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/*
* 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 <AK/ScopeGuard.h>
#include <AK/Time.h>
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
KResultOr<int> Process::sys$select(Userspace<const Syscall::SC_select_params*> user_params)
{
REQUIRE_PROMISE(stdio);
Syscall::SC_select_params params {};
if (!copy_from_user(¶ms, user_params))
return EFAULT;
if (params.nfds < 0)
return EINVAL;
Thread::BlockTimeout timeout;
if (params.timeout) {
Optional<Time> timeout_time = copy_time_from_user(params.timeout);
if (!timeout_time.has_value())
return EFAULT;
timeout = Thread::BlockTimeout(false, &timeout_time.value());
}
auto current_thread = Thread::current();
u32 previous_signal_mask = 0;
if (params.sigmask) {
sigset_t sigmask_copy;
if (!copy_from_user(&sigmask_copy, params.sigmask))
return EFAULT;
previous_signal_mask = current_thread->update_signal_mask(sigmask_copy);
}
ScopeGuard rollback_signal_mask([&]() {
if (params.sigmask)
current_thread->update_signal_mask(previous_signal_mask);
});
fd_set fds_read, fds_write, fds_except;
if (params.readfds && !copy_from_user(&fds_read, params.readfds))
return EFAULT;
if (params.writefds && !copy_from_user(&fds_write, params.writefds))
return EFAULT;
if (params.exceptfds && !copy_from_user(&fds_except, params.exceptfds))
return EFAULT;
Thread::SelectBlocker::FDVector fds_info;
Vector<int> fds;
for (int fd = 0; fd < params.nfds; fd++) {
u32 block_flags = (u32)Thread::FileBlocker::BlockFlags::None;
if (params.readfds && FD_ISSET(fd, &fds_read))
block_flags |= (u32)Thread::FileBlocker::BlockFlags::Read;
if (params.writefds && FD_ISSET(fd, &fds_write))
block_flags |= (u32)Thread::FileBlocker::BlockFlags::Write;
if (params.exceptfds && FD_ISSET(fd, &fds_except))
block_flags |= (u32)Thread::FileBlocker::BlockFlags::Exception;
if (block_flags == (u32)Thread::FileBlocker::BlockFlags::None)
continue;
auto description = file_description(fd);
if (!description) {
dbgln("sys$select: Bad fd number {}", fd);
return EBADF;
}
fds_info.append({ description.release_nonnull(), (Thread::FileBlocker::BlockFlags)block_flags });
fds.append(fd);
}
if constexpr (IO_DEBUG || POLL_SELECT_DEBUG)
dbgln("selecting on {} fds, timeout={}", fds_info.size(), params.timeout);
if (current_thread->block<Thread::SelectBlocker>(timeout, fds_info).was_interrupted()) {
dbgln_if(POLL_SELECT_DEBUG, "select was interrupted");
return EINTR;
}
if (params.readfds)
FD_ZERO(&fds_read);
if (params.writefds)
FD_ZERO(&fds_write);
if (params.exceptfds)
FD_ZERO(&fds_except);
int marked_fd_count = 0;
for (size_t i = 0; i < fds_info.size(); i++) {
auto& fd_entry = fds_info[i];
if (fd_entry.unblocked_flags == Thread::FileBlocker::BlockFlags::None)
continue;
if (params.readfds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Read)) {
FD_SET(fds[i], &fds_read);
marked_fd_count++;
}
if (params.writefds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Write)) {
FD_SET(fds[i], &fds_write);
marked_fd_count++;
}
if (params.exceptfds && ((u32)fd_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Exception)) {
FD_SET(fds[i], &fds_except);
marked_fd_count++;
}
}
if (params.readfds && !copy_to_user(params.readfds, &fds_read))
return EFAULT;
if (params.writefds && !copy_to_user(params.writefds, &fds_write))
return EFAULT;
if (params.exceptfds && !copy_to_user(params.exceptfds, &fds_except))
return EFAULT;
return marked_fd_count;
}
KResultOr<int> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> user_params)
{
REQUIRE_PROMISE(stdio);
Syscall::SC_poll_params params;
if (!copy_from_user(¶ms, user_params))
return EFAULT;
if (params.nfds >= m_max_open_file_descriptors)
return ENOBUFS;
Thread::BlockTimeout timeout;
if (params.timeout) {
auto timeout_time = copy_time_from_user(params.timeout);
if (!timeout_time.has_value())
return EFAULT;
timeout = Thread::BlockTimeout(false, &timeout_time.value());
}
sigset_t sigmask = {};
if (params.sigmask && !copy_from_user(&sigmask, params.sigmask))
return EFAULT;
Vector<pollfd> fds_copy;
if (params.nfds > 0) {
Checked nfds_checked = sizeof(pollfd);
nfds_checked *= params.nfds;
if (nfds_checked.has_overflow())
return EFAULT;
fds_copy.resize(params.nfds);
if (!copy_from_user(fds_copy.data(), ¶ms.fds[0], nfds_checked.value()))
return EFAULT;
}
Thread::SelectBlocker::FDVector fds_info;
for (size_t i = 0; i < params.nfds; i++) {
auto& pfd = fds_copy[i];
auto description = file_description(pfd.fd);
if (!description) {
dbgln("sys$poll: Bad fd number {}", pfd.fd);
return EBADF;
}
u32 block_flags = (u32)Thread::FileBlocker::BlockFlags::Exception; // always want POLLERR, POLLHUP, POLLNVAL
if (pfd.events & POLLIN)
block_flags |= (u32)Thread::FileBlocker::BlockFlags::Read;
if (pfd.events & POLLOUT)
block_flags |= (u32)Thread::FileBlocker::BlockFlags::Write;
if (pfd.events & POLLPRI)
block_flags |= (u32)Thread::FileBlocker::BlockFlags::ReadPriority;
fds_info.append({ description.release_nonnull(), (Thread::FileBlocker::BlockFlags)block_flags });
}
auto current_thread = Thread::current();
u32 previous_signal_mask = 0;
if (params.sigmask)
previous_signal_mask = current_thread->update_signal_mask(sigmask);
ScopeGuard rollback_signal_mask([&]() {
if (params.sigmask)
current_thread->update_signal_mask(previous_signal_mask);
});
if constexpr (IO_DEBUG || POLL_SELECT_DEBUG)
dbgln("polling on {} fds, timeout={}", fds_info.size(), params.timeout);
if (current_thread->block<Thread::SelectBlocker>(timeout, fds_info).was_interrupted())
return EINTR;
int fds_with_revents = 0;
for (unsigned i = 0; i < params.nfds; ++i) {
auto& pfd = fds_copy[i];
auto& fds_entry = fds_info[i];
pfd.revents = 0;
if (fds_entry.unblocked_flags == Thread::FileBlocker::BlockFlags::None)
continue;
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Exception) {
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::ReadHangUp)
pfd.revents |= POLLRDHUP;
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::WriteError)
pfd.revents |= POLLERR;
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::WriteHangUp)
pfd.revents |= POLLNVAL;
} else {
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Read) {
VERIFY(pfd.events & POLLIN);
pfd.revents |= POLLIN;
}
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::ReadPriority) {
VERIFY(pfd.events & POLLPRI);
pfd.revents |= POLLPRI;
}
if ((u32)fds_entry.unblocked_flags & (u32)Thread::FileBlocker::BlockFlags::Write) {
VERIFY(pfd.events & POLLOUT);
pfd.revents |= POLLOUT;
}
}
if (pfd.revents)
fds_with_revents++;
}
if (params.nfds > 0 && !copy_to_user(¶ms.fds[0], fds_copy.data(), params.nfds * sizeof(pollfd)))
return EFAULT;
return fds_with_revents;
}
}
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