ladybird/Kernel/Syscalls/read.cpp
Brian Gianforcaro 5f6ab77352 Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum
Switch to using type-safe bitwise operators for the BlockFlags class,
this cleans up a lot of boilerplate casts which are necessary when the
enum is declared as `enum class`.
2021-03-08 18:47:40 +01:00

125 lines
4.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
using BlockFlags = Thread::FileBlocker::BlockFlags;
KResultOr<ssize_t> Process::sys$readv(int fd, Userspace<const struct iovec*> iov, int iov_count)
{
REQUIRE_PROMISE(stdio);
if (iov_count < 0)
return EINVAL;
// Arbitrary pain threshold.
if (iov_count > (int)MiB)
return EFAULT;
u64 total_length = 0;
Vector<iovec, 32> vecs;
vecs.resize(iov_count);
if (!copy_n_from_user(vecs.data(), iov, iov_count))
return EFAULT;
for (auto& vec : vecs) {
total_length += vec.iov_len;
if (total_length > NumericLimits<i32>::max())
return EINVAL;
}
auto description = file_description(fd);
if (!description)
return EBADF;
if (!description->is_readable())
return EBADF;
if (description->is_directory())
return EISDIR;
int nread = 0;
for (auto& vec : vecs) {
if (description->is_blocking()) {
if (!description->can_read()) {
auto unblock_flags = BlockFlags::None;
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
return EINTR;
if (!has_flag(unblock_flags, BlockFlags::Read))
return EAGAIN;
// TODO: handle exceptions in unblock_flags
}
}
auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
if (!buffer.has_value())
return EFAULT;
auto result = description->read(buffer.value(), vec.iov_len);
if (result.is_error())
return result.error();
nread += result.value();
}
return nread;
}
KResultOr<ssize_t> Process::sys$read(int fd, Userspace<u8*> buffer, ssize_t size)
{
REQUIRE_PROMISE(stdio);
if (size < 0)
return EINVAL;
if (size == 0)
return 0;
dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
auto description = file_description(fd);
if (!description)
return EBADF;
if (!description->is_readable())
return EBADF;
if (description->is_directory())
return EISDIR;
if (description->is_blocking()) {
if (!description->can_read()) {
auto unblock_flags = BlockFlags::None;
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
return EINTR;
if (!has_flag(unblock_flags, BlockFlags::Read))
return EAGAIN;
// TODO: handle exceptions in unblock_flags
}
}
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
return EFAULT;
auto result = description->read(user_buffer.value(), size);
if (result.is_error())
return result.error();
return result.value();
}
}