ladybird/Kernel/FileSystem/ProcFS.cpp
Andreas Kling 300402cc14 Kernel: Make it possible for KBufferBuilder creation to fail
This patch adds KBufferBuilder::try_create() and treats it like anything
else that can fail. And so, failure to allocate the initial internal
buffer of the builder will now propagate an ENOMEM to the caller. :^)
2021-09-07 15:54:23 +02:00

586 lines
21 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Spencer Dixon <spencercdixon@gmail.com>
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Singleton.h>
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/FileSystem/ProcFS.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Heap/kmalloc.h>
#include <Kernel/Process.h>
#include <Kernel/Sections.h>
#include <LibC/errno_numbers.h>
namespace Kernel {
static Singleton<ProcFSComponentRegistry> s_the;
ProcFSComponentRegistry& ProcFSComponentRegistry::the()
{
return *s_the;
}
UNMAP_AFTER_INIT void ProcFSComponentRegistry::initialize()
{
VERIFY(!s_the.is_initialized());
s_the.ensure_instance();
}
UNMAP_AFTER_INIT ProcFSComponentRegistry::ProcFSComponentRegistry()
: m_root_directory(ProcFSRootDirectory::must_create())
{
}
KResultOr<NonnullRefPtr<ProcFS>> ProcFS::try_create()
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFS());
}
ProcFS::ProcFS()
{
}
ProcFS::~ProcFS()
{
}
KResult ProcFS::initialize()
{
m_root_inode = static_ptr_cast<ProcFSDirectoryInode>(TRY(ProcFSComponentRegistry::the().root_directory().to_inode(*this)));
return KSuccess;
}
Inode& ProcFS::root_inode()
{
return *m_root_inode;
}
ProcFSInode::ProcFSInode(const ProcFS& fs, InodeIndex index)
: Inode(const_cast<ProcFS&>(fs), index)
{
}
ProcFSInode::~ProcFSInode()
{
}
void ProcFSInode::flush_metadata()
{
}
KResult ProcFSInode::add_child(Inode&, const StringView&, mode_t)
{
return EROFS;
}
KResultOr<NonnullRefPtr<Inode>> ProcFSInode::create_child(StringView, mode_t, dev_t, UserID, GroupID)
{
return EROFS;
}
KResult ProcFSInode::remove_child(const StringView&)
{
return EROFS;
}
KResult ProcFSInode::chmod(mode_t)
{
return EPERM;
}
KResult ProcFSInode::chown(UserID, GroupID)
{
return EPERM;
}
KResult ProcFSInode::truncate(u64)
{
return EPERM;
}
KResultOr<NonnullRefPtr<ProcFSGlobalInode>> ProcFSGlobalInode::try_create(const ProcFS& fs, const ProcFSExposedComponent& component)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSGlobalInode(fs, component));
}
ProcFSGlobalInode::ProcFSGlobalInode(const ProcFS& fs, const ProcFSExposedComponent& component)
: ProcFSInode(fs, component.component_index())
, m_associated_component(component)
{
}
void ProcFSGlobalInode::did_seek(OpenFileDescription& description, off_t new_offset)
{
if (new_offset != 0)
return;
auto result = m_associated_component->refresh_data(description);
if (result.is_error()) {
// Subsequent calls to read will return EIO!
dbgln("ProcFS: Could not refresh contents: {}", result.error());
}
}
KResult ProcFSGlobalInode::attach(OpenFileDescription& description)
{
return m_associated_component->refresh_data(description);
}
KResultOr<size_t> ProcFSGlobalInode::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* fd) const
{
return m_associated_component->read_bytes(offset, count, buffer, fd);
}
StringView ProcFSGlobalInode::name() const
{
return m_associated_component->name();
}
KResult ProcFSGlobalInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const
{
VERIFY_NOT_REACHED();
}
KResultOr<NonnullRefPtr<Inode>> ProcFSGlobalInode::lookup(StringView)
{
VERIFY_NOT_REACHED();
}
InodeMetadata ProcFSGlobalInode::metadata() const
{
MutexLocker locker(m_inode_lock);
InodeMetadata metadata;
metadata.inode = { fsid(), m_associated_component->component_index() };
metadata.mode = S_IFREG | m_associated_component->required_mode();
metadata.uid = m_associated_component->owner_user();
metadata.gid = m_associated_component->owner_group();
metadata.size = 0;
metadata.mtime = m_associated_component->modified_time();
return metadata;
}
KResultOr<size_t> ProcFSGlobalInode::write_bytes(off_t offset, size_t count, const UserOrKernelBuffer& buffer, OpenFileDescription* fd)
{
return m_associated_component->write_bytes(offset, count, buffer, fd);
}
KResultOr<NonnullRefPtr<ProcFSDirectoryInode>> ProcFSDirectoryInode::try_create(const ProcFS& procfs, const ProcFSExposedComponent& component)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSDirectoryInode(procfs, component));
}
ProcFSDirectoryInode::ProcFSDirectoryInode(const ProcFS& fs, const ProcFSExposedComponent& component)
: ProcFSGlobalInode(fs, component)
{
}
ProcFSDirectoryInode::~ProcFSDirectoryInode()
{
}
InodeMetadata ProcFSDirectoryInode::metadata() const
{
MutexLocker locker(m_inode_lock);
InodeMetadata metadata;
metadata.inode = { fsid(), m_associated_component->component_index() };
metadata.mode = S_IFDIR | m_associated_component->required_mode();
metadata.uid = m_associated_component->owner_user();
metadata.gid = m_associated_component->owner_group();
metadata.size = 0;
metadata.mtime = m_associated_component->modified_time();
return metadata;
}
KResult ProcFSDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(procfs().m_lock);
return m_associated_component->traverse_as_directory(procfs().fsid(), move(callback));
}
KResultOr<NonnullRefPtr<Inode>> ProcFSDirectoryInode::lookup(StringView name)
{
MutexLocker locker(procfs().m_lock);
auto component = TRY(m_associated_component->lookup(name));
return component->to_inode(procfs());
}
KResultOr<NonnullRefPtr<ProcFSLinkInode>> ProcFSLinkInode::try_create(const ProcFS& procfs, const ProcFSExposedComponent& component)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSLinkInode(procfs, component));
}
ProcFSLinkInode::ProcFSLinkInode(const ProcFS& fs, const ProcFSExposedComponent& component)
: ProcFSGlobalInode(fs, component)
{
}
InodeMetadata ProcFSLinkInode::metadata() const
{
MutexLocker locker(m_inode_lock);
InodeMetadata metadata;
metadata.inode = { fsid(), m_associated_component->component_index() };
metadata.mode = S_IFLNK | m_associated_component->required_mode();
metadata.uid = m_associated_component->owner_user();
metadata.gid = m_associated_component->owner_group();
metadata.size = 0;
metadata.mtime = m_associated_component->modified_time();
return metadata;
}
ProcFSProcessAssociatedInode::ProcFSProcessAssociatedInode(const ProcFS& fs, ProcessID associated_pid, InodeIndex determined_index)
: ProcFSInode(fs, determined_index)
, m_pid(associated_pid)
{
}
KResultOr<size_t> ProcFSProcessAssociatedInode::write_bytes(off_t, size_t, const UserOrKernelBuffer&, OpenFileDescription*)
{
VERIFY_NOT_REACHED();
}
KResultOr<NonnullRefPtr<ProcFSProcessDirectoryInode>> ProcFSProcessDirectoryInode::try_create(const ProcFS& procfs, ProcessID pid)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSProcessDirectoryInode(procfs, pid));
}
ProcFSProcessDirectoryInode::ProcFSProcessDirectoryInode(const ProcFS& procfs, ProcessID pid)
: ProcFSProcessAssociatedInode(procfs, pid, SegmentedProcFSIndex::build_segmented_index_for_pid_directory(pid))
{
}
KResult ProcFSProcessDirectoryInode::attach(OpenFileDescription&)
{
return KSuccess;
}
InodeMetadata ProcFSProcessDirectoryInode::metadata() const
{
MutexLocker locker(m_inode_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return {};
auto traits = process->procfs_traits();
InodeMetadata metadata;
metadata.inode = { fsid(), traits->component_index() };
metadata.mode = S_IFDIR | traits->required_mode();
metadata.uid = traits->owner_user();
metadata.gid = traits->owner_group();
metadata.size = 0;
metadata.mtime = traits->modified_time();
return metadata;
}
KResultOr<size_t> ProcFSProcessDirectoryInode::read_bytes(off_t, size_t, UserOrKernelBuffer&, OpenFileDescription*) const
{
VERIFY_NOT_REACHED();
}
KResult ProcFSProcessDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(procfs().m_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return EINVAL;
return process->procfs_traits()->traverse_as_directory(procfs().fsid(), move(callback));
}
KResultOr<NonnullRefPtr<Inode>> ProcFSProcessDirectoryInode::lookup(StringView name)
{
MutexLocker locker(procfs().m_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return ESRCH;
if (name == "fd"sv)
return TRY(ProcFSProcessSubDirectoryInode::try_create(procfs(), SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions, associated_pid()));
if (name == "stacks"sv)
return TRY(ProcFSProcessSubDirectoryInode::try_create(procfs(), SegmentedProcFSIndex::ProcessSubDirectory::Stacks, associated_pid()));
if (name == "unveil"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::Unveil, associated_pid()));
if (name == "pledge"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::Pledge, associated_pid()));
if (name == "fds"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::OpenFileDescriptions, associated_pid()));
if (name == "exe"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::BinaryLink, associated_pid()));
if (name == "cwd"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::CurrentWorkDirectoryLink, associated_pid()));
if (name == "perf_events"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::PerformanceEvents, associated_pid()));
if (name == "vm"sv)
return TRY(ProcFSProcessPropertyInode::try_create_for_pid_property(procfs(), SegmentedProcFSIndex::MainProcessProperty::VirtualMemoryStats, associated_pid()));
return ENOENT;
}
KResultOr<NonnullRefPtr<ProcFSProcessSubDirectoryInode>> ProcFSProcessSubDirectoryInode::try_create(const ProcFS& procfs, SegmentedProcFSIndex::ProcessSubDirectory sub_directory_type, ProcessID pid)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSProcessSubDirectoryInode(procfs, sub_directory_type, pid));
}
ProcFSProcessSubDirectoryInode::ProcFSProcessSubDirectoryInode(const ProcFS& procfs, SegmentedProcFSIndex::ProcessSubDirectory sub_directory_type, ProcessID pid)
: ProcFSProcessAssociatedInode(procfs, pid, SegmentedProcFSIndex::build_segmented_index_for_sub_directory(pid, sub_directory_type))
, m_sub_directory_type(sub_directory_type)
{
}
KResultOr<size_t> ProcFSProcessSubDirectoryInode::read_bytes(off_t, size_t, UserOrKernelBuffer&, OpenFileDescription*) const
{
VERIFY_NOT_REACHED();
}
KResult ProcFSProcessSubDirectoryInode::attach(OpenFileDescription&)
{
return KSuccess;
}
void ProcFSProcessSubDirectoryInode::did_seek(OpenFileDescription&, off_t)
{
VERIFY_NOT_REACHED();
}
InodeMetadata ProcFSProcessSubDirectoryInode::metadata() const
{
MutexLocker locker(m_inode_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return {};
auto traits = process->procfs_traits();
InodeMetadata metadata;
metadata.inode = { fsid(), traits->component_index() };
metadata.mode = S_IFDIR | traits->required_mode();
metadata.uid = traits->owner_user();
metadata.gid = traits->owner_group();
metadata.size = 0;
metadata.mtime = traits->modified_time();
return metadata;
}
KResult ProcFSProcessSubDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(procfs().m_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return EINVAL;
switch (m_sub_directory_type) {
case SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions:
return process->traverse_file_descriptions_directory(procfs().fsid(), move(callback));
case SegmentedProcFSIndex::ProcessSubDirectory::Stacks:
return process->traverse_stacks_directory(procfs().fsid(), move(callback));
default:
VERIFY_NOT_REACHED();
}
VERIFY_NOT_REACHED();
}
KResultOr<NonnullRefPtr<Inode>> ProcFSProcessSubDirectoryInode::lookup(StringView name)
{
MutexLocker locker(procfs().m_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return ESRCH;
switch (m_sub_directory_type) {
case SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions:
return process->lookup_file_descriptions_directory(procfs(), name);
case SegmentedProcFSIndex::ProcessSubDirectory::Stacks:
return process->lookup_stacks_directory(procfs(), name);
default:
VERIFY_NOT_REACHED();
}
}
KResultOr<NonnullRefPtr<ProcFSProcessPropertyInode>> ProcFSProcessPropertyInode::try_create_for_file_description_link(const ProcFS& procfs, unsigned file_description_index, ProcessID pid)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSProcessPropertyInode(procfs, file_description_index, pid));
}
KResultOr<NonnullRefPtr<ProcFSProcessPropertyInode>> ProcFSProcessPropertyInode::try_create_for_thread_stack(const ProcFS& procfs, ThreadID stack_thread_index, ProcessID pid)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSProcessPropertyInode(procfs, stack_thread_index, pid));
}
KResultOr<NonnullRefPtr<ProcFSProcessPropertyInode>> ProcFSProcessPropertyInode::try_create_for_pid_property(const ProcFS& procfs, SegmentedProcFSIndex::MainProcessProperty main_property_type, ProcessID pid)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ProcFSProcessPropertyInode(procfs, main_property_type, pid));
}
ProcFSProcessPropertyInode::ProcFSProcessPropertyInode(const ProcFS& procfs, SegmentedProcFSIndex::MainProcessProperty main_property_type, ProcessID pid)
: ProcFSProcessAssociatedInode(procfs, pid, SegmentedProcFSIndex::build_segmented_index_for_main_property_in_pid_directory(pid, main_property_type))
, m_parent_sub_directory_type(SegmentedProcFSIndex::ProcessSubDirectory::Reserved)
{
m_possible_data.property_type = main_property_type;
}
ProcFSProcessPropertyInode::ProcFSProcessPropertyInode(const ProcFS& procfs, unsigned file_description_index, ProcessID pid)
: ProcFSProcessAssociatedInode(procfs, pid, SegmentedProcFSIndex::build_segmented_index_for_file_description(pid, file_description_index))
, m_parent_sub_directory_type(SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions)
{
m_possible_data.property_index = file_description_index;
}
ProcFSProcessPropertyInode::ProcFSProcessPropertyInode(const ProcFS& procfs, ThreadID thread_stack_index, ProcessID pid)
: ProcFSProcessAssociatedInode(procfs, pid, SegmentedProcFSIndex::build_segmented_index_for_thread_stack(pid, thread_stack_index))
, m_parent_sub_directory_type(SegmentedProcFSIndex::ProcessSubDirectory::Stacks)
{
m_possible_data.property_index = thread_stack_index.value();
}
KResult ProcFSProcessPropertyInode::attach(OpenFileDescription& description)
{
return refresh_data(description);
}
void ProcFSProcessPropertyInode::did_seek(OpenFileDescription& description, off_t offset)
{
if (offset != 0)
return;
(void)refresh_data(description);
}
static mode_t determine_procfs_process_inode_mode(SegmentedProcFSIndex::ProcessSubDirectory parent_sub_directory_type, SegmentedProcFSIndex::MainProcessProperty main_property)
{
if (parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions)
return S_IFLNK | 0400;
if (parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::Stacks)
return S_IFREG | 0400;
VERIFY(parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::Reserved);
if (main_property == SegmentedProcFSIndex::MainProcessProperty::BinaryLink)
return S_IFLNK | 0777;
if (main_property == SegmentedProcFSIndex::MainProcessProperty::CurrentWorkDirectoryLink)
return S_IFLNK | 0777;
return S_IFREG | 0400;
}
InodeMetadata ProcFSProcessPropertyInode::metadata() const
{
MutexLocker locker(m_inode_lock);
auto process = Process::from_pid(associated_pid());
if (!process)
return {};
auto traits = process->procfs_traits();
InodeMetadata metadata;
metadata.inode = { fsid(), traits->component_index() };
metadata.mode = determine_procfs_process_inode_mode(m_parent_sub_directory_type, m_possible_data.property_type);
metadata.uid = traits->owner_user();
metadata.gid = traits->owner_group();
metadata.size = 0;
metadata.mtime = traits->modified_time();
return metadata;
}
KResult ProcFSProcessPropertyInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const
{
VERIFY_NOT_REACHED();
}
KResultOr<size_t> ProcFSProcessPropertyInode::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const
{
dbgln_if(PROCFS_DEBUG, "ProcFS ProcessInformation: read_bytes offset: {} count: {}", offset, count);
VERIFY(offset >= 0);
VERIFY(buffer.user_or_kernel_ptr());
if (!description) {
auto builder = TRY(KBufferBuilder::try_create());
auto process = Process::from_pid(associated_pid());
if (!process)
return KResult(ESRCH);
TRY(try_to_acquire_data(*process, builder));
auto data_buffer = builder.build();
if (!data_buffer)
return KResult(EFAULT);
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;
}
if (!description->data()) {
dbgln("ProcFS Process Information: Do not have cached data!");
return KResult(EIO);
}
MutexLocker locker(m_refresh_lock);
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;
}
KResultOr<NonnullRefPtr<Inode>> ProcFSProcessPropertyInode::lookup(StringView)
{
return EINVAL;
}
static KResult build_from_cached_data(KBufferBuilder& builder, ProcFSInodeData& cached_data)
{
cached_data.buffer = builder.build();
if (!cached_data.buffer)
return ENOMEM;
return KSuccess;
}
KResult ProcFSProcessPropertyInode::try_to_acquire_data(Process& process, KBufferBuilder& builder) const
{
// FIXME: Verify process is already ref-counted
if (m_parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::OpenFileDescriptions) {
TRY(process.procfs_get_file_description_link(m_possible_data.property_index, builder));
return KSuccess;
}
if (m_parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::Stacks) {
TRY(process.procfs_get_thread_stack(m_possible_data.property_index, builder));
return KSuccess;
}
VERIFY(m_parent_sub_directory_type == SegmentedProcFSIndex::ProcessSubDirectory::Reserved);
switch (m_possible_data.property_type) {
case SegmentedProcFSIndex::MainProcessProperty::Unveil:
return process.procfs_get_unveil_stats(builder);
case SegmentedProcFSIndex::MainProcessProperty::Pledge:
return process.procfs_get_pledge_stats(builder);
case SegmentedProcFSIndex::MainProcessProperty::OpenFileDescriptions:
return process.procfs_get_fds_stats(builder);
case SegmentedProcFSIndex::MainProcessProperty::BinaryLink:
return process.procfs_get_binary_link(builder);
case SegmentedProcFSIndex::MainProcessProperty::CurrentWorkDirectoryLink:
return process.procfs_get_current_work_directory_link(builder);
case SegmentedProcFSIndex::MainProcessProperty::PerformanceEvents:
return process.procfs_get_perf_events(builder);
case SegmentedProcFSIndex::MainProcessProperty::VirtualMemoryStats:
return process.procfs_get_virtual_memory_stats(builder);
default:
VERIFY_NOT_REACHED();
}
}
KResult ProcFSProcessPropertyInode::refresh_data(OpenFileDescription& description)
{
// For process-specific inodes, hold the process's ptrace lock across refresh
// and refuse to load data if the process is not dumpable.
// Without this, files opened before a process went non-dumpable could still be used for dumping.
auto process = Process::from_pid(associated_pid());
if (!process)
return KResult(ESRCH);
process->ptrace_lock().lock();
if (!process->is_dumpable()) {
process->ptrace_lock().unlock();
return EPERM;
}
ScopeGuard guard = [&] {
process->ptrace_lock().unlock();
};
MutexLocker locker(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(try_to_acquire_data(*process, builder));
return build_from_cached_data(builder, static_cast<ProcFSInodeData&>(*cached_data));
}
}