ladybird/Kernel/ProcessExposed.cpp
Andreas Kling 280694bb46 Kernel: Update atime/ctime/mtime timestamps atomically
Instead of having three separate APIs (one for each timestamp),
there's now only Inode::update_timestamps() and it takes 3x optional
timestamps. The non-empty timestamps are updated while holding the inode
mutex, and the outside world no longer has to look at intermediate
timestamp states.
2022-08-22 17:56:03 +02:00

250 lines
8.3 KiB
C++

/*
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Debug.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/FileSystem/ProcFS.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/PerformanceEventBuffer.h>
#include <Kernel/Process.h>
#include <Kernel/ProcessExposed.h>
namespace Kernel {
static Spinlock s_index_lock { LockRank::None };
static InodeIndex s_next_inode_index = 0;
namespace SegmentedProcFSIndex {
static InodeIndex __build_raw_segmented_index(u32 primary, u16 sub_directory, u32 property)
{
VERIFY(primary < 0x10000000);
VERIFY(property < 0x100000);
// Note: The sub-directory part is already limited to 0xFFFF, so no need to VERIFY it.
return static_cast<u64>((static_cast<u64>(primary) << 36) | (static_cast<u64>(sub_directory) << 20) | property);
}
static InodeIndex build_segmented_index_with_known_pid(ProcessID pid, u16 sub_directory, u32 property)
{
return __build_raw_segmented_index(pid.value() + 1, sub_directory, property);
}
static InodeIndex build_segmented_index_with_unknown_property(ProcessID pid, ProcessSubDirectory sub_directory, unsigned property)
{
return build_segmented_index_with_known_pid(pid, to_underlying(sub_directory), static_cast<u32>(property));
}
InodeIndex build_segmented_index_for_pid_directory(ProcessID pid)
{
return build_segmented_index_with_unknown_property(pid, ProcessSubDirectory::Reserved, to_underlying(MainProcessProperty::Reserved));
}
InodeIndex build_segmented_index_for_sub_directory(ProcessID pid, ProcessSubDirectory sub_directory)
{
return build_segmented_index_with_unknown_property(pid, sub_directory, to_underlying(MainProcessProperty::Reserved));
}
InodeIndex build_segmented_index_for_main_property(ProcessID pid, ProcessSubDirectory sub_directory, MainProcessProperty property)
{
return build_segmented_index_with_known_pid(pid, to_underlying(sub_directory), to_underlying(property));
}
InodeIndex build_segmented_index_for_main_property_in_pid_directory(ProcessID pid, MainProcessProperty property)
{
return build_segmented_index_with_known_pid(pid, to_underlying(ProcessSubDirectory::Reserved), to_underlying(property));
}
InodeIndex build_segmented_index_for_thread_stack(ProcessID pid, ThreadID thread_id)
{
return build_segmented_index_with_unknown_property(pid, ProcessSubDirectory::Stacks, thread_id.value());
}
InodeIndex build_segmented_index_for_file_description(ProcessID pid, unsigned fd)
{
return build_segmented_index_with_unknown_property(pid, ProcessSubDirectory::OpenFileDescriptions, fd);
}
InodeIndex build_segmented_index_for_children(ProcessID pid, ProcessID child_pid)
{
return build_segmented_index_with_unknown_property(pid, ProcessSubDirectory::Children, child_pid.value());
}
}
static size_t s_allocate_global_inode_index()
{
SpinlockLocker lock(s_index_lock);
s_next_inode_index = s_next_inode_index.value() + 1;
// Note: Global ProcFS indices must be above 0 and up to maximum of what 36 bit (2 ^ 36 - 1) can represent.
VERIFY(s_next_inode_index > 0);
VERIFY(s_next_inode_index < 0x100000000);
return s_next_inode_index.value();
}
ProcFSExposedComponent::ProcFSExposedComponent() = default;
ProcFSExposedComponent::ProcFSExposedComponent(StringView name)
: m_component_index(s_allocate_global_inode_index())
{
auto name_or_error = KString::try_create(name);
if (name_or_error.is_error())
TODO();
m_name = name_or_error.release_value();
}
ProcFSExposedDirectory::ProcFSExposedDirectory(StringView name)
: ProcFSExposedComponent(name)
{
}
ProcFSExposedDirectory::ProcFSExposedDirectory(StringView name, ProcFSExposedDirectory const& parent_directory)
: ProcFSExposedComponent(name)
, m_parent_directory(parent_directory)
{
}
ProcFSExposedLink::ProcFSExposedLink(StringView name)
: ProcFSExposedComponent(name)
{
}
ErrorOr<size_t> ProcFSGlobalInformation::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const
{
dbgln_if(PROCFS_DEBUG, "ProcFSGlobalInformation @ {}: read_bytes offset: {} count: {}", name(), offset, count);
VERIFY(offset >= 0);
VERIFY(buffer.user_or_kernel_ptr());
if (!description)
return Error::from_errno(EIO);
MutexLocker locker(m_refresh_lock);
if (!description->data()) {
dbgln("ProcFSGlobalInformation: Do not have cached data!");
return Error::from_errno(EIO);
}
auto& typed_cached_data = static_cast<ProcFSInodeData&>(*description->data());
auto& data_buffer = typed_cached_data.buffer;
if (!data_buffer || (size_t)offset >= data_buffer->size())
return 0;
ssize_t nread = min(static_cast<off_t>(data_buffer->size() - offset), static_cast<off_t>(count));
TRY(buffer.write(data_buffer->data() + offset, nread));
return nread;
}
ErrorOr<void> ProcFSGlobalInformation::refresh_data(OpenFileDescription& description) const
{
MutexLocker lock(m_refresh_lock);
auto& cached_data = description.data();
if (!cached_data) {
cached_data = adopt_own_if_nonnull(new (nothrow) ProcFSInodeData);
if (!cached_data)
return ENOMEM;
}
auto builder = TRY(KBufferBuilder::try_create());
TRY(const_cast<ProcFSGlobalInformation&>(*this).try_generate(builder));
auto& typed_cached_data = static_cast<ProcFSInodeData&>(*cached_data);
typed_cached_data.buffer = builder.build();
if (!typed_cached_data.buffer)
return ENOMEM;
return {};
}
ErrorOr<void> ProcFSSystemBoolean::try_generate(KBufferBuilder& builder)
{
return builder.appendff("{}\n", static_cast<int>(value()));
}
ErrorOr<size_t> ProcFSSystemBoolean::write_bytes(off_t, size_t count, UserOrKernelBuffer const& buffer, OpenFileDescription*)
{
if (count != 1)
return EINVAL;
MutexLocker locker(m_refresh_lock);
char value = 0;
TRY(buffer.read(&value, 1));
if (value == '0')
set_value(false);
else if (value == '1')
set_value(true);
else
return EINVAL;
return 1;
}
ErrorOr<void> ProcFSSystemBoolean::truncate(u64 size)
{
if (size != 0)
return EPERM;
return {};
}
ErrorOr<size_t> ProcFSExposedLink::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription*) const
{
VERIFY(offset == 0);
MutexLocker locker(m_lock);
auto builder = TRY(KBufferBuilder::try_create());
if (!const_cast<ProcFSExposedLink&>(*this).acquire_link(builder))
return Error::from_errno(EFAULT);
auto blob = builder.build();
if (!blob)
return Error::from_errno(EFAULT);
ssize_t nread = min(static_cast<off_t>(blob->size() - offset), static_cast<off_t>(count));
TRY(buffer.write(blob->data() + offset, nread));
return nread;
}
ErrorOr<NonnullLockRefPtr<Inode>> ProcFSExposedLink::to_inode(ProcFS const& procfs_instance) const
{
return TRY(ProcFSLinkInode::try_create(procfs_instance, *this));
}
ErrorOr<NonnullLockRefPtr<Inode>> ProcFSExposedComponent::to_inode(ProcFS const& procfs_instance) const
{
return TRY(ProcFSGlobalInode::try_create(procfs_instance, *this));
}
ErrorOr<NonnullLockRefPtr<Inode>> ProcFSExposedDirectory::to_inode(ProcFS const& procfs_instance) const
{
return TRY(ProcFSDirectoryInode::try_create(procfs_instance, *this));
}
void ProcFSExposedDirectory::add_component(ProcFSExposedComponent const&)
{
TODO();
}
ErrorOr<NonnullLockRefPtr<ProcFSExposedComponent>> ProcFSExposedDirectory::lookup(StringView name)
{
for (auto& component : m_components) {
if (component.name() == name) {
return component;
}
}
return ENOENT;
}
ErrorOr<void> ProcFSExposedDirectory::traverse_as_directory(FileSystemID fsid, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(ProcFSComponentRegistry::the().get_lock());
auto parent_directory = m_parent_directory.strong_ref();
if (parent_directory.is_null())
return Error::from_errno(EINVAL);
TRY(callback({ "."sv, { fsid, component_index() }, DT_DIR }));
TRY(callback({ ".."sv, { fsid, parent_directory->component_index() }, DT_DIR }));
for (auto const& component : m_components) {
InodeIdentifier identifier = { fsid, component.component_index() };
TRY(callback({ component.name(), identifier, 0 }));
}
return {};
}
}