mirror of
https://github.com/RGBCube/serenity
synced 2025-05-31 13:28:11 +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.
111 lines
3.6 KiB
C++
111 lines
3.6 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 <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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using BlockFlags = Thread::FileBlocker::BlockFlags;
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static ErrorOr<NonnullRefPtr<OpenFileDescription>> open_readable_file_description(Process::OpenFileDescriptions const& fds, int fd)
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{
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auto description = TRY(fds.open_file_description(fd));
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if (!description->is_readable())
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return EBADF;
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if (description->is_directory())
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return EISDIR;
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return description;
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}
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static ErrorOr<void> check_blocked_read(OpenFileDescription* description)
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{
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if (description->is_blocking()) {
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if (!description->can_read()) {
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auto unblock_flags = BlockFlags::None;
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if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
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return EINTR;
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if (!has_flag(unblock_flags, BlockFlags::Read))
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return EAGAIN;
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// TODO: handle exceptions in unblock_flags
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}
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}
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return {};
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}
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ErrorOr<FlatPtr> Process::sys$readv(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(open_readable_file_description(fds(), fd));
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int nread = 0;
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for (auto& vec : vecs) {
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TRY(check_blocked_read(description));
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auto buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len));
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auto nread_here = TRY(description->read(buffer, vec.iov_len));
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nread += nread_here;
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}
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return nread;
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}
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ErrorOr<FlatPtr> Process::sys$read(int fd, Userspace<u8*> buffer, 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$read({}, {}, {})", fd, buffer.ptr(), size);
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auto description = TRY(open_readable_file_description(fds(), fd));
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TRY(check_blocked_read(description));
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auto user_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, size));
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return TRY(description->read(user_buffer, size));
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}
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// NOTE: The offset is passed by pointer because off_t is 64bit,
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// hence it can't be passed by register on 32bit platforms.
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ErrorOr<FlatPtr> Process::sys$pread(int fd, Userspace<u8*> buffer, size_t size, Userspace<off_t const*> userspace_offset)
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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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auto offset = TRY(copy_typed_from_user(userspace_offset));
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if (offset < 0)
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return EINVAL;
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dbgln_if(IO_DEBUG, "sys$pread({}, {}, {}, {})", fd, buffer.ptr(), size, offset);
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auto description = TRY(open_readable_file_description(fds(), fd));
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if (!description->file().is_seekable())
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return EINVAL;
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TRY(check_blocked_read(description));
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auto user_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, size));
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return TRY(description->read(user_buffer, offset, size));
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}
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}
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