mirror of
https://github.com/RGBCube/serenity
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046d6855f5
This makes the Scheduler a lot leaner by not having to evaluate block conditions every time it is invoked. Instead evaluate them as the states change, and unblock threads at that point. This also implements some more waitid/waitpid/wait features and behavior. For example, WUNTRACED and WNOWAIT are now supported. And wait will now not return EINTR when SIGCHLD is delivered at the same time.
142 lines
4.7 KiB
C++
142 lines
4.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/NumericLimits.h>
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#include <Kernel/FileSystem/FileDescription.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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ssize_t Process::sys$writev(int fd, Userspace<const struct iovec*> iov, int iov_count)
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{
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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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{
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Checked checked_iov_count = sizeof(iovec);
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checked_iov_count *= iov_count;
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if (checked_iov_count.has_overflow())
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return -EFAULT;
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}
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u64 total_length = 0;
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Vector<iovec, 32> vecs;
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vecs.resize(iov_count);
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if (!copy_n_from_user(vecs.data(), iov, iov_count))
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return -EFAULT;
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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 = file_description(fd);
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if (!description)
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return -EBADF;
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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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int rc = do_write(*description, buffer.value(), vec.iov_len);
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if (rc < 0) {
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if (nwritten == 0)
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return rc;
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return nwritten;
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}
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nwritten += rc;
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}
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return nwritten;
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}
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ssize_t Process::do_write(FileDescription& description, const UserOrKernelBuffer& data, size_t data_size)
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{
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ssize_t total_nwritten = 0;
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if (!description.is_blocking()) {
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if (!description.can_write())
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return -EAGAIN;
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}
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if (description.should_append())
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description.seek(0, SEEK_END);
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while ((size_t)total_nwritten < data_size) {
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if (!description.can_write()) {
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if (!description.is_blocking()) {
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// Short write: We can no longer write to this non-blocking description.
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ASSERT(total_nwritten > 0);
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return total_nwritten;
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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>(nullptr, 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)
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return total_nwritten;
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return nwritten_or_error.error();
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}
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if (nwritten_or_error.value() == 0)
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break;
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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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ssize_t Process::sys$write(int fd, const u8* data, ssize_t size)
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{
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REQUIRE_PROMISE(stdio);
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if (size < 0)
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return -EINVAL;
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if (size == 0)
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return 0;
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#ifdef DEBUG_IO
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dbg() << "sys$write(" << fd << ", " << (const void*)(data) << ", " << size << ")";
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#endif
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auto description = file_description(fd);
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if (!description)
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return -EBADF;
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if (!description->is_writable())
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return -EBADF;
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auto buffer = UserOrKernelBuffer::for_user_buffer(const_cast<u8*>(data), (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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