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https://github.com/RGBCube/serenity
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79fa9765ca
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace! This was a slightly tedious refactoring that took a long time, so it's not unlikely that some bugs crept in. Nevertheless, it does pass basic functionality testing, and it's just real nice to finally see the same pattern in all contexts. :^)
114 lines
3.5 KiB
C++
114 lines
3.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/NumericLimits.h>
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#include <Kernel/Debug.h>
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#include <Kernel/FileSystem/OpenFileDescription.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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ErrorOr<FlatPtr> Process::sys$writev(int fd, Userspace<const struct iovec*> iov, int iov_count)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(stdio);
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if (iov_count < 0)
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return EINVAL;
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// Arbitrary pain threshold.
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if (iov_count > (int)MiB)
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return EFAULT;
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u64 total_length = 0;
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Vector<iovec, 32> vecs;
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if (!vecs.try_resize(iov_count))
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return ENOMEM;
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TRY(copy_n_from_user(vecs.data(), iov, iov_count));
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for (auto& vec : vecs) {
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total_length += vec.iov_len;
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if (total_length > NumericLimits<i32>::max())
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return EINVAL;
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}
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auto description = TRY(fds().open_file_description(fd));
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if (!description->is_writable())
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return EBADF;
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int nwritten = 0;
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for (auto& vec : vecs) {
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auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
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if (!buffer.has_value())
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return EFAULT;
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auto result = do_write(*description, buffer.value(), vec.iov_len);
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if (result.is_error()) {
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if (nwritten == 0)
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return result.release_error();
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return nwritten;
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}
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nwritten += result.value();
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}
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return nwritten;
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}
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ErrorOr<FlatPtr> Process::do_write(OpenFileDescription& description, const UserOrKernelBuffer& data, size_t data_size)
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{
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size_t total_nwritten = 0;
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if (description.should_append() && description.file().is_seekable()) {
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TRY(description.seek(0, SEEK_END));
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}
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while (total_nwritten < data_size) {
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while (!description.can_write()) {
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if (!description.is_blocking()) {
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if (total_nwritten > 0)
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return total_nwritten;
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else
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return EAGAIN;
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}
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auto unblock_flags = Thread::FileBlocker::BlockFlags::None;
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if (Thread::current()->block<Thread::WriteBlocker>({}, description, unblock_flags).was_interrupted()) {
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if (total_nwritten == 0)
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return EINTR;
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}
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// TODO: handle exceptions in unblock_flags
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}
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auto nwritten_or_error = description.write(data.offset(total_nwritten), data_size - total_nwritten);
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if (nwritten_or_error.is_error()) {
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if (total_nwritten > 0)
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return total_nwritten;
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if (nwritten_or_error.error().code() == EAGAIN)
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continue;
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return nwritten_or_error.release_error();
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}
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VERIFY(nwritten_or_error.value() > 0);
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total_nwritten += nwritten_or_error.value();
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}
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return total_nwritten;
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}
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ErrorOr<FlatPtr> Process::sys$write(int fd, Userspace<const u8*> data, size_t size)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(stdio);
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if (size == 0)
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return 0;
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if (size > NumericLimits<ssize_t>::max())
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return EINVAL;
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dbgln_if(IO_DEBUG, "sys$write({}, {}, {})", fd, data.ptr(), size);
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auto description = TRY(fds().open_file_description(fd));
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if (!description->is_writable())
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return EBADF;
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auto buffer = UserOrKernelBuffer::for_user_buffer(data, static_cast<size_t>(size));
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if (!buffer.has_value())
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return EFAULT;
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return do_write(*description, buffer.value(), size);
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}
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}
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