mirror of
https://github.com/RGBCube/serenity
synced 2025-05-19 00:45:08 +00:00
bad6d50b86
This change lays the foundation for making the require_promise return an error hand handling the process abort outside of the syscall implementations, to avoid cases where we would leak resources. It also has the advantage that it makes removes a gs pointer read to look up the current thread, then process for every syscall. We can instead go through the Process this pointer in most cases.
108 lines
3.4 KiB
C++
108 lines
3.4 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(Pledge::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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TRY(vecs.try_resize(iov_count));
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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 = TRY(UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len));
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auto result = do_write(*description, buffer, 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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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(Pledge::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 = TRY(UserOrKernelBuffer::for_user_buffer(data, static_cast<size_t>(size)));
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return do_write(*description, buffer, size);
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}
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}
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