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			251 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			251 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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| 
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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/FileDescription.h>
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| #include <Kernel/Process.h>
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| 
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| namespace Kernel {
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| 
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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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| 
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|     if (!copy_from_user(¶ms, user_params))
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|         return -EFAULT;
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| 
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|     if (params.nfds < 0)
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|         return -EINVAL;
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| 
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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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| 
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|     auto current_thread = Thread::current();
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| 
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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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| 
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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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| 
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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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| 
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|         auto description = file_description(fd);
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|         if (!description) {
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|             dbgln("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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| 
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|     if constexpr (IO_DEBUG || POLL_SELECT_DEBUG)
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|         dbgln("selecting on {} fds, timeout={}", fds_info.size(), params.timeout);
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| 
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|     if (current_thread->block<Thread::SelectBlocker>(timeout, fds_info).was_interrupted()) {
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|         dbgln_if(POLL_SELECT_DEBUG, "select was interrupted");
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|         return -EINTR;
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|     }
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|     if (params.nfds >= m_max_open_file_descriptors)
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|         return -ENOBUFS;
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| 
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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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| 
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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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| 
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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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| 
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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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|             dbgln("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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| 
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|     auto current_thread = Thread::current();
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| 
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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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| 
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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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| 
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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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| 
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|     int fds_with_revents = 0;
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|     return fds_with_revents;
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| }
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| 
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| }
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