_index = this->tree->GetEntrySetIndex(header.index, node.GetIndex());
return ResultSuccess();
}
Result BucketTree::Visitor::FindEntrySetWithoutBuffer(s32 *out_index, s64 virtual_address, s32 node_index) {
/* Calculate node extents. */
const auto node_size = this->tree->node_size;
const auto node_offset = (node_index + 1) * static_cast<s64>(node_size);
fs::SubStorage &storage = tree->node_storage;
/* Read and validate the header. */
NodeHeader header;
R_TRY(storage.Read(node_offset, std::addressof(header), NodeHeaderSize));
R_TRY(header.Verify(node_index, node_size, sizeof(s64)));
/* Create the node, and find. */
StorageNode node(node_offset, sizeof(s64), header.count);
R_TRY(node.Find(storage, virtual_address));
R_UNLESS(node.GetIndex() >= 0, fs::ResultOutOfRange());
/* Return the index. */
*out_index = this->tree->GetEntrySetIndex(header.index, node.GetIndex());
return ResultSuccess();
}
Result BucketTree::Visitor::FindEntry(s64 virtual_address, s32 entry_set_index) {
const auto entry_set_size = this->tree->node_size;
PooledBuffer pool(entry_set_size, 1);
if (entry_set_size <= pool.GetSize()) {
return this->FindEntryWithBuffer(virtual_address, entry_set_index, pool.GetBuffer());
} else {
pool.Deallocate();
return this->FindEntryWithoutBuffer(virtual_address, entry_set_index);
}
}
Result BucketTree::Visitor::FindEntryWithBuffer(s64 virtual_address, s32 entry_set_index, char *buffer) {
/* Calculate entry set extents. */
const auto entry_size = this->tree->entry_size;
const auto entry_set_size = this->tree->node_size;
const auto entry_set_offset = entry_set_index * static_cast<s64>(entry_set_size);
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fs::SubStorage &storage = tree->entry_storage;
/* Read the entry set. */
R_TRY(storage.Read(entry_set_offset, buffer, entry_set_size));
/* Validate the entry_set. */
EntrySetHeader entry_set;
std::memcpy(std::addressof(entry_set), buffer, sizeof(EntrySetHeader));
R_TRY(entry_set.header.Verify(entry_set_index, entry_set_size, entry_size));
/* Create the node, and find. */
StorageNode node(entry_size, entry_set.info.count);
node.Find(buffer, virtual_address);
R_UNLESS(node.GetIndex() >= 0, fs::ResultOutOfRange());
/* Copy the data into entry. */
const auto entry_index = node.GetIndex();
const auto entry_offset = impl::GetBucketTreeEntryOffset(0, entry_size, entry_index);
std::memcpy(this->entry, buffer + entry_offset, entry_size);
/* Set our entry set/index. */
this->entry_set = entry_set;
this->entry_index = entry_index;
return ResultSuccess();
}
Result BucketTree::Visitor::FindEntryWithoutBuffer(s64 virtual_address, s32 entry_set_index) {
/* Calculate entry set extents. */
const auto entry_size = this->tree->entry_size;
const auto entry_set_size = this->tree->node_size;
const auto entry_set_offset = entry_set_index * static_cast<s64>(entry_set_size);
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fs::SubStorage &storage = tree->entry_storage;
/* Read and validate the entry_set. */
EntrySetHeader entry_set;
R_TRY(storage.Read(entry_set_offset, std::addressof(entry_set), sizeof(EntrySetHeader)));
R_TRY(entry_set.header.Verify(entry_set_index, entry_set_size, entry_size));
/* Create the node, and find. */
StorageNode node(entry_set_offset, entry_size, entry_set.info.count);
R_TRY(node.Find(storage, virtual_address));
R_UNLESS(node.GetIndex() >= 0, fs::ResultOutOfRange());
/* Copy the data into entry. */
const auto entry_index = node.GetIndex();
const auto entry_offset = impl::GetBucketTreeEntryOffset(entry_set_offset, entry_size, entry_index);
R_TRY(storage.Read(entry_offset, this->entry, entry_size));
/* Set our entry set/index. */
this->entry_set = entry_set;
this->entry_index = entry_index;
return ResultSuccess();
}
}