mirror of
https://github.com/RGBCube/serenity
synced 2025-05-24 08:35:07 +00:00
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.
255 lines
9.4 KiB
C++
255 lines
9.4 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/ScopeGuard.h>
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#include <AK/Time.h>
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#include <Kernel/FileSystem/FileDescription.h>
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#include <Kernel/Process.h>
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//#define DEBUG_IO
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//#define DEBUG_POLL_SELECT
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namespace Kernel {
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int Process::sys$select(const Syscall::SC_select_params* user_params)
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{
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REQUIRE_PROMISE(stdio);
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Syscall::SC_select_params params;
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SmapDisabler disabler;
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if (!copy_from_user(¶ms, user_params))
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return -EFAULT;
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if (params.nfds < 0)
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return -EINVAL;
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Thread::BlockTimeout timeout;
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if (params.timeout) {
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timespec timeout_copy;
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if (!copy_from_user(&timeout_copy, params.timeout))
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return -EFAULT;
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timeout = Thread::BlockTimeout(false, &timeout_copy);
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}
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auto current_thread = Thread::current();
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u32 previous_signal_mask = 0;
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if (params.sigmask) {
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sigset_t sigmask_copy;
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if (!copy_from_user(&sigmask_copy, params.sigmask))
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return -EFAULT;
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previous_signal_mask = current_thread->update_signal_mask(sigmask_copy);
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}
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ScopeGuard rollback_signal_mask([&]() {
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if (params.sigmask)
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current_thread->update_signal_mask(previous_signal_mask);
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});
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fd_set fds_read, fds_write, fds_except;
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if (params.readfds && !copy_from_user(&fds_read, params.readfds))
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return -EFAULT;
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if (params.writefds && !copy_from_user(&fds_write, params.writefds))
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return -EFAULT;
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if (params.exceptfds && !copy_from_user(&fds_except, params.exceptfds))
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return -EFAULT;
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Thread::SelectBlocker::FDVector fds_info;
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Vector<int> fds;
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for (int fd = 0; fd < params.nfds; fd++) {
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u32 block_flags = (u32)Thread::FileBlocker::BlockFlags::None;
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if (params.readfds && FD_ISSET(fd, &fds_read))
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::Read;
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if (params.writefds && FD_ISSET(fd, &fds_write))
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::Write;
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if (params.exceptfds && FD_ISSET(fd, &fds_except))
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::Exception;
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if (block_flags == (u32)Thread::FileBlocker::BlockFlags::None)
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continue;
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auto description = file_description(fd);
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if (!description) {
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dbg() << "sys$select: Bad fd number " << fd;
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return -EBADF;
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}
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fds_info.append({ description.release_nonnull(), (Thread::FileBlocker::BlockFlags)block_flags });
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fds.append(fd);
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}
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#if defined(DEBUG_IO) || defined(DEBUG_POLL_SELECT)
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dbg() << "selecting on " << fds_info.size() << " fds, timeout=" << params.timeout;
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#endif
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if (current_thread->block<Thread::SelectBlocker>(timeout, fds_info).was_interrupted()) {
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dbg() << "select was interrupted";
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return -EINTR;
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}
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if (params.readfds)
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FD_ZERO(&fds_read);
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if (params.writefds)
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FD_ZERO(&fds_write);
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if (params.exceptfds)
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FD_ZERO(&fds_except);
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int marked_fd_count = 0;
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for (size_t i = 0; i < fds_info.size(); i++) {
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auto& fd_entry = fds_info[i];
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if (fd_entry.unblocked_flags == Thread::FileBlocker::BlockFlags::None)
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continue;
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if (params.readfds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Read)) {
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FD_SET(fds[i], &fds_read);
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marked_fd_count++;
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}
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if (params.writefds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Write)) {
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FD_SET(fds[i], &fds_write);
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marked_fd_count++;
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}
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if (params.exceptfds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Exception)) {
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FD_SET(fds[i], &fds_except);
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marked_fd_count++;
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}
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}
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if (params.readfds && !copy_to_user(params.readfds, &fds_read))
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return -EFAULT;
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if (params.writefds && !copy_to_user(params.writefds, &fds_write))
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return -EFAULT;
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if (params.exceptfds && !copy_to_user(params.exceptfds, &fds_except))
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return -EFAULT;
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return marked_fd_count;
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}
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int Process::sys$poll(Userspace<const Syscall::SC_poll_params*> user_params)
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{
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REQUIRE_PROMISE(stdio);
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// FIXME: Return -EINVAL if timeout is invalid.
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Syscall::SC_poll_params params;
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if (!copy_from_user(¶ms, user_params))
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return -EFAULT;
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SmapDisabler disabler;
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Thread::BlockTimeout timeout;
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if (params.timeout) {
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timespec timeout_copy;
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if (!copy_from_user(&timeout_copy, params.timeout))
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return -EFAULT;
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timeout = Thread::BlockTimeout(false, &timeout_copy);
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}
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sigset_t sigmask = {};
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if (params.sigmask && !copy_from_user(&sigmask, params.sigmask))
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return -EFAULT;
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Vector<pollfd> fds_copy;
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if (params.nfds > 0) {
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Checked nfds_checked = sizeof(pollfd);
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nfds_checked *= params.nfds;
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if (nfds_checked.has_overflow())
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return -EFAULT;
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fds_copy.resize(params.nfds);
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if (!copy_from_user(&fds_copy[0], ¶ms.fds[0], params.nfds * sizeof(pollfd)))
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return -EFAULT;
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}
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Thread::SelectBlocker::FDVector fds_info;
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for (size_t i = 0; i < params.nfds; i++) {
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auto& pfd = fds_copy[i];
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auto description = file_description(pfd.fd);
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if (!description) {
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dbg() << "sys$poll: Bad fd number " << pfd.fd;
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return -EBADF;
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}
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u32 block_flags = (u32)Thread::FileBlocker::BlockFlags::Exception; // always want POLLERR, POLLHUP, POLLNVAL
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if (pfd.events & POLLIN)
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::Read;
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if (pfd.events & POLLOUT)
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::Write;
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if (pfd.events & POLLPRI)
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block_flags |= (u32)Thread::FileBlocker::BlockFlags::ReadPriority;
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fds_info.append({ description.release_nonnull(), (Thread::FileBlocker::BlockFlags)block_flags });
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}
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auto current_thread = Thread::current();
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u32 previous_signal_mask = 0;
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if (params.sigmask)
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previous_signal_mask = current_thread->update_signal_mask(sigmask);
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ScopeGuard rollback_signal_mask([&]() {
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if (params.sigmask)
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current_thread->update_signal_mask(previous_signal_mask);
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});
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#if defined(DEBUG_IO) || defined(DEBUG_POLL_SELECT)
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dbg() << "polling on " << fds_info.size() << " fds, timeout=" << params.timeout;
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#endif
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if (current_thread->block<Thread::SelectBlocker>(timeout, fds_info).was_interrupted())
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return -EINTR;
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int fds_with_revents = 0;
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for (unsigned i = 0; i < params.nfds; ++i) {
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auto& pfd = fds_copy[i];
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auto& fds_entry = fds_info[i];
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pfd.revents = 0;
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if (fds_entry.unblocked_flags == Thread::FileBlocker::BlockFlags::None)
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continue;
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Exception) {
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::ReadHangUp)
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pfd.revents |= POLLRDHUP;
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::WriteError)
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pfd.revents |= POLLERR;
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::WriteHangUp)
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pfd.revents |= POLLNVAL;
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} else {
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Read) {
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ASSERT(pfd.events & POLLIN);
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pfd.revents |= POLLIN;
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}
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::ReadPriority) {
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ASSERT(pfd.events & POLLPRI);
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pfd.revents |= POLLPRI;
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}
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if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Write) {
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ASSERT(pfd.events & POLLOUT);
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pfd.revents |= POLLOUT;
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}
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}
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if (pfd.revents)
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fds_with_revents++;
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}
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if (params.nfds > 0 && !copy_to_user(¶ms.fds[0], &fds_copy[0], params.nfds * sizeof(pollfd)))
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return -EFAULT;
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return fds_with_revents;
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}
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}
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