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/*
* Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/SysFS/Subsystems/Kernel/GlobalInformation.h>
#include <Kernel/Process.h>
namespace Kernel {
ErrorOr<size_t> SysFSGlobalInformation::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const
{
dbgln_if(SYSFS_DEBUG, "SysFSGlobalInformation @ {}: 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("SysFSGlobalInformation: Do not have cached data!");
return Error::from_errno(EIO);
}
auto& typed_cached_data = static_cast<SysFSInodeData&>(*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;
}
SysFSGlobalInformation::SysFSGlobalInformation(SysFSDirectory const& parent_directory)
: SysFSComponent(parent_directory)
{
}
ErrorOr<void> SysFSGlobalInformation::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) SysFSInodeData);
if (!cached_data)
return ENOMEM;
}
auto builder = TRY(KBufferBuilder::try_create());
TRY(Process::current().jail().with([&](auto const& my_jail) -> ErrorOr<void> {
if (my_jail && !is_readable_by_jailed_processes())
return Error::from_errno(EPERM);
return {};
}));
TRY(const_cast<SysFSGlobalInformation&>(*this).try_generate(builder));
auto& typed_cached_data = static_cast<SysFSInodeData&>(*cached_data);
typed_cached_data.buffer = builder.build();
if (!typed_cached_data.buffer)
return ENOMEM;
return {};
}
}
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