mirror of
https://github.com/RGBCube/serenity
synced 2025-05-31 11:38:11 +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.
124 lines
4.2 KiB
C++
124 lines
4.2 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/ScopeGuard.h>
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#include <AK/Time.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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using BlockFlags = Thread::FileBlocker::BlockFlags;
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ErrorOr<FlatPtr> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> user_params)
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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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auto params = TRY(copy_typed_from_user(user_params));
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if (params.nfds >= OpenFileDescriptions::max_open())
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return ENOBUFS;
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Thread::BlockTimeout timeout;
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if (params.timeout) {
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auto timeout_time = TRY(copy_time_from_user(params.timeout));
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timeout = Thread::BlockTimeout(false, &timeout_time);
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}
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sigset_t sigmask = {};
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if (params.sigmask)
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TRY(copy_from_user(&sigmask, params.sigmask));
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Vector<pollfd, FD_SETSIZE> fds_copy;
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if (params.nfds > 0) {
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Checked<size_t> 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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TRY(fds_copy.try_resize(params.nfds));
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TRY(copy_from_user(fds_copy.data(), ¶ms.fds[0], nfds_checked.value()));
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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 = TRY(fds().open_file_description(pfd.fd));
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BlockFlags block_flags = BlockFlags::Exception; // always want POLLERR, POLLHUP, POLLNVAL
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if (pfd.events & POLLIN)
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block_flags |= BlockFlags::Read;
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if (pfd.events & POLLOUT)
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block_flags |= BlockFlags::Write;
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if (pfd.events & POLLPRI)
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block_flags |= BlockFlags::ReadPriority;
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if (pfd.events & POLLWRBAND)
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block_flags |= BlockFlags::WritePriority;
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TRY(fds_info.try_append({ move(description), 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 constexpr (IO_DEBUG || POLL_SELECT_DEBUG)
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dbgln("polling on {} fds, timeout={}", fds_info.size(), params.timeout);
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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 == BlockFlags::None)
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continue;
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if (has_any_flag(fds_entry.unblocked_flags, BlockFlags::Exception)) {
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::ReadHangUp))
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pfd.revents |= POLLRDHUP;
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::WriteError))
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pfd.revents |= POLLERR;
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::WriteHangUp))
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pfd.revents |= POLLNVAL;
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} else {
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::Read)) {
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VERIFY(pfd.events & POLLIN);
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pfd.revents |= POLLIN;
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}
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::ReadPriority)) {
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VERIFY(pfd.events & POLLPRI);
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pfd.revents |= POLLPRI;
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}
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::Write)) {
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VERIFY(pfd.events & POLLOUT);
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pfd.revents |= POLLOUT;
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}
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if (has_flag(fds_entry.unblocked_flags, BlockFlags::WritePriority)) {
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VERIFY(pfd.events & POLLWRBAND);
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pfd.revents |= POLLWRBAND;
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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)
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TRY(copy_to_user(¶ms.fds[0], fds_copy.data(), params.nfds * sizeof(pollfd)));
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return fds_with_revents;
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}
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}
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